Bracket Debonding Force and Remnant Adhesive Resin Between Different Adhesives

OBJECTIVES: The aim of this in vitro study is to determine (1) shear debonding forces of two one step and an antibacterial self etch adhesive for orthodontic metal brackets (2) bond failure interface using a modified Adhesive Remnant Index (ARI). METHODS: 36 defect free premolars were randomly assigned into three groups. The teeth received the following treatments: Group 1: Adper Prompt L-Pop (3M) + Transbond XT (3M) (n=11) Group 2: Protect Bond (Kuraray) + Transbond XT (n=10) Group 3: Transbond Plus Self Etching Primer (3M) + Transbond XT (n=11). All samples were stored in deionized water at 37^o C for 24 hours. Shear debonding test was performed by applying a vertical force to the base of the bracket. The cross head speed was 5 mm/min. RESULTS: Maximum load that a specimen can withstand until failure was determined. The results were (mean; standard error; standard deviation, respectively) Group1: 92.6691 N; 11.6339; 38.5853 Group2: 133.3920 N; 13.1789; 41.6754 Group 3: 61.5127 N; 8.3297; 27.6265. Kruskal-Wallis Test revealed that the difference between the groups was statistically significant (p= .002; p< .05). Mann-Whitney Test showed that both groups were statistically different from each other. Compared groups and the corresponding p values were (1-2; p=.049) (1-3; p=.022) (2-3; .002). Failed brackets were examined by an optical microscope at X16 magnification to determine the bond failure interface using a modified ARI. The distribution of ARI score for groups was: [(ARI score; no of specimen), respectively] Group 1 [(0; 1); (1; 2); (2; 0); (3; 2); (4; 5); (5; 2)] Group 2 [(0; 1); (1; 1); (2; 4); (3; 2); (4; 1); (5; 3)] Group 3 [(0; 1); (1; 2); (2; 1); (3; 1); (4; 3); (5;2)]. CONCLUSION: Protect Bond has sufficient mechanical properties and also antibacterial effect that makes it a good choice for orthodontic bonding.