The effect of adding Bioglass 45S5 to orthodontic adhesive on the shear bond strength of metal orthodontic brackets: an in vitro study

Aim: This study aimed to evaluate the effect of incorporating Bioglass (BG) 45S5 into an orthodontic adhesive on the shear bond strength (SBS) of metal orthodontic brackets bonded to enamel and the adhesive remnant index (ARI) score. Methods: In this in vitro study, 55 extracted sound premolars were randomly divided into five groups (n=11 each). Metal brackets were bonded using Ambar FGM orthodontic adhesive without BG (control group) and with BG 45S5 added at concentrations of 5%, 10%, 15%, and 20% by weight in groups 2 to 5, respectively. The SBS was measured using a universal testing machine, and the ARI score was determined under a stereomicroscope at ×10 magnification. Data were analyzed using one-way ANOVA at a significance level of α=0.05. Results: The highest mean SBS was observed in the 20% BG Group (48.28±24.5 MPa), followed by the control group (35.81±11.11 MPa), 15% BG Group (19.64±5.42 MPa), 10% BG Group (16.3±9.33 MPa), and 5% BG Group (14.21±4.23 MPa). The SBS in the 20% BG Group was significantly higher than in the control (P=0.013), 5% BG (P=0.000), and 10% BG (P=0.002) groups. No significant differences were found in ARI scores among the groups (P=0.810). Conclusion: Adding BG 45S5 to the orthodontic adhesive at concentrations of 5%, 10%, and 15% did not significantly affect the SBS, but a 20% concentration increased the SBS. Incorporating BG at these levels does not adversely impact the SBS or ARI scores.