Effects of sandblasting metal bracket base on the bond strength of a resin-modified glass ionomer cement: an in vitro study.

The introduction of air abrasion (sandblasting) technology to orthodontics may allow reaching optimum bond strength between the metal bracket and resin-modified glass ionomer cement. This study examined the effects of sandblasting metal bracket bases on the in vitro tensile bond strength of a resin-modified glass ionomer cement. Two-hundred foil-mesh based brackets were divided into ten groups and combinations of three sizes of aluminum oxide powder (25, 50 and 110 microm) and three sandblasting times (3, 6 and 9 seconds) were tested. One group was not sandblasted and used as control. Analysis of variance showed that bond strength was significantly affected by the sandblasting time (p < 0.001) and size of the aluminum oxide powder (p < 0.001). Only the group (SO(25)) sandblasted with 25 microm aluminum oxide powder for 3 seconds yielded higher mean bond strength than that of the control group. The bond strength values were also analyzed using a Weibull analysis, which showed the most favorable size (25 microm) and time combination (3 seconds), and the 5% and 90% probabilities of failures. This study suggests that sandblasting time and particle size have and important effect on the bond between the metal bracket and resin-modified glass ionomer cement.