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Effects of Thermal Cycling on Surface Texture of Restorative Composite Materials
Abstract
The purpose of this study was to evaluate the effect of thermal cycling on the surface texture of restorative materials. Disk-shaped specimens made of seven resin composites (Beautifil: BF; Esthet-X: EX; Filtek Supreme: FS; Inten-S: IS; Point 4: PT; Solare: SR; and Venus: VS) were finished with 1-microm alumina suspension, and then thermocycled between 4 and 60 degrees C in distilled water for 20,000 or 50,000 cycles with a dwell time of 60 seconds. Staining susceptibility and mean surface roughness, Ra, were examined, and surface texture was observed by scanning electron microscopy. Dye penetration test showed that the surfaces of all resin composites were more stained after thermal cycling. Mean Ra of all resin composites, except PT, significantly increased after 50,000 thermal cycles. Dislodgement of filler particles was observed for all resin composites after thermal cycling, except FS. It was concluded that thermal cycling significantly affected the surface texture of the seven examined resin composites.
... Several studies comparing the mechanical properties of resin matrix ceramics show different results due to their microstructures. For example [9], the difference between the type of filler in cerasmart (zirconia-silica) gives this material greater hardness and toughness than Lava Ultimate. On the other hand, Lava Ultimate, because of its crystalline content (32% ZrO 2 ) -compared to the crystalline content (20.6% Al 2 O 3 ) in Enamic -, has higher flexural strength [10][11][12][13]. ...
... This same Cerasmart, when compared to lithium disilicate, showed greater wear [30]. Degradation When exposed to the oral environment, resin materials show increased roughness [9] which, when greater than 2µm, increases the possibility of bacterial deposition, leading to a higher incidence of periodontal disease or caries [33]. Regarding in vitro studies, Cerasmart has greater flexural strength after aging than other resin matrix ceramics, such as Vita Enamic and Lava Ultimate [21,34]. ...
... Regarding in vitro studies, Cerasmart has greater flexural strength after aging than other resin matrix ceramics, such as Vita Enamic and Lava Ultimate [21,34]. In addition to surface roughness [35], the mechanical properties of materials may change due to the degradation of the organic matrix, loss of charge particles [9] and destruction of silane adhesion to charge particles [36], causing a reduction in the flexural strength of resin matrix ceramics [21,34]. The effect of brushing and artificial storage on surface roughness depends on the material and polishing system, with a difference in the behavior of resin matrix ceramics related to their microstructure. ...
Resin matrix ceramics consist in a polymeric matrix with predominantly inorganic refractory compounds which may include porcelain, glass, ceramics, and glass ceramics, and are divided into three subgroups: Nanoceramics, Vitroceramics, and Zirconia-silica. The aim of this study was to compare, through a literature review, the mechanical and biological properties of resin matrix ceramics, with glass matrix ceramics and polycrystalline ceramics. After reviewing 44 articles found in the US National Library of Medicine (PubMed) database (studies published in English, human clinical studies, in vitro or in vivo studies) that evaluated some properties of this material, such as elasticity modulus, wear resistance, adhesiveness, stain resistance and hardness, this article concluded that, although they belong to the same group, resin matrix ceramics are different from each other due to their microstructures. Moreover, when compared to other ceramic groups, it showed some superior properties, such as flexural strength, fatigue strength and internal adaptation.
Indexing terms
Ceramics; Composite resins; Computer-aided design; Resins
... It was also demonstrated that nanocluster fillers contributed to a greater water uptake and increased the susceptibility to fracture compared to conventional fillers 10,11) . Furthermore, several studies reported a loss of nanoparticles from the composite surface after long-term water storage or thermocycling 4,12) . Similarly to conventional fillers, silanization of the nanofillers is necessary prior to their incorporation into the resin matrix, so it has been speculated that non-optimized silane coupling treatment might lead to the detachment of isolated nanofiller and/ or the dismantlement of nanoclusters 4,13) . ...
... As a consequence of different thermal expansion coefficients of fillers and resin matrix, microcracks could develop within the matrix and/or nanocluster fillers. Moreover, long-term exposure to higher temperature could enhance the hydrolytic degradation of silane coating on filler surface 12,25,26) and thus cause debonding at the filler/matrix interface. Depending on the number of thermal cycles, the detachment of fillers from the matrix at the surface could increase the surface roughness of the composites 12) which might lead to increased light scattering/absorption at the surface and hence decreased amount of transmitted light (AV). ...
... Moreover, long-term exposure to higher temperature could enhance the hydrolytic degradation of silane coating on filler surface 12,25,26) and thus cause debonding at the filler/matrix interface. Depending on the number of thermal cycles, the detachment of fillers from the matrix at the surface could increase the surface roughness of the composites 12) which might lead to increased light scattering/absorption at the surface and hence decreased amount of transmitted light (AV). In this study, 10,000 TC did not significantly change AV compared with the values after 1-week water storage except for FSU whose AV decreased significantly after 5,000 TC and remained similar after 10,000 TC. ...
The effect of 1-week water storage and subsequent 10,000 thermal cycles on light transmission properties (straight-line transmission (G0), diffusion (DF), the amount of transmitted light (AV)), translucency parameter (TP) and refractive index (RI) of four nanofilled flowable composites was examined. The composites included Filtek Supreme Ultra Flowable Restorative (FSU), Estelite Flow Quick (EFQ), Estelite Universal Flow, (EUF), and Clearfil Majesty ES Flow (ESF), all of A3 shade. For composites with lower filler load (FSU, EFQ), water storage increased G0, AV and TP, but subsequent thermocycling decreased them. An opposite tendency was found for DF. Materials with higher filler load (EUF, ESF) were not significantly affected by aging conditions. RI of EFQ and EUF containing bisphenol A polyethoxy methacrylate (Bis-MPEPP) increased significantly after thermocycling. Additionally, morphological changes were observed using scanning electron microscopy which revealed cracks within nanocluster fillers and dislocation of particles in FSU and EFQ after thermocycling.
... The oral environment is subject to thermal stress and pH fluctuations from food and beverage consumption, which can impact the surface properties of resin materials, leading to long-term discoloration [13]. Over time, direct dental restorations, particularly resin composites, may exhibit surface wear and filler-matrix debonding, resulting in void formation [14]. In laboratory settings, the aging of dental material is typically evaluated through factors such as increased water sorption, surface roughness, and color changes, along with reduced strength and hardness [13,15]. ...
... The thermocycling in the staining solution simulated the combined effects of thermal stress, acidic pH, and fluid dynamics from beverage consumption [17]. Previous studies confirmed that resin-based materials are prone to discoloration under these factors [14,38]. Red wine, known for its high staining potential due to tannins, alcohol, and a low pH, surpasses beverages like coffee and tea [39]. ...
This study assessed the susceptibility to staining and surface roughness of white-spot lesions (WSLs) treated with resin infiltration (RIT) and microabrasion (MA) under simulated aging through thermocycling in red wine. Seventy-eight extracted human premolars with artificial WSLs were divided into three groups: untreated WSLs (control), RIT-treated (ICON®, DMG), and MA-treated (Opalustre®, Ultradent). Each group was further split: one subgroup immersed in artificial saliva and the other thermocycled in red wine. The color change (∆E) and surface roughness (Ra) were measured before and after staining using a spectrophotometer and a non-contact profilometer. Thermocycling in red wine increased color change (ΔE) across all groups, with the highest values observed for MA (43.94 ± 3.57), followed by RIT (31.40 ± 4.89). Surface roughness (Ra) was highest in untreated WSLs (0.61 ± 0.18 µm) and lowest in RIT (0.15 ± 0.03 µm). While RIT and MA similarly improved WSL appearance, RIT exhibited superior smoothness. These findings suggest that RIT provides a more durable surface with reduced roughness, although staining susceptibility remains comparable to MA. Moderate positive correlation was found between ΔE and Ra, indicating that roughness is one of the factors influencing color changes.
... Color parameters were assessed using the CIE L*a*b*color space system [9]. The color differences between the filling and the surrounding porcelain (∆E fp ) at T0, T1, T2, T3 and T4, as well as the color alterations of the surfaces (i.e., the surrounding porcelain [∆E p ] and the filling [∆E f ]) from T0 to T1, T2, T3, and T4 were calculated using the following equations: Surface roughness (Ra, µm) was measured at T0 and T4 using Surface roughness tester machine (TR200 with a 2.5mm cut-off, 5µm diamond stylus radius, and a 90° stylus angle, Time Group, China), with three measurements taken and the average reported as the roughness for both time points [10]. The effects of the beverage, the filling, and their interaction on ∆E fp , ∆E f and ∆E p were assessed using a two-way analysis of variance (ANOVA), followed by the Tukey post hoc. ...
... Regarding composite resin materials, various studies have reported inconsistent effects of thermocycling on surface roughness. While certain studies have reported no significant effects after a specified number of thermocycling cycles [9,21], others have documented notable alterations in roughness levels [10]. This discrepancy suggests that various composite resins may exhibit differing responses to thermocycling. ...
Objectives: This study aimed to investigate the aesthetic aspect of screw-retained restorations by examining three different types of filling materials used for the access cavity, highlighting the significance of aesthetics in implant restorations. Materials and Methods: In this laboratory investigation, simulation samples of screw-retained restorations were filled with flowable composite resin (group F), opaque and flowable composite resin (group O) and porcelain plug (group P) at baseline (T0). The samples were subjected to thermocycling twice (T1 and T3), undergoing 1000 cycles in coffee, orange juice, and distilled water, followed by washing performed after each thermocycling (T2 and T4). Colorimetric analysis and surface roughness measurements were conducted, and the data were statistically analyzed using. two-way analysis of variance (ANOVA), ,Tukey post hoc, two-way analysis of covariance (ANCOVA), and paired-t test. P<0.05 was considered significant. Results: The type of filling material had a significant effect on the color difference observed between the restoration and filling materials (P<0.05). Notably, samples from group P exhibited a more pronounced color difference at T4, despite showing a lower color difference at T0, when compared to group O. Conclusion: The use of porcelain plugs did not provide a notable advantage over the combination of flowable and opaque composite resins, particularly given the difficulties in fabricating and positioning porcelain plugs within the access cavity. Therefore, it is recommended to utilize flowable composite resins in conjunction with an opaque composite resin layer beneath, to effectively conceal any dark shades from the underlying metal.
... 23 previous study showed that thermal cycling significantly affected the surface texture of composites with dislodgement of filler particles this was in disagreement with our study. 24 However, a correlation between thermocycling and clinical longevity of dental composites is difficult due to the varied cycles number, different temperatures, dwell time and intervals between baths used in the studies. Therefore, the larger fillers of Beautiful II resulted in a rougher surface compared to the other composites, as the filler particles exposed at its surface after degradation are coarser, leading to a higher Ra value, another aggravating factor that might have affected the surface roughness of Beautifil II is its high water sorption compared to other nanofilled resin composites. ...
... 27 Composites containing hydrophilic components, like TEGDMA or TEGMA as a matrix component, may be more susceptible to matrix degradation,because they allow water to penetrate more easily due to its hydrophobicity. 24 like Beautifil II (nohybrid) composite resin,which contains more TEG-MA as a matrix component than others. ...
Background and objectives: To evaluate and compare the color stability and surface roughness of different composite resins after using different polishing systems and then submitting to accelerating artificial aging (AAA) and staining by black tea. Method: Twenty disk-shaped specimens (were compacted into the custom-made cylindrical plastic mold that had an internal diameter of 10 mm and a depth of 2 mm) were prepared for each composite resin type (3M Z350, Tokoyama palfique and shofu Beautifil II) for a total of 60 specimens, each composite group was divided into two subgroups according to the polishing system (n=10) (Shofu super-snap polishing disks and Eve Diacomp Plus Twist wheel). Color parameters (L*, a*, and b*) and surface roughness were measured before and after accelerating artificial aging (2000-4000 thermal cycle) and staining. Results: It was observed that all resin-based materials showed an increase in color change value and surface roughness values after 2000 thermal cycles. while after 4000 thermal cycles only the surface roughness value decreased in all resin-based materials. Conclusion: all resin-based materials showed clinically acceptable color stability and surface roughness >0.2 µm) after (2000 thermal cycle) and staining. Keywords: color stability, surface roughness, thermal cycle, staining.
... Various studies revealed that, the surface roughness of the resin and ceramic materials was adversely impacted by the in vitro thermocycling procedure. [7,13,20,21] Therefore, the aim of this study was to assess the influence of four different (two-step) polishing systems on surface roughness of four resin composite materials (Naofill, Nanohybrid, Microfill, and Microhybrid) when subjected to thermocycling aging. The null hypothesis tested was that there would be no difference in surface roughness among the polished resin composites or among the different polishing systems when subjected to thermocycling. ...
... These results agreed with many other studies, [7,20,21,32] who studied the effects of thermocycling on composite restoration microhardness, roughness, and color. Dos Santos et al. [32] observed that thermocycling (3000 cycle) raised the resin composites surface roughness, however after 10,000 thermal cycles, there was a pattern toward decreasing surface roughness values. ...
Background:
Surface smoothness considered to be a significant part of the appearance and success of the restorative materials. The aim of this study was to assess the influence of four different polishing systems on surface roughness of four resin composite materials when subjected to thermocycling.
Materials and methods:
This research was designed as a comparative study. Four resin composites were used which are: Nanofill composite (Filtek Supreme XT), nanohybrid composite (Tetric EvoCeram), microfill composite (Renamel Microfill), and microhybrid composite (Filtek Z250). Sixty disk-shaped specimens of each resin composite were prepared then divided into four groups according to the polishing system (n = 15); which were Sof-Lex Spiral, Diatech Shapeguard, Venus Supra, and Astropol. The specimens of each group were polished following the manufactures' instructions, then surface roughness, Ra values in μm were measured initially and after the specimens subjected to thermal cycling. The influence of resin composites, polishing systems, thermocycling, and their interaction effects on surface roughness (Ra mean values) was statistically analyzed mainly by using the repeated measures two-way analysis of variance test, whereas the Bonferroni''s post hoc test was applied for pair-wise comparisons. P ≤ 0.05 was used as the significant level.
Results:
The results of this study revealed that Filtek Supreme XT recorded significantly the lowest mean surface roughness (Ra) of 0.2533 ± 0.073 μm (P < 0.001). The Sof-Lex Spiral polishing system revealed significantly the lowest mean surface roughness (Ra) of 0.2734 ± 0.0903 μm (P = 0.004). Regardless of composite type and polishing system, there was a statistically significant increase in mean surface roughness values (Ra) in μm after thermocycling (0.2251 ± 0.0496 μm and 0.3506 ± 0.0868 μm, respectively) (P < 0.001).
Conclusion:
Resin composite type, polishing method, and thermocycling aging significantly affected the surface roughness of composites; Nanofill composite and Sof-Lex Spiral polishing system provided the lowest values of surface roughness which increased after thermocycling.
