Simonides Consani

University of Campinas, Conceição de Campinas, São Paulo, Brazil

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Publications (187)108.14 Total impact

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    ABSTRACT: This study investigated the effect of simulated microwave disinfection (SMD) on the linear dimensional changes, hardness and impact strength of acrylic resins under different polymerization cycles.
    Minerva stomatologica 06/2014;
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    ABSTRACT: Energy dispersive X-ray spectroscopy microanalysis (EDX), scanning electron microscopy (SEM), and Archimedes' Principle were used to determine the characteristics of inorganic filler particles in five dental alginates, including Cavex ColorChange (C), Hydrogum 5 (H5), Hydrogum (H), Orthoprint (O), and Jeltrate Plus (JP). The different alginate powders (0.5 mg) were fixed on plastic stubs (n = 5) and sputter coated with carbon for EDX analysis, then coated with gold, and observed using SEM. Volume fractions were determined by weighing a sample of each material in water before and after calcining at 450(°)C for 3 h. The alginate materials were mainly composed of silicon (Si) by weight (C-81.59%, H-79.89%, O-78.87%, H5-77.95%, JP-66.88%, wt). The filler fractions in volume (vt) were as follows: H5-84.85%, JP-74.76%, H-70.03%, O-68.31%, and C-56.10%. The tested materials demonstrated important differences in the inorganic elemental composition, filler fraction, and particle morphology.
    BioMed Research International 01/2014; 2014:178064. · 2.71 Impact Factor
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    ABSTRACT: This study evaluated the effect of adding diphenyliodonium hexafluorphosphate (DPI) as a third component of the free-radical photoinitiator system of model resin cements on their photopolymerization kinetics/stress and fundamental properties. A model resin cement containing a 1:1 mass ratio of 2,2-bis[4-(2-hydroxy-3-methacryloxypropoxy)phenyl]propane and triethyleneglycol dimethacrylate was obtained. Camphorquinone (1mol%) and 2-(dimethylamino)ethyl methacrylate (2mol%) were added to monomer blend. Six mixtures were obtained by incorporation of 0 (control), 0.25, 0.5, 1, 2, or 4mol% of DPI. The cements were loaded with a 60% mass fraction of silanated glass fillers. Polymerization kinetics (using Fourier-transform near-infrared spectroscopy), flexural strength and modulus, water uptake/solubility, and polymerization stress were assessed. Data were statistically analyzed using one-way ANOVA and Student-Newman-Keuls' test (P≤0.05). In the DPI-modified materials, the onset of autodeceleration occurred earlier and at higher conversion compared with the control cement. The addition of DPI also led to a more active early-stage polymerization. The flexural modulus was generally higher for DPI-containing materials. Water uptake and solubility were generally lower for materials with DPI fractions ≥0.5%. Significant increase of polymerization stress was observed only in the group with 1mol% of DPI compared with the control cement. The effect of DPI on the photopolymerization reactivity of the cement is concentration-dependent; the use of DPI could result in better polymerization efficiency of resin-based cements.
