[Comparative study of microleakage in class V restorations].
The aim of this study was to analyze the laboratorial performance of dentin-bonding agents, glass ionomer cements and compomers, regarding the sealing of the gingival margins of class V cavities, prepared on the cementoenamel junction. Standardized class V cavities (4 x 3 x 2 mm) were prepared on the buccal and lingual/palatal surfaces of 20 extracted human third molars. Forty cavities were restored with different combinations of materials, as follows: group 1 (G1)--Vitremer (3M); group 2 (G2)--Vitremer (3M) and Syntac Sprint/Tetric Ceram (Vivadent); Group 3 (G3)--Syntac Sprint/Tetric Ceram (Vivadent); Group 4 (G4)--Prime & Bond 2.1/Variglass (Dentsply). After thermocycling in methylene blue dye, the specimens were longitudinally sectioned and analyzed with a stereoscopic lens in order to evaluate the leakage on the gingival margin. The obtained data were analyzed with the Mann-Whitney test, and the results revealed significantly better sealing (p = 0.05) in G1, when compared with G4. No significant differences were seen between the other groups. Under the given conditions, Vitremer offered better sealing of the gingival margin than the system Prime & Bond 2.1/Variglass.