... [15][16][17] When a restorative material exposed to the oral environment for a long time, some changes occur in its aesthetic properties such as staining, plaque accumulation, gingival irritation and discoloration. 18 Restorations are also exposed to thermal stresses during normal oral functions. Thermal stresses disrupt the structure of restorative materials and may adversely affect their mechanical properties. ...
... In many studies, the effects of thermal stresses on restorative materials have been examined. 18,19 Scanning electron microscopy (SEM) is another effective method for evaluating the surface topography, filler amount, size, and interface of restorations. SEM is particularly recommended for evaluating the types of failures that restorations undergo, as well as surface alterations and wear. ...
Background: To evaluate the mechanical and surface properties of two glass ionomer restorative systems (EQUIA Fil, Ionostar Molar) and a resin composite (Charisma Classic ) after thermocycling. Methods: Twenty disk-shaped samples were prepared from each material in teflon molds according to manufacturer’s instructions. After the samples were stored in distilled water at 37 0C for 24 h, microhardness and surface roughness measurements were performed from each group and repeated after 5000 and 10000 thermocycling. Scanning electron microscopy examinations were also performed. The data were analyzed by using Wilcoxon signed rank and Bonferroni corrected multiple comparison tests.Results: EQUIA did not exhibit significant differences in its micohardness values after thermocycling (p > 0.0056). In contrast, Ionostar Molar and Charisma Classic exhibited statistically significant decreases in baseline microhardness after 5000 and 10000 thermocycling processes (each p < 0.0056). However, there were no significant differences between 5000 and 10000 thermocycling groups for Charisma Classic (p = 0.007). Ionostar Molar exhibited no statistically significant differences between its surface roughness values before and after thermocycling groups (p > 0.0017). Similarly, there were no significant differences between baseline and 5000 thermocycling groups for EQUIA and Charisma Classic (p > 0.0017). However, a statistically significant increase was observed after 10000 thermocycles for both of these two materials (p < 0.001 and p = 0.002, respectively).Conclusion: The EQUIA and Ionostar Molar exhibited mechanical features similar to those of a resin composite, and thus, represent promising materials for permanent restorations. Keywords: Glass ionomer, scanning electron microscopy, surface properties
... [13][14][15][16][17] Furthermore, this process can be intensified by differences in temperature 13,15 and has undesirable consequences for the restoration, such as microbial plaque accumulation and restorations with alterations in color and appearance. 14,18 Many in vitro studies have shown that commonly used beverages such as coffee, tea, red wine, cola, and fruit juice can cause significant changes in the color of restorative materials. [19][20][21][22][23][24][25][26][27][28][29][30][31] Maintenance of ceramic characteristics is essential from an esthetic perspective, because restorations that mimic only the shape and color of adjacent teeth are easily detected and can lead to treatment failure. ...
... Additionally, studies should include cycling of the materials in solutions at different temperatures, simulating the laboratory conditions of the oral environment more faithfully. 18,19 Furthermore, in the present study, the temperature usually used for the intake of the beverage was replicated, with a higher temperature for the coffee and lower temperatures for the cola, orange juice, and red wine. This is because temperature differences can interfere with color change because they influence the surface porosity of the material. ...
Statement of problem:
The stability of the optical characteristics of dental ceramics is essential. Degradation of these materials resulting from pH or temperature alterations in the oral cavity can lead to treatment failure.
Purpose:
The purpose of this in vitro study was to evaluate the color change (ΔE), the L* coordinate, the translucency parameter, and the contrast ratio of lithium disilicate ceramic exposed to commonly used and potentially colorant solutions.
Material and methods:
Fifty lithium disilicate specimens were prepared and divided into 5 groups according to the immersion solution (artificial saliva, orange juice, cola, coffee, and red wine). Immersions in acidic beverages were alternated in a thermocycler with artificial saliva. The control group was immersed in artificial saliva at 37°C throughout the immersion period. After 168 hours of immersion, the color parameters were assessed with a spectrophotometer and calculated using the because system on 2 backgrounds (black and white) and in 2 time periods, before thermocycling and after thermocycling. Data were submitted to analysis of variance followed by the Tukey honest significant difference test (α=.05).
Results:
Greater color change (ΔE) and lower L* coordinate values were observed after immersion in orange juice and cola. Regarding the translucency parameter and contrast ratio, the immersion in coffee resulted in greater opacity and lower translucency of the material.
Conclusions:
Alterations in the color stainability, the L* coordinate values, the translucency parameter, and the contrast ratio of the lithium disilicate ceramic were observed, according to the acidic solutions tested.
... Both thermal stress and pH variations may affect the surface and structural integrities of composite resin materials and render the restorations more susceptible to staining and discoloration. 44,45 As experimental testing in vitro remains to be a vital tool in assessing the color stability and stain resistance of new aesthetic restorative materials, it is important to devise a new model that considers the effects of thermal stress, pH variation, complexity of dietary colorants, and dynamic nature of fluid flow and allows differentiation of adsorption from absorption. ...
... It has been shown that thermal stress and acidic challenges may affect the surface integrity of the composite resins and render them susceptible to discoloration. 44,45 As composite resin restorations in oral cavity endure thermal stress and acidic challenges associated with ingesting hot and cold acidic beverages on a daily basis, any color stability study model must consider the effects of changing temperatures and pH values. As common beverages and foods are in a multitude of combinations of colors, immersion of composite resin discs in a single type of colored fluid does not reflect the staining potential of human drinking and eating behaviour. ...
... Therefore, the better adaptability of both resins in Class III at baseline is justified, since it is closer to the spectrophotometric reading location in the middle third of the tooth. Also, it is expected that the color of resin composites changes after thermocycling, which significantly affects the surface texture [23]. Hydrolytic degradation occurred after thermal cycling, and due to ruptures at the matrix-resin interface, fillers were exposed in some places and more pronounced scratches and grooves were formed [24]. ...
Objective
To assess the efficacy of monochromatic resins in capturing adjacent tooth color across various shades and cavity types, both before and after thermocycling. Furthermore, the surface roughness of the restorations was evaluated.
Methodology
This is a laboratory test that used 40 mandibular incisors with a healthy crown obtained from the Human Teeth Bank of the UFVJM School of Dentistry. The teeth were randomly assigned to two groups: one group was restored with Omnichroma composite resin, while the other one was restored with Vittra APS Unique composite resin. Three preparations were performed on each tooth in both groups, namely: Classes III, IV and V. Evaluations of USPHS and modified FDI criteria, analysis of roughness using a using a digital surface roughness tester and color reading with a spectrophotometer before and after thermocycling were performed. The data were submitted to descriptive statistics, Chi-square test and the T-test using the SPSS software, and a p-value of < 0.05 was considered statistically significant.
Results
There was no significant difference between the groups in relation to the parameters of shape (p > 0.05), marginal integrity (p > 0.05) and color (p > 0.05) in the USPHS analysis, as well as the ΔE in the CIEL* a* b* analysis (p > 0.05) and color in the FDI analysis (p > 0.05), in all classes. Clinically detectable differences were observed between classes IV (ΔE = 3.80) and V (ΔE = 5.02) restorations of the Omnichroma resin compared to the tooth. The ∆E of Vittra resin was considered unacceptable in all classes (ΔE varied from 4.35 to 5.52). The Vittra resin class III restoration showed the best adaptability (L*: p = 0.462; a*: p = 0.252 and b*: p = 0.335). There was no statistically difference between groups in the surface roughness analysis either initially (p = 0.564) or after thermocycling (p = 0.690).
Conclusions
It was concluded that the color match of the composite resins Omnichroma and Vittra APS Unique was found to be clinically satisfactory in USPHS and FDI analysis. Both resins showed low surface roughness.
... [3] TEGDMA, a composite matrix component, is more prone to degradation due to its hydrophilicity, unlike Bis-GMA, which absorbs more water. [4] TEGDMA also undergoes greater enzymatic hydrolysis than aromatic monomers like Bis-EMA or Bis-GMA. [5] Replacing TEGDMA with less water-soluble Bis-EMA and UBis stabilizes and improves composites. ...
A BSTRACT
Background
Direct composite restorations face abrupt temperature changes, varying pH, and surface deterioration in the oral environment. Atomic force microscopy (AFM) provides visual and numerical data on surface roughness.
Aim
This study evaluates and compares the surface roughness of composite restorative materials after simulating oral conditions.
Materials and Methods
Three composite groups ( n = 16 each) were tested. Group A: Microhybrid, Group B: Nanofilled, and Group C: Nanohybrid. Each group was divided into four subgroups ( n = 4 each): distilled water (control), black coffee, Coca-Cola, and Red Bull. After thermocycling and immersion, surface roughness was measured using AFM.
Results
Nanocomposites with uniform monomodal fillers showed the least surface disintegration and superior properties.
Conclusion
Resin chemistry, including filler size and matrix composition, is crucial for composite properties and performance under function.
... Como se ha visto en las anteriores investigaciones y en el presente estudio el termociclado con 10.000 ciclos, correspondientes a un año en cavidad oral, no afectó a la rugosidad, esto se podría deber a que hay estudios donde usan más ciclos como el de Yuan et al 14 . donde a 18.000 ciclos térmicos si hubo cambios significativos (P<.001) y los especímenes mostraron superficies más ásperas usando un microscopio de interferometría de luz blanca, por otro lado, Mi-nami et al 21 . observaron un aumento de rugosidad media con 50.000 ciclos térmicos, lo cual correspondería aproximadamente a 5 años en boca. ...
Objetivo: Valorar In Vitro la rugosidad superficial de un ionómero de vidrio modificado con resina (RMGI), resina nanohíbrida y un composite bioactivo mediante un rugosímetro antes y después del proceso de envejecimiento acelerado por termociclado. Materiales y métodos: estudio experimental In Vitro, se elaboraron 20 cuerpos de prueba de cada biomaterial (Filtek Z250, ACTIVA Bioactive y Fuji II), divididos en 6 grupos (3 con termociclado- 3 sin termociclado), fueron almacenados en agua destilada a 37 ºC por 24 horas. Se sometieron la mitad de las muestras de cada grupo a termociclado hasta cumplir 10.000 ciclos a 5º C y 55º C para simular envejecimiento en cavidad oral a un año, a todas las muestras se les realizó un análisis de rugosidad con un rugosímetro en cuatro posiciones. El análisis estadístico se realizó en el programa Stata-14, para la comparación entre los tres grupos se utilizó una prueba ANOVA para valores paramétricos y una prueba de Kruskal-Wallis para no paramétricos, para la comparación individual de los grupos se usó una t-Student para valores paramétricos y una U de Mann-Whitney para no paramétricos. Resultados: antes del termociclado, la resina obtuvo un valor promedio de 0,49 µm, el composite bioactivo 0,36 µm y el RMGI 0,49 µm, y después del termociclado la resina 0,44 µm, el composite bioactivo 0,34 µm y el RMGI de 0,36 µm. Conclusión: los tres materiales de restauración no mostraron diferencias estadísticas antes y después del termociclado, mostrando un grado de rugosidad similar y clínicamente aceptables a 10.000 ciclos.
... 14 Depending on the surface change, plaque accumulation, discoloration, gingival problems, and caries may occur in restorations. [15][16][17] In addition, dietary intake of acidic beverages causes high tooth wear, deterioration of restorative materials, restoration failure, and problems in long-term clinical use. 18 Studies have shown that acidic beverages negatively affect the microhardness and microroughness of composite and glass ionomer-based restorative materials. ...
Background: This study aimed to compare the surface microhardness and roughness values of different glass ionomer-based restorative materials after acidic aging. Methods: Three restorative glass ionomers, ChemFil Rock, Equia Forte, and Ketac Molar, were examined in this study. Glass ionomer samples with dimensions of 8 mm in diameter and 2 mm in height were produced in a Teflon mold. The samples’ baseline microhardness and roughness were measured before the acidic aging process, and the measurements were taken again after the aging process. The 1-way analysis of variance test, the Bonferroni post hoc test, the Kruskal–Wallis test, and the Dunn’s post hoc test were used to statistically assess the results. The significance level was set at .05. Results: There is a statistically significant difference between the preaging material groups in terms of the mean microhardness values (H = 39.819, P = .000). Accordingly, the microhardness value average of the Equia Forte group (65.57) is higher than the average of the Ketac Molar group (47.75) and the average of the ChemFil Rock group (38.31) (P < 0.05). After the aging procedure, the mean microhardness value of the ChemFil Rock group (36.94) was statistically lower than the mean of the Ketac Molar group (48.92) and the mean of the Equia Forte group (48.58) (P < 0.05). It is seen that the lowest Ra, Rt, and Rv values before (Ra: 3.05; Rt: 24.58; Rv: 10.4) and after aging (Ra: 2.28; Rt: 17.65; Rv: 7.52) belong to the ChemFil Rock material group (P < 0.05). However, no statistically significant difference was detected between the groups in terms of roughness change rates (ΔRa, ΔRt, ΔRv) (P > 0.05). Conclusion: Acidic aging adversely affected the microhardness of the materials, which is important for clinical success. The lowest microhardness value before and after acidic aging was determined in the ChemFil Rock group. No significance could be detected between the groups in terms of changes in surface roughness values.
... Additionally, thermal stresses encountered during normal oral functions can disrupt the structure of restorative materials and potentially impact their mechanical properties. Numerous studies have investigated the effects of thermal stresses on restorative materials [9,10]. Therefore, characterizing dental restorative materials using thermocycling provides a better simulation of their clinical service life and enhances understanding of their behavior in such conditions. ...
Background and objective
Glass ionomer cement (GIC), also known as polyalkenoate cement, has been extensively used in dentistry for both luting and restorative purposes. Despite being the first choice for aesthetic restorations due to their chemical bonding ability to teeth, GICs have faced challenges such as low mechanical properties, abrasion resistance, and sensitivity to moisture, leading to the search for improved materials.
This study aims to assess the effects of thermocycling on the compressive, flexural strength, and microhardness of green-mediated nanocomposite-modified GIC in comparison to traditional GIC.
Methodology
Green-mediated nanoparticles, consisting of chitosan, titanium, zirconia, and hydroxyapatite (Ch-Ti-Zr-HA), were synthesized using a one-pot synthesis technique to form nanocomposites. These nanocomposites were then incorporated into GIC specimens in varying concentrations (3%, 5%, and 10%), denoted as Group I, Group II, and Group III, respectively. Group IV served as the control, consisting of conventional GIC. To assess the performance of the novel restorative materials over an extended period, compressive strength, flexural strength, and microhardness were measured before and after thermocycling using a universal material testing machine. Furthermore, scanning electron microscopy (SEM) analysis was carried out following the thermocycling process. The collected data were subjected to statistical analysis through one-way analysis of variance (ANOVA) and paired t-tests.
