Comparison of microleakage of composite restorations using fifth and sixth generation dentin bonding agent: an in vivo study

Comparative Evaluation of Microleakage With Total-Etch, Universal (Self-Etch Mode), and Nano Adhesive Systems in Class V Composite Restorations: An In-Vitro Study

OBJECTIVES

The adhesion of bonding agents and their longevity are of interest to dentistry. Microleakage remains the major cause of composite restoration failures, which in turn depends on bonding between the restorative material and tooth substrate. The objective of this study is to evaluate and compare the microleakage with total-etch, universal, and nano adhesive systems in Class V composite restorations, utilizing a dye penetration method.

METHODS

Forty-five extracted premolars were included in the present study, and a Class V cavity on the facial surface of each tooth was prepared. The samples were divided into three groups of 15 teeth each depending on the bonding agents used, following which composite restoration was done. Specimens were thermocycled, and nail varnish was applied except around the restorations. Specimens were then immersed in 2% methylene blue for 24 hours and rinsed; sectioning was done and viewed under a stereomicroscope with 10X magnification.

RESULTS

The mean microleakage score was reported to be significantly higher in the universal adhesive system in the self-etch mode (3.60 ± 0.55) when compared with the total-etch adhesive system (2.40 ± 0.55) and least in the nano adhesive system (1.20+.45) (p value <.05).

CONCLUSION

The study findings revealed that nano adhesives showed lesser microleakage as compared to total-etch and universal adhesive systems.

CLINICAL SIGNIFICANCE

The study strengthens the findings that the nano adhesives have reduced microleakage, resulting in better marginal integrity and increased longevity of restoration. This study signifies that an eighth-generation bonding agent is reported to be better than the other bonding agents used in this study.

Polymerization stress--is it clinically meaningful?

OBJECTIVES

The objective of this article is to discuss the evidence for polymerization shrinkage and shrinkage stress of dental composite restoratives in terms of its potential relevance to the clinical situation

METHODS

Articles relating to the issue of polymerization contraction stress generation in dental composite materials, and the factors that influence it, were reviewed and included. Particular attention was paid to evidence derived from clinical studies. Articles were identified through PubMed and through the bibliographies of other articles.

RESULTS

There is extensive evidence for the presence of polymerization contraction stress in dental composites, as well as evidence for its deleterious effects, which include marginal leakage, gap formation, cuspal deflection, tooth cracking, reduced bond strength and lowered mechanical properties of the restorative. There is little, if any, direct evidence for the clinical effect of these contraction stresses. No study has directly established a link between these stresses and enhanced postoperative sensitivity or recurrent caries, for example. However, the concern over these stresses and the manner in which they influence the placement of current composite materials demonstrates that they are considered to be very important.

CONCLUSION

Though no direct evidence exists to prove that the generation of contraction stress in dental composite restorations causes reduced clinical longevity, the indirect evidence from numerous in vitro studies and the concern over controlling their effects proves that they are clinically relevant.