Article

18-year survival of posterior composite resin restorations with and without glass ionomer cement as base

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Abstract

Advantages and disadvantages of using intermediate layers underneath resin-composite restorations have been presented under different perspectives. Yet, few long-term clinical studies evaluated the effect of glass-ionomer bases on restoration survival. The present study investigated the influence of glass-ionomer-cement base in survival of posterior composite restorations, compared to restorations without base. Original datasets of one dental practice were used to retrieve data retrospectively. The presence or absence of an intermediate layer of glass-ionomer-cement was the main factor under analysis, considering survival, annual failure rate and types of failure as outcomes. Other investigated factors were: patient gender, jaw, tooth, number of restored surfaces and composite. Statistical analysis was performed using Fisher's exact test, Kaplan-Meier method and multivariate Cox-regression. In total 632 restorations in 97 patients were investigated. Annual failure rates percentages up to 18-years were 1.9% and 2.1% for restorations with and without base, respectively. In restorations with glass-ionomer-cement base, fracture was the predominant reason for failure, corresponding to 57.8% of total failures. Failure type distribution was different (p=0.007) comparing restorations with and without base, but no effect in the overall survival of restorations was found (p=0.313). The presence of a glass-ionomer-cement base did not affect the survival of resin-composite restorations in the investigated sample. Acceptable annual failure rates after 18-years can be achieved with both techniques, leading to the perspective that an intermediate layer, placed during an interim treatment, may be maintained without clinical detriment, but no improvement in survival should be expected based on such measure. Copyright © 2015 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

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... It was, therefore, not possible to monitor the reasons why and when the restoration was repaired or replaced or a tooth was lost in this period. For future examinations, it would be of great interest to reduce the interval between the next follow-up examinations to be able to better monitor the restorations over time, assess possible alterations, register the reasons for failure as in other studies [14,[47][48][49], and record exactly when the failure occurred, in order to be able to describe the survival data in a Kaplan-Meier plot. The history of the restorations could not be investigated from the dental records of the university clinic, as the patients had all changed to different dental offices sometime after the first follow-up examination. ...
... Several studies have reported that the tooth type has a direct effect on the longevity of the restoration, with restorations placed in premolars showing significantly better performance than restorations placed in molars [5,14,34,49,57,60,68]. Palotie et al. [69] found in a 13-year period of observation that restorations in premolars experienced fewer failures than restorations in molars, with an annual failure rate of 3.1% and 5.2%, respectively. ...
... Considering the impact of the number of restored surfaces on the longevity of restoration, there are several studies showing significantly lower failure rates for single-surface than for multi-surface restorations in posterior teeth [5,14,57,59,62,70]. Van de Sande et al. stated in their clinical study about the survival of posterior composite restorations after 18 years that the number of restoration surfaces could favor the collapse of the restoration, primarily because of the less sound tooth structure that remains, therefore significantly affecting the longevity of restorations [49]. The clinical study at hand, however, found no significant difference in longevity regarding single-or multi-surface restorations after applying Bonferroni-Holm. ...
Article
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The purpose of this observational follow-up clinical study was to observe the quality of posterior composite restorations more than 23 years after application. A total of 22 patients, 13 male and 9 female (mean age 66.1 years, range 50–84), with a total of 42 restorations attended the first and second follow-up examinations. The restorations were examined by one operator using modified FDI criteria. Statistical analysis was performed with the Wilcoxon Mann–Whitney U test and Wilcoxon exact matched-pairs test with a significance level of p = 0.05. Bonferroni–Holm with an adjusted significance level of alpha = 0.05 was applied. With the exception of approximal anatomical form, significantly worse scores were seen for six out of seven criteria at the second follow-up evaluation. There was no significant difference in the first and second follow-up evaluations in the grades of the restorations with regard to having been placed in the maxilla or mandible, as well as for one-surface or multiple-surface restorations. The approximal anatomical form showed significantly worse grades at the second follow-up when having been placed in molars. In conclusion, the study results show that significant differences regarding FDI criteria in posterior composite restorations occur after more than 23 years of service. Further studies with extended follow-up time and at regular and short time intervals are recommended.
... In other words, the placement of a lining may adversely affect the biomechanical properties of a composite-restored tooth unit, specifically its resistance to fracture. Also, a long-term clinical study by van de Sande et al. 25 evaluated the effect of linings on the survival of posterior composites. It was concluded that the presence of a lining neither extended nor reduced the survival of composite restorations. ...
... Additionally, it was determined that there is no evidence to support the replacement of lost dentine with a 'dentine replacement' material. 25 Indeed, support was given to the findings of Opdam et al. 24 that such an approach may make the restoration more liable to suffer failure by fracture. 25 Such thinking is reinforced by the findings of the recent Cochrane review which concluded that 'using a liner is an unnecessary step in routine composite-based restorations in adult posterior teeth' . ...
... 25 Indeed, support was given to the findings of Opdam et al. 24 that such an approach may make the restoration more liable to suffer failure by fracture. 25 Such thinking is reinforced by the findings of the recent Cochrane review which concluded that 'using a liner is an unnecessary step in routine composite-based restorations in adult posterior teeth' . 6 ...
... In other words, the placement of a lining may adversely affect the biomechanical properties of a composite-restored tooth unit, specifically its resistance to fracture. Also, a long-term clinical study by van de Sande et al. 25 evaluated the effect of linings on the survival of posterior composites. It was concluded that the presence of a lining neither extended nor reduced the survival of composite restorations. ...
... Additionally, it was determined that there is no evidence to support the replacement of lost dentine with a 'dentine replacement' material. 25 Indeed, support was given to the findings of Opdam et al. 24 that such an approach may make the restoration more liable to suffer failure by fracture. 25 Such thinking is reinforced by the findings of the recent Cochrane review which concluded that 'using a liner is an unnecessary step in routine composite-based restorations in adult posterior teeth' . ...
... 25 Indeed, support was given to the findings of Opdam et al. 24 that such an approach may make the restoration more liable to suffer failure by fracture. 25 Such thinking is reinforced by the findings of the recent Cochrane review which concluded that 'using a liner is an unnecessary step in routine composite-based restorations in adult posterior teeth' . 6 ...
Article
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The consequences of no more linings under composite restorations are many and varied. This paper considers a number of these consequences and the impact they may have on the future use of composites in clinical practice.
... More recently, a long-term clinical study by van de Sande et al. [22] evaluated the effect of glass-ionomer-cement liners in the survival of posterior composite restorations, compared to restorations without liners. The authors concluded that the use of the liner did not affect the survival of rein composite restorations [22]. ...
... More recently, a long-term clinical study by van de Sande et al. [22] evaluated the effect of glass-ionomer-cement liners in the survival of posterior composite restorations, compared to restorations without liners. The authors concluded that the use of the liner did not affect the survival of rein composite restorations [22]. The authors further concluded that there is no evidence to support the approach whereby attempts are made to restore posterior teeth using a dentine replacement material to replace dentine overlaid by composite or ceramic to replace lost enamel [22]. ...
... The authors concluded that the use of the liner did not affect the survival of rein composite restorations [22]. The authors further concluded that there is no evidence to support the approach whereby attempts are made to restore posterior teeth using a dentine replacement material to replace dentine overlaid by composite or ceramic to replace lost enamel [22]. Indeed, the authors state that it is possible that such an approach may make the restoration more liable to suffer failure by fracture [22]. ...
Article
Objectives: To investigate opinions on, and current use of lining materials prior to the placement of posterior resin composite restorations by general dental practitioners (GDPs) in the UK. A further objective was to investigate aspects of posterior resin composite restoration placement techniques employed by UK GDPs. Methods: A questionnaire was devised to gain the information sought. It was sent to 500 UK dentists, chosen at random from the register of the General Dental Council. Results: Three hundred and fifty four replies were received, which gave a response rate of 71%. Eighty two percent of respondents reported placing lining materials in deep cavities to be restored with resin composite. Regarding moderately deep cavities, half of the respondents indicated a preference to place a lining material, whilst 44% were not sure if a lining was required. The remaining 6% did not respond to the question. Of the respondents, 39% reported that they did not place lining materials in shallow cavities. Regarding techniques for posterior resin composite placement, two-step etch and rinse systems were the most common adhesive bonding systems used (60%). The majority of respondents (80%) reported not using rubber dam when restoring posterior teeth with resin composite. Conclusions: There was considerable confusion about the need to place a lining prior to resin composite restorations placement in moderate depth and shallow cavities, whilst most favoured the placement of a lining in deep posterior cavities. The majority of GDPs may not routinely use rubber dam for the placement of posterior resin composite restorations. Clinical significance: Decision making and operative techniques for cavity linings under posterior composite restorations in moderately deep and deep cavities is contentious among dentists, resulting in a need to generate more convincing, practice-relevant data on the use of lining materials to inform the dental profession.
... 5 Além disso, um fator considerado como desvantagem na utilização das resinas compostas diz respeito ao estresse de contração de polimerização, mas esse efeito tem sido pouco determinante para a longevidade de restaurações em estudos clínicos. [8][9][10] Estudos clínicos prospectivos e retrospectivos têm sido publicados comparando a taxa de sobrevivência de diferentes materiais restauradores. Os estudos clínicos prospectivos permitem randomização e comparações mais adequadas entre os tratamentos. ...
... 10,12 Adicionalmente, é importante destacar que existem estudos clínicos publicados com grandes períodos de acompanhamento comparando materiais restauradores tradicionais, que estão presentes no mercado até o momento atual. 8,[13][14][15][16] As principais causas de falhas de restaurações diretas reportadas para dentes posteriores são lesões de cárie secundária e fratura da restauração ou do dente. 4 As evidências atuais permitem inferir que restaurações do tipo Classe I apresentam sucesso clínico elevado. ...
Article
Full-text available
Este estudo clínico retrospectivo investigou a influência de variáveis independentes na longevidade de restaurações extensas de resina composta em até 15 anos de acompanha- mento. Foi utilizado um banco de dados de 97 pacientes aten- didos em uma clínica odontológica privada. A análise estatísti- ca utilizada foi o teste exato de Fisher, método Kaplan-Meier e Análise Multivariada de Regressão de Cox. Foram explorados na análise os fatores como tipos de resina utilizados, extensão das cavidades, posição, tipo do dente envolvido e sexo. Das 242 restaurações avaliadas, 90 apresentaram algum tipo de falha, sendo as mais frequentes fratura da restauração (20,7%) e cá- rie secundária (7%). Entre os fatores avaliados, houve diferença estatisticamente significativa para o tipo de dente (p=0,001) e a localização no arco (p=0,04).
... The sandwich restorative technique is an alternative choice to reduce marginal microleakage and secondary caries and to prevent the clinical failure of composite restorations. A substantial part of CR is replaced with glass ionomer cement (GIC) [10] that chemically bonds to enamel and dentin; exhibits thermal expansion similar to hard dental tissues, a low elastic modulus, and biocompatibility; and releases fluoride [10,16,19]. ...
... From a clinical standpoint, the use of a cavity lining has a weakening effect on the overall strength of the restoration, resulting in more fracturing of composite restorations [16]. The bond strength between GIC and dentin is only 25% of the strength of composite resin [5]. ...
... In this dimension, there is no study available focussing on the outcome of anterior and posterior teeth on a tooth level. The vast majority of studies or reviews only focus on posterior teeth [3][4][5][6][7]10,11,13,14,[25][26][27][28]. Nevertheless, we see two major aspects for interpretation. ...
... Especially when focussing on the sustainability aspect, our results raise questions. There are studies from single dental practices or practice networks available revealing better long-term success rates for permanent dental restorations [7,8,25,27]. Annual failure rates of 2% [27] over 18 years or success rates of 65% at 17 years [25] are published. ...
Article
Objectives: The aim of this study was to examine re-interventions after restorative treatment. Methods: The data was collected from the digital database of a major German national health insurance company. Only permanent teeth were observed. Placing a permanent restoration other than a crown regardless of involved surfaces and material was the study intervention. The data did not allow for a differentiation between fillings and inlays that were estimated only a very small portion of the restorations. Success was defined as not undergoing any restorative re-intervention with fillings or inlays on the same tooth (primary outcome) and assessed with Kaplan-Meier survival analyses over four years. An additional analysis was conducted rating "crowning" and "extraction" of respective teeth as target events. Differences were tested with the Log-Rank-test. A multivariate Cox regression analyses was carried out. Results: A total of 17,024,344 restorations placed in 4,825,408 anterior teeth and 9,973,177 posterior teeth could be traced. Focussing on the primary outcome re-intervention, the cumulative four-year success rate was 69.9% for one surface restorations, 74.8% for two surface restorations, 66.6% for three surface restorations and 61.0% for four surface and more extended restorations. These differences were significant (p<0.0001). Focussing on all three target events re-intervention, crowning and extraction, the cumulative four-year success rate was 66.1% for one surface restorations, 67.5% for two surface restorations, 63.0% for three surface restorations and 55.8% for four surface and more extended restorations. The number of restoration surfaces as well as the tooth position remained significant in the multivariate Cox regression. Conclusions: The sustainability of restorative dental treatment under the terms and conditions of the German national health insurance system shows room for improvement. From a public health perspective, special focus should be laid on primary and secondary prevention to minimize the restorative treatment need. Clinical significance statement: This study shows that re-interventions are observed regularly after restorative treatment. Therefore, preventive and restorative strategies should be revisited and optimised.
