Influência da incorporação de uma catequina nas propriedades físico-químicas de um sistema adesivo universal e o desempenho clínico em lesões cervicais não cariosas: estudos “in vitro” e clínico randomizado

Abstract

One of the strategies to increase the clinical longevity of adhesive restorations is the use of substances responsible for inhibiting proteolytic enzymes present in dentin. For this, the present study evaluated the effect of the incorporation of 0.1% (w/w) epigallocatechin-3-gallate (EGCG) into a universal adhesive (SBU) on the degree of conversion (DC), water sorption, solubility, flexural strength, modulus of elasticity and bond strength to dentin (WS, SL, FS, ME and μTBS, respectively) by means of microtensile tests (after 24 hours, 6 and 12 months of storage) and micropermeability. In addition, clinical performance was evaluated when applied in self-etch (SE) and etch-and-rinse (ER) strategies in non-carious cervical lesion restorations (LCNC). Initially, the analysis of the degree of conversion was performed by the FTIR. Adhesive specimens were made following the ISO standard for the WS, SL, FS and ME tests. Subsequently, 40 teeth were randomly divided into four groups (n = 10): control etch-and-rinse (ER); control self-etch (SE); experimental etch-and-rinse (ER-EGCG); and experimental self-etch (SE-EGCG). Then, the adhesion procedures and bond strength tests were performed on a universal test machine. Micropermeability was performed using laser confocal microscopy. For the randomized clinical trial, 29 volunteers were selected, and 160 LCNC restorations were performed by a single operator, randomly assigned to the four groups described above. The evaluation of the clinical performance of the restorations was performed by the FDI method (World Dental Federation) in the immediate periods and after 6 and 12 months by two "blind" evaluators. Data from the DC, WS, SL, FS and ME tests were statistically analyzed using the t-test (p <0.05). Microtensile bond strength test data (μTBS) were analyzed using the two-way ANOVA test (p <0.05) and the clinical evaluation data were evaluated by the McNemar and Kruskal-Wallis test (p <0.05). The in vitro results showed difference only in WS and ME of the SBU after EGCG incorporation (p <0.05), with no statistically significant difference in the other properties tested. Regarding the bond strength, the SE-EGCG group showed an increase in the mean union strength when compared to the control SE group after 12 months of storage (p <0.05). In the ER strategy, there was no significant difference between the groups in all the evaluated periods (p>0.05). Regarding the micropermeability analyze, the self-etching groups showed a better behavior, independent of the presence of EGCG. After 12 months, the retention rates were 97.37% for the SE group, 94.73% for the SE-EGCG group and 100% for the ER and EGCG groups. In conclusion, the incorporation of 0.1% EGCG into the universal adhesive tested did not significantly affect its physico-chemical properties and had a positive effect on bond strength after 12 months when applied in the self-etching strategy. In addition, it did not impair the clinical performance of LCNC restorations after 12 months.