[Enamel micro-abrasion]

Enamel conditioning (elimination of dental plaque and creation of an irregular surface) is an essential step before bonding of orthodontic brackets. The most popular procedure in our practice is bonding with resin which requires enamel etching in order to get enough shear bond strength. Many studies have tried to evaluate the effects of enamel bonding using the acid-etching procedure as well as the changes caused by detachment of brackets. Thanks to the development of other adhesives such as glass ionomer cements which chemically bind to the enamel, new enamel conditioning methods appeared, in particular sandblasting with aluminium oxide particles. This technique is a mechanical preparation of the tooth that avoids the harmful effects of acid products. By suitably choosing the parameters of sandblasting (pressure, time and quantity of powder), enamel loss is lower than with the acid-etch procedure and the surface of the enamel seems less affected. However the bond strength remains superior to the values required for treatment. The presented results indicate that enamel sandblasting can be considered as an alternative for the acid-etching technique currently used in orthodontic practice because it creates sufficient strength and respects enamel thickness better.