... Another technique paper compared the 18-year survival of posterior composite resin restorations placed with or without a glass ionomer base. 30 A total of 632 restorations placed in 97 patients within a single dental practice were tracked for up to 18 years after placement. Annual failure rates were not statistically different for restorations with (1.9%) and without (2.1%) ...
... The study evaluated a database from the Swedish Social Insurance Agency for treatments provided between July 1, 2007 (before the change in reimbursement) to June, 30,2009. Treatment rendered in the Public Dental Health Service and the private sector were analyzed. ...
Article
Statement of problem: It is clear the contemporary dentist is confronted with a blizzard of information regarding materials and techniques from journal articles, advertisements, newsletters, the internet, and continuing education events. While some of that information is sound and helpful, much of it is misleading at best. Purpose: This review identifies and discusses the most important scientific findings regarding outcomes of dental treatment to assist the practitioner in making evidence-based choices. This review was conducted to assist the busy dentist in keeping abreast of the latest scientific information regarding the clinical practice of dentistry. Material and methods: Each of the authors, who are considered experts in their disciplines, was asked to peruse the scientific literature published in 2015 in their discipline and review the articles for important information that may have an impact on treatment decisions. Comments on experimental methodology, statistical evaluation, and overall validity of the conclusions are included in many of the reviews. Results: The reviews are not meant to stand alone but are intended to inform the interested reader about what has been discovered in the past year. The readers are then invited to go to the source if they wish more detail. Conclusions: Analysis of the scientific literature published in 2015 is divided into 7 sections, dental materials, periodontics, prosthodontics, occlusion and temporomandibular disorders, sleep-disordered breathing, cariology, and implant dentistry.
... Using base materials may compromise bond strength and surface of the composite restoration, and increase the risk of secondary caries [11]. Therefore, it is important to consider advantages and disadvantages and follow evidence-based recommendations for their use [9,11,27]. ...
Article
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Background This study investigated the practices and opinions of Turkish dentists regarding the management of deep caries lesions using an online questionnaire. Methods The questionnaire had two sections: the first collected demographic data, while the second focused on clinical practices, including radiographic techniques, rubber dam usage, liner choices, pulp protection, and post-endodontic restoration methods. Results The survey response rate was 20.4%. 18 participants were excluded due to incomplete responses in the survey. A total of 390 survey texts (19.5%) were analyzed. The gender distribution of the participants was as follows: 60% female and 40% male. Notably, none of the respondents used rubber dams for endodontic treatment. Male dentists were less likely to use a base under restorations (p < 0.05). Female dentists preferred single-session pulp capping for pulpal perforations (p < 0.05). Public hospitals utilized fewer panoramic films, while Oral and Dental Health Centers used fewer periapical films for diagnoses (p < 0.05). Glass ionomer cement was the most commonly used base material, and direct composite resin was the preferred choice for post-endodontic restorations, in contrast to the less favored indirect composite resin. Conclusions Despite its advantages, the application of rubber dam was infrequent. Glass ionomer cement emerged as the predominant base material across all restoration types, exhibiting variability among dentists in diagnosis, treatment, and material selection.
... This study showed that CGIC base did not affect the survival of resin composite restorations. 78 ...
Article
Full-text available
The World Health Organization (WHO) has added glass ionomer cement (GIC) to the WHO Model List of Essential Medicines since 2021, which represents the most efficacious, safe and cost-effective medicines for priority conditions. With the potential increase in the use of GIC, this review aims to provide an overview of the clinical application of GIC with updated evidence in restorative and preventive dentistry. GIC is a versatile dental material that has a wide range of clinical applications, particularly in restorative and preventive dentistry. It has unique properties, such as direct adhesion to tooth structures, minimal shrinkage or expansion, a similar coefficient of thermal expansion to natural tooth structure, biocompatibility, and long-lasting fluoride release. According to the chemical composition, GIC can be classified as conventional glass ionomer cement (CGIC) and resin-modified glass ionomer cement (RMGIC). It has been used as restorative materials, luting cement for indirect restorations, liner and base of restorations, and dental sealants. While its use as a base material and liner is debatable, the clinical application of GIC as restorative cement, luting cement, and dental sealant is supported by current research.
... The base lining might also have an influence on the fracture resistance as well as fracture geometry. This fact is controversially discussed in the literature and still needs to be examined in detail [44,[47][48][49]. In this regard it was also shown that a GIC base is beneficial in reducing strain and marginal leakage and therefore it is recommended when endodontically treated teeth undergo direct restoration with the resin composite [50]. ...
Article
Full-text available
(1) Background: The in vitro study aimed to investigate mechanical characteristics of resin composites and their suitability in direct restauration of endodontically treated teeth (ETT). (2) Methods: 38 endodontically treated premolars with occlusal access cavities were directly restored using the following resin composites and adhesives: Tetric Evo Ceram® + Syntac classic® (n = 10), Venus Diamond® + iBond Total-Etch® (n = 10), Grandio® + Solobond M® (n = 9), Estelite® Sigma Quick + Bond Force® (n = 9). After thermocycling, the elastic modulus, shear-bond-strength, fracture load (Fmax) and fracture mode distribution were evaluated. Statistical analysis: one-way ANOVA, t-test, Kruskal–Wallis test; p < 0.05. (3) Results: Grandio® showed the highest E-modulus (15,857.9 MPa) which was significant to Venus Diamond® (13,058.83 MPa), Tetric Evo Ceram® (8636.0 MPa) and Estelite® Sigma Quick (7004.58 MPa). The highest shear-bond-strength was observed for Solobond M® (17.28 MPa), followed by iBond® (16.61 MPa), Syntac classic® (16.41 MPa) and Bond Force® (8.37 MPa, p < 0.05). The highest fracture load (Fmax) was estimated for ETT restored with Venus Diamond® (1106.83 N), followed by Estelite® Sigma Quick (1030.1 N), Tetric Evo Ceram® (1029 N) and Grandio® (921 N). Fracture-mode distribution did not show any significant differences. (4) Conclusions: The observed resin composites and adhesives show reliable mechanical characteristics and seem to be suitable for direct restoration of endodontically treated teeth.
... Resin composites are the most used restorative materials for direct restorations. Mechanical properties and optical behavior benefit the material used in anterior and posterior teeth, offering a long-term evaluation success (1)(2)(3). Its range of clinical indications, adhesive properties associated with dental adhesives, and possible repair or replacements push clinical usage in daily practice. ...
Article
Full-text available
The natural outcome of dental composite restorations highly depends on the translucency of the enamel layer and fluorescence. This study aimed to evaluate the Translucency Parameter (TP) and Fluorescence Intensity (FI) of five different resin composite systems. Seven discs of each composite brand were prepared in a circular increasing thickness. For TP, a spectrophotometer measured the samples’ colors. The color difference within the white/black backgrounds obtained the translucency parameter. For FI, samples were exposed to UV light, and ten photographs per group were taken. Each specimen was analyzed digitally. A mixed model analysis to a 95% confidence level analyzed groups differences. Higher values of TP were observed for ED and EL, followed by FZ. The lowest values were observed for EO and FO. FI values descending order was EL>FO>EO>ED>FZ. The composition of fillers and organic matrix influenced the behavior of fluorescence and translucency of resin composites. Key words:Resin composite, fluorescence, color, translucency parameter.
... Ao entrar em contato com a água, a resina composta pode sofrer movimentação ex- Inicialmente, pode haver um amolecimento da matriz orgânica pela solubilização de monômeros insaturados ou pela quebra de ligações químicas das macromoléculas, resultando em maiores taxas de deslizamento entre as cadeias poliméricas ( VAN DE SANDE et al., 2015). ...
Article
Introdução: A resina composta tem sido amplamente utilizada por suas propriedades restauradoras. No entanto, quando exposta à água, o material resinoso sofre diferentes mecanismos químicos e físicos, como a sorção de água e solubilidade. Esses efeitos podem produzir alterações volumétricas e mudanças físicas, alterando as características do material. Objetivo: discorrer acerca das consequências clínicas dos fenômenos de sorção e solubilidade na resina composta. Materiais e Métodos: uma revisão da literatura foi realizada por meio de artigos científicos publicados nos últimos anos presentes em bases de dados eletrônicos, como PubMED/Medline, Lilacs e Scielo. Resultados e Discussão: Os compósitos de resina não são estáveis, pois interagem constantemente com o ambiente oral. Sua principal interação é com água, que se difunde na matriz. As resinas compostas que contêm, além do BIS-GMA, uma alta concentração de TEGDMA, tendem a absorver mais água devido às ligações éter hidrofílicas presentes nesses compósitos. Com isso, uma série de efeitos deletérios podem ocorrer. Conclusão: A expansão volumétrica, lixiviação, degradação hidrolítica e instabilidade da cor são as principais consequências da sorção e solubilidade da resina composta. Esses fenômenos provocam alterações dimensionais e diminuição das propriedades mecânicas repercutindo, sobremaneira, na longevidade das restaurações em resina composta.
... Los liners o bases cavitarias presentan módulo de elasticidad similar a la dentina y algunos de ellos tienen propiedades adhesivas (en particular, los ionómeros de vidrio), por lo que se integran formando un gran sólido (1,2). Así, cada vez se hace más hincapié en la integridad de la interfaz entre el material restaurador y el diente preparado. ...
... In several studies, the use of an intermediate GIC liner negatively influenced the restorations' survival, resulting in more fracture of composite resin 10,29,42,78,79 . An AFR of 3.8% was observed for class II restorations with glass ionomer bases while observing an AFR of 1.4% for restorations without a base material 42 In opposite, other studies observed no effect on restoration longevity when using GIC liners 45,71,80 . The thickness and type of glass-ionomer cement used could explain the different results observed 10 45 . ...
Chapter
Composite restorations have shown excellent survival rates on anterior and posterior teeth, with secondary caries, tooth/restoration fracture and aesthetic demand being the main reasons for failures. Due to materials improvements overtime, current materials’ properties have revelated a minor influence on the survival of composites in clinical studies. When hybrid or nanohybrid composites are used, low AFR could be expected. Thus, patient-related factors and operators are fundamental to be considered on restoration longevity. Invasive behavior toward restoration replacement results in a decrease in the survival of restoration . Restorations should be carried out in a health promotion environment, emphasizing preventive practices. The adoption of healthy behaviors by patients will consequently led to “healthy” restorations, increasing the longevity of treatments. The adoption of minimally invasive dentistry for the management of deteriorated restorations, such as refurbishment or repair restorations, should be considered in routine practice. In this way, dentists should react less in front of small defects of restorations, indicating replacements only when other alternatives are not plausible. This chapter explains long-term survival and reasons for the failure of composite restorations, including all correlated factors.
... 23 In addition, GICs showed superior clinical sur-r r vival rates for deep dentin and hypermineralized dentin. 22,32 ...
Article
Purpose: To morphologically evaluate the interface between a conventional glass-ionomer cement (GIC) and dentin one day after placement, as well as the changes at the interface after one year of aging/functioning in monkey teeth. Materials and methods: On the buccal surfaces of seven intact teeth in each of two monkeys, shallow class V cavities were prepared, which were then filled with Fuji IX GP (GC) to provide 1-year in vivo data. A year later, two more teeth in each monkey were similarly prepared and restored for the 1-day in vivo group. The following day, the restored teeth were extracted and the restoration interfaces observed using transmission electron microscopy (TEM). In addition, restorations were similarly placed in two extracted human teeth (control, 1-day in vitro group) and observed a day after placement using TEM. Results: The 1-day in vivo and in vitro results showed that the GIC appeared to bond to dentin through a demineralized zone similar to the hybrid layer produced by resinous adhesives. However, the interface between GIC and dentin after 1 year in vivo appeared to change over time: many needle-like crystals were detected within the remineralized layer and along the collagen fibrils. Slow diffusion of ions resulted in pores, which filled with mineral crystals and made the pores smaller. Conclusion: The interface between GIC and dentin morphologically changes over time, and recrystallization or remineralization at the interface may occur (1 year in vivo).
... On the other side, from clinical point of view, it has been proposed that the use of glass ionomer cavity bases would diminish the overall strength of the composite restoration [19]. Though, long-term clinical study by van de Sande and her colleagues showed that presence of a GIC base did not affect the survival of posterior composite restorations [20]. ...
