Bond Strength Comparison of Color Change Adhesives for Orthodontic Bonding

Objective: To compare the shear bond strengths of the two different color change adhesives to a commonly used conventional light cure adhesive while using a self-etching primer. Also, to compare any changes in those shear bond strengths over time. Materials and Methods: One hundred and eighty extracted bovine incisors were randomly divided into nine groups of 20 teeth each. The teeth were prepared with a self-etching primer. Metal lower incisor brackets were bonded directly to each tooth with two different color change adhesives and a control. The teeth were debonded in shear at three different time points (15 minutes, 24 hours, 1 week) using an Instron at 1.omm/min. The teeth that were to be debonded at 24 hours and 1 week were stored in distilled water at 37° C to simulate the oral environment. The data were analyzed by a two-way analysis of variance (ANOVA) and with Fisher's PLSD multiple comparisons test at the .o5 level of significance. Adhesive Remnant Index (ARI) scores were calculated for each tooth debonded. Results: Transbond PLUS at 1 week had the highest mean shear bond strength at 14.7 MPa. Grengloo tested at 24 hours had the lowest mean shear bond strength at 11.3 MPa. The mean shear bond strengths for the remaining seven groups had a range of 12-14.5 MPa. Transbond XT and Grengloo at 24 hours had the lowest average ARI scores at 1.1 Transbond PLUS at 24 hours and 1 week had the highest average ARI scores at 2.7. Conclusions: Time had no effect on the bond strength values of the three adhesives. Grengloo had a statistically lower shear bond strength than Transbond PLUS. Grengloo had the lowest average ARI.