Effect of surface treatments on the bond strength of brackets bonded with a compomer.

Purpose: To evaluate the effectiveness of the compomer Dyract AP for bonding brackets when conditioning the enamel with phosphoric acid and a non-rinsing conditioner (NRC), in comparison with a control group in which the resin orthodontic adhesive system Transbond XT was used.

Methods: The brackets were bonded to extracted premolars which were divided into three groups: (1) Acid/Transbond XT, (2) NRC/Dyract AP and (3) Acid/Dyract AP. Shear bond strength was measured with a universal testing machine. The crosshead speed was 1mm/minute. The adhesive remnant on the tooth after debonding was determined using image analysis equipment.

Results: The bond strength of Acid/Transbond XT was significantly higher than bond strengths of Acid/Dyract AP and NRC/Dyract AP (P< 0.017). No significant differences were observed between Acid/Dyract AP and NRC/Dyract APBond strength values (P> 0.017). Acid/Transbond XT left significantly more adhesive on the tooth than Acid/Dyract AP and NRC/Dyract AP, whereas NRC/Dyract AP left significantly less adhesive than Acid/Dyract AP (P< 0.05).