Article
Full-text available
Fiber-reinforced glass ionomer cement Short fiber-reinforced composite Root canal treated molar teeth Occlusal cavity a b s t r a c t Objectives: The aim was to investigate the fatigue performance of endodontically treated (ET) molars restored by various dentin-replacing materials and material configurations. Moreover, the impact of additional adhesive treatment with glass-ionomer cement (GIC) was evaluated. Methods: 250 intact molars were collected and randomly distributed into ten groups (n = 25). After endodontic procedure standard Class I cavities were prepared and restored with different direct restorative techniques and dentin-replacing materials. Two-group were restored with either packable or flowable short fiber-reinforced composites (SFRCs). Two-group were restored by experimental fiber-reinforced GIC with and without adhesive treatment. Four-group were restored by conventional and resin-modified GICs with or without adhesive treatment. One-group was restored with a dual-cure composite resin and last group was restored with only conventional composite resin (control). Fatigue-survival was measured for all specimens using a cyclic-loading machine until fracture occurred or a number of 40.000 cycles were achieved. Kaplan-Meyer survival analysis was conducted, followed by pairwise log-rank post hoc comparisons. Fracture mode was then examined by means of optical microscopy and SEM. Results: Group restored with flowable SFRC showed significantly higher survival (p < 0.05) compared to all of the groups, except for group restored with packable SFRC (p > 0.05). Group restored with fiber-reinforced GIC had significantly (p < 0.05) higher survival rates compared to other commercial GICs. SEM demonstrated change of the fracture line when fracture reached the SFRC layer.
... On the other side, from clinical point of view, it has been proposed that the use of glass ionomer cavity bases would diminish the overall strength of the composite restoration [19]. Though, long-term clinical study by van de Sande and her colleagues showed that presence of a GIC base did not affect the survival of posterior composite restorations [20]. ...
Article
Objectives The aim was to investigate the fatigue performance of endodontically treated (ET) molars restored by various dentin-replacing materials and material configurations. Moreover, the impact of additional adhesive treatment with glass-ionomer cement (GIC) was evaluated. Methods 250 intact molars were collected and randomly distributed into ten groups (n = 25). After endodontic procedure standard Class I cavities were prepared and restored with different direct restorative techniques and dentin-replacing materials. Two-group were restored with either packable or flowable short fiber-reinforced composites (SFRCs). Two-group were restored by experimental fiber-reinforced GIC with and without adhesive treatment. Four-group were restored by conventional and resin-modified GICs with or without adhesive treatment. One-group was restored with a dual-cure composite resin and last group was restored with only conventional composite resin (control). Fatigue-survival was measured for all specimens using a cyclic-loading machine until fracture occurred or a number of 40.000 cycles were achieved. Kaplan-Meyer survival analysis was conducted, followed by pairwise log-rank post hoc comparisons. Fracture mode was then examined by means of optical microscopy and SEM. Results Group restored with flowable SFRC showed significantly higher survival (p < 0.05) compared to all of the groups, except for group restored with packable SFRC (p > 0.05). Group restored with fiber-reinforced GIC had significantly (p < 0.05) higher survival rates compared to other commercial GICs. SEM demonstrated change of the fracture line when fracture reached the SFRC layer. Significance Direct restoration of Class I in ET molars with the use of SFRCs as dentin-replacing materials demonstrated its ability to reinforce the dental structures and to increase the fatigue resistance in this specific clinical situation.
... High patient aesthetics demands and concerns regarding dental amalgam toxicity have played an essential role in the rise of resin composite restorations in dentistry. Although popular, studies have reported mean failure rates for posterior resin composite restorations ranging from one to three percent [1][2][3] and 24.1% for anterior restorations 4) . The resin composite restoration longevity depends on several factors such as the patient caries risk, the presence of parafunctional habits such as bruxism, and the patients age 5) . ...
Article
This study evaluated the post-irradiation mechanical property development of six resin composite-based restorative materials from the same manufacturer starting at 1 h post irradiation, followed by 24 h, 1 week, and 1 month after fabrication. Samples were stored in 0.2M phosphate buffered saline until testing. Flexural strength, flexural modulus, flexural toughness, modulus of resiliency, fracture toughness, and surface microhardness were performed at each time interval. Mean data was analyzed by Kruskal Wallis and Dunn’s post hoc testing at a 95% level of confidence (α=0.05). Results were material specific but overall, all resin composite material mechanical properties were found to be immature at 1 h after polymerization as compared to that observed at 24 h. It may be prudent that clinicians advise patients, especially those receiving complex posterior composite restorations, to guard against overly stressing these restorations during the first 24 h.
... 20 Van de Sande et al. reported that the 18-year survival of posterior composite resin restorations was not detrimentally affected by the use of a glass ionomer cement base. 22 However, the beneficial effect of RM GIC/RBC sandwichtype restoration has been disputed by many authors; Opdam et al.'s systematic review and meta-analysis on the longevity of posterior composite restorations questioned the advantage of this technique. 23 Furthermore, van Dijken stated that the elastic wall concept obtained with the intermediary poly-acid modified resin composite layer could not be shown to be superior in the long term clinical evaluation. ...
Article
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Aim and objective: The purpose of this study was to investigate the fracture resistance of marginal ridges restored using different techniques (amalgam, open sandwich technique, and incremental placement) and to compare these with smart dentin replacement (SDR) bulk-fill. Materials and methods: Amalgam, dispersalloy; a nanohybrid resin composite (Tetric N Ceram), a resin-modified glass ionomer cement (RMGIC) base (Fuji II LC), and flowable bulk-fill composites (SureFil SDR) were used. Standardized class II (occluso-distal) OD cavities were prepared on 60 (n = 12) extracted premolars, and five different protocols were used to restore the teeth: group 1, dispersalloy; group 2, dispersalloy with 4 mm Fuji II LC base; group 3, incrementally placed Tetric N Ceram; group 4, Tetric N Ceram with 4 mm Fuji II LC base; and group 5, Tetric N Ceram with SureFil SDR. The restorations were thermocycled then fractured using a universal testing machine, the maximum fracture load of the specimens was measured (N), and the type of fracture was recorded. Statistical analysis was carried out using one-way analysis of variance. Results: Amalgam groups showed the lowest fracture resistance, with no significant difference between the based and nonbased groups. The highest fracture resistance was displayed by Tetric N Ceram with SDR base, and it was significantly higher than all the groups except the Tetric N Ceram nonbased group. The RMGIC based Tetric N Ceram displayed intermediate fracture resistance. The majority of the restorations showed mixed types of fracture except for nonbased amalgam, which mostly failed cohesively through amalgam. SDR-based composite was the only group that showed severe tooth failures. Conclusions: The use of a 4 mm thick RMGIC base had no detrimental effect on the fracture resistance of class II amalgam and composite restorations. Clinical significance: Bulk-fill SureFil SDR placed under a conventional resin-based composite had similar fracture resistance to incrementally placed composite but higher than amalgam and composite restorations based on RMGIC.
... Placement of a lining may affect the restored tooth's biomechanical properties adversely, limits the available surface area for bonding and reduces the thickness of resin composite. Sande and colleagues 19 concluded that the presence of a lining neither extend nor reduce the survival of resin-based composite restorations. Furthermore, the application of a dentine bonding agent will seal the restoration and the underlying dentine protecting the pulp from stimuli and bacterial ingress. ...
Article
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Objective: To evaluate awareness among the General Dentists of Lahore regarding the use of lining materials under posterior resin restorations. Study Design: Cross-sectional study. Place and Duration of Study: The study was conducted in Lahore, from Sep 2019 to Jan 2020. Methodology: Non-probability consecutive sampling technique was used. A sample size of 271 was calculated. The questionnaires were distributed by 2 surveyors to the general dentists of Lahore, Pakistan. Results: The response rate was 100%. Amongst these dentists, 191 (63.87%) affirmed that they use lining materials in initial depth cavities, 248 (82.94%) used lining material under moderate depth restorations and 285 (95.31%) used lining materials under advanced depth cavities with calcium hydroxide being the most commonly used material. Conclusion: The findings of the present study indicate that general dentists of Lahore are unaware of the contemporary concepts regarding the placement of cavity liners and tend to place liners in initial and moderate depth cavities under posterior resin restorations.
... Evaluation was carried out under a dental operating light, using flat surfaced mouth mirrors, dental explorers and direct vision with the aid of an intraoral camera * . In addition digital photographs were taken using digital camera for future reference and documentation (16) . The variations for some characteristics at various recall examinations need to be interpreted with caution. ...
... The performance of composite resins and glassceramics has been studied, and fair clinical long-term survival rates have been reported for both materials. [5][6][7][8][9][10] Nevertheless, the 2 materials have their differences. Composite resins offer advantages such as single-session application, wear-friendliness, 11 ease of repair, and lower cost. ...
Article
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Statement of problem Composite resins and glass-ceramics are both used to restore worn teeth. Which restoration material is more durable is unclear. Purpose The purpose of this in vitro study was to evaluate the load to failure of thin composite resins and glass-ceramic restorations on enamel and dentin under increasing repetitive loads. Material and methods Glass-ceramic blocks (IPS e.max CAD; Ivoclar Vivadent AG) were shaped into cylinders (Ø4.0×1.0 mm), crystallized, and adhesively luted to bovine dentin and enamel substrates that were embedded in polymethyl methacrylate (n=20). Identical direct composite resin restorations (Clearfil AP-X; Kuraray Noritake Dental Inc) were made and directly applied on the same substrates (n=20). All specimens were tested in a pneumatic device with a stainless steel ball that provided a stepwise increase of the load (N) starting at 250 N and increasing by 50 N after every 10 000 cycles to a maximum of 1150 N. Failures were detected by a displacement sensor and defined by chipping of restorative material or catastrophic failure. Results On dentin, composite resin showed a significantly higher fatigue resistance than glass-ceramic. On enamel, no significant difference was found between the 2 materials. Conclusions When bonded to dentin, thin direct composite resin restorations were more durable than glass-ceramics. When bonded to enamel, no difference was found.
... For those situations, using the stepwise removal and selective removal technique, GIC is recommended as it has similar bond strength to both normal and caries-affected dentin [39,40]. GIC has superior clinical survival results for deep dentin and hypermineralized dentin as well [18,41]. This is because of its resilience, low polymerization shrinkage and good sealing ability. ...
Article
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Objective The purpose of this study was to determine the bond stability and the change in interfacial ultra-structure of a conventional glass-ionomer cement bonded to dentin, with and without pre-treatment using a polyalkenoic acid conditioner. Methods The occlusal dentin surfaces of six teeth were ground flat. Glass-ionomer cement was bonded to the surfaces either with or without polyalkenoic acid conditioning. The teeth were sectioned into 1-mm² stick-shaped specimens. The specimens obtained were randomly assigned to two groups with different periods of storage in water: 1 week and 1 year. The micro-tensile bond strength (μTBS) was determined for each storage time. Additional specimens were prepared for Transmission Electron Microscopy (TEM); they were produced with or without prior polyalkenoic acid conditioning in the same way as in the μTBS test. Results There was no significant difference in μTBS to conditioned dentin and non-conditioned dentin (p > 0.05). The failures appeared to be of a mixed nature, although aging caused more areas of cohesive than adhesive failure in both groups. The TEM observation showed an intermediate layer, a matrix-rich layer and a partially demineralized layer in the polyalkenoic acid conditioned group. Significance Aging did not reduce the bond strength of the conventional glass-ionomer cement to dentin with or without the use of a polyalkenoic acid conditioner.
... Assessment of the mechanical behavior of materials in large class Ι composite restorations revealed a reduction in stress level at the dentin/restoration interface by the use of this technique [8]. However, based on clinical evaluations, the application of GICs may weaken the restoration and increase the risk of fracture of composite restorations [9]. ...
Article
Full-text available
Background Glass Ionomer Cements (GICs) are frequently used as base or liner before the application of restorative materials. The success of this approach depends on the bond strength of GICs to composite resin. Objectives This study to assess the modified microtensile bond strength of glass ionomer to composite resin using universal adhesive in self-etch and total-etch modes. Methods Samples were fabricated of resin-modified GIC (RMGIC) and conventional GIC(CGIC) (6 x 1 x 1 mm), and were randomly divided into 8 groups. Clearfil SE Bond and G-Premio universal adhesive in self-etch and total-etch modes were used according to the manufacturers’ instructions. Z250 composite was applied over the GIC (12 x 1 x 1 mm), and light-cured. The microtensile bond strength was measured using a universal testing machine. The samples in each group were evaluated under an electron microscope to determine the mode of failure. Data were analyzed using one-way ANOVA and Tukey’s test. Results The microtensile bond strength of RMGI used with Clearfil SE Bond was significantly higher than that of other groups (6.57±1.15 MPa) (P<0.05). The maximum and minimum microtensile bond strength values of CGIC after applying the bonding agents were recorded after using G-Premio total-etch mode (1.34±0.77 MPa) and SE Bond in total-etch mode(1.18±79 MPa), respectively. Conclusion Application of of G-Premio in both modes did not show any significant different bond strength in both glass ionomers. The bond strength of RMGIC was higher than that of CGIC, and the maximum bond strength of RMGI was achieved by the use of SE Bond.
... Many researchers are pursuing an improvement on material composition and its behavior, especially for less stress on polymerization shrinkage. However, a majority of failures happen because of other reasons, like patient risk factors(OPDAM et al., 2010;VAN DE SANDE et al., 2015;VAN DIJKEN, 2010). Athough clinical studies have the advantage of showing real restoration behavior, they demand a lot of time to show conclusive results. ...
... Many researchers are pursuing an improvement on material composition and its behavior, especially for less stress on polymerization shrinkage. However, a majority of failures happen because of other reasons, like patient risk factors(OPDAM et al., 2010;VAN DE SANDE et al., 2015;VAN DIJKEN, 2010). Athough clinical studies have the advantage of showing real restoration behavior, they demand a lot of time to show conclusive results. ...
