Does different application modes of universal adhesives with universal resin composites affect the microleakage in class V cavities? An in vitro study.

Aim: Composite restorations often have gingival margins near the cemento-enamel junction (CEJ), where the microleakage of these margins can significantly contribute to the restoration failure, especially in the cervical lesions. It is important to determine the microleakage is crucial, as it typically occurs through the interfacial gap between the tooth and the restoration. Various resin composites and techniques have been developed to minimize this gap and reduce the risk of microleakage. The aim of this in vitro study was to evaluate the levels of microleakage of different modes of a universal adhesive and two novel resin composites in restoring class V cavities in the central incisors.

Methods: Sixty-six freshly extracted sound human central incisors of the similar size were randomly assigned to 2 groups (n = 33 per group) according to the brand of resin composite. Each group was further divided into 3 subgroups based on the Scotch Bond Universal (3 M ESPE, Saint Paul, MN, USA) application protocol used: (a) total etch, (b) self-etch and (c) selective etch. After composite restoration completed with Omnichroma (Tokuyama Dental Corp., Tokyo, Japan) and Filtek Universal Restorative (3 M ESPE, Saint Paul, MN, USA), each tooth was immersed in a 0.5% basic fuchsin dye solution at 37C for 24 h. After dye penetration, teeth were sectioned and evaluated with conventional (scoring) and digital methods (ImageJ). The intra- and inter-examiner agreement was estimated according to the Kappa statistics and the results were analyzed with the one-way ANNOVA and the Kruskal-Wallis test (p < 0.05).

Results: The rates of microleakage of the gingival and incisal margins are statistically similar, regardless of the composite brand and the method of application of the universal adhesive.

Conclusion: The microleakage exhibited by current adhesives and resins is independent of the adhesive application mode and measurement method.