    Dental Materials 10/2013; 29:1251-5. · 3.77 Impact Factor
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    ABSTRACT: Objective: The aim of this study was to evaluate the compatibility of commercial dental adhesives to model resin cements (MRCs), using the microshear bond strength (msbs) test. Method: A model Bis­GMA/TEGDMA (1:1 molar ratio) was prepared and diphenyliodonium (DPI) added at different concentrations (0-control, 0.5 or 1 mol%). The MRC were loaded with a 60% mass fraction of silanated Ba­Al­Si glass fillers (Esstech Inc). Twenty-four disc-shaped specimens (6 mm in diameter; 2 mm thick) of each MRC were prepared and randomly divided into 3 groups (n=8), according to the adhesive system used (Scotchbond Multi-Purpouse-SBMP, Singlebond 2-SB2 and ExciTE-EX). For the msbs test, adhesive cylinders were built on the disc surfaces using Tygon tubes (TGY-030, 0.7 mm diameter). The adhesives were light-cured for 10 s, using a light-emitted diode source, with 680 mW/cm2. The bond strength test were carried out in a universal test machine at a crosshead speed of 0.5 mm, using an orthodontic wire loop (0.2mm). The msbs values were submitted to the two-way ANOVA and Tukey’s post-hoc test (a=0.05). Result: SBMP and EX presented similar values of msbs, statistically higher than SB2, regardless of the concentration of DPI. Conclusion: The dental adhesives tested presented are compatible with the resin cements modified by DPI, and the concentration of this component had no influence on the msbs values to the commercial adhesives.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: Objectives: :To evaluate the effect of different surface treatments on the tensile bond strength of indirect composite. Methods: Fifty caries-free extracted bovine incisors teeth were made flat until the dentin was exposed. The dentin etching was made with 37 % phosphoric acid and the ScothBond Multi-Purpose Plus System (3M ESPE) was applied according to the manufacturer’s instructions. Fifty blocks (5 mm x 5 mm x 2 mm) of indirect composite Sinfony (3M ESPE) were fabricated using a silicone matrix. The blocks were randomly divided into 5 groups (n=10), based on the surface treatment to be performed: (A): abrasion with spherical diamond bur, (B): abrasion with spherical diamond bur + silane + Bond, (C): etching with 10% hydrofluoric acid; (D): etching with 10% hydrofluoric acid + silane + Bond and; (E): no treatment. After surface treatments, the blocks were cemented using Rely-X ARC (3M ESPE). After 24 h, microtensile sticks were made from bonded specimens and loaded in tension until failure. The tensile bond strength tests were carried out using a universal testing machine at cross-head speed of 0.5 mm/minute. The data were submitted to analysis of variance and Tukey's test (5%). Results: Group Mean of tensile bond strength (MPa) A 26.64 C B 28.48 C C 26.62 C D 39.46 A E 33.13 B Conclusions: Group D showed the best results for tensile bond strength. Groups A, B and C showed the lowest results. Group D (control) showed intermediate result.
    IADR/AADR/CADR General Session and Exhibition 2013; 03/2013
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    ABSTRACT: Background/purposePolymerization contraction stress is an undesirable and inevitable characteristic of adhesive restorations. It is important to understand the stress distribution to improve the clinical effectiveness of resin composite restoration. The aim of this study was to evaluate the polymerization shrinkage stress created in tooth photoelastic models using different filling techniques.Materials and methodsTwenty Class II tooth models were obtained. They were distributed into four experimental groups (n = 5) according to the following restorative techniques: resin composite with horizontal insertion, resin composite with oblique insertion, flowable composite + resin composite with horizontal insertion, and flowable composite + resin composite with oblique insertion restoration. Restored photoelastic models were analyzed using a plane polariscope. The stress along seven points of adhesive interface was analyzed from images of each insertion, at the baseline (immediately) and 24 hours after polymerization. Maximum shear stress data were obtained and submitted to two-way ANOVA analysis followed by Tukey's posthoc test at P = 0.05.ResultsHorizontal and oblique techniques have shown differences in stress patterns. No difference between stress values of horizontal and oblique techniques was found. Groups restored with flow composite showed significant higher stress levels than those restored only with universal composite.Conclusion The use of flow composite created higher polymerization stress effects on the class II restoration than does the conventional restoration technique.
    Journal of Dental Sciences. 03/2013; 8(1):53–60.