... [14,15] Initially, there may be a softening of the organic matrix by hygroscopic expansion, by solubilizing unsaturated monomers or by breakage of macromolecule chemical bonds, resulting in higher rates of boundary slip between the polymer chains. [16][17][18] In a next step, hydrolysis or hydration of siloxane bonds of the silane layer will occur due to the degradation of matrix-filler bonds; surface or internal cracks and porosity would facilitate water access to this interface. [13,19] Finally, there could be solubilization of the particles by releasing ions of the components [20,21] and the presence of other solvents, lubricants, electrolytes, or enzymes, [15,21,22] along with mechanical cycling that would accelerate the process, occurs. ...
Article
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A significant deterioration of the properties can drastically compromise the survival rate of restorative materials. The aim of this study was to assess flexural strength and hardness of three composite classes: hybrid composite resin (HCR), nanoparticulate composite resin (NCR), and silorane-based composite resin (SBCR). One hundred specimens were prepared for hardness testing by using a split metallic mold measuring 10 mm in diameter and 2 mm deep. Twenty specimens were prepared for each restorative material, randomly assigned for storage in air, distilled water, or mineral oil. After intervals of 24 hours, 30, 60, 90, and 120 days, hardness and flexural strength tests were initially compared in two levels: “storage medium” and “time” within each material group. A two-way analysis of variance was performed (p<0.05) on the variables “material” and “storage time” (p<0.05). The HCR showed to be stable with regard to the evaluation of flexural strength and hardness (p<0.05). A significant reduction occurs for the NCR in comparison to the other groups (p<0.05). The NCR presented the lowest values of hardness and flexural strength kept on water over time. The characteristics of material showed a strong influence on the decrease of the mechanical properties analyzed.
... A clinical study showed that the presence of a GIC base did not affect the survival of resin-composite restorations. [48] Further clinical investigations are recommended to verify in vitro test results. ...
Article
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Objective: The aim of this study was to evaluate the influence of different base materials on fracture strength of mesio-occlusal-distal (MOD) composite restorations. Materials and Methods: Forty-eight extracted, intact maxillary molar teeth with standardized, deep MOD cavities were randomly assigned into four groups according to the base material placed: Control group (CO); no base material, SDR group; bulk-fill flowable composite, CGIC group; chemically curing glass ionomer cement (GIC), and RGIC group; light curing resin reinforced GIC. All the specimens were then restored with a nanocomposite (CeramX Duo/Dentsply) in combination with etch and rinse adhesive following the manufacturer's instructions. After aging fracture, strength of the specimens was tested by the application of a ramped oblique load to the buccal cusp in a universal testing machine. Mean fracture strength values for each group were calculated and compared using one-way ANOVA (P = 0.05). Fracture patterns of the specimens were also evaluated. Results: The mean loads necessary to fracture the samples were as follows: control: 819.22 ± 253.65; SDR: 694.46 ± 266. 55; CGIC: 559.15 ± 277.34; RGIC 861.87 ± 277.28: N. The control and RGIC groups showed significantly higher fracture strength than CGIC and SDR groups (P < 0.05). Although the mean fracture strength value of SDR group was higher than that of CGIC group, the difference between these groups was not statistically significant (P > 0.05). Most frequently observed fracture patterns were adhesive (58.3%) in CO, cohesive (50%) in SDR group, cohesive (83.3%) in CGIC group, and mixed (41.7%) in RGIC group. Conclusions: Resin-modified glass-ionomer cement as a base material or restoration of the tooth only with composite resin resulted in higher fracture strength than composite resin restoration with a conventional glass ionomer base or a flowable bulk-fill material. Fracture pattern distributions diversed according to the base material placed under composite restoration.
... Some studies were conducted in private dental practises or analysed data from there [14][15][16]. They reported annual failure rates ranging from 0% [15] to 4% [14]. ...
Conference Paper
Objectives: Knowledge about outcomes of restorative dental treatment under practice conditions is still sparse. The aim of this study was to evaluate re-interventions after restorative dental treatment under practice conditions using a large insurance database. Methods: This retrospective study based on claims data from the digital database of a major German national health insurance company. The study was approved by the responsible ethics board. Fee codes and treatment dates allowed for tracing clinical courses. Only teeth of patients who had been members of the insurance company for the whole four-year period 2010 to 2013 were eligible. Kaplan-Meier-survival-analyses were conducted for all teeth after restorative treatment (dental fillings and inlays) except of crowns. Success was defined as not undergoing any restorative re-intervention at the same tooth. Testing for differences among success rates was performed with the Log-Rank-test (P=0.05). Results: A number of 17,024,344 teeth could be traced after restorative treatment. The cumulative four-year success rates were 69.9% for one surface restorations, 74.8% for two surface restorations, 66.6% for three surface restorations and 61.0% for four surface and more extended restorations. These differences were significant (p<0.0001). Conclusions: The sustainability of restorative dental treatment under the terms and conditions of the German national health insurance system shows room for improvement. From a public health perspective, special focus should be laid on primary and secondary prevention to minimize the restorative treatment need.
... Some studies were conducted in private dental practises or analysed data from there [14][15][16]. They reported annual failure rates ranging from 0% [15] to 4% [14]. ...
Article
Full-text available
Objectives: There is only sparse knowledge concerning the outcomes of treatments with posterior permanent restorations in general practice settings. This study aimed at evaluating outcomes based on a large dataset by using a novel approach on a tooth surface basis. Materials and methods: The study based on routine data from a major German national health insurance company. Respective treatment fee codes allowed for tracking the clinical courses on a tooth surface level. The study intervention was defined as the placement of a restoration on an interproximal or occlusal posterior tooth surface regardless of its actual extension and material on which no information was available. All surfaces restored between January 1st, 2010 and December 31st, 2013 were included. Kaplan-Meier survival analyses were conducted to estimate four-year survival. The primary outcome was a restorative re-intervention on the same tooth surface. Separate analyses were performed for the secondary outcomes “crowning” and “extraction”. Results: Over ten million interproximal surfaces and eight million occlusal surfaces in nine million posterior teeth had been restored. At 4 years, the cumulative survival rates concerning the primary outcome “re-intervention” for mesial surfaces (81.4%; CI 81.3–81.5%) and distal surfaces (81.2%; CI 81.1–81.2%) differed significantly from those for occlusal surfaces (77.0%; CI 76.9–77.0%). Restored surfaces in premolars showed significantly higher survival rates compared to molars. Four-year survival rates for the secondary outcome “crowning” were 91.9% (CI 91.8—91.9%) for mesial surfaces, 92.1% (CI 92.1–92.2%) for distal surfaces and 93.3% (CI 93.2–93.3%) for occlusal surfaces. The respective rates for the secondary outcome “extraction” were 94.5% (CI 94.5–94.5%) for mesial surfaces, 94.8% (CI 94.7–94.8%) for distal surfaces and 95.4% (CI 95.4–95.5%) for occlusal surfaces. Conclusions: Re-interventions after restorative treatment play a significant role in general practice settings. Surface-related survival rates of restorations reveal a need for improvement. Clinical relevance: This study allows the estimation of the probability of re-interventions after restoring posterior tooth surfaces. It is based on several million cases from general practises under the terms and conditions of a national health insurance system.
... While these studies, keeping variables under control, show the potential performance of restorations under ideal conditions (Heintze and Rousson 2012), in practice-based studies, risk factors on different levels are present and can be investigated (van de Sande et al. 2013;Opdam et al. 2014). Only few data of selected general practices are available (Opdam et al. 2010;da Rosa Rodolpho et al. 2011;Baldissera et al. 2013;van de Sande et al. 2013van de Sande et al. , 2015, as well as data from Scandinavian public health care (Kopperud et al. 2012;Pallesen et al. 2013) showing AFRs varying from those comparable to university studies of 1% to 2% up to higher failure rates (4%-5%), especially for high-caries risk groups (Opdam et al. 2010;van de Sande et al. 2013). Survival data on posterior restorations placed by larger groups of GDPs often result from crosssectional studies, suggesting limited survival of posterior amalgam and especially composite restorations with median survival times of 5 to 8 y (Mjör and Jokstad 1993;Burke et al. 1999;Sunnegårdh-Grönberg et al. 2009). ...
Article
The aim of this retrospective practice-based study was to investigate the survival of direct class II restorations placed by a group of general dental practitioners (GDPs) and to analyze the effect of practice-, patient-, and tooth/restoration-related factors. Electronic patient files of 24 general dental practices were used for collecting the data for this study. From the patient files, survival rates of 222,836 composites, amalgams, glass ionomers, and compomers placed in 61,121 patients by 67 GDPs between 1999 and 2011 were analyzed by Kaplan-Meier statistics and a multiple Cox regression. The investigated group of GDPs placed restorations with a satisfactory survival (mean AFR 10 , 4.9%; 95% confidence interval, 2.1 to 7.7), although a wide variation in annual failure rate (AFR) existed between the different operators, varying between 2.6% and 7.0%. Restorations placed in young adults (21–30 y old) survived longest, whereas they showed a shorter survival in children (hazard ratio [HR], 1.553) and the elderly (HR, 1.593). Restorations in molar teeth, restorations placed in endodontically treated teeth, and multisurface restorations are more at risk for reintervention. However, restoration size (included surfaces) has a greater impact on restoration survival in premolar teeth. For the future, improved data collection at the practice/operator, patient, and tooth/restoration level (e.g., risk assessment and diagnoses) will provide the opportunity to evaluate even more extensively the risk factors involved. Knowledge Transfer Statement: The results of this study give insight into the long-term survival of direct dental restorations and the influencing practice-, patient-, and tooth/restoration-related variables.
... Commonly, larger cavities received the capping or base materials; thus, the size of the restored cavity had a greater influence on the failures of the restorations than the capping material, after the adjustment of the data. Corroborating with our results, a recent long-term clinical study showed no difference in posterior composite restoration survival when using a Bsoft^intermediate material compared to those without intermediate material [23]. In Brazil, there is a preference for tooth-colored direct materials, such as GIC and composite materials, to restore primary and permanent teeth of children and adolescents [24]. ...
Article
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Objective The aim of this retrospective university-based study has been to evaluate the longevity and factors associated with failures of adhesive restorations performed in deep carious lesions of permanent molars after complete (CCR) and selective caries removal (SCR). Materials and methods The sample was composed of composite resin and resin-modified glass ionomer cement (RMGIC) restorations placed in permanent molars of children attending a university dental service who were followed up for up to 36 months. Information collected retrospectively from clinical records was used for analyzing data. The following factors were investigated: gender, caries experience, visible plaque and gingival bleeding indexes, operator’s experiences, number of restored surfaces, and type of capping and restorative materials. The Kaplan-Meier survival test was used to analyze the longevity of the restorations. Multivariate Cox regression analysis with shared frailty was used to assess the factors associated with failures (p < 0.05). Results Four hundred seventy-seven restorations carried out in 297 children (9.1 ± 1.7 years) were included in the analysis. The survival of the restorations reached 57.9 % up to 36 months follow-up with an overall annual failure rate of 16.7 %. There was no difference in restoration longevity when CCR or SCR was performed (p = 0.163); however, CCR presented more pulp exposure (p < 0.001). Multi-surface restorations showed more failures than single-surface (HR 3.22, 95 % CI 1.49; 6.97), and teeth restored with RMGIC had a lower survival rate than those restored with composite resin (HR 4.11, 95 % CI 1.91; 8.81). Patients with evidence of gingivitis had more risk of failure in their restorations (HR 2.88, 95 % CI 1.33; 6.24). Conclusion Overall, adhesive restorations performed in young permanent molars of high caries risk children presented limited survival, regardless of the caries removal technique. Risk factors for failure were identified as multi-surface fillings, RMGIC restorative material, and poor oral hygiene, reflected by gingival bleeding. Clinical relevance Composite fillings associated with a strict caries preventive regimen may play an important role in the survival of restorations placed in high caries risk children.
... Modified glass ionomer cement adheres to the tooth structure [9] and is chemically compatible with composite [10]. Its application under restorations increases success rate of treatment [11]. However, the currently used indirect pulp capping materials require an additional step to restorative procedure and have no antiinflammatory properties [12]. ...
