SEM analysis of the interference between bleaching and enamel etching

Aim. SEM (Scanning Electron Microscope) evaluation of the existance of micromorphological differences between unbleached enamel (SNS) and bleached enamel (SS) and between etched enamel (SM) and etched after bleaching enamel (SSM). In the latter cases the etching agent has been applied right after bleaching to explore potential interferences between the two processes. Methods. 12 upper incisors have been selected. The professional bleaching agent Opalescence Quick 45% PF (Ultradent Products Inc.) has been applied for 30 minutes on part of the vestibular surface of each specimen. After rinsing the specimens, a 37% ortophosphoric acid (Best Etch – Vista Dental Products) has been applied for 45 seconds on the whole surface, including the enamel part that had been bleached. The effect on the enamel surface has been evaluated with the scanning electron microscope (SEM). Results. and Conclutions. We obtained 48 pictures that showed micromorphological differences between SNS and SS. In most of the cases (9 specimens on 12 examined) there are no micromorphological differences between SM and SSM; but since on the other 25% of the cases, the difference between SM and SSM is rimarkable, we can hypothesize that is the natural composition of the idrossiapathite of each element that determines the final answer to the consecutive use of peroxide and ortophosphoric acid.