Results
The findings demonstrated that, in comparison to the control group, both the mean compressive strength and flexural strength, as well as hardness, were notably higher for the 10% and 5% nanocomposite-modified GIC specimens before and after thermocycling (P < 0.05). Notably, there was no notable difference observed between the 5% and 10% concentrations (P > 0.05). These results suggest that incorporating green-mediated nanocomposites (Ch-Ti-Zr-HA) modified GIC at either 5% or 10% concentration levels leads to improved mechanical properties, indicating their potential as promising alternatives in dental restorative materials.
Conclusions
Based on our findings, it can be inferred that the 10% and 5% concentrations of green-mediated (Ch-Ti-Zr-HA) modified GIC exhibit superior compressive and flexural strength compared to conventional GIC. Additionally, analysis of the scanning electron microscope (SEM) morphology revealed that green-mediated GIC displays smoother surface characteristics in contrast to conventional GIC. These results underscore the potential advantages of utilizing green-mediated nanocomposite-modified GIC in dental applications, suggesting enhanced mechanical properties and surface quality over conventional.
... The oral environment, including variations in temperature and humidity, can compromise the long-term success of restorations [16,17]. Thermal stresses disrupt the structure of restorative materials and may adversely affect their mechanical properties [18,19]. ...
... Ceramic restorations are subject to surface degradation when exposed to aqueous solutions or changes in pH [3][4][5]. Additionally, this process can be intensified by temperature differences [6], which leads to undesirable outcomes for the restoration, such as microbial plaque accumulation and changes in color and appearance [7]. Many in vitro studies have shown that the color of restorative materials can be significantly changed as a result of exposure to common beverages, such as coffee [8][9][10]. ...
Heat-pressed lithium disilicate (LDS)-based glass–ceramic ingots are widely used for the fabrication of dental restorations. Repressing or repeat processing the remaining parts of these ingots has been reported to not adversely affect their mechanical properties. However, there is not enough information on the stainability of crowns constructed from these repeated heat-processed LDS ceramic ingots. Seventy-two identical ceramic crowns were constructed from three different repeated heat-processed LDS ceramic ingots representing three groups (n = 24): E-max (Ivoclare), Lisi (GC), and Celtra (Dentsply Sirona). Each group was subdivided into two subgroups (n = 12) representing experimental (coffee) and control groups. Color changes were assessed according to the CIE L * a * b * system and measured initially, after coffee staining and after brushing. All groups were susceptible to staining; however, they showed different behaviors with respect to the three axes of the CIE L * a * b * system. In general, immersion in coffee followed by brushing decreased the staining of all tested ceramic crowns to the acceptability threshold of color change (ΔE = 2.7). Routine brushing of coffee-stained ceramic crowns made from repeatedly processed LDS, LDS-HDM, and ZLS ceramic ingots restored their color to clinically acceptable levels.
... 52 Temperature variations might cause cyclic shrinkage and expansion, causing different volumetric changes between fillers and matrix. 51 It is worth mentioning that staining susceptibility induced by smoke, can significantly increase if associated with alcohol intake. The acidic pH of alcoholic beverages may increase sorption and solubility of RBCs. ...
Objective:
To conduct a systematic review on color stability of dental resin-based composites (RBC) exposed to conventional and electronic cigarettes.
Materials and methods:
In vitro studies reporting on the color stability of RBC exposed to conventional cigarettes or to e-cigarettes: both Tobacco Heating Systems (THS) and Electronic Nicotine Delivery Systems (ENDS). The quality of the included studies was assessed with the QUIN tool (risk-of-bias tool for assessing in vitro studies conducted in dentistry). A systematic search, following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) was performed on four (n = 4) databases (Embase, Medline, Scopus, Web of Science) for articles published until March 28th, 2022.
Results:
Of the 365 screened articles, 13 were included in this review. All the included articles analyzed conventional cigarette smoke (CS), four analyzed Electronic Nicotine Delivery Systems (ENDS) and two Tobacco Heating Systems (THS). In terms of study design, smoke exposure time, smoke flow, type and number of cigarettes a high variability was reported.
Conclusions:
The available evidence suggests that CS smoke significantly affects color stability. Electronic cigarettes show less color change that seems to be easily recovered under clinical acceptability thresholds, although evidence is scarce.
Clinical significance:
Clinicians should be aware, and should therefore warn their patients, that RBCs are subjected to irreversible color change if exposed to smoke. Electronic cigarettes (both ENDS and THS) induce less color change that can be recovered with repolishing or whitening procedures.
... In addition, due to cigarette combustion, these changes can be enhanced by increased temperature [31]. Thermal variations can modify the surface texture of these materials, making them more susceptible to staining [47]. Some other substances that may also be present in the composition of cigarettes can be transferred to the smoke during combustion, such as cocoa and sugars, presenting staining potential due to their dark tone and ability to adhere to the surface of composites [22]. ...
Objectives To evaluate the effect of a mechanical polishing protocol (MPP) performed continuously on the surface roughness and color stability of a denture base acrylic resin and artificial teeth exposed to different pigmenting substances.
Materials and Methods Seventy specimens of each material (n=10) were exposed to: distilled water (DW, negative control); cigarette smoke (CS); immersion in coffee (CF); association CS+CF; and association of each pigmenting condition to the MPP (CS+MPP, CF+MPP and CS+CF+MPP). The MPP used aluminum oxide paste and felt wheel coupled to an electric motor. Color stability and surface roughness were evaluated by standard procedures at baseline and after 12 and 24 days. Two-way mixed ANOVA was used for statistical analysis.
Results In most experimental conditions, the polishing controlled the roughness changes, making roughness values significantly lower (p<0.05) than those observed in the negative control group, as well as significantly reduced (p<0.05)the color change even for the groups submitted to the association of cigarette smoke and coffee in both materials.
Conclusions The proposed MPP, when carried out at biweekly intervals, was able to control the increase in surface roughness and reduce the color change on the tested acrylic resin-based prosthetic materials.
Clinical Relevance Continuous polishing of removable dental prostheses can bring more durability, reducing the deleterious effect of agents such as cigarette and coffee. As it is a simple procedure to perform, the development of a portable device would allow the polishing to be done at home by the users of these prostheses.
... Composition and manufacturer specifications of tested materials[20,45,46]. ...
Color preservation of esthetic dental restorative materials in the oral environment represents, besides longevity, a concern, and there is still limited knowledge related to the effect of aging on the optical behavior of resin matrix ceramics. The study analyzed the finishing and thermocycling of resin matrix ceramic material surfaces, in order to assess their consequences on optical properties. Five resin matrix CAD/CAM ceramics, namely a polymer-infiltrated ceramic and four types of nanoparticle-filled resins, were selected for the study, and finished by polishing and glazing. Thermocycling was chosen as the in vitro aging method. Surface microroughness, optical and hardness evaluations were achieved before and after artificial aging. Statistical analyses were performed with IBM SPSS Statistics software at a significance value of p < 0.05. Micro-roughness values increased after thermocycling, but were kept under the clinically accepted values. The optical characteristics of resin matrix ceramics were not significantly modified by thermocycling. Values of the glazed samples became closer to those of the polished ones, after hydrothermal aging, even if the differences were insignificant. Thermocycling significantly decreased the microhardness, mainly for glazed samples. This could be the consequence of glaze removal during thermocycling, which means that glazes provide a surface protection for a limited time.
... As shown in this study, a significantly decreased in VHN after thermocycling may lead to an increase surface roughness after a period of use. 15,28 On the other hand, adhesive resin penetrating into the composite may prevent the occurrence of voids and defects inside the composite. ...
Objectives This study evaluated the surface microhardness of composite, affected by surface coating with different dental adhesive systems.
Materials and Methods A total of 100 composite discs were divided into five groups. Group 1 was uncoated (control group C), and groups 2 to 5 were coated with different adhesive systems (OptiBond FL: FL, OptiBond SOLO Plus: SOLO, OptiBond XTR: XTR, and OptiBond All in one: AIO, respectively). The Vickers microhardness (VHN) was measured without and with 500 thermocycles.
Statistical Analysis The data were analyzed using two-way ANOVA and Tukey's posthoc test at the 95% confidence level.
Results At 24 hours, the VHN of C (59.96 ± 3.68) and FL (59.83 ± 4.54) were significantly higher than SOLO (51.73 ± 4.63) and AIO (51.45 ± 4.11). The VHN of XTR (54.96 ± 3.68) was not significant compared with that of C and all other groups. After thermocycling, VHN were significantly decreased in all groups. However, there were no significant differences among all groups.
Conclusions At 24 hours, composite coated with different adhesive systems have different effects to VHN. Thermocycling all adhesive resin systems coated on composite surface significantly decreased the VHN.
... Previous studies have suggested that pretreatments like sandblasting and tribochemical silica airborne particle abrasion are efficient in improving the bond strength of resin nanoceramic and resin-based materials [25,26]. HF etching is recommended for etchable ceramics, in order to enhance surface roughness, wettability and microretention and to reveal hydroxyl groups, which favors the chemical bonding with monomers [27]. ...
Due to the little information related to surface processing and conditioning of resin matrix ceramic materials previous glazing, the main purpose of this in vitro study was to investigate the effect of different surface treatments on the surface morphology of different resin composite materials. Five types of resin composite CAD-CAM materials: a resin composite ceramic Vita Enamic (E) and four types of nanoparticle-filled resins, like Lava Ultimate (L), Cerasmart (C), Shofu HC (S), Hyramic (H) were taken into consideration. Specimens received the following surface treatment protocols: conventional polishing [p], polishing and glazing [pg], conditioning with CoJet [c], conditioning with CoJet and glazing [cg], sandblasting [s], sandblasting and glazing [sg], etching [e], etching and glazing [eg]. Surface roughness was analyzed for all samples and nanosurface topographic characterization was made by Atomic Force Microscopy. The highest roughness was registered for sandblasted surfaces [s], followed by tribochemical silica airborne particle abrasion [c], and etching [e]. A very strong correlated conditioning behavior of resin nanoceramic materials, like L, C and S samples was found. The microroughness decreased thus [s] > [c] > [e]. These are moderate correlated with H, and are moderate negative correlated to E, where e is more efficient. Three-dimensional images indicated visible grain boundaries after conditioning, for all materials. After polishing and glazing, surfaces became smoother. For all tested conditioning and finishing methods, surface roughness values were within clinically acceptable limits. Finishing by polishing was proved to be a good choice for all materials taken into consideration, polishing and glazing likewise, excepting Hyramic. For Enamic and Shofu HC sandblasting or tribochemical conditioning and glazing and for Hyramic polishing and glazing are not the best options, related to nanoroughness values. Referring to the nanosurface topography, for Enamic, Cerasmart and Hyramic, glazing would be the method of choice, associated with the adequate conditioning method for each material.
... Thermocycling may affect the surface integrity of the CRs and render them susceptible to discoloration. [42,43] Finally, future studies are needed to assess the effect of Equia Forte Coat on the color stability of Equia Forte Fil in vivo. ...
Aim:
The purpose of this in vitro study was to evaluate the effect of the Equia Forte Coat on the color stability of Equia Forte Fil.
Materials and methods:
Sixty discs of Equia Forte Fil were randomly divided into two groups. One group of 30 samples was treated with Equia Forte Coat according to the manufacturer's directions. The other 30 discs were not coated. All discs were continuously soaked in cola for 7 consecutive days. The color changes in the Equia Forte Fil samples were determined using a colorimeter. The color difference (△E) was calculated using the Commission Internationale de l'Eclairage L*a*b* coordinates.
Results:
There was a significant difference in ΔE between the two groups (P < 0.0001). The group with Equia Forte Coat had significantly less color change than the group without the Equia Forte Coat.
Conclusion:
The application of the Equia Forte Coat significantly improved the color stability of Equia Forte Fil.
... Both the resin-based materials showed an increase in roughness values after polishing and 1000 thermal cycles. Previous studies also showed that thermal cycling significantly affected the surface texture of composites with dislodgement of filler particles [27,28]. Restorations should be finished properly not only for aesthetic reasons, but also for oral health reasons. ...
... A SL de materiais poliméricos diz respeito à lixiviação de monômeros não reagidos quando em contato com a água e está relacionada ao grau de conversão dos materiais 31 Com a utilização de 2 mil ciclos de termociclagem, já foi possível observar uma influência na estabilidade de cor dos materiais avaliados, apesar dos valores terem ficado abaixo do limiar considerado perceptível clinicamente 26 . O envelhecimento térmico, aplicado neste estudo por meio da termociclagem, é capaz de reproduzir alterações dinâmicas de tensões e temperatura a fim de simular às condições da cavidade oral 53,54 . O grupo Z350XT demonstrou maior alteração de cor comparado ao grupo ES. ...
Objetivo: Avaliar o efeito do envelhecimento térmico por termociclagem na estabilidade de cor e rugosidade superficial de duas resinas compostas, avaliar grau de conversão (GC), sorção (SO), solubilidade (SL) e microdureza. Material e método: Foram confeccionados 10 espécimes (6 mm x 1 mm) para cada resina: Filtek Z350 XT (Z350XT) e Estelite Sigma Quick (ES). Foram avaliados: GC, utilizando um espectrofotômetro no infravermelho, SO e SL. A avaliação da microdureza Vickers (MV) e densidade de ligações cruzadas foram realizadas antes e após a imersão em etanol por 24h. A rugosidade superficial e a estabilidade de cor (CIEDE2000) foram avaliadas antes e após envelhecimento térmico por 2 mil ciclos, alternando 30 s a 5º, 37º e 55ºC. A estabilidade de cor e translucidez foram avaliadas com um espectrofotômetro. Os dados foram submetidos ao teste t (α=0,05). Resultados: ES apresentou resultados de GC maiores (62,5% ± 3,7) que Z350XT (48,7% ± 6,9) (p=0,004). Ambas resinas apresentaram resultados de SO e SL similares. A MV final da ES diminuiu 13% com relação a inicial (p= 0,115). Z350XT apresentou diminuição de 17% (p=0,004). ES apresentou aumento de 115% na rugosidade superficial após a termociclagem (p= 0,001), enquanto a Z350XT apresentou diminuição de 35% (p= 0,299). ES apresentou menor alteração de cor (0,280 ± 0,093), quando comparado a Z350XT (0,549 ± 0,183). A translucidez foi similar para ambos materiais (ES=30,80; Z350XT=30,35). Conclusão: A termociclagem influenciou na alteração de cor e rugosidade superficial das resinas compostas, demonstrando que podem ser alteradas pela degradação na matriz polimérica.
... Indeed, it has been reported that the bond between the resin matrix and the filler particles also affect surface roughness, besides the amount of filler and filler particle size. [26] Biofilm formation on dental surfaces is a complex phenomenon that involves different key factors. [13] The quantity of biofilm varies according to the surface characteristics of materials, and surface roughness is regarded as a parameter influencing biofilm formation on both oral tissues and dental materials. ...
Aim:
The aims of this study were to evaluate the surface morphology and surface roughness of restorative materials containing glass ionomer, analyze Streptococcus mutans biofilm formation on the surface of materials, and determine the correlation between surface roughness and biofilm.