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    ABSTRACT: This study evaluated an alternative method for thermal cycling test on the microleakage and bond strength of the polymer-dentin bond. For the microleakage test the cavities were restored with a TEGDMA+UDMA+bis-EMA composite polymer light cured for 20 s. Samples were immersed in 2% methylene blue solution for 2 h and sectioned. Microleakage scores were submitted to Kruskal-Wallis test. For the shear bond strength test the adhesive was applied to dentin, photoactivated for 10 s and the composite polymer incrementally photoactivated. Samples were submitted to shear bond strength test in a machine with a cross-head speed of 0.5 mm/min and data were submitted to ANOVA and Tukey's test. Studied groups were: 1 - without thermocycling; 2 - thermocycled at 5 ºC and 55 ºC with intermediate bath at 37 ºC; 3 - thermocycled at 5 ºC and 37 ºC; 4 - thermocycled at 37 ºC and 55 ºC; 5 - thermocycled at 5 ºC and 55 ºC (traditional test). Cold baths promoted greater microleakage when compared to control and hot bath, whereas control and hot bath were similar. Cold baths presented significant lower shear bond strength than those submitted to hot bath and control. It was concluded that the alternative method for thermal cycling test showed that cold temperatures increased the microleakage and decreased the bond strength of the polymeric adhesive.
    Materials Research 12/2012; 15(6):1045-1049. · 0.52 Impact Factor
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    ABSTRACT: This study evaluated the temperature variation in the pulp chamber during photoactivation of two restorative composite resins (Filtek P90 silorane-based composite and Heliomolar methacrylate-based composite) with either a quartz-tungsten-halogen (QTH) or light-emitting diodes (LED) light-curing unit (LCU) and using dentin thicknesses (0.5 and 1.0 mm). Standardized cavities (2x2x2 mm) were prepared in 80 bovine incisors, which were randomly assigned to 8 groups according to the photoactivation method and dentin thickness. Filtek P90 and Heliomolar (both in shade A3) were used with their respective adhesive systems (P90 self-etch primer / P90 adhesive bond and Excite adhesive). All experiments were carried out in a controlled environment (37°C). The temperature variations (°C) were recorded using a digital thermometer attached to a K-type thermocouple. The results were analyzed statistically by ANOVA and Tukey's test (α=0.05). For composite/dentin thickness interaction, temperature increase was significantly higher in 0.5 mm dentin thickness (40.07°C) compared with 1.0 mm dentin thickness (39.61°C) for Filtek P90. For composite/LCU interaction, the temperature increase was significantly higher for Filtek P90 (39.21°C - QTH and 40.47°C - LED) compared with Heliomolar (38.40°C - QTH and 39.30°C - LED). The silorane-based composite promoted higher temperature increase in the pulp chamber than the methacrylate-based composite.
    Brazilian dental journal 12/2012; 24(3):258-62.
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    ABSTRACT: The type IV dental stone is widely used for the fabrication of dyes and master casts for fixed and removable partial prostheses. It is typically normal to wait at least 24 hours for the casts to dry prior to beginning the laboratory procedures. The waiting time has been shown to be greatly reduced by using microwave drying. This study evaluated the influence of drying techniques at room temperature and microwave oven on the linear dimensional change, compressive strength and detail reproduction in type IV dental stones. Three type IV dental stone brands were selected; elite Rock, Shera Premium and Durone IV. Two different drying protocols were tested in 4 groups (n=10); G1 - room temperature (25±4ºC) dried for 2 hours; G2 - room temperature dried for 24 hours; G3 - room temperature dried for 7 days and G4 - microwave oven dried at 800 W for 5 minutes and after 2 hours at room temperature. After drying, the samples were assayed for dimensional charges. The sample surface was submitted to the ImageTool 3.0 software for compressive strength in a universal testing machine with a cell load of 50 KN at a crosshead speed of 0.5 mm/minutes and the detail reproduction was analyzed with a stereomicroscope at 25x magnification. The statistical analysis of the linear dimensional change and compressive strength data were conducted by the ANOVA test followed by the Tukey test (p<0.05). Detailed reproduction values were reported in percentages. For the compressive strength test, Elite Rock and Durone IV did not present significant differences between G2 and G4, while Shera Premium did not present differences between G3 and G4. The best reproduction levels were observed for G3. Dental stone microwave oven drying showed a linear dimensional change similar to after room temperature drying for 24 hours and 7 days. The compressive strength of the stone dried in the microwave oven was similar to those dried at room temperature for 24 hours, with the exception of Shera Premium, which had similar results for microwave and room temperature drying for 7 days. For the microwave drying method the detail reproduction levels for samples dried at room temperature for 24 hours and 7 days were similar, except for the Durone IV.
