Sistemas adesivos de cura dual em cavidades dentinárias de 4 mm: efeito sobre propriedades físicas de interfaces adesivas

Abstract

The proper polymerization of adhesive system influences the mechanical properties and longevity of restoration. In deeper restorations, dual cure adhesives may be a viable alternative in pursuit of complete polymerization. Objective: To evaluate the influence of different adhesive strategies on the degree of conversion on hybrid layer (DC), bond strength (BS) and failure pattern (FP) of adhesive interfaces of dental cavities. Methods: A total of 153 bovine incisors (n = 17) were used to create cavities with 4 mm depth and high C-factor C of magnitude 2.2,which were then restored with the composites Filtek Z250 XT [XT], Filtek Bulk Fill [FB] and Filtek Bulk Fill Flow [FF] with the adhesives Single Bond Universal [SB], Adper Scotchbond Multiuso Plus cured [MPf] or without photo-activation [MPd].The DC analysis was performed in micro Raman, the BS in a universal testing machine and the PF was done with stereoscopic magnifying glass. Data of DC were analyzed by three-way analysis of variance (ANOVA) and Tukey test (p<0.05) and data of BS by two-way ANOVA and Tukey test (p<0.05), while the FP were analyzed through descriptive statistics. Results: There was no statistically significant difference between top and bottom regions for resin and adhesive for the DC. There was a statistically significant difference between the adhesives (p<0.05) for DC and BS. There was a statistically significant difference between the resins (p<0.05) for the DC and BS. The failure pattern recorded a greater amount of cohesive failure in the samples. Conclusions: The Adper ™ Scotchbond ™ Multi-Purpose Plus Adhesive strategies with and without photoactivation increased the degree of conversion and bond strength compared to self-etch adhesive Single Bond Universal. Moreover, efficient polymerization of the base of sample assures a good polymerization of the adhesive systems on the bottom side of 4 mm cavities for restorations with Bulk Fill resins.