Materials and methods:
Four restorative materials: resin-modified glass ionomer; giomer; amalgomer; and glass carbomer were used and for each material, 6 mm in diameter and 2 mm in thickness disc-shaped specimens were prepared to evaluate the surface morphology (n = 3), surface roughness (n = 16), and biofilm (n = 20). Surface morphology was analyzed with a scanning electron microscope. Surface roughness was evaluated via an atomic force microscope. The biofilm was evaluated by counting the colony-forming units. Surface roughness measurements were evaluated using a one-way analysis of variance and Tukey HSD test. Biofilm parameters were analyzed using the Kruskal-Wallis H and Mann-Whitney U test. Pearson's correlation test was used to determine the correlation between surface roughness and biofilm.
Results:
While the highest roughness values were obtained for amalgomer and glass carbomer, the lowest roughness values belonged to giomer and resin-modified glass ionomer. Statistically significant differences in the number of adherent bacteria were observed between the materials only on day 1. No statistically significant correlation was determined between surface roughness and biofilm.
Conclusions:
The resin content and small filler particle size of material positively affect surface roughness. However, there is no direct relationship between surface roughness and biofilm.
... It is considered an important physical property of dental materials (5) . Color change in acrylic resins can result from intrinsic and/or extrinsic factors (6)(7)(8) . Intrinsic factors are related to acrylic resin discoloration, including alterations to the matrix (9,10) . ...
... Studies that evaluate the optical properties of the ceramics often immersed the samples in artificial saliva and other beverages, but additional studies used thermocycling the materials at different temperatures and for several cycles simulating the oral environment [33,34]. For this study, 10,000 cycles were elected to represent ten years of oral environment [35][36][37]. ...
Dental ceramic restorations are widely spread nowadays due to their aesthetics and biocompatibility. In time, the colour and structure of these ceramic materials can be altered by aging processes. How does artificial aging affect the optical and surface roughness of ceramics? This study aims to assess the effect of thermocycling, surface treatments and microstructure upon translucency, opalescence and surface roughness on CAD-CAM and heat-pressed glass-ceramic. Forty-eight samples (1.5 mm thickness) were fabricated from six types of A2 MT ceramic: heat-pressed and milled glass-ceramic (feldspathic, lithium disilicate and zirconia reinforced lithium silicate). The samples were obtained respecting the manufacturer's instructions. The resulted surfaces (n = 96) were half glazed and half polished. The samples were subjected to thermocycling (10,000 cycles) and roughness values (Ra and Rz), colour coordinates (L*, a*, b*) and microstructural analyses were assessed before and after thermocycling. Translucency (TP) and opalescence (OP) were calculated. Values were statistically analysed using ANOVA test (one way). TP and OP values were significantly different between heat-pressed and milled ceramics before and also after thermocycling (p < 0.001). Surface treatments (glazing and polishing) had a significant effect on TP and OP and surface roughness (p < 0.05). The heat-pressed and milled zirconia reinforced lithium silicate glass-ceramic experienced a loss in TP and OP. Ra and Rz increased for the glazed samples, TP and OP decreased for all the samples after thermocycling. Microstructural analyse revealed that glazed surfaces were more affected by the thermocycling and especially for the zirconia reinforced lithium silicate ceramic. Optical properties and surface roughness of the chosen ceramic materials were affected by thermocycling, surface treatments and microstructural differences. The least affected of the ceramics was the lithium disilicate ceramic heat-pressed polished and glazed.
... In vivo, a dental composite filling will experience an average intra-oral temperature of approximately 37 • C when no other thermal stimulus is applied [5,6]. However, eating, drinking and breathing induces intra-oral thermal fluctuations which have been shown, using thermocouples, to range between 4−60 • C [1,7] and will be partially transferred to the composite filling material. The thermal response of the resin phase will be influenced by the chemical structure of the constituent monomers [8], the degree of reactive group conversion and the polymer network structure. ...
Objective:
The structure of the polymer phase of dental resin-based-composites is highly sensitive to photo-polymerisation variables. The objective of this study was to understand how different polymer structures, generated with different photo-polymerisation protocols, respond to thermal perturbation.
Methods:
Experimental resins were prepared from a series of Bis-GMA/TEGDMA blends (40/60, 50/50 and 60/40 wt.%), with either Camphorquinone/DMAEMA or Lucirin TPO as the photo-initiator system. Resins were photo-polymerised, in a disc geometry, at either relatively 'high' (3000 mW cm-2 for 6 s) or 'low' (300 mW cm-2 for 60 s) irradiances ensuring matched radiant exposures (18 J cm-2). Specimens were heated, from 20-160 °C at a rate of 5 °C min-1, whilst simultaneous synchrotron X-ray scattering measurements were taken at 5 °C increments to determine changes in polymer chain segment extension and medium-range order as a function of temperature. For each unique resin composition (n = 3), differential scanning calorimetry was used to measure glass transition temperatures using the same heating protocol. A paired t-test was used to determine significant differences in the glass transition temperature between irradiance protocols and photo-initiator chemistry at ɑ = 0.05.
Results:
Resins pre-polymerised through the use of TPO and or high irradiances demonstrated a reduced rate of chain extension indicative of lower thermal expansion and a larger decrease in relative order when heated below the glass transition temperature. Above the transition temperature, differences in the rate of chain extension were negligible, but slower converted systems showed greater relative order. There was no significant difference in the glass transition temperature between different photo-initiator systems or irradiance protocols.
Significance:
The evolution of chain extension and medium-range order during heating is dependent on the initial polymer structure which is influenced by photo-polymerisation variables. Less ordered systems, generated at faster rates of reactive group conversion displayed reduced chain extension below the glass transition temperature and maintained lower order throughout heating.
... (8) Color change in acrylic resins can result from intrinsic and extrinsic factors. (9,10) Intrinsic discoloration is due to the aging of material, which results from exposure to physical and chemical conditions that involve thermal changes and humidity. (11) Extrinsic factors, such as absorption and adsorption, can promote discoloration. ...
Aims: The purpose of this study was to evaluate the effect of dry pressure curing technique after immersion in distilled water for 1 ,4 and 12 weeks on the water sorption, solubility, and color change of heat cured acrylic resin as compared with conventional curing technique, also to evaluate the effect of immersion period on these properties. Materials and methods: Sixty specimens of vertex regular heat cured acrylic resin denture base material were used in this study, curing by two different technique, conventional curing technique and dry pressure curing technique, then immersed in distilled water for 1,4, and 12 week . The water sorption and solubility test were measured by means of mass change in the materials after water saturation and dehydration. While the color change test was measured by the samples converted to digital images on computer by using digital scanner, then the digital images were prepared with dimension 760 pixels*960 pixels for each samples by software program Adob Photoshop 9.0, by MATLAB 2010 program the image was analyzed to the basic primary colors RGB, then converted to (CIE L*a*b*) system by Photoshop 9.0 program, the CIE L*a*b* color difference metric were used to perform color change test. Mean values were compared statistically with T-test, one way analysis of variance and by Duncan's multiple range test to determined the significant different among the groups at p 0.05 in different times immersion (1,4,and 12 weeks). In comparisons between immersion time that there was significant difference at p≤ 0.05 in water sorption, solubility, and color change test for both curing techniques. Conclusion: The dry pressure curing technique has an effect on the water sorption and solubility ratios but no effect on color change of heat cured acrylic resin, while the immersion period have an effect on the water sorption, solubility, and color change.
... Minami ve ark. yedi farklı kompozit rezinin (Beatifil, Esthet-X, Filtek Supreme, Inten-S, Point 4, Solare, Venus) yüzey pürüzlülüğünü 20.000 ve 50.000 termal siklus sonrası değerlendirmişler ve döngü sayısı arttıkça pürüzlülüğün arttığını bildirmişlerdir(21). Bu çalışmada 5000 termal siklus sonrası anlamlı bir fark bulunmayışının nedeni termal siklus sayısının daha düşük olması olabilir. ...
Özet: Amaç: Seromerler, seramik kullanımında çeşitli kısıtlamaların bulunduğu vakalarda, özellikle parafonksiyonel alışkanlığa sahip veya periodontal destek dokuları yetersiz bireylerde gerilim kırıcı özellikleri nedeni ile iyi bir alternatiftirler. Klinik kullanımda dental materyallerle ilgili önemli kriterlerden biri de yüzey özellikleridir ancak, belirli sürelerde ağız ortamında kullanım sonucunda yüzey özellikleri değişebilmektedir. Bu çalışmanın amacı Co-Cr metal alt yapı üzerine uygulanmış bir seromer materyalin farklı yaşlandırma işlemleri sonrası in vitro olarak yüzey pürüzlülüğünü değerlendirmektir. Gereç ve Yöntem: Disk şeklindeki Co-Cr alt yapılar üzerine (10x2 mm), bir seromer materyal olan Ceramage (Shofu, Japonya) 6 mm çapında ve 2 mm yüksekliğinde olacak şekilde yerleştirilerek polimerize edilmiştir (n=36). Distile suda bekletme, termal siklus ve fırçalama simulatörü uygulamalarına tabi tutulan örneklerin ortalama yüzey pürüzlülüğü değerleri bir profilometre cihazı ile ölçülmüştür. Yaşlandırma işlemleri sonrası örneklerin yüzeyleri taramalı elektron mikroskobu ile incelenmiştir. Verilerin istatistiksel analizi, tekrarlanan ölçümlü varyans analizi kullanılarak yapılmıştır. Bulgular: Örneklerin yaşlandırma işlemleri öncesi ve sonrası ortalama Ra değerleri sırasıyla distile suda bekletme için (0,34 µm±0,06; 0,36 µm±0,01), termal siklus uygulaması için (0,26 µm±0,02; 0,29 µm±0,02), ve fırçalama uygulaması için (0,28 µm±0,09; 0,44 µm±0,09) olarak ölçülmüştür. Başlangıç yüzey pürüzlülüğü değerleri ile kıyaslandığında örneklerin ortalama yüzey pürüzlülüğü değerlerindeki artışın en fazla fırçalama simulasyonu sonrası olduğu bulunmuştur (p<0,05). Sonuç: Bu in vitro çalışmanın sınırları dahilinde fırçalama simulasyonunun bir seromer materyal olan Ceramage’ın yüzey pürüzlülüğünde diğer yaşlandırma işlemleriyle karşılaştırıldığında önemli bir artışa yol açtığı sonucuna varılmıştır.
... As shown in Figs. 5 and 6, the filler particles were commonly dislocated or their attachment to the matrix was loosened. A similar phenomenon was previously observed in an S-PRG containing composite [35]. ...
Objective:
The influence of light-curing of a one-step self-etch adhesive (1-SEA) prior to the application of different bonding agents (BA) on the micro-tensile bond strength (μTBS) to dentin after 24h and thermal cycling was investigated. Additionally, the degree of conversion was evaluated using Fourier-transform infrared spectroscopy.
Methods:
Three ion-releasing BAs, BZF-21 (experimental BA), Clearfil SE Protect (CSP), and FL-Bond II (FL-II), were applied subsequently to G-Premio Bond (1-SEA, GPB). Prior to their application, GPB was either light-cured (10s, 1000mW/cm2) or remained uncured. GPB was used as a control and Clearfil SE Bond 2 (CSE2) as a gold-standard 2-step reference. After resin-composite build-up and 24-h water storage (24h), half of the specimens were subjected to 15,000 thermal cycles (TC). Then, the specimens were sectioned into beams and tested under tensile load (1mm/min). The acquired data were analyzed using a 2-way ANOVA and Student's t-test with Bonferroni correction, and a two-parameter Weibull analysis, α=0.05.
Results:
The μTBS of GPB increased significantly in the uncured groups with BZF-21 (24h: p<0.001, TC: p<0.001) and CSP (24h: p=0.039, TC: p<0.001), and in the light-cured group with CSP after TC (p=0.044). The groups with FL-II were not significantly different from GPB (p=1). No significant difference was found between CSE2 and the uncured groups GPB+BZF-21 (24h: p=1, TC: p=0.452) and GPB+CSP (24h: p=0.671, TC: p=0.566).
Significance:
BZF-21 and CSP improved the μTBS of GPB to dentin both immediately and after TC. Higher μTBSs were obtained when GPB remained uncured prior to BA application.
... In this way, the third null hypotheses should be rejected. Similar results were obtained by Minami et al.,16 who showed that the thermocycling procedure also significantly affected the surface texture of resin materials with filler displacement after the process. ...
Aim:
The aim of the present study was to evaluate the effect of different polishing methods on the surface roughness of resin-based composites subjected to a thermocycling procedure.
Methods:
A total of 192 specimens were divided into 24 groups, according to composite materials (Filtek Z250, Point 4, Renamel Nanofill, Filtek Supreme Plus, Renamel Microfill, and Premise) and finishing and polishing systems (Sof-Lex Pop On, Super Snap, Flexidisc, and Flexidisc+Enamelize). The specimens were subjected to thermocycling (5000 cycles).
Results:
Filtek Supreme Plus showed the lowest surface roughness values before thermocycling. After thermocycling, Filtek Supreme Plus continued to have the lowest surface roughness, with a statistically-significant difference for the other materials. After thermocycling, there was no statistically-significant difference among all the polishing techniques studied.
Conclusions:
The thermocycling was concluded as being able to change composite resins' surface roughness, whereas different finishing and polishing methods did not result in surface roughness changes after thermocycling.
... According to Ertas., et al. [34], nano-hybrid composite resins are more color stable than micro hybrid composite resins when subjected to staining solutions. Furthermore, staining results in liquid absorption of the superficial layer of the composite resin over time [37]. Staining of composite resins increase with surface roughness [38]; surface morphology and absorption mechanism [39,40]. ...
Objectives: Staining effect of solutions on temporary crowns is a frequent problem. Discoloration of dental materials after long term usage is an important issue in clinical practice. Furthermore, there is limited information on staining effect of different beverages on color stability of various temporary crown materials. Conclusion: Results indicated that color stability is affected by both material types and beverages. The bis-acryl resin composite material was found more color stable than methyl methacrylate resin temporary crown material. After 1 week and 4 weeks immersion time, coffee and tea showed more staining than the other solutions in two temporary crown materials. Results: The data were statistically analyzed using ANOVA and Tukey tests. Bis-acryl composite resin materials were more color stable than methacrylate resin materials after 1 week immersion time (p<0.05). However, after 4 weeks immersion time, there was no significant difference among bis-acryl coffee, bis-acryl tea, methacrylate distilled water and methacrylate cola groups. Bis-acryl-cola and bis-acryl-distilled water exhibited significantly lower color change than the other solutions after 4 weeks. Methods: A total of 80 cylindrical specimens from A2 shade self-curing bis-acryl composite and methyl methacrylate temporary crown materials were fabricated (n = 10). The initial color measurements were taken by using a digital spectrophotometer, according to CIE L*a*b* system. Then specimens were placed in staining solutions (distilled water, coffee, tea and cola). The other measurements of specimens were taken after 1 week and 4 weeks immersion time.
