RESUMEN
The purpose of the present study was to evaluate, in vitro, the effect of three different cavity configurations on the microleakage of resin composite root-end fillings. Conventional root therapy was peformed in 60 anterior human teeth. Apicectomies were made, teeth were randomly divided in three groups and the apical cavities were prepared as following: Group 1 - classic Class I cavities; group 2 - saucer-shaped cavities; group 3 - adhesive cavities (round angles). The cavities were prepared with high speed pieces under air-water cooling and burs were replaced after four preparations. All cavities were restored with a self-etching adhesive system (Clearfil SE Bond, Kurakay) and a hybrid resin composite (Filtek Z-250, 3M Espe®). Teeth were isolated with two coats of nail varnish, except for the apical region, and immersed in methylene blue for 14 days, at 37ºC. Specimens were washed, sectioned and evaluated for absence or presence of dye penetration, in a stereomicroscope (40 X). Data were subjected to statistical analysis using Kruskal-Wallis test, with p<0.05. The degree of dye leakage was low in all groups (75-90% leakage-free specimens). No statistically significant difference was found between the three groups (p>0.05). Within the limitations of this study, cavity configuration did not have influence on microleakage of composite restorations used in root-end cavities.