Article
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Objectives The aim of this study was to produce indomethacin-loaded nanocapsules (IndOH-NCs) and evaluate the influence of their incorporation into an adhesive resin. Materials and Methods Indomethacin was encapsulated by the deposition of preformed polymer. IndOH-NCs were characterized by laser diffractometry, Fourier transformed infrared spectrometry, transmission electron microscopy (TEM), scanning electron microscopy, high-performance liquid chromatography (HPLC), and MTT assay. Nanocapsules (NCs) were incorporated into an adhesive in concentrations of 1, 2, 5, and 10 %. The addition was visualized by TEM and drug release was evaluated by HPLC until 120 h of immersion in simulated body fluid (SBF). Drug diffusion through dentin was tested using a Franz diffusion cell apparatus and quantified by HPLC. The degree of conversion (DC), softening in ethanol, and microtensile bond strength (μTBS) were evaluated to determine whether the nanocapsules influenced the adhesive. Data were analyzed using one-way ANOVA and Tukey’s post hoc test for DC, softening in ethanol, μTBS, and cytotoxicity, and paired t test for comparison between the initial and final Knoop microhardness. Results IndOH-NCs, with a spherical shape and a mean diameter of 165 nm, were incorporated into an adhesive. Indomethacin content was 7 mg drug/g powder. IndOH-NCs maintained high cell viability. At 120 h, an amount of 13.83 % of indomethacin was released, and after 7 days, 7.07 % of this drug was diffused through dentin for an adhesive containing 10 % of nanocapsules. No alteration in the DC, softening in ethanol, and μTBS resulted from NC addition. Conclusions IndOH-NCs may be incorporated into adhesive systems, without compromising properties, to add an anti-inflammatory drug controlled release for restorative procedures in deep cavities. Clinical significance Here is the first step toward the goal of providing agents to act at an inflammatory process of pulp tissue through dental adhesives via encapsulation of drug.
Article
Objectives: To compare clinical performance of resin composite posterior Class-II restorations placed with etch-and-rinse adhesive or open sandwich technique using glass-ionomer cement. Methods: Data on Class II restorations placed by one dentist between 1990 and 2016 were collected from patient files, including caries risk, tooth related variables, applied materials and dates of last check-up visit and restoration placement. Open sandwich restorations were placed before 2001, while after 2001, a total-etch technique using etch-and-rinse 3-step adhesive was used when placing a Class II composite restoration. For statistical analysis, Kaplan-Meier statistics and a multilevel Cox-Regression was conducted (p < 0.05). Annual Failures Rates (AFR) were calculated. Results: 675 Class II restorations were placed in 91 patients, 491 total-etch restorations (observation time 2-18 y), and 184 open sandwich restorations (observation time 19-29 y) showing AFRs at 15 years as 2.9 % for total-etch and 9.7 % for open sandwich restorations. Secondary caries as failure was equally distributed among the 2 groups and 27 % of the failures in the open sandwich group were due to proximal deterioration of glass-ionomer cement. The Cox-regression showed a significant higher risk for failure for the open sandwich technique compared to total-etch class-II composite restorations (HR = 2.9; p < 0.001). Significance: Application of glass-ionomer cement using the open sandwich technique cannot be recommended for class-II restorations as being more complex and showing poorer clinical performance.
Article
Objectives This study aimed to evaluate the bond strength (BS), degree of conversion (DC), calcium release (CR), and viscosity (VS) of experimental self-adhesive calcium-based cements for pulp capping purposes. Three resin-based experimental cements containing no calcium (CONTROL), calcium hydroxide (HYDROCAL), and calcium chloride (CLORECAL) were synthesized and compared with a commercial resin-based calcium hydroxide cement (Ultra-Blend Plus® - ULTRAPLUS). Material and methods For the BS, a testing machine performed in bovine dentin (n = 10). The DC (n = 5) was measured through Fourier Transform Infrared Spectroscopy coupled to an attenuated total reflectance device (FTIR/ATR). The CR (n = 5) was analyzed through an atomic absorption spectrophotometer at 3 h, 24 h and 72 h. A rheometer was used to obtain the VS (n = 5). The data were statistically analyzed using one and two-way ANOVA/Tukey tests (α = 0.05). Results For BS, all experimental materials showed statistically higher values than the commercial material (p < 0.01). For the DC, the CONTROL and HYDROCAL cements showed statistically higher values than the others (p < 0.01). CLORECAL and ULTRAPLUS showed statistically higher CR values after 72 h (p < 0.01). The HYDROCAL and CLORECAL cements showed statistically higher VS values than the others (p < 0.01). Conclusion Therefore, the experimental calcium chloride-based cement presented a better overall behavior.
Article
Background The best treatment option for large caries in permanent posterior teeth is still a matter of uncertainty in dental literature. The authors conducted a network meta-analysis to address the challenges related to rehabilitation of these teeth. Types of Studies Reviewed The authors selected prospective and retrospective studies that compared at least 2 different treatment alternatives for permanent teeth with a minimum of 5 years of follow-up. The authors searched databases from MEDLINE, Scopus, Cochrane Library, and Web of Science in October 2019 without language or year of publication restrictions. Results From 11,263 studies identified, 43 studies fulfilled the eligibility criteria and were included in the final review. Only 13 studies were randomized controlled trials and were classified as low risk of bias. Gold (annual failure rate of 0.29%) and metal ceramic (annual failure rate of 0.52%) crowns performed better for indirect restorations and direct resin composite performed better for direct restorations (annual failure rate of 2.19%). The most substantial comparisons were between feldspathic and glass ceramics, followed by direct resin composite and amalgam; there were no statistically significant differences between these interventions. Results of the pairwise meta-analysis showed mainly glass ionomer as significantly more prone to failure than amalgam and direct composite resin. Conclusions and Practical Implications Reference standard direct and indirect materials except for glass ionomer can be used for restorations of large posterior caries.
Article
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Objective The aim of this paper was to review the current literature on cavity bases while focusing on the role of zinc oxide eugenol (ZOE) and resin-modified glass ionomers (RMGI) as cavity bases. Materials and Methods A thorough literature search between 1970 and 2020 was done using Scopus, PubMed, and Google Scholar databases. The keywords of the search strategy were as below: cavity liners and bases, pulp protection, zinc oxide eugenol, and resin-modified glass ionomer. No specific inclusion or exclusion criteria were applied as to what articles would be included in this review. Conclusion This review emphasizes that the available literature provides very little evidence to support the routine use of a base under amalgam or composite restorations. This review favors the adoption of “no more lining or bases” in shallow and moderate cavity preparations. However, an exception might be a “protective base” of RMGI following the application of calcium hydroxide (CH) liners in deep cavities. Bonded RMGIs are suitable cavity base materials and should always replace zinc oxide eugenol bases in daily practice.
Article
Selective carious tissue-removal strategies require specific considerations in selection of restorative materials. A tight marginal seal placed over hard dentin and sound enamel is essential. For selective removal of carious tissue with permanent restoration, bioactive materials, such as high-viscosity glass-ionomer cement (HV-GIC) or calcium silicates, may be preferred over caries-affected firm or leathery dentin to improve remineralization. HV-GICs have the best clinical evidence of caries-arresting effect and demonstrate sufficient longevity as long-term provisional restorations that can later be used in open or closed sandwich restorations. As with any material, oral health maintenance remains important for long-term survival of restorations.
Article
The use of resin composite for routine restoration of cavities in posterior teeth is now commonplace, and will increase further following the Minamata Agreement and patient requests for tooth-coloured restorations in their posterior teeth. It is therefore relevant to evaluate the published survival rates of such restorations. A Medline search identified 144 possible studies, this being reduced to 24 when inclusion criteria were introduced. Of these, ten directly compared amalgam and composite, eight were cohort studies, and six were systematic reviews. It was concluded that posterior composites may provide restorations of satisfactory longevity and with survival rates generally similar to those published on amalgam restorations. However, the ability of the operator in placing the restoration may have a profound effect. CPD/Clinical Relevance: With the increasing use of composite for restorations in posterior teeth, it is relevant to note that these may provide good rates for survival.
Article
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For covering the shortages of traditional treatments, a novel and non-invasive system was developed with the simple adaption of nature's own repair process, while an extrinsic electric field was introduced to improve its remineralization kinetics. In an in vivo study, acid-etched rabbit dentine was used to evaluate the remineralization efficacy and safety of the system. The exposed dentine tubules were fully occluded after 5 hours/1.0 mA and 8 hours/0.5 mA of remineralization. After 5 hours of remineralization (1.0 mA), the micro-hardness of the demineralized dentine was fully recovered, equal to native rabbit dentine. Haematoxylin-eosin staining demonstrated no obvious inflammatory reaction. This study provides a feasible solution to realize rapid repair of dentine.
Article
The restoration of damaged posterior teeth using direct composite materials is an integral component of contemporary dental practice. Resin-based materials are now routinely used to solve a wide range of restorative problems from the minimally invasive management of early carious lesions to the total restoration of severely worn dentitions. As there is a wide variation in the teaching and practice of posterior composite techniques worldwide, this paper aims to provide an evidence-based update designed to help clinical teams equip practices with suitable materials and equipment and optimize all clinical stages of posterior composite procedures. CPD/Clinical Relevance: Knowledge, understanding and advanced practical skill in posterior composite restorations is an essential requirement for contemporary clinical dentistry.
Article
Background: Resin-based composite (RBC) is currently accepted as a viable material for the restoration of caries for posterior permanent teeth requiring surgical treatment. Despite the fact that the thermal conductivity of the RBC restorative material closely approximates that of natural tooth structure, postoperative hypersensitivity is sometimes still an issue. Dental cavity liners have historically been used to protect the pulp from the toxic effects of some dental restorative materials and to prevent the pain of thermal conductivity by placing an insulating layer between restorative material and the remaining tooth structure. This is an update of the Cochrane Review first published in 2016. Objectives: The objective of this review was to assess the effects of using dental cavity liners in the placement of Class I and Class II resin-based composite posterior restorations in permanent teeth in children and adults. Search methods: Cochrane Oral Health's Information Specialist searched the following databases: Cochrane Oral Health's Trials Register (to 12 November 2018), the Cochrane Central Register of Controlled Trials (CENTRAL; 2018, Issue 10) in the Cochrane Library (searched 12 November 2018), MEDLINE Ovid (1946 to 12 November 2018), Embase Ovid (1980 to 12 November 2018) and LILACS BIREME Virtual Health Library (Latin American and Caribbean Health Science Information database; 1982 to 12 November 2018). We searched ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. No restrictions were placed on the language or date of publication when searching the electronic databases. Selection criteria: We included randomized controlled trials assessing the effects of the use of liners under Class I and Class II posterior resin-based composite restorations in permanent teeth (in both adults and children). We included both parallel and split-mouth designs. Data collection and analysis: We utilized standard methodological procedures prescribed by Cochrane for data collection and analysis. Two review authors screened the search results and assessed the eligibility of studies for inclusion against the review inclusion criteria. We conducted risk of bias assessments and data extraction independently and in duplicate. Where information was unclear we contacted study authors for clarification. Main results: Eight studies, recruiting over 700 participants, compared the use of dental cavity liners to no liners for Class I and Class II resin-based composite restorations.Seven studies evaluated postoperative hypersensitivity measured by various methods. All studies were at unclear or high risk of bias. There was inconsistent evidence regarding postoperative hypersensitivity (either measured using cold response or patient-reported), with a benefit shown at some, but not all, time points (low-quality evidence).Four trials measured restoration longevity. Two of the studies were judged to be at high risk and two at unclear risk of bias. No difference in restoration failure rates were shown at 1 year follow-up, with no failures reported in either group for three of the four studies; the fourth study had a risk ratio (RR) 1.00 (95% confidence interval (CI) 0.07 to 15.00) (low-quality evidence). Three studies evaluated restoration longevity at 2 years follow-up and, again, no failures were shown in either group.No adverse events were reported in any of the included studies. Authors' conclusions: There is inconsistent, low-quality evidence regarding the difference in postoperative hypersensitivity subsequent to placing a dental cavity liner under Class I and Class II posterior resin-based composite restorations in permanent posterior teeth in adults or children 15 years or older. Furthermore, no evidence was found to demonstrate a difference in the longevity of restorations placed with or without dental cavity liners.
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Prospective clinical studies of composite restorations revealed their safety and longevity; however, studies did not elucidate the dynamic mechanisms of deterioration caused by fractures and secondary caries. Therefore, the aims of this 29-y controlled study were 1) to follow up on the clinical behavior of posterior composite restorations annually and 2) to compare clinical outcomes with micromorphologic scanning electron microscopy features. After ethical approval, the single-arm study commenced in 1987 with 194 class I or II primary posterior composite restorations with glass ionomer cement providing pulp protection. Each restoration was evaluated annually for 15 y and then again at 29 y per the US Public Health Service–compatible Clinical, Photographic and Micromorphologic coding index, with clinical and photographic criteria for anatomic form, color matching, surface quality, wear, marginal integrity, secondary caries, and clinical acceptability. Parallel micromorphologic criteria were applied at baseline and after 1, 3, 5, 7, 10, 15, and 29 y to assess surface roughness, texture, marginal integrity, fractures, ledges, and marginal gaps with semiquantitative coding and with quantitative 3-dimensional scanning electron microscopy profilometric measurements of marginal grooves next to the enamel, grooves within the bonding zone, and ledges. Statistical analysis included the calculation of the annual failure rate and the use of Kaplan-Meier methodology and nonparametric tests. The cumulative survival rates were 91.7% (6 y), 81.6% (12 y), and 71.4% (29 y). The mean annual failure rate was 1.92%. Significant changes in the restoration-tooth interface from baseline to 5 y resulted in functional masticatory equilibrium. Clinical deterioration year by year, including micromorphologic microfractures and wear, reflected unique dynamic changes in long-term surviving restorations with very low secondary caries and fracture risks (German Network for Health Care Research VfD 29 99 003924).
