An in Vitro Comparison of Shear Bond Strength and Adhesive Remnant Index Among Conventional Acid Etching, Self-Etching Primer, And Er,Cr:YSGG Laser

Abstract

Background: Optimal orthodontic bonding requires enamel pretreatment to achieve sufficient shear bond strength (SBS) while minimizing enamel damage. Conventional acid etching, self-etch primers, and laser etching are widely used, each with distinct benefits and drawbacks.Objective: To compare SBS and Adhesive Remnant Index (ARI) values of orthodontic brackets bonded using conventional acid etching, self-etch primer, and Er,Cr:YSGG laser at two power settings (1 W and 1.5 W).Materials and Methods: Eighty extracted maxillary premolars were randomly assigned to four groups (n=20): Group 1 – 37% phosphoric acid etching; Group 2 – Er,Cr:YSGG laser at 1 W; Group 3 – Er,Cr:YSGG laser at 1.5 W; Group 4 – self-etch primer. Brackets were bonded with Transbond XT and tested for SBS using an Instron testing machine. ARI was scored under ×10 stereomicroscopy. Data were analyzed using ANOVA and Tukey’s post hoc test at a significance level of 0.05.Results: Mean SBS values were: acid etch – 12.77 ± 1.93 MPa; self-etch primer – 13.00 ± 1.97 MPa; laser 1.5 W – 10.52 ± 2.01 MPa; laser 1 W – 7.82 ± 1.46 MPa. ANOVA showed significant differences (p < 0.001). Post hoc tests confirmed that both acid etch and self-etch primer groups had significantly higher SBS than laser groups. ARI scores revealed more adhesive remaining on enamel in acid etch and self-etch groups, whereas laser groups had lower ARI scores, indicating reduced adhesive remnants. Conclusion: Conventional acid etching and self-etch primer achieved significantly higher SBS than Er,Cr:YSGG laser etching. Laser-treated enamel showed reduced adhesive remnants, suggesting a potential advantage in minimizing enamel damage during debonding.