Abstract: Objective：To compare shear bond strength(SBS) of rebonded metal orthodontic brackets between three kinds of treatment methods．Method：80 extracted human premolars were selected and evenly divided into four groups. The brackets were bonded to the 80 premolars and were debonded with shear tests to record the SBS. Residual adhesives on the base mesh of the brackets were treated with three different methods. In group I, new brackets were reused. In group Ⅱ, Ⅲ, Ⅳ, the base mesh were dealt with sandblasting, burning or carbide bur grinding, respectively. The brackets were rebonded and shear tests were performed among different groups. Results: In group I and group Ⅱ,the SBS of the second bonding was very closed to the first bonding, there was no significant difference between the second bonding and the first bonding ( P > 0 .0 5 ), In group Ⅲ and group Ⅳ, the SBS of the second bonding was significantly lower than the first bonding ( P ＜ 0 .0 5 ). There was no significant difference of the SBS of the second bonding between group Ⅱ and group I（P＞0.05）， In group Ⅲ and group Ⅳ, the SBS of the second bonding was significantly lower than the SBS of the second bonding In group I ( P ＜ 0 .0 5 ). Conclusion: To obtain enough bonding strength, was suggested to remove residual adhesives from the base mesh of bracket, carbide bur grinding and burning should not be used.

Key words: Orthodontic bracket, Bonding, Shear bond strength (SBS ), Sandblasting