Abstract
Aims: This in vitro study was conducted to investigate the effect of various bur types, bonding agents, and resin composite restorative materials on the microleakage at occlusal and gingival tooth/composite interfaces. Materials and methods: One hundred and sixty non carious, extracted human premolars were mounted in acrylic resin, the teeth were randomly divided into four groups (n=40) according to the bur types (diamond round bur, diamond fissure bur, carbide round bur, and carbide fissure bur). A standardize class V (3×2×2) mm dimensions cavity was prepared on the facial surface of each tooth (each group with corresponding bur type), then each group was divided into two subgroups (n=20) ac-cording to the type of adhesive systems used (P&B NT,& I-Bond), after that each subgroup farther divided in to two subgroups (n=10) according to the type of composite restorative materials (Arabesk & Tg) the final number of groups were (16) of (10) teeth in each. After the specimens were finished they stored for one month in 37ºc distilled water, thermo cycled for 500 cycles between (5ºc & 55ºc) and immersed in 0.5% methylene blue solution for 24h., and then sectioned longitudinally. For both occlusal and gingival margins, dye penetration at the tooth/composite interfaces were scored from 0-3 under stereomicroscope at a magnification x10, data were analyzed using unpaired T-test, ANOVA, and Duncan’s multiple rang test at 5% significant level. Results: T-test represent that there was less microleakage at occlusal margins than the gingival margins. ANOVA and Duncan’s multiple rang tests show that the less leakage was occurred with the use of carbide fissure bur at both occlusal and gingiv-al margins while the diamond round bur show the highest leakage at both margins. P&B NT show less leakage than I-Bond at the occlusal margin but there was no significant difference between P&B NT & I-Bond at the gingival margins also there was no significant difference between the ( Arabesk & Tg ) restorations at both occlusal and gingival margins. Conclusions: Within the limitations of this study results show that there was less microleakage at the occlusal margin than that at the gingival margins, and the use of carbide fissure bur to prepare the cavities for receiving resin composite materials show the least microleakage than other type of burs, and although phosphoric acid has been intensely used to etch the dental substrates (enamel and dentin) for providing a good bonding, self-etching adhesives can be considered an alternative methods to provided a good bonding for restorative procedures
