An in Vitro Study on The Effects of Er, Cr: Ysgg Laser on The Enamel and Dentin Morphology and Microleakage

Objectives: The evaluation of the enamel and dentin cavity surface morphologies by Scanning Electron Microscopy (SEM) in Class II occlusogingival slot cavities which were prepared and etched by Er, Cr: YSGG (Erbium, Chromium: Yttrium, Scandium, Gallium, Garnet) laser and assessing their effects on the microleakage at composite resin restorations, and also comparing them with those of traditional methods. Material and Methods: Fifty-five non-carious, sound extracted human molar teeth were divided into five groups: bur preparation + acid etching (Group I), bur preparation + laser etching (Group II), laser preparation + laser etching (Group III), laser preparation (Group IV), laser preparation + acid etching (Group V). The resin-tooth interface was evaluated based on microleakage. SEM examinations of laser irradiated samples (Groups II, III, IV, V) revealed a lack of smear layer, irregular and crater-like surface in enamel. Also, these examinations revealed opened dentinal tubules orifice, step-like flattered surface, and lack of smear layer in dentin. Results: Statistically significant differences were found among the occlusal (p=0.003) and gingival regions microleakage (p=0.001) in groups. In Group V at the gingival, microleakage was significantly greater than the other groups (p<0.05). In Group II, the microleakage at the occlusal was found significantly greater than Groups I, IV, and V. When the microleakage at occlusal and gingival were compared among each group, only group V showed statistically significant difference (p<0.05). Conclusions: According to the results of this study, it was determined that there is no need for the etching process after laser preparation.