    Journal of applied oral science: revista FOB 10/2012; 20(5):588-93. · 0.39 Impact Factor
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    ABSTRACT: Objectives: Recently, Zn-doped dental adhesives have been advocated to interfere with matrix metalloproteinase-mediated collagen degradation. Nevertheless, there is no information about the effects induced by the inclusion of Zn nitrate on the chemical-physical properties of MDP-based (10-methacryloyloxi-decyl-phosphate) self-etch adhesives. Thus, this investigation aimed at evaluating whether the presence of Zn interfere with the chemical interaction of MDP-based adhesives and dentine. Methods: MDP was solvated in a 1:1-water:ethanol solution. MDP was mixed with 0, 1, 2, 3 or 4 ppm of calcium in presence or absence of zinc. Remaining free-calcium (calcium not chemically bonded to MDP) was measured by atomic absorption spectroscopy (AAS). Further AAS was realized with zinc+MDP following a similar protocol in absence of calcium to evaluate the potential formation of MDP-zinc salt. Three experimental solutions were prepared and analysed for each mixture (n=3). MDP-containing self-etch adhesives Clearfil SE Bond (CSE, primer solution) and Clearfil S3 (S3) (Kuraray Medical, Japan) were doped with 5wt% of zinc. Zinc-doped and zinc-free adhesives were applied following manufacturer’s recommendations to flat dentine surfaces of extracted human third molars and restorations were built up. After 24h immersion in distilled water at 37ºC, the bonded teeth were cut into ~1mm² sticks and submitted to µTBS testing. Data were analysed with ANOVA, paired t-test and Tukey’s test (p<0.05). Results: µTBS showed mean bond strength (MPa) of 39.8±7.3 for CSE, 19.3±4.9 for zinc-doped CSE and 38.3±8.6 for S3. Zinc-doped S3 was not tested because all sticks failed prematurely. AAS showed reduced free-calcium by adding MDP (p<0.001) and an increase in free calcium when adding zinc (p=0.009). Formation of monomer-zinc salt occurred as a reduction of free-zinc by adding MDP (p<0.001). Conclusions: These outcomes showed that zinc may jeopardise the bond strength of MDP-containing adhesives and MDP-calcium salts formation. Addition of zinc should be avoided in this type of self-etch adhesive.
    PER/IADR Congress 2012; 09/2012
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    ABSTRACT: Objective: To evaluate the depth of cure of experimental resin cements (ERC) containing an initiator system with Diphenyliodonium Hexafluorphosphate (DPI) cured with LED (Radii Cal). Method: Experimental resin cements based in Bis-GMA/TEGDMA (1:1 molar ratio) was obtained and DPI added at concentrations of 0 (control), 0.25, 0.5, 1 or 2 mol%, resulting in five ERC. Cylindrical specimens were prepared filling a matrix (13 mm in length and 2 mm Ø) simulating a root canal, and the resin cement was light cured with LED (800 mw/cm2 - 40 J/cm2). After this, the specimens were stored for 24 h, sectioned using a diamond blade at 2, 6, 10 mm and polished with silicon carbide papers #2000. Degree of conversion (DC) was determined by FTIR spectroscopy and results were submitted to the Kruskal-Wallis and Dunn tests. Result: The DC was statistically lower in the cements without DPI (Control) in all depths evaluated, compared to the cements with 0.5; 1 and 2mol% of DPI. Control and 2mol% DPI groups presented reduced DC with 10mm, enabling the evaluation in this depth. The concentrations of 0.25; 0.5 and 1mol% promoted adequate curing even in 10 mm depth. Conclusion: The addition of DPI increased the DC of the ERC even at 10 mm in depth, using the concentrations of 0.25; 0.5 and 1%. The absence of DPI or 2mol% DPI was not capable to produce adequate curing with 10 mm depth.
