The Effect of Cutting Efficacy of Diamond Burs on Microleakage of Class V Resin Composite Restorations Using Total Etch and Self Etch Adhesive Systems

Objective: in this study, the effect of bur cutting efficacy was evaluated on microleakage of class v composite restorations with two adhesive systems. materials and methods: class v cavities were produced on sound extracted human teeth, which had been assigned randomly to one of six groups (n=15) as follows: groups 1 and 6 were prepared using used rough diamond bur; group 2 and 5 were prepared using new rough diamond bur; group 3 and 4 were prepared using soft diamond bur. after applica-tion of single bond (3m dental product, usa) in groups 4,5 and 6 and clearfil se bond [kurary medical inc. japan] in groups 1,2 and 3, all cavities were restored with composite resin. the teeth were thermocycled and microleakage was evaluated by dye penetration. kruskal-wallis and mann-whitney tests with bonferroni's correction were used for statis-tical analysis. results: the results showed that gingival margins significantly leaked more than occlusal margins for all bur types and bonding systems. using the same adhesive system in gingi-val margins, significant difference was seen between bur types and using the same bur type in occlusal margins, there was a significant difference between the two types of adhe-sive systems. conclusion: cutting efficiency of bur had a great effect on microleakage of resin compo-site restorations. so long term use of burs may result in an increase in microleakage of composite resin restorations.