Shear Bond Strengths of 3 Commonly Used Orthodontic Adhesives

Abstract

Background: The purpose of this study was to compare the Shear Bond Strengths (SBS) of three types of orthodontic adhesives and to compare the Adhesive Remnant Index (ARI) after debonding. Materials and Methods: One hundred and seventy-four upper central incisors were extracted and randomly divided to 6 groups (n=29) based on the type of adhesive and two-time intervals post bonding (30 minutes (T1) and 24 hours (T2)): 1) Transbond XT™ 2) BracePaste®, 3) GoTo™. Stainless steel orthodontic brackets were bonded to the teeth. Debonding was completed by an instron machine and shear bond strength recorded together with the ARI following examination under stereo optical microscope with magnification of 10x. Normal distribution was tested using histograms, box plots, the Shapiro-Wilks test and the Kolmogorov-Smirnov’s test. The linear correlation between shear bond strength and ARI score was measured using Pearson’s correlation coefficient by individual test groups and for pooled data. To examine significance of ARI score by group multiple chi-square testing was used. All the analyses were carried out using SPSS version 25.0 and Stata version 15.0. Results: The bond strength of Transbond XT™ was the highest and the strengths at T1 and T2 were not statistically different. The statistical significance was set at 5%. The bond strength of GoTo™ adhesive significantly increased from T1 (200.49N ± 49.77) to T2 (234.89N ± 39.83). BracePaste® showed a statistically significant reduction of its bond strength after 24 hours; 165.07 ± 22.56, down from 187.40N ± 36.90 at T1. This was also significantly less than for the former two adhesives. Water ageing of 24 hrs had a positive impact on Transbond™ and GoTo™ but a negative one on BracePaste®. Transbond XT™ showed the highest score of 3 for ARI at T1 70% and T2 46% followed by GoTo 52% and 35% and BracePaste® 48% and 33%. Conclusion: Transbond XT™ and GoTo™ adhesives showed superior SBS at T1 and showed statistically higher SBS at T2 than for BracePaste®