Comparison between Self-etching and Acid-etching by Clinic Statistic and SEM

Objectives: To compare the bonding effect and decalcification of self-etching and acid-etching in orthodontics by clinic statistic and scan electron microscope. Methods: Twenty-six orthodontic patients were selected and disposed with 37% phosphate acid on their left teeth, Transbond™ Plus self-etching primer (3M Unitek) on their right teeth. Then Transbond XT Light Cure Adhesive (3M Unitek) was used to bond MBT™ brackets on both sides. The ratios of adhesive failure within three months were compared. The resin tag and enamel decalcification around adhesion were observing by Scan Electron Microscope (SME) in control, 37% phosphate acid and self-etching group. Results: There was no significant difference of adhesive failure between 37% phosphate acid-etching group (2.44%) and self-etching group (2.02%) by X² Test. The resin tags of self-etching group were shorter and thicker, more quantity and regular than the acid-etching group, while lighter enamel decalcification was found in self-etching group. Conclusion: The bonding effect of self-etching and acid-etching are not significant different in clinic, but self-etching is better than acid- etching at the point of enamel decalcification lesion.