In vitro evaluation of shear bond strengths of colour change adhesives.

The aims of this study were to test whether the shear bond strengths (SBS) of three commercially available colour change adhesives (CCAs), Transbond Plus Color Change Adhesive, Grēngloo, and Blūgloo, are different and to compare their bond strengths with a traditional light cure adhesive, Light Bond. Forty-eight human permanent premolar teeth extracted for orthodontic reasons and without any caries or visible defects were used in this study. The brackets were bonded with Light Bond (group I), Grēngloo (group II), Blūgloo (group III), and Transbond Plus CCA (group IV). After bonding, the SBS of the brackets were tested with a Universal testing machine. Analysis of variance indicated a significant difference between groups I and IV (P < 0.001). No significant difference was found between groups II, III, and IV (P > 0.05). Adhesive remnant index (ARI) scores for all groups were not significantly different (P > 0.05). Significant difference existed between the SBS of Transbond Plus CCA and Light Bond. Although Transbond Plus CCA yielded the lowest SBS values, no statistically significant difference was found between bond strength values of the three commercially available CCAs. All three CCAs can be safely used in orthodontic practice since they yielded acceptable bond strengths. A higher incidence of ARI scores 4 and 5 revealed that bond failures in all test groups were mainly at the adhesive interface.