Systematic reviews: I. The correlation between laboratory tests on marginal quality and bond strength. II. The correlation between marginal quality and clinical outcome.
ABSTRACT An accepted principle in restorative dentistry states that restorations should be placed with the best marginal quality possible to avoid postoperative sensitivity, marginal discoloration, and secondary caries. Different laboratory methods claim to predict the clinical performance of restorative materials, for example, tests of bond strength and microleakage and gap analysis. The purpose of this review was twofold: (1) find studies that correlated the results of bond strength tests with either microleakage or gap analysis for the same materials, and (2) find studies that correlated the results of microleakage and/or gaps with the clinical parameters for the same materials. Furthermore, influencing factors on the results of the laboratory tests were reviewed and assessed.
For the first question, searches for studies were conducted in the MEDLINE database and IADR/AADR abtracts online with specific search and inclusion criteria. The outcome for each study was assessed on the basis of the statistical test applied in the study, and finally the number of studies with or without correlation was compiled. For the second question, results of the quantitative marginal analysis of Class V restorations published by the University of Zürich with the same test protocol and prospective clinical trials were searched that investigated the same materials for at least 2 years in Class V cavities. Pearson correlation coefficients were calculated for pooled data of materials and clinical outcome parameters such as retention loss, marginal discoloration, marginal integrity, and secondary caries. For the correlation of dye penetration and clinical outcome, studies on Class V restorations published by the same research institute were searched in MEDLINE that examined the same adhesive systems as the selected clinical trials.
For the correlation bond strength/microleakage, 30 studies were included into the review, and for the correlation bond strength/gap analysis 18 studies. For both topics, about 80% of the studies revealed that there was no correlation between the two methods. For the correlation quantitative marginal analysis/clinical outcome, data were compared to the clinical outcome of 11 selected clinical studies. In only 2 out of the 11 studies (18%) did the clinical outcome match the prognosis based on the laboratory tests; the remaining studies did not show any correlation. When pooling data on 20 adhesive systems, no correlation was found between the percentage of continuous margin of restorations placed in extracted premolars and the percentage of teeth that showed no retention loss in clinical studies, no discoloured margins, acceptable margins, or absence of secondary caries. With regard to the correlation of dye penetration and clinical studies, no sufficient number of studies was found that matched the inclusion criteria. However, literature data suggest that there is no correlation between microleakage data as measured in the laboratory and clinical parameters.
The results of bond strength tests did not correlate with laboratory tests that evaluated the marginal seal of restorations such as microleakage or gap analysis. The quantitative marginal analysis of Class V fillings in the laboratory was unable to predict the performance of the same materials in vivo. Therefore, microleakage tests or the quantitative marginal analysis should be abandoned and research should focus on laboratory tests that are validated with regard to their ability to satisfactorily predict the clinical performance of restorative materials.
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ABSTRACT: Background: Macro-bond strength tests resulted in cohesive failures and overestimation of bond strengths. To reduce the flaws, micro-bond strength tests were introduced. They are the most commonly used bond strength tests. Objective: Thus the objective of this review is to critically review the reliability of micro-bond strength tests used to evaluate resin-tooth interface. Data Collection: Relevant articles published between January 1994 and July 2013 were collected from Pubmed database, Google scholar and hand searched journals of Conservative Dentistry, Endodontics and Dental materials. Data Synthesis: Variables that influence the test outcome are categorized into substrate related factors, factors related to specimen properties, specimen preparation and test methodology. Impact of these variables on the test outcome is critically analyzed. Conclusion: Micro-bond tests are more reliable than macro-bond tests. However, no standard format exists for reporting the bond strength tests which could lead to misinterpretation of the data and bonding abilities of adhesives.Journal of Conservative Dentistry 09/2014; 17(5):420-426.
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ABSTRACT: Objective: The aims of this study were to (1) introduce a novel three-dimensional (3D) method using micro-computed tomography (μCT) imaging to visualize and quantify the polymerization volumetric shrinkage of one regular composite and one bulk fill composite and (2) evaluate the effect bonding agent application has on polymerization shrinkage pattern within the preparation walls. Method: Standardized class I cavities (2.5 mm depth X 5mm length X 5mm wide) were prepared in 24 extracted human third molars. They were divided into 4 groups (n=6): Group 1, regular composite without bonding agent (Vitalescence, Ultradent Product Inc, South Jordan, UT, USA); Group 2, low shrinkage composite without bonding agent (SureFil SDR Flow, Dentsply Caulk, Milford, DE, USA); Group 3, regular composite with bonding agent (Peak Universal Bond, Ultradent Product Inc, South Jordan, UT, USA); Group 4, low shrinkage composite with bonding agent (XP Bond, Dentsply Caulk, Milford, DE, USA). Each tooth was scanned via µCT at cavity preparation, after cavity filling, and after light-cured polymerization. Acquired μCT data were imported into Amira software for analysis. Result: The proposed method revealed that all restorations underwent volumetric polymerization shrinkage, with significant differences between them, regardless of adhesive application. The bulk fill composite showed lower change in volume when compared to the regular one. The use of dental adhesive decreased the volumetric shrinkage. Conclusion: This experiment confirms that dental adhesive application at the interface restoration–tooth is a critical factor to counteract the volumetric loss and unwanted gaps following light-curing. μCT imaging has the potential to be a feasible quantification tool to quantify resin composite shrinkage and to detect the location of gaps generated by polymerization shrinkage.AADR Annual Meeting & Exhibition 2014; 03/2014
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ABSTRACT: Adhesive systems are selected based on their bond strengths achieved while testing in laboratories. These bond strengths can predict the longevity of a restoration to some extent. There were several discrepancies in the reported bond strengths. To critically review the reliability of macro-bond strength tests used to evaluate resin-tooth interface. Relevant literature published between January 1983 and May 2013 was collected from PubMed database, Google scholar, and hand-searched journals of Conservative Dentistry, Endodontics and Dental materials. Variables that influence the test outcome are categorized into substrate-related factors, factors related to specimen properties, preparation of specimens, and test methodology. Impact of these variables on the test outcome is critically analyzed. There is lack of a standard format for reporting the bond strength tests, which could lead to misinterpretation of the data and bonding abilities of adhesives.Journal of Conservative Dentistry 07/2014; 17(4):305-11.