IN VITRO EVALUATION OF MARGINAL MICROLEAKAGE IN RESTORATIONS CLASS V WITH COMPOSITE RESINS

OBJECTIVE: The aim of this study was to evaluate the marginal microleakage in restorations with three different composite resins. MATERIAL AND METHODS: Thirty premolars were used, where class V cavities were made. The samples were divided into three groups: G1 (Microparticulate), G2 (Micro-hybrid), G3 (Nano-hybrid). After the restorations have been made, the samples were thermocycled for 250 cycles. The teeth were waterproofed and placed in 1% methylene blue solution for 24 hours. The samples were sectioned in lingual vestibular direction and dye penetration was evaluated with the aid of a stereoscopic magnifying glass based on the scores: Grade 0: no infiltration; Grade 1: dye infiltration until one third of the surrounding wall; Grade 2: until two-thirds of the surrounding wall; Grade 3: until three-thirds of the surrounding wall, reaching or not the bottom wall. Infiltration findings were statistically evaluated using the non-parametric Kruskal-Wallis test. RESULTS: The quantitative evaluation of the degree of dye penetration showed that all groups had marginal infiltration, however they had it in varying degrees, highlighting that the nano-hybrid composite resin presented the lowest values of marginal infiltration and the microparticulate composite resin had the highest values, and the group of micro-hybrid and nano-hybrid composite resin did not present statistically significant differences. CONCLUSION: All the groups evaluated have undergone infiltration to some degree.