Effect of cavity preparation techniques and different preheating procedures on microleakage of class V resin restorations

OBJECTIVES This study aimed to evaluate the extent of microleakage of a single type of composite resin (Clearfil Majesty Posterior, Kuraray, Osaka, Japan) following different preheating procedures in Class V cavities prepared with a diamond bur or Er:YAG (erbium: yttrium aluminum garnet) laser. METHODS The study randomly divided 72 permanent molar teeth divided into eight groups (n = 9): G1: Diamond bur-unheated composite resin (room temperature-24 ºC); G2: Diamond bur-composite preheated to 37 ºC; G3: Diamond bur-composite preheated to 54 ºC; G4: Diamond bur-composite preheated to 68 ºC; G5: Er:YAG laser-unheated composite resin (room temperature-24 ºC); G6: Er:YAG laser-composite preheated to 37 ºC; G7: Er:YAG laser-composite preheated to 54 ºC; and G8: Er:YAG laser-composite preheated to 68 ºC. The specimens were subjected to a thermal cycling regimen of 5000 cycles between 5 and 55 ºC; then they were immersed in a solution of 0.5% basic fuchsin dye for 24 hours. The dyed specimens were sectioned in the buccolingual direction and dye penetration was scored in a blinded manner using a five-point qualitative scale. Microleakage scores were analyzed with the Kruskall-Wallis, Mann-Whitney U, and Wilcoxon tests. RESULTS There were no statistically significant differences between the microleakages of composite applied to cavities prepared by either the Er:YAG laser or diamond bur (P>.05). Statistical analysis revealed significant differences between the enamel and dentin in all restorations (P<.001). However, there were no significant differences among the preheated groups (P>.05). CONCLUSIONS For all groups, microleakage values were higher at gingival margins than at occlusal margins. The use of the Er:YAG laser at different preheating procedures did not influence the marginal sealing in Class V composite resin restorations.