Lingual orthodontics (Part 3): Intraoral sandblasting and indirect bonding

Bracket loss is a severe complication in the course of orthodontic treatment, especially when using lingual appliances. High adhesive strength between bracket and tooth is therefore an important requirement for the successful integration of lingual orthodontics into everyday practice. The present article examines the influence of intraoral sandblasting prior to etching on the adhesive strength of indirect bonding. The shear bond strength of 20 cylinders made of composite were measured 24 hours after these had been bonded onto the enamel of bovine teeth. The enamel was prepared by sandblasting (Microetcher, 50 microns Al2O3) for 3 seconds prior to bonding, followed by 30 seconds of enamel etching with 37% phosphoric acid. Twenty specimens were tested without sandblasting in the control group. The results show that intraoral sandblasting prior to etching can significantly (p < 0.001) increase the adhesive strength between enamel and bonding material. Thus intraoral sandblasting is an integral part of the indirect bonding record described in the second section of this article.