Cavity preparation devices: Effect on microleakage of Class V resin-based composite restorations

Purpose : To evaluate the effect of cavity preparation device (i.e. carbide bur, diamond bur, air abrasive, Sonicsys, and Er:YAG laser) on microleakag e of Class V resin-based composite (RBC) restorations, the tooth restoratio n interface and dentin ultrastructure. Materials and Methods: Eight groups (n=18) of 9 human molars each were prepared on the buccal and lingual surfa ces for Class V RBC restorations using five preparation devices: Group 1: c arbide bur #8 round; Group 2: diamond bur #801; Group 3: KCP 1000 air abras ion unit; Group 4: Sonicsys Approx.; Group 5: Er:YAG laser; Group 6: carbid e bur plus air abrasive; Group 7: carbide bur plus laser, and Group 8: lase r without etching. Circular cavity preparations, 3 nun diameter and 1.5 mm deep, were cut at the CEJ on the buccal and lingual surfaces of each tooth. A bevel was placed on the enamel margin. All cavities were restored using Single Bond adhesive system and Silux Plus according to manufacturer's dire ctions, with the exception that no etchant was used with Group 8. After the rmocycling, specimens were tested for microleakage using silver nitrate met hodology. Dye penetration data was collected and subjected to non-parametri c statistical analysis. SEM analysis of the dentin-RBC interface, as well a s the effect of each cavity preparation device on the surface of dentin was performed. Results: Microleakage did not occur in enamel for any method of cavity preparation when the enamel was etched prior to adhesive applicatio n. Kruskal-Wallis One-way ANOVA revealed differences in dentin microleakage among the tested groups at alpha = 0.05. Mann-Whitney Test for Paired Comp arisons at (alpha = 0.01 demonstrated significantly greater dentin microlea kage in Groups 5 and 7 compared to all groups except Group 3 (air abrasive) . Although Group 8 had the least microleakage in dentin, this was not signi ficantly different from Groups 1, 2, 4 and 6. SEM observation revealed hybr idization at the dentin-resin interface for all groups except for Group 8 ( laser prepared, non-etched). Surface analysis showed differences related to the operating mode of each preparation device.