SEM Study on Enamel Conditioning with Er,Cr:YSGG Laser and Phosphoric-acid

Objectives: The aim of this study was to evaluate the effects of different conditioning methods on enamel surfaces. Because of the purpose, the effects of acid-etching, Er,Cr:YSGG Laser and combined treatment (laser + acid-etching) applications were compared with each other. Methods: Twelve freshly extracted intact human third molars were used in the study. Previously, buccal enamel were cut from crowns of the teeth and then smoothed by using SiC disk (600 grit). Group 1: 37% phosphoric-acid gel was applied for 30 sec on the smoothed enamel surfaces. Group 2: Only laser applied (6 W for 20 sec). Group 3: Both conditioning procedures (laser + acid-etching) were applied to these smooth enamel surfaces. In each group, for enamel specimens were examined. After conditioning procedures were applied on enamel surfaces, morphological changes were evaluated by SEM at magnifications of x2000 and x3000. Results: In Group 1 clean prisms were observed on the etched enamel surfaces. In Group 2 a melted recrystallized lava surface was seen and also the edge of prisms were observed to be both sharp and high. In Group 3 (laser + acid-etching) more homogeneous roughed surfaces were obtained. Conclusions: There were great morphological differences in the enamel surfaces caused by these three methods. The micromorphological properties of roughened surfaces showed that, laser application only can not be used as an alternative to acid-etching, but combined treatment can be applied or is to be prefered above that instead of acid-etching method to obtain succesful bonding between enamel surface and adhesive.