Article
Purpose: To see whether applying four different liners under short fiber-reinforced composite (SFRC), everX Posterior, compared to conventional composite resin, Z250, affected their strengthening property in premolar MOD cavities. Materials and methods: Mesio-occluso-distal (MOD) cavities were prepared in 120 sound maxillary premolars divided into 10 groups (n = 12) in terms of two composite resin types and 4 liners or no liner. For each composite resin, in 5 groups no liner, resin-modified glass ionomer (RMGI), conventional flowable composite (COFL), self-adhesive flowable composite resin (SAFL), and self-adhesive resin cement (SARC) were applied prior to restoring incrementally. After water storage and thermocycling, static fracture resistance was tested. Data (in Newtons) were analyzed using two-way ANOVA (α = 0.05). Results: Fracture resistance was significantly affected by composite resin type (p = 0.02), but not by the liner (p > 0.05). The interaction of the two factors was not statistically significant (p > 0.05). SFRC exhibited higher fracture strength (1470 ± 200 N) compared to conventional composite resin (1350 ± 290), irrespective of the application of liners. Application of SARC and SAFL liners led to a higher number of restorable fractures for both composite resins. Conclusions: The four liners can be used without interfering with the higher efficacy of SFRC, compared to conventional composite resins, to improve the fracture strength of premolar MOD cavities.
Chapter
Dental restorations are subjected to various challenges in the oral environment virtually as soon as the placement is complete. The restorative complex experiences a cascade of events over the first 24 to 48 hours post-restoration until reaching equilibrium. Over time, biofilms of multiple composition and cariogenic abilities accumulate as a cyclic event. Acidic, abrasive as well as mechanical stresses of different extents and magnitudes during mastication exert additional challenges on composite restorations. Thermal, mechanical and chemical aging processes all adversely affect restorations and in certain cases lead to failure. Can we predict or postpone failures? This chapter addresses factors related to the clinical longevity of direct resin composite restorations, including recent data from clinical studies, the meaning of clinical failures, the optimal restorative resin composite, the expected clinical lifespan of restorations and answered/unanswered questions concerning the intraoral performance of direct resin composite restorations. The chapter is concluded addressing strategies to improve the clinical longevity of resin composite restorations.
Article
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Backgrounds: Composites are increasing in popularity as restorative materials. This growing role indicates the necessity of studies on their clinical outcome. Methods: Clinical studies published on the performance of posterior composite restorations were included except those of less than a 24-month assessment period. Results of non-vital, anterior or primary teeth and cervical-single-surface restorations were also excluded. Records about composite type, number of final recall restorations, failure/survival rate, and assessment period and failure reasons were analyzed for each decade. Results: Overall survival/failure rates for studies in 1995-2005 were 89.41%/10.59% and for 2006-2016 were 86.87%/13.13% respectively. In 1995-2005 the reasons for failure were secondary caries (29.47%) and composite-fracture (28.84%) with low tooth-fracture (3.45%) compared to reasons of failure in 2006-2016, which were secondary caries (25.68%), composite-fracture (39.07%), and tooth-fracture (23.76%). An increase in incidence of composite-fracture, tooth-fracture and need for endodontic treatment as failure reasons was noted in latter decade in addition to a decrease in secondary caries, post-operative sensitivity, unsatisfactory marginal adaptation and wear. Conclusion: The overall rates of failure showed little difference, but the causes showed a notable change. This is believed to be a reflection of increased use of composites for larger restorations and possibly changes of material characteristics. This article is protected by copyright. All rights reserved.
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The aim of this meta-analysis, based on individual participant data from several studies, was to investigate the influence of patient-, materials-, and tooth-related variables on the survival of posterior resin composite restorations. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines, we conducted a search resulting in 12 longitudinal studies of direct posterior resin composite restorations with at least 5 years' follow-up. Original datasets were still available, including placement/failure/censoring of restorations, restored surfaces, materials used, reasons for clinical failure, and caries-risk status. A database including all restorations was constructed, and a multivariate Cox regression method was used to analyze variables of interest [patient (age; gender; caries-risk status), jaw (upper; lower), number of restored surfaces, resin composite and adhesive materials, and use of glass-ionomer cement as base/liner (present or absent)]. The hazard ratios with respective 95% confidence intervals were determined, and annual failure rates were calculated for subgroups. Of all restorations, 2,816 (2,585 Class II and 231 Class I) were included in the analysis, of which 569 failed during the observation period. Main reasons for failure were caries and fracture. The regression analyses showed a significantly higher risk of failure for restorations in high-caries-risk individuals and those with a higher number of restored surfaces.
Article
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There have been many developments in operative dentistry in recent years, including a progressive shift to the use of resin composites, rather than dental amalgam, in the restoration of posterior teeth. This shift allows the adoption of minimal intervention approaches, thereby helping to conserve and preserve remaining tooth tissues and structures. This paper presents the position of the Academy of Operative Dentistry European Section (AODES) in relation to posterior resin composites. The AODES considers adhesively bonded resin composites of suitable composition and properties to be the "material of choice" for use in direct minimal intervention approaches to the restoration of posterior teeth. In so doing, the AODES emphasises the importance of the practice of evidence-based, minimal intervention dentistry, including the use of refurbishment and repair techniques to extend the longevity of restorations. Guidance, based on best available evidence, has been made in relation to certain aspects of resin composite placement techniques in posterior teeth.
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This in vitro study investigated the effect of hydrodynamic flow through mechanical loading on development of secondary caries lesions. Forty-eight bovine tooth specimens (enamel and dentin; sizes 3.2 x 3.2 x 2.0 mm) were restored with resin-composite on polystyrene bars; 18 samples were bonded, and 30 were not bonded. Specimens were suspended in a lactic acid solution (pH = 5; 14 days) in a modified brushing machine, and artificial caries lesions were formed. During caries development, specimens were mechanically loaded at the surface of the polystyrene bar, bent so that the tooth- composite interfaces were subjected to opening forces (16x/min). Loads applied were either none (Control Bonded, CB, n = 6; and Control Non-bonded, CNB, n = 6), 200 gr (NB200, n = 12), or 350 gr (NB350 and B350, both n = 12). Before and after caries development, specimens were imaged with transverse wavelength-independent microradiography (T-WIM), and lesion depth (LD) and mineral loss (ML) were calculated at 4 different locations. An independent t test was used to compare the LD and ML at the 4 different locations. A statistically significant effect of the level of loading (comparing groups NB200 and NB350) and of bonding (comparing groups NB350 and B350) could be observed, with a higher load and absence of bonding leading to more advanced lesions.
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Aim: To determine the volumetric polymerization shrinkage of four different types of composite resin and to evaluate microleakage of these materials in class II (MOD) cavities with and without a resin-modified glass ionomer cement (RMGIC) liner, in vitro. Materials and methods: One hundred twenty-eight extracted human upper premolar teeth were used. After the teeth were divided into eight groups (n=16), standardized MOD cavities were prepared. Then the teeth were restored with different resin composites (Filtek Supreme XT, Filtek P 60, Filtek Silorane, Filtek Z 250) with and without a RMGIC liner (Vitrebond). The restorations were finished and polished after 24 hours. Following thermocycling, the teeth were immersed in 0.5% basic fuchsin for 24 hours, then midsagitally sectioned in a mesiodistal plane and examined for microleakage using a stereomicroscope. The volumetric polymerization shrinkage of materials was measured using a video imaging device (Acuvol, Bisco, Inc). Data were statistically analyzed with Kruskal-Wallis and Mann-Whitney U-tests. Results: All teeth showed microleakage, but placement of RMGIC liner reduced microleakage. No statistically significant differences were found in microleakage between the teeth restored without RMGIC liner (p>0.05). Filtek Silorane showed significantly less volumetric polymerization shrinkage than the methacrylate-based composite resins (p<0.05). Conclusion: The use of RMGIC liner with both silorane- and methacrylate-based composite resin restorations resulted in reduced microleakage. The volumetric polymerization shrinkage was least with the silorane-based composite.
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This practice-based retrospective study evaluated the survival of resin composite restorations in posterior teeth, focusing on the influence of potential patient risk factors. In total, 306 posterior composite restorations placed in 44 adult patients were investigated after 10 to 18 yrs. The history of each restoration was extracted from the dental records, and a clinical evaluation was performed with those still in situ. The patient risk status was assessed for caries and "occlusal-stress" (bruxism-related). Statistical analysis was performed by the Kaplan-Meier method and Cox-regression multivariate analysis. In total, 30% of the restorations failed, of which 82% were found in patients with 1 or 2 risk factors. Secondary caries was the main reason of failure within caries-risk patients, whereas fracture was the main reason in "occlusal-stress-risk" patients. The patient variables gender and age did not significantly affect survival, but risk did (p < .001). Tooth type (p < .001), arch (p = .013), and pulpal vitality (p = .003) significantly affected restoration survival. Within the limits of this retrospective evaluation, the survival of restorations is affected by patient risk factors, which should be included in survival analyses of restorations.
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Objectives: To investigate in a prospective follow up the longevity of posterior resin composites (RC) placed in permanent teeth of children and adolescents attending Public Dental Health Service. Methods: All posterior RC placed, in the PDHS clinics in the cities of Copenhagen and Frederiksberg in Denmark between November 1998 and December 2002, in permanent teeth of children and adolescents up to 18 years, were evaluated in an up to 8 years follow up. The endpoint of each restoration was defined, when repair or replacement was performed. Survival analyses were performed between subgroups with Kaplan-Meier analysis. The individual contribution of different cofactors to predict the outcome was performed with Cox regression analysis. Results: Totally 2881 children with a mean age of 13.7 years (5-18) received 4355 RC restorations placed by 115 dentists. Eighty percent were placed in molars and 49% were Class I. Two percent of restorations with base material and 1% of the restorations without base material showed postoperative sensitivity (n.s.). Replacements were made in 406 and repairs in 125 restorations. Kaplan-Meier analysis showed a cumulative survival at 8 years of 84.3%, resulting in an annual failure rate of 2%. Lower patient age, more than one restoration per patient, placement of a base material and placement of RC: in molars, in cavities with high number of surfaces, in lower jaw teeth, showed all significant higher failure rates. Five variables had significant importance for the end point, replacement/repair of the resin composite restorations: age of patient, age of operator, jaw, tooth type and cavity size. Significance: Posterior RC restorations placed in children and adolescents in Public Dental Health clinics showed an acceptable durability with annual failure rates comparable with those of randomized controlled RC studies in adults.
Article
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Purpose: More than five hundred million direct dental restorations are placed each year worldwide. In about 55% of the cases, resin composites or compomers are used, and in 45% amalgam. The longevity of posterior resin restorations is well documented. However, data on resin composites that are placed without enamel/dentin conditioning and resin composites placed with self-etching adhesive systems are missing. Material and methods: The database SCOPUS was searched for clinical trials on posterior resin composites without restricting the search to the year of publication. The inclusion criteria were: (1) prospective clinical trial with at least 2 years of observation; (2) minimum number of restorations at last recall = 20; (3) report on dropout rate; (4) report of operative technique and materials used; (5) utilization of Ryge or modified Ryge evaluation criteria. For amalgam, only those studies were included that directly compared composite resin restorations with amalgam. For the statistical analysis, a linear mixed model was used with random effects to account for the heterogeneity between the studies. P-values under 0.05 were considered significant. Results: Of the 373 clinical trials, 59 studies met the inclusion criteria. In 70% of the studies, Class II and Class I restorations had been placed. The overall success rate of composite resin restorations was about 90% after 10 years, which was not different from that of amalgam. Restorations with compomers had a significantly lower longevity. The main reason for replacement were bulk fractures and caries adjacent to restorations. Both of these incidents were infrequent in most studies and accounted only for about 6% of all replaced restorations after 10 years. Restorations with macrofilled composites and compomer suffered significantly more loss of anatomical form than restorations with other types of material. Restorations that were placed without enamel acid etching and a dentin bonding agent showed significantly more marginal staining and detectable margins compared to those restorations placed using the enamel-etch or etch-and-rinse technique; restorations with self-etching systems were between the other groups. Restorations with compomer suffered significantly more chippings (repairable fracture) than restorations with other materials, which did not statistically differ among each other. Restorations that were placed with a rubber-dam showed significantly fewer material fractures that needed replacement, and this also had a significant effect on the overall longevity. Conclusion: Restorations with hybrid and microfilled composites that were placed with the enamel-etching technique and rubber-dam showed the best overall performance; the longevity of these restorations was similar to amalgam restorations. Compomer restorations, restorations placed with macrofilled composites, and resin restorations with no-etching or self-etching adhesives demonstrated significant shortcomings and shorter longevity.