... 50 Several investigations have focused on the effects of thermocycling on microhardness, roughness, and color of composite restorations. [52][53][54] Dos Santos and colleagues 54 reported that 3,000 thermal cycles increased roughness values for all resin-based composites and there was a tendency for reduced surface roughness values after 10,000 thermal cycles. In this study, all the composite specimens were thermocycled for 10,000 cycles. ...
Objectives:
The purpose of this in vitro study was to evaluate the effects of different finishing/polishing techniques on the surface roughness of nanocomposites after thermocycling aging.
Materials and methods:
Five contemporary resin-based composites (Clearfil Majesty ES-2, Filtek Z550, Estelite∑Quick, Zenit, Filtek Z250) were tested. For each resin-based composite, 50 disc-shaped specimens were prepared and groups were divided into five subgroups according to the finishing/polishing methods (n = 10): control, finishing/polishing brush, finishing/polishing disc, and two different finishing/polishing wheels. Before and after aging, the surface roughness of specimens was measured. For each treatment method two samples were analyzed using a scanning electron microscope. Two-way analysis of variance and paired samples t-tests were used to evaluate the data and the means were compared by Bonferroni tests (p ≤ 0.05).
Results:
Before aging, the Filtek Z250 resin with the Mylar strip group showed the lowest surface roughness (Ra) value (0.13 ± 0.03 µm, p < 0.05) and the Clearfil Majesty ES 2 resin with Occlubrush finishing/polishing system showed the highest (0.7 ± 0.13 µm, p < 0.05). After aging, the Clearfil Majesty ES 2 resin with the Mylar strip group showed the highest surface roughness (Ra) value (0.96 ± 0.4 µm) and the Clearfil Majesty ES 2 resin with the Sof-Lex aluminum oxide disc finishing/polishing system showed the lowest surface roughness (Ra) value (0.25 ± 0.06 µm, p < 0.05).
Conclusions:
Composite type and finishing/polishing method significantly affected the surface roughness of composites before and after thermocycling aging.
Clinical significance:
There were significant interactions between finishing/polishing methods and composite types for surface roughness. The results give clinicians some flexibility in choosing appropriate finishing/polishing techniques for each resin composite material. (J Esthet Restor Dent 28:247-261, 2016).
... Substantial improvements have been made in the field of resin composites during the last few decades, so restorative dentists currently have a wide range of materials available for use in clinical practice. However, the long-term success of a composite resin depends on its properties, particularly its resistance and durability in the oral environment (3). ...
We compared flexural strength (FS) in four resin composites before and after three protocols for thermal cycling aging. Four resin composites were evaluated: Enamel Plus Hri, Gradia Direct Posterior, Grandioso, and Grandioso Flow. Sixty specimens (2 × 2 × 25 mm) were fabricated using a split metallic mold and light-cured for 30 s. The specimens were then randomly divided into four groups and tested using one of the following thermal cycling procedures: 1) storage in deionized water for 24 h (control group), 2) 15,000 cycles, 3) 30,000 cycles, and 4) 45,000 cycles. Each thermal cycling procedure was conducted between 5°C and 55°C, with a dwell time of 30 s. All specimens were subjected to a three-point bending test, to determine FS (0.5 mm/min). "Material" and "thermal aging" were significantly associated with FS (P < 0.001). A statistically significant interaction between the two factors was also detected (P < 0.001). In the non-aged groups, nanohybrid composites had the highest FS. FS significantly decreased after thermal cycling protocols in all composites tested. Gradia composite exhibited decrease in FS only after 45,000 cycles. In contrast, FS significantly decreased in the Grandioso Flow composite at 15,000 cycles. The trend in the decrease varied among composites, and the decrement in FS was not proportional to baseline values. (J Oral Sci 57, 137-143, 2015).
... The increase on roughness after thermocycling procedures might cause several problems such as surface stain, dental plaque accumulation and wear of occluding teeth [5,11] . Furthermore , organic matrices of composites would have absorbed some water [11], causing hygroscopic expansion in resinous matrix and filler phase, thereby enhancing the weakening of matrix–filler interface [12,19]. Data from this study demonstrated some of the changes caused by thermocycling in direct restorative materials. ...
Objective:
This study aimed to investigate the surface roughness of composite resins subjected to thermal cycles procedure.
Materials and methods:
Two microfill, four microhybrid and four nanofill composites were used. The surface roughness (Ra) was initially measured in a profilometer using a cut-off 0f 0.25 mm, after 3000 and 10,000 thermal cycles. Data were subjected to ANOVA and Fischer's test (α = 0.05).
Results:
Overall, 3000 thermal cycles increased the surface roughness values for all materials and there was a trend in all groups to decrease the roughness after 10,000 thermal cycles.
Conclusions:
The composition of material, including the type of organic matrix, could be more relevant to roughness maintenance over time than the general behavior of composites based on particles fillers. The maintenance of smooth surface in resin-based composite restorations is totally dependent of organic composition of the material.
In this study, two groups of dental ceramics exposed to acidic conditions were evaluated: Group 5Y-TZP (Zirconia stabilized by 5mol% Y2O3 and obtained experimentally by chemical synthesis), and Ceramill® Zirconia Group, commercially acquired. Both materials were compacted in the form of pellets, using a mold with a diameter of 6 mm and a hydraulic press, applying a uniaxial load of 3 tons for 60 seconds. After the pressing stage, the pellets were sintered at 1500ºC for 2 hours. All the tablets produced (N=30) were weighed on an analytical scale and then divided according to the acid immersion solutions into 4 media: SA (artificial saliva), SL (orange juice), CC (cola [Coca-Cola] and C (coffee). The tablets were stored in an oven at 37ºC for 72 hours and after the end of this time they were washed in water and dried on absorbent paper. Their masses were again measured in order to evaluate the possible loss of mass during storage. The effect of the acid medium on the crystallinity of the ceramics was evaluated by X-ray diffraction (XRD) analysis, while the chemical bonds were evaluated by Infrared Vibrational Spectroscopy (FTIR). The XRD analyses indicated that, regardless of the acidic medium, none of the ceramic groups observed a change in the crystallinity pattern. The FTIR spectra indicated the presence of new absorption bands, possibly due to the permeability of the acid solutions on the surface of the ceramic samples.
Purpose
This in vitro study aimed to evaluate the effect of thermal cycling (TC) on the color stability, translucency, and surface roughness of two different gingival porcelain materials.
Materials and methods
The gingival porcelains IPS e.max Ceram Gingiva (Ceram) and IPS InLine Gingiva (InLine) were tested. A total of 66 disc‐shaped specimens were prepared and glazed using porcelain powders of G1, G3, and G5 colors. The samples were divided into two porcelain groups by their types and into three subgroups (n11) by their colors. Thermal cycling was performed at 6000 cycles simulating an oral environment of five years. The color and surface roughness measurements of the samples were made before and after the thermal cycling. Color measurements were made with a spectrophotometer. Surface roughness (mean surface roughness [Ra; μm]) was measured using a contact profilometer. Data before thermal cycling were evaluated using the Kruskal‒Wallis test followed by the Dunn Bonferonni paired comparison test. Two‐way ANOVA with repeated measurements and a pairwise comparison test with Bonferroni correction were used to evaluate the change in roughness and translucency parameter (TP) data between groups due to thermal cycling.
Results
The color change was below the clinically perceptible color change threshold (∆E00 = 2.1) in all groups after thermal cycling. However, all materials had significantly increased roughness (p<0.05). An increase in roughness was detected in the Ceram group and was higher than that in the InLine group. The change in the translucency parameters of the samples after thermal cycling was not statistically significant; a small increase was observed in all groups. The highest translucency values were seen in the G1, G3, and G5 colors.
Conclusions
Thermal cycling caused a significant increase in the roughness values (Ra) of all materials and a minimal increase in their translucency. The color change of gingival porcelains after thermal cycling was less than the clinically perceptible threshold.
This article is protected by copyright. All rights reserved
Aim
To compare the surface roughness and color stability of a novel alkasite with current direct restorative materials with and without an aging step.
Methods and Materials
Twenty-six specimens of each of the following materials were prepared: alkasite, ormocer, giomer, high-viscosity glass ionomer, glass carbomer, and nanohybrid composite (control). Half of the specimens in each group were stained, the other half of the specimens were aged and then stained. Color and surface roughness evaluations were conducted at baseline, after aging and after staining, using a dental spectrophotometer, and a three-dimentional (3D) noncontact optical profilometer, respectively. Statistical analyses were completed using one-way analysis of variance, post hoc Tukey test, and paired samples t-test.
Results
At baseline and after aging, the surface of alkasite was found to be rougher than nanohybrid composite and ormocer surfaces (p<0.05). However, in terms of roughness increase caused by aging, ormocer, nanohybrid composite, and alkasite were affected in a similar way (p>0.05). In terms of color stability, alkasite was more colored than nanohybrid composite and ormocer (p<0.05), and performed similar to giomer (p>0.05).
Conclusions
The surface roughness and color stability characteristics of alkasite material was between composite resins and glass ionomer-based materials after aging.
Statement of problem
The properties of dental computer-aided design and computer-aided manufacturing (CAD-CAM) materials vary. Studies regarding the effects of aging on the properties of these materials are lacking.
Purpose
The purpose of this in vitro study was to evaluate the changes in the mechanical and surface properties of different CAD-CAM materials after thermocycling and mechanical loading.
Material and methods
In total, 150 bar-shaped specimens (17.0×4.0×2.0 mm) were prepared from feldspathic glass-ceramic (VM; Vitablocs Mark II), lithium disilicate glass-ceramic (EX; IPS e.max CAD), zirconia-reinforced lithium silicate glass-ceramic (CD; Celtra Duo), polymer-infiltrated ceramic network (VE; Vita Enamic), and resin-nanoceramic (CS; Cerasmart). Each type was divided into 2 groups (n=15; each). One group was subjected to thermocycling in distilled water at 5 °C to 55 °C for 6000 cycles and 50 N mechanical loading for 1.2×10⁶ cycles. The other group was stored in 37 °C water for 24 hours. Nanoindentation hardness, Young modulus, and 3-point flexural strength were measured for the analyses of the mechanical properties. Surface roughness, surface microstructure, and elemental composition were measured to analyze the surface characteristics. Statistical analyses were performed with 1-way ANOVA with the Tukey HSD post hoc test, independent samples t test, Kruskal-Wallis test with Bonferroni post hoc test, Mann-Whitney U test, and 2-way ANOVA (α=.05).
Results
Before and after aging, CS exhibited the lowest hardness (1.20 to 1.04 GPa) and Young modulus (13.76 to 13.48 GPa) values (P<.05). EX exhibited the highest flexural strengths (393.43 to 391.86 MPa), and VM exhibited the lowest (109.98 to 112.73 MPa) values (P<.05). CS exhibited the highest surface roughness (Sa and Sq; 10.60 to 28.82, 14.21 to 38.27 nm) values (P<.05). After aging, the hardness and Young modulus of VM, EX, and VE decreased significantly (P<.001). No significant difference was observed in the flexural strengths of the CAD-CAM materials (P>.05). Significant increases were observed in the surface roughness of all the materials (P<.05), with altered microstructures. Except for the flexural strength, the mechanical properties and surface characteristics of the CAD-CAM materials were significantly affected by the material type after aging.
Conclusions
Before and after aging, resin-nanoceramic exhibited the lowest hardness and Young modulus, and the highest surface roughness. Lithium disilicate glass-ceramic exhibited the highest flexural strength and feldspathic glass-ceramic exhibited the lowest value. After aging, increased surface roughness and microstructure alterations were observed. Significant interactions between aging process and material type were found for the mechanical properties and surface characteristics except for the flexural strength.
Statement of problem
The color stability and mechanical properties of luting agents influence the esthetics and longevity of ceramic restorations. However, studies evaluating the color changes and mechanical properties of luting agents under ceramic laminates activated by using different methods are lacking.
Purpose
The purpose of this in vitro study was to evaluate the effects of different modes of photoactivation on the nanohardness and elastic modulus of resin cements and dental adhesives and on the color stability of ceramic laminate veneers.
Material and methods
Forty-four lithium disilicate blocks (7×8×0.6 mm) were cemented onto bovine enamel and divided into 4 groups according to the polymerization light (Radii-Cal or Valo) used and the mode of activation of the dental adhesive (no previous photoactivation or previous photoactivation). Single Bond Universal dental adhesive and RelyX Veneer resin cement were used in all experimental groups. Color stability was measured using a UV-2450 ultraviolet-visible spectrophotometer before and after ultraviolet-B artificial accelerated aging (n=8). The nanohardness and the elastic modulus of the adhesive and resin cement were measured using a nanohardness tester (n=3). The color stability and mechanical properties were measured and analyzed using ANOVA and the Tukey least significant difference test (α=.05).
Results
No difference in color stability or mechanical properties of the resin cement among the polymerization lights was detected (P>.05). Specimens that underwent previous photoactivation of the adhesive using the Valo polywave unit exhibited higher elastic modulus values than those that did not undergo previous photoactivation (P<.001).
Conclusions
The Valo polywave polymerization light improved mechanical properties and color stability more than the Radii-Cal unit. Previous activation of the dental adhesive in the dental enamel with the Valo polywave polymerization light yielded more satisfactory results.
The application of modeling resin could affect the surface quality and color of resin composites.
To evaluate the effects of modeling resin on the microhardness, roughness, and color of composite restorations, with and without thermocycling.
Sixty disc-shaped specimens for each resin composite were prepared in three groups: Group 1: A resin composite disc was cured against a polyester matrix and finished/polished; Group 2: A composite instrument was wetted with Bisco Modeling Resin (Bisco, Schaumburg, IL, USA) to smooth the composite surface, which was cured against a polyester matrix and finished/polished; Group 3: A composite instrument was wetted with modeling resin to smooth the composite surface, which was cured against a polyester matrix. Microhardness, roughness, and color were measured 24 hours after curing and after 10,000 thermocycles.
Modeling resin significantly influenced the microhardness of GrandioSO (Voco, Cuxhaven, Germany) and Gradia Direct Posterior (GC America, Alsip, IL, USA), and the surface roughness of GrandioSO, Filtek Silorane (3M ESPE, St Paul, MN, USA), and Aelite All Purpose Body (Bisco) (p < 0.05). The microhardness of the Group 1 resin composites was affected by thermocycling (p < 0.05); however, thermocycling had no significant effect on surface roughness (p > 0.05). Tested composites showed clinically perceptible color changes after thermocycling. In Group 1, Filtek Ultimate (3M ESPE) showed the lowest color change (p < 0.05), and in Group 2, Filtek Silorane showed the highest significant color changes (p < 0.05).
Modeling resin did not affect the microhardness, surface roughness, and color of Aelite LS Posterior (Bisco), Filtek Ultimate (3M ESPE), and Clearfil Majesty Esthetic (Kuraray Medical Inc, Tokyo, Japan) specimens. Also, thermocycling process only affected microhardness of tested resin composites.
