Microinfiltração marginal de cavidades classe V restauradas com diferentes tipos de resina composta

Abstract

This study evaluated, in vitro, the influence of different types of composite resins in microleakage of class V cavities with margins in enamel and dentin. Cavities were prepared on the buccal face of forty bovine incisors with spherical carbide bur (#8) on the enamel/cementum junction. The teeth were randomly divided into 4 groups (n=10): GI: Charisma; GII: Venus; GIII: Direct Empress; GIV: Filtek Z350XT. Then, an etch-and-rinse adhesive system (Single Bond 2, 3M / ESPE) was applied as recommended by the manufacturer’s instructions. The specimens were restored incrementally (1.0 mm), and lightcured for 20s, with light intensity of 600mW/cm2. Following, they were subjected to the microleakage test with 50% silver nitrate solution. The specimens were sectioned longitudinally and dye penetration rate was analyzed according the following score: (0) no dye penetration; (1) dye penetration limited to the enamel; (2) dye reaching the dentin; (3) dye reaching the pulp wall. Data were statistically analyzed for the "restorative material" factor with the Kruskal-Wallis test (α=0.05). For the "margin" factor (enamel vs. dentine), the Mann-Whitney test (α=0.05) was applied. The results showed no statistical difference between the groups for the "restorative material" factor, both in enamel (p=0.78) and dentin (p=0.68). Nevertheless, the "margin" factor showed a significant difference between the two types of tissue, with better results found in enamel margin (p=0.018). In conclusion, class V composite resin restorations have demonstrated a better microleakage performance in enamel margin than dentin margin. Key words: Composite resins; Dental Enamel; Dentin; Microleakage.