    IADR General Session 2012; 06/2012
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    ABSTRACT: Objective: The aim of this study was to evaluate the depth of cure of experimental resin cements (ERC) containing an initiator system with Diphenyliodonium Hexafluorphosphate (DPI) (Sigma-Aldrich). Method: A model Bis-GMA/TEGDMA (Sigma-Aldrich) (1:1 molar ratio) was obtained and DPI added at concentrations of 0 (control), 0.25, 0.5, 1 or 2 mol%, resulting in five ERC. The cements were loaded with a 60% mass fraction of silanated Ba-Al-Si glass fillers (Esstech Inc). Cylindrical specimens were constructed filling a matrix (13 mm in length and 2 mm in diameter) to simulate a root canal and light cured with Bluephase LED (Ivoclar-Vivadent) (40 J/cm2). After this, the specimens were stored for 24 h, sectioned using a diamond blade at 2, 6, 10 mm in depth and polished with silicon carbide papers #2000. Degree of conversion (DC) was determined by FTIR spectroscopy and results were submitted to the Kruskal-Wallis and Dunn tests. Result: Control shows a significant decrease of DC after 6 mm, 10 mm could not be tested. ERC containing 0.25 and 2 mol% presented significant decrease of DC after 10 mm. The groups containing 0.5 and 1 mol% were statistically similar and showed the higher values of DC at 10 mm in depth. Conclusion: DPI addition resulted an increase of DC of the ERC even at 10 mm in depth, using the concentrations of 0,5 and 1%.
    IADR General Session 2012; 06/2012
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    ABSTRACT: Objective: To evaluate the effects of four different light-curing protocols on the microtensile bond strength (μTBS), ultimate tensile strength (UTS), Knoop micro-hardness (KH) and cross-link density survey (CLD) of a nanofilled resin composite. Methods: Filtek Supreme XT (3M-ESPE) was used for built ups on flat dentin using the following light-curing approaches: Standard Irradiance (SI); High Irradiance (HI); Pulse-Delay (PD); Soft-Start (SS). After different storage periods (24h or 6 months), the specimens were cut into sticks and submitted to μTBS testing. Hourglass specimens were evaluated for UTS and KH in 24h and 6 months. For cross-link density evaluation, KH of cylindrical specimens was performed before and after immersion in absolute ethanol for 24h. The results were statistically analyzed to ANOVA and Tukey’s test (p<0.05). Results: For KH (KHN), HI (102) obtained the highest top hardness in 24h (p<0.05). After 6 months, SS (35) presented higher bottom hardness than PD (25), but with no statistical difference compared to HI (27) and SI (29) (p>0.05). For UTS (MPa), after 6 months SS (90.2) showed statistical higher results than the other groups (p<0.05). A significant decrease on UTS and KH was observed after 6-months compared to the 24h groups. The μTBS was not affected by the different light-curing approaches (p=0.874) and, no statistical differences were observed between 24h and 6-months storage (p=0.185). The CLD evaluation showed a statistical drop (p<0.001) in KH in the specimens light-cured using PD (21.5%) or SS (20.5%) (step-curing protocols) compared to those light-cured with continuous mode (SI - 12.9%; HI - 12.7%). Conclusion: The SS mode may improve the UTS and KH of nanofilled composite without compromising the μTBS of dentin-bonded specimens. However, both the step-curing protocols may compromise the cross-link density of the polymeric composite.