The effect of modeling resin on surface microhardness, roughness, and color stability of composite materials depends on the type of resin composite. In clinical practice, the adverse effects of modeling resin might be alleviated by a proper finishing and polishing procedure.
Objectives: Measure and compare internal color stability of three light-cured composites and one
chemically bonded material after their accelerated aging. Materials and Methods: Color stability
tests included nano-filled Filtek Supreme XT (3M ESPE), nano-hybrid Tetric Evo Ceram (Ivoclar Vivadent),
microhybrid Herculite XRV (Kerr) of light cured and Bisfil II (Bisco) of self cured composites.
All samples were immersed in distilled water of 37°C and kept in a dark chamber during 24
hours. Thereafter they were divided into three groups. Accelerated aging was performed in accordance
with the two different protocols, i.e. water bath at 60°C and ISO 7491. Control group specimens
were stored in distilled water at 37°C for 30 days. Color differences, ΔE were calculated from
CIE L*a*b* coordinates measured with spectrophotometer against white backing before and after
aging of samples. The color perceptibility threshold was set at 1.7 and acceptability threshold
at 3.5. Statistical tests carried out on the groups included paired t-test and ANOVA (p≤0.05). Results:
All tested materials showed clinically unacceptable color changes after accelerated aging in
water bath, whereas photoaging induced perceptible color change in all light-cured composites.
Nano-engineered composites significantly changed their color also in the control group. Conclusions:
Internal color stability of tested materials depends on aging conditions and type of dental
composite. Chemically-cured material showed better color stability by photo aging.
This in vitro research verified the possibility of eliminating staining caused by coffee and red wine in five composite resins, after being submitted to thermal cycling. Thirty-six specimens were prepared and immersed in water at 37°C for 24 hours. After polishing, specimen color was measured in a spectrophotometer Cintra 10 UV (Visible Spectrometer, GBC, Braeside, VIC, Australia). All specimens were submitted to thermal cycling at temperatures of 5 and 55°C with a dwell time of 1 minute, for 1,000 cycles in a 75% ethanol/water solution. After thermal cycling, the specimens were immersed in water at 37°C until 7 days had elapsed from the time the specimens were prepared. All specimens were then taken to the spectrophotometer for color measurement. The specimens were divided into three groups (N = 12): distilled water (control), coffee, and red wine. For the staining process to occur on only one surface, all the sides, except one, of the surfaces were isolated with white wax. The specimens were immersed in one of the solutions at 37°C for 14 days. The specimens were dried and taken to the spectrophotometer for color measurement. After this, the specimens were submitted to 20 µm wear three times, and the color was measured after each one of the wear procedures. Calculation of the color difference was made using CIEDE2000 formula. According to the methodology used in this research, it was concluded that the staining caused by coffee and red wine was superficial and one wear of 20 µm was sufficient to remove the discoloration.
Discoloration is one of the main causes of esthetic restoration replacement. As demonstrated in this study, repolishing could be an alternative method for removing staining, once it is superficial. This procedure can avoid the substitution of functional restorations and prevent trauma to the sound tooth structure.
The staining effect of tobacco smoke on resin color is clinically observed. However, there is no evidence determining whether this staining is increased on texturized surfaces or if the color change is superficial and can be removed by repolishing procedures.
To evaluate the effect of tobacco smoke on the color of a composite with smooth or texturized surfaces, before and after repolishing.
Forty composite specimens were allocated into four groups (N = 10): Smooth surface not exposed (G1) and exposed to tobacco smoke (G2), texturized surface not exposed (G3), and exposed to tobacco smoke (G4). During 21 days, G2 and G4 were daily exposed to the smoke from 20 cigarettes. Color measurements were carried out at baseline, after 21 days, and after repolishing. Variables L* (luminosity), b* (blue-yellow), and DeltaE (total color change) were statistically analyzed (repeated measures analysis of variance/Tukey).
Texturized and smooth specimens presented similar luminosity at baseline. Tobacco smoke significantly reduced L* in G2 and G4, and increased b* in G4. After repolishing, L* increased and b* reduced in stained groups, but values continued to be different from baseline ones. Repolishing significantly reduced DeltaE, but values from stained groups were still greater than that from unstained groups.
Tobacco smoke changes the color of composite, and surface texture can increase the staining. Repolishing reduces superficial staining, but this procedure may not return the composite to baseline color.
Smokers that will receive anterior composite restorations should be warned about the negative cosmetic effect of the smoking habit on the color of restorations.
Acrylic resin denture teeth are widely used due to the chemical bond to the acrylic resin of the denture base. However, discoloration of acrylic resin denture teeth can be a problem.
The purpose of this study was to investigate the effect of polymerization methods and thermal cycling on the color change of acrylic resin denture teeth.
Ten different brands of acrylic resin denture teeth were evaluated: Art Plus (AP), Biolux (BX), Biotone IPN (BI), Magister (MG), Mondial 6 (MD), Premium 6 (PR), SR Vivodent PE (SR), Trilux (TR), Trubyte Biotone (TB), and Vipi Dent Plus (VP). Each brand was divided into 2 groups (n=12); each group was subjected to 1 of 2 polymerization methods (microwave, 500 W for 3 minutes, or water bath, 74 degrees C for 9 hours). After polymerization, all of the specimens were thermal cycled between 5 degrees C and 55 degrees C with 30-second dwell times for 5000 cycles. The specimen colors were measured with a spectrophotometer, using the CIE L*a*b* system, at baseline (B), after polymerization (P), and after thermal cycling (T). Color differences (DeltaE) were calculated for periods between P and B (PB), T and B (TB), and T and P (TP). A DeltaE of < or =3.3 was considered clinically acceptable. The data were evaluated by 3-way repeated-measures ANOVA and the Tukey HSD test (alpha=.05).
The highest DeltaE values were obtained for BI and SR teeth; these were significantly higher than the values obtained for the other brands (P<.05). There was no significant difference between the 2 polymerization methods. There was no significant difference between TB and PB for either polymerization method.
The DeltaE values are within acceptable clinical limits for all brands, for both polymerization methods and different measurement periods.
For the clinical wear of composite filing materials to be reduced, compositional factors such as degree of cure, filler level, and silanation level should be optimized. An oral-wear-stimulating machine was used to explore the effects of these factors on abrasion and attrition wear as well as on opposing enamel wear. The composites were made from Sr glass (1-2 micron avg) and a 50/50 Bis-GMA/TEGDMA resin. Series I (A-D, E) were light-cured (Triad II) for 9, 12, 25, and 40 sec/side to produce degree of cure (DC) as measured by FTIR of 56, 60, 61, and 63%, respectively. E received an additional heat cure (120 degrees C for 10 min) to reach a DC of 66%. Series II (D, F-I) were filled to 62, 53, 48, 37, and 28 vol%, respectively. In series III (D, J-M), the portion of fillers treated with a silane coupler (MPS) was 100, 80, 60, 40, and 20%, respectively. Samples were cycled 50,000 times against an enamel antagonist in a poppy seed/PMMA slurry in the oral wear simulator to produce abrasion (load = 20 N) and attrition (load = 70 N) simultaneously. Wear depth (micron: n = 5) was measured by profilometry. Results for each series were analysed by ANOVA/Turkey's (p < or = 0.05). The wear depths did reflect cure values, though only the abrasion difference for E < A was significant. Greater wear was correlated with lower filler levels (r2 = 0.88; p < 0.05), significantly increasing below 48 vol% (G). Wear increased linearly as the percent of silane-treated fillers was reduced (r2 = 0.99; p < 0.05). Abrasion and attrition did not differ significantly for any composite. Wear of the opposing enamel was largely unchanged by these factors. Compositional factors including degree of cure, filler level, and silanation directly affected the wear resistance of dental composites evaluated in an oral wear simulator.
The roughness of intraoral hard surfaces can influence bacterial plague retention. The present review evaluates the initial surface roughness of several intraoral hard materials, as well as changes in this surface roughness as a consequence of different treatment modalities.
Articles found through Medline searches were included in this review if they met the following criteria: 1) stated threshold surface roughness values and reputed change in surface roughness due to different manipulation techniques; or 2) included standardized surface conditions that could be compared to the treated surface.
Recently, some in vivo studies suggested a threshold surface roughness for bacterial retention (Ra = 0.2 micron) below which no further reduction in bacterial accumulation could be expected. An increase in surface roughness above this threshold roughness, however, resulted in a simultaneous increase in plaque accumulation, thereby increasing the risk for both caries and periodontal inflammation. The initial surface roughness of different dental materials (e.g., teeth, abutments, gold, amalgam, acrylic resin, resin composite, glass ionomer or compomer and ceramics) and the effect of different treatment modalities (e.g., polishing, scaling, brushing, condensing, glazing or finishing) on this initial surface roughness were analyzed and compared to the threshold surface roughness of 0.2 micron. The microbiological effects of these treatment modalities, if reported, are also discussed and compared to recent in vivo data.
Based on this review, the range in surface roughness of different intraoral hard surfaces was found to be wide, and the impact of dental treatments on the surface roughness is material-dependent. Some clinical techniques result in a very smooth surface (compressing of composites against matrices), whereas others made the surface rather rough (application of hand instruments on gold). These findings indicated that every dental material needs its own treatment modality in order to obtain and maintain a surface as smooth as possible.
To evaluate the effects of two home-use bleaching gels (Nite-White and Contrast PM) on the surface roughness of one high-viscosity glass ionomer cement (Fuji IX GP), four polyacid-modified resin-based composites (Dyract AP, F2000, Elan and Compoglass F), two resin-modified glass-ionomer cements (Vitremer and Fuji II LC), a microfilled fluoride-releasing resin-based composite (Tetric) and a microfilled non-fluoridated resin-based composite (Valux) were used as controls. The null hypotheses tested were: (1) the use of bleaching gels would not result in surface roughness values different from those obtained at baseline; (2) differences in the amount of carbamide peroxide present in the gels would not influence surface roughness. Thirty specimen disks (the first 10 used for controls and the balance divided randomly into two groups) were made for each material according to the manufacturers' instructions. Finishing and polishing of the test and control specimens was performed after 24 hours using a sequential series of three (medium, fine and superfine) Sof-Lex disks, keeping the restoration surface wet. For every sequence, 10 strokes were made in one direction using a low-speed handpiece. Ultrasonic cleaning of the polished specimens was performed for two minutes in distilled water to remove any surface debris. Prior to bleaching treatment, the specimens were stored in 37 degrees C deionized water for 24 hours. The specimens were exposed to the bleaching gels for a period that simulated the equivalent of 15 days (eight hours/day) under bleaching treatment. The average surface roughness (Ra) of the control and treated specimens was measured. Three separate Ra measurements along the direction of rotation of the finishing and perpendicular to the finishing direction and edge of the mold were made for each specimen surface. After treatment with bleaching gels, there was an increase in surface roughness for F2000, Dyract AP, Elan, Valux and Tetric, while Fuji IX, Fuji II LC, Vitremer and Compoglass F displayed decreased surface roughness values, suggesting that the effects of the gels appear to be material-dependent. Although Contrast PM contains 5% more carbamide peroxide as the active ingredient, the second null hypothesis was rejected for Fuji IX, Vitremer, Dyract AP, Compoglass F, Elan and Valux.
Proper finishing of restorations is desirable not only for aesthetic considerations but also for oral health. The primary goal of finishing is to obtain a restoration that has good contour, occlusion, healthy embrasure forms and a smooth surface. This study investigated: 1) analyzing the surface roughness of three resin composites finished and polished with a new one-step and two conventional multi-step polishing systems and 2) evaluating the effectiveness of one-step polishing system and surface morphology using scanning electron microscope analysis (SEM). Specimens (N = 72) measuring 8-mm in diameter x 2-mm in thickness were fabricated in a plexiglass mold covered with a Mylar strip using three esthetic resin composites. After polymerization six specimens per resin composite received no finishing treatment and served as a control. Fifty-four specimens were randomly polished with Sof-Lex discs, Enhance disc with polishing paste or PoGo for 30 seconds after being ground wet with a 1200 grit silicon carbide paper. The average surface roughness of each polished specimen was determined with a profilometer (Surtronic 4). The data were analyzed using repeated measures ANOVA and Scheffe's post-hoc test of multiple comparisons (p < or = 0.01). Representative samples of the mentioned finishing procedures were selected and examined using a scanning electron microscope (SEM). There was no surface roughness in all resin composites tested against Mylar strip. The results showed no difference between the surfaces of Clearfil ST and Esthet-X polished with PoGo and the Mylar group (p > or = 0.01). Among all the polishing systems tested, PoGo exhibited the smoothest finish for all resin composites. The combination of Enhance and Prisma Gloss polishing paste exhibited the highest roughness values for Filtek A110 and Clearfil ST; however, it gave the same Ra values as PoGo for Esthet-X (p < or = 0.01). SEM analysis of Esthet-X samples confirmed the profilometer's results. The surfaces of the Clearfil ST discs polished with PoGo resemble that of Mylar, while Enhance and Sof-Lex exposed and dislodged the filler particles. PoGo scratched in some places Filtek A110's surface, while Enhance produced mostly a Mylar-like surface with dislodged fillers in some places.
The purpose of the present study was to evaluate the color stability of selected indirect composite resins. Twenty-six specimens each of Dentacolor, VisioGem, Brilliant D. I., and Concept were fabricated and immersed in chlorhexidine, coffee, and tea. The modifying effect of saliva on staining was also studied. Coffee and tea both stained the tested materials, but tea stained more than coffee. The addition of chlorhexidine and saliva increased staining when used with tea. Most staining was superficial and could be removed with regular oral hygiene; however, residual staining, which might become cumulative, was recorded. Brilliant D. I. samples exhibited the most discoloration and Concept samples the least.
The water sorption and solubility of three hybrid and one microfine composite are reported. The values obtained are dependent on composite type and resin system. Incomplete polymerization of the two materials resulted in increased solubility and sorption due to incomplete conversion of the monomer. The marked increased in both parameters will have clinical significance on the durability of the material.
Resin-modified glass ionomer cements (RMGIC) and polyacid-modified resin composites (PMC, compomers) are two recently introduced material groups supposed to replace traditional cements in operative dentistry. The new restoratives release initially fluoride in different relatively high concentrations, which decrease gradually during the first weeks in vivo. Earlier studies showed a stronger subclinical inflammatory reaction around different conventional tooth colored restorative materials than around intact enamel. The aim of this study was to compare intra-individually the initiation of gingival inflammation around, aged RMGIC, PMC and resin composite restorations. Subgingivally located Class III restorations were placed in 17 patients. Each patient received one of each of the experimental materials. All patients were placed on an oral hygiene regime 1-year after finishing of the restorations. Gingivitis was induced during a one-week period without oral hygiene. The gingival condition was assessed by sampling of gingival crevicular fluid (GCF), registration of the amount of bacterial plaque and by registration of bleeding after gentle probing of the entrance of the gingival sulcus (SBI) on the experimental filling- and control-enamel surfaces at days 0 and 7. No differences were seen in plaque and gingival index scores between the materials at both days. The GCF increased significantly for all surfaces during the experimental gingivitis period. At day 7 significantly lower GCF was sampled around the enamel surfaces. In conclusion, the differences between the materials did not result in measurable differences concerning clinical or subclinical signs of gingivitis.
