In Vitro Comparison of Shear Bond Strength (SBS) of Orthodontic Brackets Bonded with 4 Adhesive Materials and Debonded at Different Time Intervals

Aim: This study compared the SBS of orthodontic brackets that were bonded on buccal enamel of premolars either with composite resins or with RMGI after 2 and 24 hours and after 4 weeks. Methods: 220 premolars extracted due to orthodontic reasons were divided in four groups: In 2 groups brackets were bonded with composite resins: GC connect and Transbond XT-3M, and in 2 groups with RMGI: GC FUJI LC Capsule and GC Automix. Each group was divided to 3 different time intervals: 2H, 24H and 4 weeks. At each time interval the brackets were tested using a constant load of 2.5 N and the shear bond strength recorded as stress at maximal load was recorded in MPa. Results: Our study shows that the RMGI glue GC LC Capsule had the highest shear bond strength after 2H (11.6 MPa) and after 24H (8.5 MPa) with significance of P<0.001 Conclusions: As shown also in previous studies GC Fuji LC Capsule should be considered as a safe material for bracket bonding and caries protection during orthodontic treatment, due to fluoride release around the bracket.