    IADR General Session 2012; 06/2012
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    ABSTRACT: To evaluate the effects of four different light-curing protocols on the microtensile bond strength (μTBS), ultimate tensile strength (UTS), Knoop micro-hardness (KH) and cross-link density (CLD) of a nano-filled resin composite. Filtek Supreme XT (3M-ESPE) was used for the entire experiments following four light-curing approaches: ST, standard irradiance; HI, high irradiance; PD, pulse delay; SS, soft start. The specimens were submitted to different storage periods (24h or 6 months), cut into match-sticks and subsequently submitted to μTBS testing. Hourglass specimens were also prepared for UTS and KH. Cylindrical specimens were prepared for the CLD evaluation after absolute ethanol challenge. The results were statistically analyzed with a two-way ANOVA and Tukey's test (α=0.05). For UTS and KH, continuous irradiance (PD and SS) induced statistically higher results (p<0.05) both after 24h and 6 months of water storage compared to ST and HI groups. However, a drop in UTS and KH was obtained after 6 months in all groups. The μTBS was not affected by the different light-curing approaches and, no statistical differences (p>0.05) were observed between 24h and 6 months storage. The CLD evaluation showed a statistical drop in KH after 24h of ethanol storage for PD and SS (step-curing protocols) compared to those attained in continuous mode (ST and HI). The soft-start mode may improve the UTS and KH of nano-filled resin composites without compromising the resin-dentine μTBS. However, both the step-curing protocols may reduce the cross-link density of the composite polymeric network. High irradiances photo-polymerization may be adequate for direct aesthetic restorations such as veneers and onlays. Meanwhile, the soft start protocol would seem more appropriate for the photo-polymerization of high c-factors class I and II restorations.
    Journal of dentistry 06/2012; 40(10):802-9. · 3.20 Impact Factor
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    ABSTRACT: Objectives To evaluate the effects of four different light-curing protocols on the microtensile bond strength (μTBS), ultimate tensile strength (UTS), Knoop micro-hardness (KH) and cross-link density (CLD) of a nano-filled resin composite. Methods Filtek Supreme XT (3M-ESPE) was used for the entire experiments following four light-curing approaches: ST) Standard irradiance; HI) High irradiance; PD) Pulse delay: SS) Soft Start. The specimens were submitted to different storage periods (24 h or 6 months), cut into match-sticks and subsequently submitted to μTBS testing. Hourglass specimens were also prepared for UTS and KH. Cylindrical specimens were prepared for the CLD evaluation after absolute ethanol challenge. The results were statistically analyzed with a two-way ANOVA and Tukey's test (α=0.05). Results For UTS and KH, continuous irradiance (PD and SS) induced statistically higher results (p < 0.05) both after 24 h and 6 months of water storage compared to ST and HI groups. However, a drop in UTS and KH was obtained after 6 months in all groups. The μTBS was not affected by the different light-curing approaches and, no statistical differences (p > 0.05) were observed between 24 h and 6 months storage. The CLD evaluation showed a statistical drop in KH after 24 h of ethanol storage for PD and SS (step-curing protocols) compared to those attained in continuous mode (ST and HI). Conclusion The soft-start mode may improve the UTS and KH of nano-filled resin composites without compromising the resin-dentin μTBS. However, both the step-curing protocols may reduce the cross-link density of the composite polymeric network. Clinical Significance High irradiances photo-polymerization may be adequate for direct aesthetic restorations such as veneers and onlays. Meanwhile, the soft start protocol would seem more appropriate for the photo-polymerization of high c-factors class I and II restorations.
    Journal of Dentistry 06/2012; · 3.20 Impact Factor
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    ABSTRACT: We compared polymerization stress in two commercial composites and three experimental composites made using camphorquinone (CQ) and/or phenylpropanedione (PPD) as photoinitiators. The internal surfaces of photoelastic resin discs with cylindrical cavities were roughened and treated with adhesive. Composites were divided into five groups: two commercial composites (Filtek Silorane and Filtek Z250) and three experimental composites with CQ/amine, CQ/PPD/amine, and PPD/amine. Composites were photopolymerized inside cavities, and subjected to photoelastic analysis immediately and at 24 hours and 7 days later using a plane polariscope. Stress created by Silorane (3.08 ± 0.09 MPa) was similar to that of Z250 (3.19 ± 0.13 MPa) immediately after photopolymerization (p > 0.05). After 24 hours and 7 days, Z250 (3.53 ± 0.15 and 3.69 ± 0.10 MPa, respectively) showed higher stress than Silorane (3.19 ± 0.10 and 3.16 ± 0.10 MPa, respectively). Qualitative analysis immediately after photopolymerization showed composite/CQ promoted higher stress than PPD, but stress levels at other evaluated times were statistically similar, varying between 3.45 ± 0.11 MPa and 3.92 ± 0.13 MPa. At 24 hours and 7 days, Silorane created the lowest stress. All photoinitiators created comparable tensions during polymerization.
