Shear bond strength of two different antibacterial adhesive systems an in vitro study

Objective: to evaluate the effect of addition of two antibacterial agents on shear bond strengths of orthodontic brackets. Material and methods: thirty non carious human maxillary premolars teeth were randomly divided into three equal groups 1, 2 and 3 each of 10 teeth. In group 1 orthodontic bracket were bonded to teeth with Transbond XT and served as control group. In group 2, brackets were bonded using 2.5% w/w cetylpyridinium chloride (CPC) added to Transbond XT adhesive system. Meanwhile, in group 3, a fluoride releasing antibacterial self etching primer Clearfil Protect Bond was used with Transbond XT system. The load required to debond brackets was measured by universal testing machine at a cross head speed of 0.5mm/min. Results: Mean shear bond strengths were 10.75 MPa for group 1, 9.44 MPa for group 2 and 8.96 MPa for group 3.One way analysis of variance showed a significant difference between three groups (p<0.05). Multiple comparisons Tuckey HSD showed a significant difference between group 1 and both 2 and 3 (p<0.05) while there was no significant difference between group2 and 3(p>0.05). Cohesive failure was the predominant bond failure pattern (ARI score 2 and 3).Also, there was no significant difference in the failure sites between the three groups (p>0.05). Conclusions: Despite the significant reduction in the bond strength of antibacterial modified adhesive systems; Transbond XT with 2.5%CPC and Transbond XT with Clearfil Protect Bond, they still provide sufficient bond strength and could be used for orthodontic bonding taking into consideration their antibacterial benefits.