AIR ABRASION OF FAILED BONDED METAL BRACKETS - A STUDY OF SHEAR BOND STRENGTH AND SURFACE CHARACTERISTICS AS DETERMINED BY SCANNING ELECTRON-MICROSCOPY

Failed bonded orthodontic brackets generally require their replacement with a new bracket. The introduction of air abrasion (microetching) t echnology to orthodontics may allow for immediate use of these failed brackets. This study compared the in vitro shear bond strengths of pre viously failed bonded metal brackets (experimental group) subjected to air abrasion with new untreated brackets (control group). All bonding used a light-cured orthodontic bonding system, In addition, represent ative samples from each group were examined by scanning electron micro scopy. The results of this study found no significant differences in s hear bond strengths between the two groups. Scanning electron microsco py examination of the air abraded brackets revealed a roughened mesh s urface with residual bonded material in the bracket base, This simple technique should allow for the immediate reuse of previously failed bo nded metal brackets.