    Brazilian oral research 06/2012; 26(3):202-8.
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    ABSTRACT: Objective: This study evaluated the temperature variation into the pulp chamber during the light curing of two composite resins: Filtek P90 (silorane-based composite, 3M ESPE) and Heliomolar (methacrylate-based composite, Ivoclar Vivadent). Method: Standardized cavities (2x2x2 mm) were prepared in 80 bovine incisors, which were randomly assigned to eight groups according to the photo-activation methods and dentin thickness. Two light curing units were used: quartz-tungsten-halogen – QTH (780 mW/cm2 for 40s) and light emitting diode – LED (900 mW/cm2 for 40s); and different dentin thicknesses: 0.5 and 1.0 mm. For the Heliomolar composite, the specimens were etched with Scotchbond Etching Gel 35% phosphoric acid for 20s, rinsed with water for 20s, and have the water excess removed with absorbent paper. Two layers of Excite adhesive system were applied and the photo-activation was done after the second layer application. Then, Heliomolar composite resin was applied and photo-activated. For the Filtek P90, the application of Silorane self-etch primer for 15s and the photo-activation (10s) was done. Application of Silorane adhesive bond and the photo-activation (10s) was done. Then, Filtek P90 composite resin was applied and photo-activated. All experiments were carried out in a controlled environment (37ºC and 50±10% relative humidity). The temperature variations in Celsius were recorded using a digital thermometer attached to a type-K thermocouple, which was inserted into the root canal to be in direct contact with the pulp chamber dentin. The results were subjected to Anova and Tukey’s test (α=0.05). Result: The increase of pulp chamber temperature was statistically higher for the P90 (39.84±0.91ºC) compared to the Heliomolar (38.85±0.51ºC). For Filtek P90, there was difference between the dentin thicknesses (0.5mm dentin thickness – 40.07±0.93ºC and 1.0mm dentin thickness – 39.61±0.86ºC). Conclusion: Higher density of energy promotes higher increase of pulp chamber temperature and silorane composite promoted higher temperature increase.
    AADR Annual Meeting 2012; 03/2012
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    ABSTRACT: OBJECTIVE: This study evaluated the mechanical characteristics and stress distribution of the hybrid technique fixation of the sagittal split ramus osteotomy. STUDY DESIGN: In the mechanical test, 10 polyurethane replicas of human hemimandibles of each group were submitted to linear loading test. For the photoelastic evaluation, 3 hemimandible replicas of photoelastic resin were subjected to photoelastic analysis. In the finite element analysis, 3 computer models simulated the displacement and the results of maximum principal stress were analyzed. RESULTS: The results of this study demonstrated that the fixation technique with 3 bicortical screws presented better mechanical resistance and stress distribution pattern when compared with the hybrid technique that, on the other hand, presents better results in comparison with a miniplate and monocortical screws. CONCLUSIONS: The results suggest that the hybrid technique increased the resistance and improved stress distribution of miniplate/monocortical screw fixation, maintaining most of the advantages of this technique.