Article
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The aim of this study was to evaluate in vitro fluoride (F) release from 4 restorative materials (3M ESPE): Ketak Molar Easymix [KME - conventional glass ionomer cement (GIC)]; Rely-X luting 2 [RL2 - resin-modified GIC (RMGIC)]; Vitremer (VIT- RMGIC); and Filtek Z250 [Z250 - negative control]. Disc-shaped specimens were fabricated according to the manufacturer's instructions and placed into 10 mL of reverse osmosis water at 37°C until the analyses were done using a liquid membrane for selective F ion electrode (Orion 710). F release was evaluated every 6 h in the first day and thereafter daily during 28 days (d). The results were analyzed statistically by two-way ANOVA and Tukey's test (α=0.05). Mean F release and standard deviation values (in ppm) were: KME: 6 h- 0.34 ± 0.04; 24 h- 1.22 ± 0.30; 7 d- 0.29 ± 0.09; 14 d- 0.20 ± 0.04; 28 d- 0.16 ± 0.01; RL2: 6 h- 2.46 ± 0.48; 24 h-12.33 ± 2.93; 7 d- 1.37 ± 0.38; 14 d- 0.80 ± 0.13; 28 d- 0.80 ± 0.21; VIT: 6 h- 0.98 ± 0.35; 24 h- 4.35 ± 1.22; 7 d- 0.66 ± 0.23; 14 d- 0.40 ± 0.07; 28 d- 0.39 ± 0.08; Z250: 6 h- 0.029 ± 0.001; 24 h- 0.024 ± 0.009; 7 d- 0.023 ± 0.004; 14 d- 0.025 ± 0.001; 28 d- 0.028 ± 0.001. RL2 RMGIC released more F than the other materials in all periods. The greatest release of F occurred in the first 24 h.
Article
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Composite restorations frequently have gingival margins apical to the cemento-enamel junction (CEJ). Microleakage at the cementodentinal margins is one of the most important causes of failure in these restorations. The current study evaluated microleakage at the occlusal and gingival margins of Class II packable composite restorations using resin-modified glass ionomer and flowable composite as liners, using the two-step etch-and-rinse and self-etch dentin-bonding systems. This in vitro study was carried out on 48 intact human premolars. Class II preparations were made with the gingival margins placed 1.0 mm apical to the CEJ. The teeth were randomly assigned to six groups of 16 boxes and restored using the following techniques: Group 1: Single Bond (3M ESPE) + Filtek P60 (3M ESPE); Group 2: Clearfil SE Bond (Kuraray) + Filtek P60; Group 3: Single Bond + Filtek Flow (3M ESPE) + Filtek P60; Group 4: Clearfil SE Bond + Filtek Flow + Filtek P60. Group 5: Single Bond + Fuji II LC (GC) + Filtek P60; Group 6: Clearfil SE Bond + Fuji II LC + Filtek P60. The restorations were thermocycled for 1000 cycles at 5{degree sign}C and 55°C, soaked in 2% methylene blue for 48 hours, then sectioned mesiodistally and viewed under a stereomicroscope for leakage at the gingival margin. The data were statistically analyzed using the Kruskal-Wallis, two-way ANOVA and Mann-Whitney U-tests. The resin-modified glass-ionomer liner demonstrated significantly less leakage than flowable composite (p<0.05). There was no difference between restorations with flowable resin composite liners and those without the liner; in addition, no significant difference was observed between the two kinds of adhesive systems. The current study supports the use of resin-modified glass ionomer as a liner in closed-sandwich technique to decrease microleakage of Class II packable composite restorations, applying either the two-step etch-and-rinse or the self-etch dentin adhesive system.
Article
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This laboratory study compared the flexural endurance limits of clinical combinations of dental composite with and without glass ionomer cement (GIC) liners. Using only composite (Filtek Z350), specimens (10 mm long x 2 mm wide x 2 mm thick) in the control group were produced. Two GICs (Vitremer and Vitrebond) were used with the composite to prepare the test groups. Flexural strength and flexural fatigue limit (FFL) tests were performed. The FFL was determined using the staircase method. Data were analyzed by one-way ANOVA and Tukey's test. There was a significant difference in flexural strength values between the composite-only specimens and those produced by composite and GIC (p < 0.05). No statistical difference was observed in the flexural strength values between composite with Vitremer and composite with Vitrebond (p < 0.05). No statistically significant differences were detected in FFL values between composite with Vitremer and composite with Vitrebond; in addition, the mean value of the composite-only specimens differed statistically from those of both composite with Vitremer and composite with Vitrebond (p < 0.05). The FFL was lower than the flexural strength, indicating a decrease in flexural strength of 45 to 50%. Using GICs with composite decreased the mechanical properties (FFL and flexural strength) of the composite.
Article
Background. The clinical diagnosis of recurrent caries is the most common reason for replacement of all types of restorations in general dental practice. Marked variations in the diagnosis of the lesions have been reported. The prevention of recurrent lesions by the use of fluoride-releasing-restorative materials has not been successful. Types of Studies Reviewed. The author focused on practice-based studies in the literature. These studies are. not scientifically rigorous, but they reflect "real-life" dental practice. Few experimental studies on recurrent carious lesions in vivo have been reported, but bacteriological studies indicate that the etiology is similar to that of primary caries. Results. Recurrent carious lesions are most often located on the gingival margins of Class II through V restorations. Recurrent caries is rarely diagnosed on Class I restorations. The diagnosis is difficult, and it is important to differentiate recurrent carious lesions from stained margins on resin-based composite restorations. Overhangs, even minute in size, are predisposed to plaque accumulation and the development of recurrent caries. The development of recurrent lesions is unrelated to microleakage. Clinical Implications. As recurrent carious lesions are localized and limited, alternative treatments to restoration replacement are suggested. Polishing may be sufficient. If not, exploratory preparations into the restorative material adjacent to the localized defect can reveal the extent of the lesion. Such explorations invariably show that the lesion does not progress along the tooth-restoration interface. The defect, therefore, may be repaired in lieu of being completely replaced. Repair and refurbishing of restorations save tooth structure. These simple procedures also increase the life span of the restoration.
Article
This in situ study investigated whether there is a relationship between gap size and wall lesion development in dentin next to 2 composite materials, and whether a clinically relevant threshold for the gap size could be established. For 21 days, 14 volunteers wore a modified occlusal splint containing human dentin samples with 5 different interfaces: 4 gaps of 50 µm, 100 µm, 200 µm, or 400 µm and 1 non-bonded interface without a gap. Eight times a day, the splint with samples was dipped in a 20% sucrose solution for 10 minutes. Before and after caries development, specimens were imaged with transversal wavelength-independent microradiography (T-WIM), and lesion depth (LD) and mineral loss (ML) were calculated at the 5 different interfaces. After correction for the confounder location (more mesial or distal), a paired t test clustered within volunteers was performed for comparison of gap widths. Results showed no trend for a relationship between the corrected lesion depth and the gap size. None of the differences in lesion depth for the different gap sizes was statistically significant. Also, the composite material (AP-X or Filtek Supreme) gave no statistically significant differences in lesion depth and mineral loss. A minimum gap size could not be established, although, in a non-bonded interface without a measurable gap, wall lesion development was never observed.
Article
Objective: The objective of this 6 year prospective randomized equivalence trial was to evaluate the long-term clinical performance of a new nano-hybrid resin composite (RC) in Class II restorations in an intraindividual comparison with its well-established conventional hybrid RC predecessor. Methods: Each of 52 participants received at least two, as similar as possible, Class II restorations. The cavities were chosen at random to be restored with an experimental nano-hybrid RC (Exite/Tetric EvoCeram (TEC); n=61) and a conventional hybrid RC (Exite/Tetric Ceram (TC); n=61). The restorations were evaluated with slightly modified USPHS criteria at baseline and then annually during 6 years. Results: Two patient drop outs with 4 restorations (2TEC, 2TC) were registered during the follow-up. A prediction of the caries risk showed that 16 of the evaluated 52 patients were considered as high risk patients. Eight TEC (2 P, 6M) and 6 TC (2P, 4M) restorations failed during the 6 years. The main reason of failure was secondary caries (43%; including the failure fracture+secondary caries it increases to 57.1%). 63% of the recurrent caries lesions were found in high caries risk participants. The overall success rate at six years was 88.1%. No statistical significant difference was found in the overall survival rate between the two investigated RC. Significance: The nano-hybrid RC showed good clinical performance during the 6 year evaluation, comparable to the well-established conventional hybrid RC.
Article
Resin composites have become the first choice for direct posterior restorations and are increasingly popular among clinicians and patients. Meanwhile, a number of clinical reports in the literature have discussed the durability of these restorations over long periods. In this review, we have searched the dental literature looking for clinical trials investigating posterior composite restorations over periods of at least 5 years of follow-up published between 1996 and 2011. The search resulted in 34 selected studies. 90% of the clinical studies indicated that annual failure rates between 1% and 3% can be achieved with Class I and II posterior composite restorations depending on several factors such as tooth type and location, operator, and socioeconomic, demographic, and behavioral elements. The material properties showed a minor effect on longevity. The main reasons for failure in the long term are secondary caries, related to the individual caries risk, and fracture, related to the presence of a lining or the strength of the material used as well as patient factors such as bruxism. Repair is a viable alternative to replacement, and it can increase significantly the lifetime of restorations. As observed in the literature reviewed, a long survival rate for posterior composite restorations can be expected provided that patient, operator and materials factors are taken into account when the restorations are performed.
Article
Resin-dentin bond strength durability testing has been extensively used to evaluate the effectiveness of adhesive systems and the applicability of new strategies to improve that property. Clinical effectiveness is determined by the survival rates of restorations placed in non-carious cervical lesions (NCCL). While there is evidence that the bond strength data generated in laboratory studies somehow correlates with the clinical outcome of NCCL restorations, it is questionable whether the knowledge of bonding mechanisms obtained from laboratory testing can be used to justify clinical performance of resin-dentin bonds. There are significant morphological and structural differences between the bonding substrate used in in vitro testing versus the substrate encountered in NCCL. These differences qualify NCCL as a hostile substrate for bonding, yielding bond strengths that are usually lower than those obtained in normal dentin. However, clinical survival time of NCCL restorations often surpass the durability of normal dentin tested in the laboratory. Likewise, clinical reports on the long-term survival rates of posterior composite restorations defy the relatively rapid rate of degradation of adhesive interfaces reported in laboratory studies. This article critically analyzes how the effectiveness of adhesive systems is currently measured, to identify gaps in knowledge where new research could be encouraged. The morphological and chemical analysis of bonded interfaces of resin composite restorations in teeth that had been in clinical service for many years, but were extracted for periodontal reasons, could be a useful tool to observe the ultrastructural characteristics of restorations that are regarded as clinically acceptable. This could help determine how much degradation is acceptable for clinical success.
Article
This retrospective longitudinal study investigated the longevity of posterior restorations placed in a single general practice using 2 different composites in filler characteristics and material properties: P-50 APC (3M ESPE) with 70vol.% inorganic filler loading (midfilled) and Herculite XR (Kerr) with 55vol.% filler loading (minifilled). Patient records were used for collecting data. Patients with at least 2 posterior composite restorations placed between 1986 and 1990, and still in the practice for regular check-up visits, were selected. 61 patients (20 male, 41 female, age 31.2-65.1) presenting 362 restorations (121 Class I, 241 Class II) placed using a closed sandwich technique were evaluated by 2 operators using the FDI criteria. Data were analyzed with Fisher's exact test, Kaplan-Meier statistics, and Cox regression analysis (p<0.05). 110 failures were detected. Similar survival rates for both composites were observed considering the full period of observation; better performance for the midfilled was detected considering the last 12 years. There was higher probability of failure in molars and for multi-surface restorations. Both evaluated composites showed good clinical performance over 22 years with 1.5% (midfilled) and 2.2% (minifilled) annual failure rate. Superior longevity for the higher filler loaded composite (midfilled) was observed in the second part of the observation period with constant annual failure rate between 10 years and 20 years, whereas the minifilled material showed an increase in annual failure rate between 10 years and 20 years, suggesting that physical properties of the composite may have some impact on restoration longevity.
Article
One of the most controversial areas of restorative dentistry is the subject of liners and bases. Currently, there is no single protocol, with respect to the use of liners and bases, for clinicians to follow. This article is an in-depth literature review that discusses the use of liners and bases and the types of materials that are available to the restorative dentist. The new emerging concept of minimally invasive dentistry will require new restorative techniques. These changes will require the clinician to reevaluate their use of liners and bases. Other clinical considerations and findings from recent research are discussed.
Article
Information about the long-term clinical survival of large amalgam and composite restorations is still lacking. This retrospective study compares the longevity of three- and four-/five-surface amalgam and composite restorations relative to patients' caries risk. Patient records from a general practice were used for data collection. We evaluated 1949 large class II restorations (1202 amalgam/747 composite). Dates of placement, replacement, and failure were recorded, and caries risk of patients was assessed. Survival was calculated from Kaplan-Meier statistics. After 12 years, 293 amalgam and 114 composite restorations had failed. Large composite restorations showed a higher survival in the combined population and in the low-risk group. For three-surface restorations in high-risk patients, amalgam showed better survival.