Six fluoride-releasing materials of shade A3 were tested: one glass ionomer (Fuji IX), one resin-modified glass ionomer (Photac-Fil), two compomers (F 2000 and Dyract AP) and two composites (Tetric Ceram and Solitaire). Disk-shaped specimens of each material were prepared according to manufacturer's instructions, polished and L*a*b* baseline measurements taken. Specimens were randomly divided into two groups and given four different treatments of UV light exposure and immersion in a staining solution. Chromo Meter color measurements were taken following each treatment. Two-way ANOVA and Duncan Multiple Range post-hoc tests were used to compare color changes as a function of the four treatment conditions and one-way ANOVA was used to compare materials for each treatment separately. The results showed significant difference in shade A3 between products. In general, the hydrophobic materials showed greater color stability and stain resistance than the hydrophilic materials. Tetric ceram had the best color stability and stain resistance, while Fuji IX had the least.
A great variety of dental materials are now available for use in restorative treatments. Much attention has been devoted to physical and chemical properties, but the biological effects of these materials have been less frequently studied.
The aim of this study is to test the influence of resin based restorations, amalgams and gold alloys, as restorative materials in immediate contact with the gingival tissues.
In 103 patients (54 male and 49 female, 39 smokers and 64 non-smokers, mean age: 34 +/- 13 years) with 255 restored teeth (101 resin-based materials, 98 amalgams, and 56 gold inlays), the marginal gingiva was examined. The restorations selected had to be in place more than 6 months. The patients participating in the study had no systemic diseases and pregnant patients were excluded, as were those under long-term medication and those with severe periodontal disease. The filling materials were examined for surface roughness, secondary carious lesions and gaps. The marginal gingiva in contact with the restorative materials was tested by reference to Bleeding Index (BI), Gingiva Index (GI), probing depth and degree of tooth mobility. As controls 255 teeth without fillings, of the same type, in the opposite jaw were used.
The 101 resin-based restorations had a mean age of 3.1 (+/- 2.0) years, the amalgam fillings were in place 6.6 (+/- 4.1) years and the gold inlays had an average age of 4.7 (+/- 4.6) years. Surface roughness was observed in 66.3% of the resin-based restorations, in 47.9% of the amalgams and in 10.7% of the gold inlays. Absence of bleeding after probing was observed for 25.7% of the resin-based restorations, for 55.1% of the amalgam fillings, and for 58.9% of the gold inlays. All classes of restored teeth showed significant differences from the controls without fillings. The mean probing depth for the resin-based fillings was 3.6 mm (control 2.4 mm), for teeth with amalgams 3mm (control: 2.4 mm) and for teeth with gold inlays 2.5 mm (control 2.1 mm). A significant difference between smokers and non-smokers was only found in the group of resin-based restorations. The Bleeding Index was significantly higher in the group of smokers (p = 0.0005) in comparison to the non-smokers, as was the Gingiva Index (p=0.0106).
The marginal adaptation of the restored teeth examined showed materially specific differences. The handling of resin-based materials, in comparison to amalgam or gold remains very sensitive and consequently there is prevalent error of technique. The high prevalence of gingival irritation in association with resin based materials may be caused by non-indicated applications, failures of technique, or simply the chemical properties of the materials.
This study evaluated the surface roughness pattern of resin-based restorative materials during brushing preceded by a regimen that simulated a dynamic pH-cycling. Restoratives included two resin composites (Renamel Microfill and Charisma), two polyacid-modified composite resins (Compoglass-F and Dyract AP) and one resin-modified glass ionomer cement (Fuji II LC Improved). Twenty standardized cylindrical specimens of each material were prepared according to a randomized complete block design. After finishing and polishing, the average surface roughness (Ra) and profile-length ratio (LR) of the specimens were determined. The experimental units were subjected to a pH-cycling regimen, and then to 10,000 brushing strokes. New readings of both the Ra and LR parameters were obtained. The same protocol of pH-cycling, brushing simulation and surface roughness measurements were repeated 10 times. Data was analyzed using ANOVA according to split-plot design and Tukey's test. Results showed the pH-cycling followed by 10,000 brushing strokes provided a remarkable increase in Ra for all restorative materials except for Renamel. Throughout the brushing simulation, Renamel, Charisma, Compoglass-F and Dyract AP showed steady textures, whereas Fuji II LC Improved exhibited a progressive increase in surface roughness. Among the materials tested, Renamel presented the smoothest surface, followed by Charisma and Compoglass-F, which did not differ from each other except at the baseline. Dyract AP was different from both these materials except at the baseline. Fuji II LC Improved had the roughest surface texture.
This study was undertaken to compare the effects of three prophylaxis pastes (Nupro with coarse, medium, or fine pumice) with a new paste (Clinpro with perlite) on the surface roughness of a resin composite (Dyract AP), a hybrid ionomer (Fuji II LC), and a compomer (TPH Spectrum).
Twenty disks (2 mm thick x 10 mm in diameter) of each material were prepared in split molds and stored for 24 hours at 37 degrees C in a 100% relative humidity humidistat. Baseline Mylar surface roughness values were determined. A single operator polished each specimen for 10 seconds with each paste. Five tracings of each specimen of surface roughness (Ra, microm) were made using a surface profilometer. Means and standard deviations were calculated, and analyzed by two-way analysis of variance (three restorative materials and four prophylaxis pastes as factors) and compared using Tukey-Kramer intervals calculated at the 0.05 level of significance.
Analysis of variance showed significant differences among restorative materials (after polishing) and prophylaxis polishing agents. Tukey-Kramer intervals for comparisons were 0.04 and 0.05 microm, respectively. All polishing agents produced significant increased roughness compared with baseline, yielding the following results (X + SD, microm) for the three restorative materials (Fuji II LC, TPH Spectrum, Dyract AP): perlite, 0.16 +/- 0.07, 0.28 +/- 0.26, 0.79 +/- 0.64; course pumice, 0.36 +/- 0.17, 0.48 +/- 0.25, 0.88 +/- 0.46; medium pumice, 0.26 +/- 0.10, 0.35 +/- 0.30, 0.46 +/- 0.21; and fine pumice, 0.16 +/- 0.06, 0.34 +/- 0.30, 0.42 +/- 0.24). Fine pumice and perlite produced the least roughness on the hybrid ionomer, medium and fine pumice on the resin composite, and perlite on the compomer.
Since prophylaxis pastes have the potential to increase the surface roughness of resin composite, hybrid ionomer, and compomer restorative materials, routine polishing during prophylaxis should be avoided.
This in vitro study evaluated the effect of tooth brushing and thermal cycling on the surface lustre and surface roughness of three ceromer systems treated with different surface finishing methods. The ceromers studied were: (1). Artglass, (2). Targis, (3). Sculpture and (4). the control group, Z 100. Half of the Targis and Sculpture groups were polished and the rest were coated with staining and glazing solution, respectively. All specimens were subjected to thermocycling 10000 times. Tooth brushing abrasion tests were performed in a customized tooth-brushing machine with 500 g weight applied on a back-and-forth cycle for 20000 repetitions. The lustre determined by measuring the light reflection area and the average roughness was compared between groups and between pre- and post-test values. All materials showed a lower lustre and rougher surface after thermocycling and tooth brushing (P < 0.05). All ceromer specimens, except glazed Sculpture, showed a higher lustre and similar roughness to the control group. The post-brushing results revealed that glazed Sculpture presented discretely fallen out glaze coatings and had maximum change. However, stained Targis showed minimum change (P < 0.05) and polished Targis presented more changes than that of the staining treatment. It is therefore concluded that the glaze coatings for Sculpture don't exhibit long-term durability, while stain coatings for Targis acted like a protective layer.
The purpose of the present study was to investigate the influence of various finishing systems on the surface roughness and staining of three packable resin composites and a conventional microhybrid one.
Three packable composites (Solitaire-Heraeus-Kulzer, ALERT-Jeneric-Pentron, SureFil-Dentsply) and a conventional microhybrid (Z250-3M-ESPE) were used. Composite specimens were prepared and polished with Poli I and Poli II aluminum oxide pastes, Ultralap diamond paste, Enhance finishing points, Politip rubber polishers, fine and extra fine diamond burs, and 30-blade tungsten carbide burs according to the manufacturers' instructions. The polished surfaces were evaluated with a profilometer, and then immersed in 2% methylene blue for 24h. Afterwards, the specimens were prepared for the spectrophotometric analysis. Results were statistically analyzed by ANOVA and Tukey test.
Significant differences were found for the surface roughness and staining recorded, with interaction among composite resins and the finishing systems used. No correlation was found between surface roughness and staining susceptibility (p=0.5657).
For most of the polishing agents used, Z250 presented the smoothest surfaces and the least dye uptake. ALERT presented the roughest surfaces, and Solitaire, the highest dye concentration. The smoothest surfaces were not necessarily the most stain resistant. Staining is highly influenced by each composite monomer and filler composition.
The purpose of this study was to evaluate the effect of various finishing and polishing procedures on the surface roughness of three new tooth-coloured restorative materials. The materials included a hybrid composite resin (Filtek Z250), a packable composite resin (Filtek P60), and an ormocer (organically modified ceramic) (Definite). Thirty-two specimens of each material were prepared and randomly divided into four finishing and polishing groups (n = 8): (i) diamond bur/silicone polishers, (ii) diamond bur/Sof-Lex discs, (iii) carbide bur/silicone polishers, (iv) carbide bur/Sof-Lex discs. Average surface roughness (Ra) in micrometers was measured with a Mitutoyo Surftest-402 Surface Roughness Tester and the data compared using anova, at P < or = 0.05. Surface topography was also assessed using the scanning electron microscope (s.e.m) from samples of each group. The Mylar strip produced the smoothest surface and finishing/polishing procedures; (ii) and (iv) were significantly smoother than (i) and (iii). The lowest variability in initial surface roughness between materials was also observed with ormocer group.
This study was undertaken to examine the effect of three different polishing systems on surface roughness of five newly developed resin composites.
Three microhybrid composites (Point 4, Kerr, Orange, CA; Esthet-X, Dentsply/Caulk, Milford, DE; Vitalescence, Ultradent, South Jordan, UT, USA), one microfilled composite (Renamel Microfill, Cosmedent, Chicago, IL, USA), and one experimental microhybrid composite (FZB, Ivoclar Vivadent, Schaan, Liechtenstein) were light cured with a Mylar strip. Fifteen specimens of each composite (6 mm in diameter and 3 mm in depth) were fabricated and randomly assigned to three groups. Specimens in each group were finished with a carbide bur (16 fluted) and three polishing systems (Astropol, Ivoclar Vivadent; Diagloss, Axis Dental, Irving, TX, USA; Sof-Lex, 3M, ESPE, St. Paul, MN, USA). The average surface roughness (Ra) and the mean peak spacing (Sm) were measured with a surface profilometer after polishing. Five tracings at different locations on each specimen were made. Data were analyzed by analysis of variance.
For Astropol, Ra ranged from 0.10 to 0.15 microm and Sm ranged from 24 to 40 microm for the five composites; for Diagloss, Ra ranged from 0.24 to 0.34 microm and Sm from 38 to 74 pm; for Sof-Lex, Ra ranged from 0.06 to 0.10 microm and Sm ranged from 16 to 22 microm. Significant differences between materials and polishing systems were observed. Polishing systems had the most important role in determining the surface roughness of resin composites.
Of the polished systems tested, Sof-Lex discs provided the lowest roughness for polishing microfilled and microhybrid composites, and the microfilled resin composite showed the lowest roughness.
To examine the effects of a paint-on 19% sodium percarbonate 'overnight' bleaching gel on the structure and integrity of enamel, dentin and some common restorative materials, with a laboratory cycling model.
Enamel, root dentin and restorative materials (glass-ionomer, composite and amalgam) were prepared in methacrylate molds with surface polishing. A treatment regimen was carried out including diurnal incubation in pooled human saliva and including twice daily toothbrushing with standard fluoridated dentifrice. Test samples were treated daily with Crest Night Effects bleaching gel, which included drying of surfaces, painting of percarbonate bleaching gel, and then incubation throughout the day (8 hours) to simulate overnight wear. Treatments were carried out over 14 days, to simulate clinical exposure periods. Control and test specimens were evaluated for surface and subsurface structure and morphological integrity utilizing surface microhardness, surface profilometry, and confocal laser scanning microscopy.
Percarbonate bleaching film treatments had no effects on enamel or root dentin surface microhardness, or on subsurface ultrastructural integrity of enamel and coronal dentin. Surface profilometry confirmed retention of small amounts of residual silicone polymers, which contributed to CLSM air objective appearance and surface roughness measures. Restoratives were generally passive to bleaching gel treatments, though composite showed a tendency to attract retained residual silicone film.
To determine hardness and solubility of light-cured resin-based composites after high intensity vs. soft-start quartz tungsten halogen irradiation.
Knoop hardness of resin-based composite specimens was measured at 1.5 mm depth after dry storage for 24 hours at 37 degrees C so as to indirectly evaluate degree of cure. Solubility was determined gravimetrically by extraction of post-cured (24 hours, 37 degrees C) specimens in 50 wt% methanol for 72 hours. Four hybrid (Filtek Z250, Herculite, Solitaire 2, Tetric Ceram), an inhomogeneously filled hybrid (InTen-S) and a microfilled (Filtek A110, formerly Silux Plus) composite were cured using the quartz tungsten halogen units Astralis 10 and Optilux 501 in the high intensity (Astralis 10 High Power: 10 seconds @ 1300 mW/cm2; Optilux Boost: 10 seconds @ 1140 mW/cm2) or soft-start modes (Astralis 10 Pulse: increase to 700 mW/cm2 within 10 seconds, three periods of 2 seconds @ 1300 mW/cm2 alternating with two periods of 2 seconds @ 700 mW/cm2; Optilux Ramp: exponential increase within 10 seconds, followed by 10 seconds @ 1140mW/cm2).
For the fast curing composites Z250, Tetric Ceram and InTen-S, equivalent hardness was observed after 10 seconds of high intensity and 20 seconds of soft-start irradiation. For the slower curing composites Herculite, Solitaire 2 and A110, the soft-start protocols produced higher hardness values. Regarding solubility however, the superiority of soft-start irradiation was also seen for Tetric Ceram and InTen-S. The lowest solubility was observed for InTen-S, followed by Z250, whereas Herculite and Solitaire 2 scored highest for this parameter.