    Oral Surgery, Oral Medicine, Oral Pathology, Oral Radiology, and Endodontology 02/2012; · 1.50 Impact Factor
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    ABSTRACT: The aim of this study was to evaluate the polymerization stress and degree of conversion of a composite submitted to different photoactivation protocols. The composite Filtek Z350 was placed in the central perforation of a photoelastic disc and polymerized using a LED-based curing unit (BluePhase II--Ivoclar Vivadent) with energy density of 12, 24 or 36 J/cm2 using the following photopolymerization protocols: continuous high intensity (HI: 1200 mW/cm2 during 10, 20 or 30s), continuous low intensity (LI: 650 mW/cmz during 18, 36 or 54s) and soft-start (SS: 150 mW/cm2 during 5 s + 1200 mW/cm2 during 9, 19 or 29s) (n = 5). Photoelastic analysis was used to evaluate polymerization shrinkage stress and FTIR was performed to determine the degree of conversion of the composite. ANOVA 3-way procedure was used to determine the significance of the main effects and their interactions followed by two-way ANOVA for each time was performed (p < 0.05). Shrinkage stress increased with higher values of energy. No statistically significant differences on polymerization shrinkage stress were found between high and low intensity activation modes. Soft-start method generated stresses that were statistically lower than continuous modes except when 12 J/cm2 was applied. Similar degree of conversion was observed for photoactivation modes used, except for soft-start mode with 12, 24 and 36J/cm2 that showed lowest levels of conversion. Energy density and activation mode influenced polymerization shrinkage stress, but no benefit on degree of conversion was observed.
    Acta odontológica latinoamericana: AOL 01/2012; 25(1):115-22.
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    ABSTRACT: The mismatch of thermal expansion and contraction between restorative materials and tooth may cause stresses at their interface, which may lead to microleakage. The present work compared the coefficient of thermal expansion (CTE) with the thermomechanical behavior of human and bovine teeth and determined if the CTE is a suitable parameter to describe tooth behavior. Fifteen human third molar and 15 bovine incisor tooth slices (6×5×2 mm) were allocated to 3 groups according to the test environment: G1 - room condition, G2 - 100% humidity, G3 - desiccated and tested in dry condition. Each specimen was weighed, heated from 20 to 70ºC at 10ºC min-1 and reweighed. The CTE was measured between 20 and 50ºC. Fresh dentin (human -0.49% ± 0.27, bovine -0.22% ± 0.16) contracted on heating under dry condition. Under wet conditions, only human teeth (-0.05% ± 0.04) showed contraction (bovine 0.00% ± 0.03) accompanied by a significantly lower (p<0.05) weight loss than in dry specimens (human 0.35% ± 0.15, bovine 0.45% ± 0.20). The desiccated dentin expanded on heating without obvious weight changes (0.00% ± 0.00). The CTE found was, respectively, in dry, wet and dissected conditions in ºC(-1): human (-66.03×10(-6), -6.82×10(-6), 5.52×10(-6)) and bovine (-33.71×10(-6), 5.47×10(-6), 4.31×10(-6)). According to its wet condition, the dentin showed different CTEs. The thermal expansion behavior of human and bovine dentin was similar. A simple evaluation of the thermal expansion behavior of tooth structure by its CTE value may not be appropriate as a meaningful consideration of the effects on the tooth-material interface.
    Brazilian dental journal 01/2012; 23(1):3-7.

Publication Stats

762 Citations
108.14 Total Impact Points

Institutions

  • 1977–2014
    • University of Campinas
      • Faculty of Dentistry from Piracicaba
      Conceição de Campinas, São Paulo, Brazil
  • 2013
    • UNIBE
      Baião, Pará, Brazil
  • 2012
    • University of Northern Parana
      Londrina, Paraná, Brazil
  • 2011
    • São Paulo State University
      • Departamento de Materiais Odontológicos e Prótese (Araçatuba)
      São Paulo, Estado de Sao Paulo, Brazil
  • 2009–2011
    • University of São Paulo
      • Ribeirão Preto School of Dentistry (FORP)
      São Paulo, Estado de Sao Paulo, Brazil
  • 2010
    • Universidade Federal do Paraná
      • Departamento de Odontologia
      Curitiba, Estado do Parana, Brazil
  • 2008–2009
    • Universidade de Passo Fundo
      Passo Fundo, Rio Grande do Sul, Brazil
  • 2007
    • Universidade do Vale do Itajaí (Univali)
      Itajahy, Santa Catarina, Brazil
  • 1994
    • Universidade Federal do Rio Grande do Sul
      Pôrto de São Francisco dos Casaes, Rio Grande do Sul, Brazil