Article
Polymerization shrinkage and shrinkage stress has been considered as one of the main disadvantages of resin composite restorations. Cavities with high C-factors increase the risk for interfacial failures. Several restorative techniques have been suggested to decrease the shrinkage stress. The purpose of this study was to evaluate the durability of techniques as oblique layering, indirect curing and/or a laminate with a poly-acid modified resin composite in direct Class I resin composite restorations in a 12-year follow-up. Each of 29 patients received one or two pair(s) rather extensive Class I restorations. The first restoration was a poly-acid modified resin composite/resin composite sandwich restoration and the second a direct resin composite restoration. Both restorations, except for the laminate layer, were placed with oblique layering and two-step curing technique. 90 restorations were evaluated annually with slightly modified USPHS criteria during 12 years. At 12 years, 38 pairs were evaluated. Two cases of slight post-operative sensitivity were observed in one patient. A cumulative failure rate of 2.4% was observed for both the resin composite and the laminate restorations. One laminate restoration showed non-acceptable color match, but was not replaced and one resin composite restoration showed a chip fracture. Five restorations were replaced due to primary proximal caries. The high failure rate expected in the high C-factor Class I cavity, associated with polymerization shrinkage and shrinkage stress, were not observed. The techniques used resulted in an excellent durability for the Class I resin composite restorations.
Article
Objective: The aim of the paper is to analyse an influence of the shape of the layers in photo-cured dental restorations of Class I on distribution of shrinkage stresses along the tooth-restoration interface. The study is a continuation of the previous considerations (Kowalczyk and Gambin (2008) [1]), where techniques, which reduce stress concentration at the top of the tooth-restoration interface, were considered. The analysis leads to proposition of new layer forming techniques, which diminish the stress peaks at the interface and prevent the crack propagation process. Methods: To find the stress distributions in the dental restoration layers and the tooth tissues the finite element method implemented in the ABAQUS (Simulia, Providence, USA) software is used. For Class I restoration of the premolar tooth, the axisymmetrical model is assumed. The restoration is made of four layers of a photo-cured composite. Between the tooth tissues and the restoration, a layer of bonding agent 0.01mm thick is placed and modeled by FEM with help of the cohesive elements. The assumed model takes into account an influence of changes of elastic properties and viscous effects. For each case of the restoration layers system, the Huber-Mises stresses are analysed. Results: The investigations show that the stresses near the restoration-tooth tissue interface are reduced due to viscous flow of the cured material and due to existence of a thin layer of the bonding agent. However, the stress distribution both, in the restoration and in the tooth tissues, is strongly dependent on a shape of the filling layers. Numerical simulations disclose that stress peaks are located at the top corners of each layer. The top corners of the last layer are the places where microleakage may occur. Stress concentrations at the corners of the preceding layers may lead to a growth of uprising crack. It will be shown that the flat layers in the restoration create relatively high values of the stress peaks. The rounded layers, with shapes close to those used in dental practice, reduce maximal stresses about 40%. According to a common opinion of dentists, the wedge-shaped layers give the best result. In the present paper, another way of the shrinkage stress reduction is proposed. Before the layering, one can cover the surface of the tooth cavity with a thin "pre-layer". Next, the remainder cavity may be filled with flat, rounded or wedged layers. It will be shown, that in the fillings with the pre-layers, stress peaks are reduced up to 75%, with respect to the fillings composed of the rounded layers only. The proposed method considerably reduces the shrinkage stress, both in the tooth restoration, as well as, in the tooth tissues. Significance: The fillings with the pre-layer are easy in application and its analysis gives promising results. The pre-layer may be applied with other layers of different shapes, and its thickness may vary. The method is recommended for cavities with a great loss of the tooth tissue.
Article
To measure cuspal deflection and tooth strain, plus marginal leakage and gap formation caused by polymerization shrinkage during direct resin composite restoration of root-filled premolars. Thirty-two first and second maxillary premolars were divided into four groups (n=8). Group 1 had standardised mesio-occlusal-distal (MOD) cavities and served as the control group. Group 2 had endodontic access and root canal treatment through the occlusal floor of the MOD cavity, leaving the axial dentine intact. Group 3 had endodontic access and root canal treatment with the mesial and distal axial dentine removed. Group 4 had endodontic access and root canal treatment with axial dentine removed and a glass ionomer base (GIC). All groups were restored incrementally using a low shrink resin composite. Cuspal deflection was measured using direct current differential transformers (DCDTs), and buccal and palatal strain was measured using strain gauges. Teeth were immersed in 2% methylene blue for 24h, sectioned and scored for leakage and gap formation under light and scanning electron microscopy. Total cuspal deflection was 4.9+/-1.3 microm for the MOD cavity (group 1), 7.8+/-3.3 microm for endodontic access with intact axial dentine (group 2), 12.2+/-2.6 microm for endodontic access without axial dentine (group 3), and 11.1+/-3.8 microm for endodontic access with a GIC base (group 4). Maximum buccal strain was 134+/-56, 139+/-61, 251+/-125, and 183+/-63 mustrain for groups 1-4 respectively, while the maximum palatal strain was 256+/-215, 184+/-149, 561+/-123, 264+/-87 mustrain respectively. All groups showed marginal leakage; however placement of GIC base significantly improved the seal (p=0.007). Cusp deflection and strain increased significantly when axial dentine was removed as part of the endodontic access. Placement of a glass ionomer base significantly reduced tooth strain and marginal leakage. Therefore, a conservative endodontic access and placement of a glass ionomer base are recommended if endodontically treated teeth undergo direct restoration with resin composite.
Article
The study conducted in a bacterial-based in vitro caries model aimed to determine whether typical inner secondary caries lesions can be detected at cavity walls of restorations with selected gap widths when the development of outer lesions is inhibited. Sixty bovine tooth specimens were randomly assigned to the following groups: test group 50 (TG50; gap, 50 microm), test group 100 (TG100; gap, 100 microm), test group 250 (TG250; gap, 250 microm) and a control group (CG; gap, 250 microm). The outer tooth surface of the test group specimens was covered with an acid-resistant varnish to inhibit the development of an outer caries lesion. After incubation in the caries model, the area of demineralization at the cavity wall was determined by confocal laser scanning microscopy. All test group specimens demonstrated only wall lesions. The CG specimens developed outer and wall lesions. The TG250 specimens showed significantly less wall lesion area compared to the CG (p < 0.05). In the test groups, a statistically significant increase (p < 0.05) in lesion area could be detected in enamel between TG50 and TG250 and in dentine between TG50 and TG100. In conclusion, the inner wall lesions of secondary caries can develop without the presence of outer lesions and therefore can be regarded as an entity on their own. The extent of independently developed wall lesions increased with gap width in the present setting.
Article
Composite resin restoration of posterior teeth necessitates a reassessment of cavity insulation and dentine conditioning. The primary function of cavity insulation under composite resin restorations is to prevent the formation of a bacterial, fluid-filled gap nearest the cavity walls. Gap formation can contribute not only to sensitivity to cold but also to pulpal complications and secondary caries. Unfortunately, none of the currently available systems for cavity insulation fulfil this basic requirement. The evidence suggests, however, that the most effective insulator is a very thin liner which does not pool in retention grooves and which can cover the entire cervical wall as well as the remaining cavity walls, except for etched enamel. Such a liner should not bond to composite resin and thus be detached from the dentine during polymerization contraction of the composite. Nor should it be leached away by the oral fluids. In order to preserve the liner, the air-filled contraction gap which forms between liner and composite should be impregnated with resin immediately after the major setting contraction of the composite. In this context the use of retention grooves in Class II and Class V cavities is recommended, to minimize the effect of thermal and occlusal stress. Combined with etched enamel walls, well-placed retention grooves can reduce the risk of gap formation and creep due to mechanical stress and the deformation potential of the tooth structure and the filling. The smear layer can disappear entirely and be replaced by fluid and bacteria. It should therefore be removed, but the smear plugs blocking the apertures of the dentinal tubules should be left undisturbed and reinforced by impregnation with fluoride.(ABSTRACT TRUNCATED AT 250 WORDS)
Article
The use of adhesive resin composites for restoration of Class V lesions often results in cervical marginal gap formation due to polymerization contraction. In this laboratory study, flexible linings applied between the bonding agent and the bulk restorative appeared to preserve the marginal integrity of Class V restorations during curing. Measurements of the polymerization contraction stress showed 20 to 50% relief due to various flexible intermediate materials. Apparently, reduction of the total stiffness by application of an intermediate layer can render the total restoration sufficiently flexible to compensate for that part of the stress that would otherwise exceed the bond strength.
Article
Teeth, adhesively restored with resin-based materials, were modeled by 3D-finite elements analysis that showed a premature failure during polymerization shrinkage and occlusal loading. Simulation of Class II MOD composite restorations with a resin bonding system revealed a complex biomechanical behavior arising from the simultaneous effects of polymerization shrinkage, composite stiffness and adhesive interface strain. Due to a polymerization contraction, shrinkage stress increases with the rigidity of the composites utilised in the restoration, while the cusp movements under occlusal loading are inversely proportional to the rigidity of the composites. The adhesive layer's strain also plays a relevant role in the attenuation of the polymerization and occlusal loading stresses. The choice of an appropriately compliant adhesive layer, able to partially absorb the composite deformation, limits the intensity of the stress transmitted to the remaining natural tooth tissues. For adhesives and composites of different rigidities, FEM analysis allows the determination of the optimal adhesive layer thickness leading to maximum stress release while preserving the interface integrity. Application of a thin layer of a more flexible adhesive (lower elastic modulus) leads to the same stress relief as thick layers of less flexible adhesive (higher elastic modulus).
Article
The present prospective, longitudinal study assessed the outcome of posterior extensive restorations and identified risk factors for failure of the restorations. The sample consisted of 722 amalgam restorations, 115 composite resin restorations and 89 crowns placed in 428 adults by one dentist from 1982 to 1999 in Belgium. Well-defined criteria were used for cavity preparation design, type of retention and selection of restorative material. At the closure of the study 48% of the restorations were well functioning, 24% were lost to lack of follow-up, and 28% had failed. The most frequent reasons for failure were fracture of restoration (8%), secondary caries (6%) and fracture of cusp (5%). Failures were more often found in premolar teeth (34%) than in molars (27%) (P=0.05) and occurred in 28% of the amalgam restorations, 30% of the resin restorations and 24% of the crowns (P=0.55). Molar restorations were more frequently repaired than replaced in contrast to premolar restorations. The highest percentage of extractions was related to complete amalgam restorations in premolars. The Kaplan-Meier median survival times were 12.8 years for amalgam restorations, 7.8 years for resin restorations, and more than 14.6 years for crowns, considering all retreatment as failures (P=0.002). The survival was influenced by extension of restoration, age of patient, pulpal vitality, 3-year period of treatment, use of base material and dentinal retentive pins. Within the limits of the study the data support the view that extensive amalgam restorations but not composite resin restorations can be used as an appropriate alternative to crowns, with due consideration to the longevity of the restorations.
Article
This review provides a survey on the longevity of restorations in stress-bearing posterior cavities and assesses possible reasons for clinical failure. The dental literature, predominantly since 1990, was reviewed for longitudinal, controlled clinical studies and retrospective cross-sectional studies of posterior restorations. Only studies investigating the clinical performance of restorations in permanent teeth were included. Longevity and annual failure rates of amalgam, direct composite restorations, compomers, glass ionomers and derivative products, composite and ceramic inlays and cast gold restorations were determined for Class I and II cavities. Mean (SD) annual failure rates in posterior stress-bearing cavities are: 3.0% (1.9) for amalgam restorations, 2.2% (2.0) for direct composites, 3.6% (4.2) for direct composites with inserts, 1.1% (1.2) for compomer restorations, 7.2% (5.6) for regular glass ionomer restorations, 7.1% (2.8) for tunnel glass ionomers, 6.0% (4.6) for ART glass ionomers, 2.9% (2.6) for composite inlays, 1.9% (1.8) for ceramic restorations, 1.7% (1.6) for CAD/CAM ceramic restorations and 1.4% (1.4) for cast gold inlays and onlays. Publications from 1990 forward showed better results. Indirect restorations exhibited a significantly lower mean annual failure rate than direct techniques (p=0.0031). Longevity of dental restorations is dependent upon many different factors, including material, patient- and dentist-related. Principal reasons for failure were secondary caries, fracture, marginal deficiencies, wear and postoperative sensitivity. We need to learn to distinguish between reasons that cause early failures and those that are responsible for restoration loss after several years of service.
Article
According to the "elastic bonding" concept, a thick intermediate layer of flexible resin has been suggested to absorb part of the polymerization shrinkage stress and to absorb shocks during function. In this study, the effect of an additional intermediate layer of a low-viscosity resin on the microrotary fatigue resistance (microRFR) of a hybrid composite bonded to dentin was evaluated. The hypotheses tested were that an intermediate layer of a low-viscosity resin (i) increases the microRFR to dentin, but (ii) has no effect on the static bond strength. Microtensile bond strength (microTBS) samples were loaded until failure or inserted in a microrotary fatigue testing device. Specimens were tested at 4 Hz until failure or until 10(5) cycles were reached. An additional intermediate elastic layer had no effect on the static microTBS, but significantly lowered the median microRFR from 28.4 MPa to 21.6 MPa. However, the application of an intermediate flexible layer had, no effect on the static microTBS. In conclusion, an additional elastic intermediate layer did decrease significantly the microRFR (rejection of hypothesis i), but did not alter the microTBS (acceptance of hypothesis ii). The decrease in microRFR most likely may be explained by the lower mechanical properties of the intermediary layer.