Effect of Orthodontic Tube Base Area and Enamel Sandblasting on Bonding Strength to Enamel: An In Vitro Study

Background: The bond strength of orthodontic tubes to the enamel surface is essential for maintaining appliance stability, especially due to high masticatory forces on molars. Strong adhesion reduces the need for rebonding, shortening treatment time. This study aimed to evaluate the impact of tube base size and enamel sandblasting on bond strength in vitro. Methods: Eighty extracted permanent molar teeth were used for this study, divided into four groups of 20 samples each: M-small base tubes (non-sandblasted enamel), SM-small base tubes (sandblasted enamel), T-large base tubes (non-sandblasted enamel), and ST-large base tubes (sandblasted enamel). Shear bond strength was measured using the Mecmesim Multitesters 2.5-I device. Statistical analysis was conducted using IBM SPSS 27.0 software, applying ANOVA and Tukey's post hoc test. Results: The highest bond strength (N) was recorded in the ST group, 85.51 ± 25.04 N, and the lowest in the M group, 50.23 ± 19.76 N. In terms of MPa, the SM group had the highest average value, 11.31 ± 3.57 MPa, while the T group had the lowest, 4.89 ± 1.33 MPa. ANOVA showed a statistically significant effect of tube base size on bond strength (p < 0.001), while sandblasting had no significant effect (p > 0.05). Conclusions: Larger base orthodontic tubes demonstrate stronger adhesion to enamel and are recommended for molars. Sandblasting the enamel does not significantly impact bond strength.