QUANTITATIVE MICROLEAKAGE OF SOME DENTINAL BONDING RESTORATIVE SYSTEMS

The quantitative microleakage of class V cementum (dentin) cavities re stored with six dentinal bonding restorative systems was determined in vitro. Ninety extracted human permanent first and second mandibular a nd maxillary premolars were used in this study. Class V preparations w ere made in cementum (dentin) at the root facial surfaces. The prepara tions were restored with 1) a dentin bonding system containing 2% HEMA and BisGMA and a light-cured microfilled composite; 2) the same mater ials only substituting META/MMA base and TBB catalyst monomers for the BisGMA sealer; 3) a dentin bonding system containing 35% HEMA with ME TA/MMA base and TBB catalyst, and a light-cured microfilled composite; 4) the same materials with an experimental light-cured hybrid composi te; 5) the same dentin bonding system only substituting the 35% glycer yl methacrylate for the 35% HEMA and using the microfilled composite; and 6) the previously described system with a substitution of 0.5 mol EDTA for the 10% citric acid -3% FeCl3. Fifteen teeth were restored wi th each procedure. The restorations were finished with 12-bladed carbi de burs 15 min after placement, the teeth were stored in saline at 37- degrees-C for 24 h, finished with Sof-Lex discs and then thermocycled in 2% methylene blue solution 500 times between 50-degrees-C and 8-deg rees-C with a dwell time of 15 s. Quantitative microleakage was determ ined by a spectrophotometric dye-recovery method and expressed in mug/ dye/restoration. The data were analyzed by ANOVA, Student-Newman-Keuls and Kruskal-Wallis tests. The quantitative microleakage of the teeth restored with the adhesive systems containing 35% glyceryl methacrylat e was significantly reduced. The bonding mechanism of glyceryl methacr ylate is not known.