This study evaluated the effects of home bleaching agents on the surface roughness of composite restoratives. Two home bleaching gels (10% and 15% carbamide peroxide, Opalescence) and five different tooth-colored restorative materials from the same manufacturer (3M-ESPE) were selected. They included microfill (Filtek A110 [FO]), flowable (Filtek Flow [FF]), polyacid-acid modified (F2000 [FT]) and minifill (Z100 [ZO]; Filtek Z250 [ZT]) composites. Thirty-six specimens of each material were fabricated, randomly divided into three groups (n=12) and treated as follows: Group 1-Stored in distilled water, Group 2-Bleached with 10% carbamide peroxide (CP) eight hours/day; Group 3-Bleached with 15% CP eight hours/day. All treatment was conducted at 37 degrees C and fresh gel applied and rinsed off daily for eight weeks. For the bleached groups, the specimens were stored in distilled water at 37 degrees C during the hiatus periods. All the specimens were subjected to roughness testing (Ra) at weeks 0, 1, 2, 4, 6 and 8 using a profilometer. The results were analyzed using general linear model with Scheffe's post-hoc tests at significance level 0.05. The results showed that the effect of bleaching on surface roughness was material and time dependent. ZT was not affected by bleaching treatment, while FT was significantly roughened after one week of bleaching with 15% CP compared to the control group. FO, FF and ZO were not significantly roughened until eight weeks of bleaching. Repolishing or replacement of tooth-colored restorations may be required after bleaching procedures.
The hypothesis tested in this study was that the self-etching system (Clearfil SE Bond, CSE) is less sensitive to surface moisture variability than the system that uses a separate acid-etching step (Single Bond, SB). Eighteen dentin specimens were bonded to composite using CSE or SB. Three different surface moisture conditions per bonding type (overwet, w; dry, d; and visibly moist, n [normal]) were applied prior to bonding dentin to composite. One cross section of each sample was analyzed with lines of nanoindentations crossing perpendicular to the bonding interface. An additional set of bonded samples was fixed and cross sectioned before the hybrid layer thickness was measured in scanning electron microscopy. The nanoindentations revealed significant differences in indentation modulus (E(i)) and hardness (H) for the hybrid layer comparing SBn, E(i) = 2.7(+/-1.6); H = 0.24(+/-0.1) GPa with SBd, E(i) = 0.9(+/-0.7); H = 0.9(+/-0.05) GPa, respectively, while CSE showed no differences among the groups. A significantly greater demineralized zone below the hybrid layer was found for SBd. The hybrid layer was wider for both CSEd and SBd. In conclusion the hypothesis was verified; CSE exhibited no significant changes of hybrid layer properties (E(i), H) at different hydration conditions, while SB had significant differences, especially after air-drying.
This study determined the effect of pH on the surface texture of commonly used posterior glass-ionomer based/containing restorative materials. The materials evaluated included a compomer (Dyract AP), a giomer (Beautifil) and two highly viscous glass ionomer cements (Fuji IX and Ketac Molar). A resin composite (Esthet-X) was used for comparison. Forty-two specimens (3-mm wide x 3-mm long x 2-mm deep) were made for each material. The specimens were divided into six groups and conditioned in the following solutions at 37 degrees C for one week: Citric acid (pH 2, 3, 4, 5 and 6) and distilled water (pH 7). After conditioning, the surface roughness (Ra, microm) of each specimen was measured using a surface profilometer (Surftest, Mitutoyo Corp, Tokyo, Japan). Data was analyzed using one-way ANOVA and Scheffe's test at a significance level of 0.05. The effects of pH on the surface texture of glass-ionomer based/containing restoratives were material dependent. Ra values ranged from 0.02 microm to 0.15 microm and 0.03 microm to 4.40 microm for pH 7 and 2, respectively. With the exception of the composite, the surface roughness of all materials evaluated was significantly affected by acids of low pH. The surface texture of highly viscous glass ionomer cements deteriorated significantly when conditioned in solutions of low pH, which makes them more susceptible to clinical failure.
The aim of this study was to compare surface roughness of flowable (Admira Flow, Filtek Flow, Tetric Flow) and packable (Admira, Filtek P60, Tetric HB) composite resin restorative materials finishing with Sof-Lex discs by means of average surface roughness (Ra) measurement using a surface profilometer and scanning electron microscopy (SEM). For each test group five specimens were prepared and roughness was measured in five different positions using a profilometer with a traversing distance of 4 mm and a cut-off value of 0.8 mm. The radius of the tracing diamond tip was 5 microm and measuring force and speed was 4 mN and 0.5 mm/s, respectively. The surface roughness of each individual disk was taken as the arithmetic mean of the Ra values measured in five different positions. Additionally, one specimen of each test group after finishing was observed under SEM with the magnification of x800 and x2500. Before finishing with Sof-Lex discs, flowable composite materials showed a smoother surface than packable composites restoratives (P < 0.05). However, after the finishing procedures similar surface textures were observed both from packable and flowable composites (P > 0.05).
This study investigated the effect of various hygiene maintenance procedures on the surface finish of minifill (Filtek A110 [AO], 3M-ESPE), flowable (Filtek Flow [FF], 3M-ESPE) and poly-acid-modified (F2000 [FT], 3M-ESPE) composites. Procedures included pumice-water slurry with rotating brush (PB), pumice-water slurry with rotating rubber cup (PC), prophylaxis paste with rubber cup (ZC), prophylaxis gel with rubber cup (GC) and air-powder polishing (AP). Specimens not exposed to these procedures were used as the control group. For each material, 48 specimens (3-mm long x 3-mm wide x 2-mm deep) were made and stored in distilled water at 37 degrees C for one month. The specimens were then treated with 1200 grit sandpaper using a lapping device, stored for an additional two months in distilled water at 37 degrees C and randomly divided into six groups (n=8). The mean surface roughness (Ra, microm) of the specimens after exposure to the various hygiene procedures was determined using a surface profilometer. Data was subjected to ANOVA/Scheffe's test at significance level 0.05. Mean Ra values ranged from 0.09 to 2.17, 0.06 to 1.38 and 0.38 to 1.25 for AO, FF and FT, respectively. The effect of hygiene procedures on surface roughness was material dependent. Among the various procedures, the smoothest surface was observed after treatment with prophylaxis gel and the roughest with air-powder polishing. For all materials, the use of pumice-water slurry with brush also caused significant roughening. Composite restorations may require re-polishing after exposure to some hygiene maintenance procedures, as Ra values exceeded the critical threshold surface roughness for bacterial adhesion (0.2 microm).
To determine the degree of surface staining of resin-based composites (RBCs) and glass-ionomer cements (GICs) after immersion in various stains and food-simulating solutions (FSS).
Six tooth-coloured restorative materials were used: a light-cured microfilled RBC (Durafil, Kulzer), a light-cured microglass RBC (Charisma, Kulzer), a polyacid-modified RBC (F2000, 3M/ESPE), a conventional GIC (Fuji IX, GC) and two resin-modified GICs (Fuji II LC, GC; Photac Fil, 3M/ESPE). Disk-shaped specimens were prepared and tested with either a matrix finish or polished using wet silicon carbide papers up to 2000 grit. All specimens were immersed in 37 degrees C distilled water for 1 week, followed by three different FSS (water, 10% ethanol, Crodamol GTCC) and five stains (red wine, coffee, tea, soy sauce and cola) for a further 2 weeks. Three specimens of each material for each stain were tested. Colour coefficients (CIE L* a* b*) were measured by a spectrophotometer after each treatment. The change in colour (DeltaEn) was calculated using the formula: DeltaEn=[(DeltaLn+(Deltaa(n))2+(Deltab(n))2]1/2.
Distilled water caused no perceptible colour change as tested by ANOVA and Tukey's tests. The effect of surface finish on staining was not statistically significant (P>0.05). There was no strong interaction between FSS and stains or between FSS and materials. There was a strong interaction between surface and material, and stain and material (P<0.001).
All materials were susceptible to staining by all stains especially coffee, red wine and tea; Fuji IX showed the least susceptibility and F2000 the greatest.
Unlabelled:
This study compared the enamel bond strengths of self-etching and one bottle adhesives, and evaluated microscopically their debonding modes. Evaluated systems were: Self-etch--Prompt L-Pop (LP); one bottle, total etch--Single Bond (SB), Prime & Bond NT (PB); compomer--Hytac Aplitip (HA), F2000 (F2); resin composite- Reference 21 Aplitip (R2), Herculite XRV (XRV), Esthet.X (EX); in the following combinations: LP/HA; LP/R2; SB/F2; SB/XRV; PB/EX. Flat surfaces of enamel were ground on caries free extracted third molars. An adhesive resin was applied to this surface and a restorative material built on it. The teeth were sectioned longitudinally into 1 mm thick specimens and trimmed to a 1 mm2 area at the enamel/adhesive interface. For each material combination, 10 specimens were tested. Microtensile bond strengths were determined at 0.5 mm min(-1). Fractured specimens were examined using confocal and scanning electron microscopy to determine failure modes. Bond strength data was analysed using Kaplan-Meier survival analysis, a log-rank test and a Bonferroni multiple comparison. Failure mode data was analysed with a chi2 test. The interface of additional fluorescent-labelled specimens was examined by laser scanning confocal microscopy. The bond strength data showed significant differences: LP/R2 > LP/HA, SB/F2 and PB/EX; SB/F2 < LP/HA, SB/XRV and PB/EX. Both compomers principally exhibited cohesive failure. Resin composite materials showed more complex failure modes. Fluorescence images demonstrated interfacial characteristics consistent with the failure modes observed.
Significance:
bond strength was not influenced by the use of self-etch or one bottle adhesives.
Finishing and polishing procedures may cause topographical changes and introduce subsurface microcracks in dental composite restoratives. Since both of these effects may contribute toward the kinetics of wear, the purpose of this study was to assess and correlate the wear and surface roughness of minifilled and nanofilled composites finished and polished by different methods.
Specimens (n=10) made of a minifilled and a nanofilled composite were finished and polished with one of the four sequences: (1) tungsten carbide burs plus Al(2)O(3)-impregnated brush (CbBr) or (2) tungsten carbide burs plus diamond-impregnated cup (CbCp), (3) diamond burs plus brush (DmBr) or (4) diamond burs plus cup (DmCp). As a control, abrasive papers were used. After surface roughness had been quantified, three-body abrasion was simulated using the OHSU wear machine. The wear facets were then scanned to measure wear depth and post-testing roughness. All sets of data were subjected to ANOVA and Tukey's tests (alpha=0.05). Pearson's correlation test was applied to check for the existence of a relationship between pre-testing roughness and wear.
Significantly smoother surfaces were attained with the sequences CbBr and CbCp, whereas DmCp yielded the roughest surface. Regardless of the finishing/polishing technique, the nanofilled composite exhibited the lowest pre-testing roughness and wear. There was no correlation between the surface roughness achieved after finishing/polishing procedures and wear (p=0.3899).
Nano-sized materials may have improved abrasive wear resistance over minifilled composites. The absence of correlation between wear and surface roughness produced by different finishing/polishing methods suggests that the latter negligibly influences material loss due to three-body abrasion.
This study evaluated the two-year clinical performance of two types of giomers (Beautifil, a surface reaction giomer and Reactmer, a full-reaction giomer), in occlusal (Class I) and cervical (Class V) cavities using the USPHS criteria. Forty-two cervical erosion and carious lesions were restored using Beautifil and Reactmer following manufacturer's instructions. Twenty occlusal cavities were restored with Beautifil. Fifteen patients (mean age 35, ranging in age from 20 to 50 years) participated in the study. The success rate for cervical Beautifil restorations after two years was 80%, while the success rate for cervical Reactmer restorations was 71%. Occlusal Beautifil restorations had a 100% success rate.
Surface wear can be a problem with directly placed composites.
This study evaluated the in vitro wear and surface roughness of two composites at different cycle intervals after being subjected to toothbrush-dentifrice abrasion. Materials and Methods: Twenty specimens of a microhybrid, Filtek Z250 (3M ESPE, St. Paul, MN, USA), and a nanofill composite, Filtek Supreme (3M ESPE), were prepared according to the manufacturer's directions. Each specimen was subjected to toothbrush-dentifrice abrasion (250 g vertical load) using a deionized water-dentifrice slurry (Close-Up, Lever Ponds Ltd., La Lucia, ZA) and toothbrush heads (Oral-B 40, Oral-B Laboratories, Delmont, CA, USA). A brushing sequence of 10,000, 20,000, 50,000, and 100,000 strokes was performed for all samples at a rate of 1.5 Hz. At baseline and each cycle interval, a surface profilometer was used to determine average surface roughness, Ra. At the same intervals, vertical loss of material was measured with a precision micrometer. Data were analyzed using repeated-measures analysis of variance at p value .05. Analyses with atomic force microscopy (AFM) and scanning electron microscopy (SEM) were also performed.
After 20,000, 50,000, and 100,000 cycles, Filtek Supreme showed less significant wear than Z250. Filtek Supreme demonstrated higher surface roughness than Z250 after 50,000 and 100,000 cycles. However, AFM and SEM images indicated a more uniform surface topography for Filtek Supreme than for Z250. Abrasion wear and surface roughness increased with each cycle interval for both materials.
Although the initial performance of both materials was similar, a greater number of brushing cycles revealed differences between the wear resistance and generated surface roughness of the materials.
The wear resistance and roughness results of Filtek Supreme suggest that it is suitable for clinical use, mainly in areas that are more subject to abrasive wear, such as Class V restorations.
The relationship between subgingival dental restorations and periodontal health has been thoroughly investigated for many years. However, longitudinal data on the subgingival microflora features after the placement of well-finished subgingival restorations are still lacking. Therefore, this study compares the short-term clinical and microbiological features occurring in the gingiva after the completion of different subgingival restorations.
Sixteen systemically healthy subjects, 10 males and six females (ages: 31.7-45.8 years; mean age 39.3+/-5.1 years), who were non-smokers and were positive for the presence of three cervical abrasion/erosion defects to be restored in three different adjacent teeth were enrolled in this study. The cervical abrasion/erosion defects were each restored by using one of three different materials: amalgam, glass ionomer cement, or composite resin. Immediately before class V cavity preparations and restorations (baseline), clinical monitoring and subgingival plaque sampling were performed in the mid-buccal aspect of each experimental restored tooth and in one adjacent sound, non-treated, control tooth. These procedures were repeated every 4 months over the following 1 year.
Throughout the study, the clinical parameters recorded did not change significantly in any of the experimental groups, and no differences were detected among them at each clinical session. Over this time, no significant changes in the composition of the subgingival microflora were observed in amalgam, glass ionomer cement, and control groups. Conversely, in the composite resin group, there was a significant increase in the total bacterial counts, and a significant (p<0.05) decrease in Gram-positive, aerobic bacteria, which was associated with a significant (p<0.05) increase in the Gram-negative, anaerobic microbiota.
Over a 1-year observation period, amalgam, glass ionomer cement, and composite resin subgingival restorations do not significantly affect the clinical parameters recorded. However, composite resin restorations may have some negative effects on the quantity and quality of subgingival plaque.
- Turker SB, Biskin T