Comparative Evaluation of a Light-Cure Adhesion Booster on Shear Bond Strength Using Four Enamel Conditioning Techniques: An <i>In Vitro</i> Study.

Abstract

<h4>Background</h4>Effective bonding of orthodontic brackets is a critical factor for treatment success. Although acid etching with phosphoric acid is the gold standard, it may result in enamel loss and soft tissue irritation. Alternative enamel conditioning methods-such as sandblasting and laser etching-when combined with adhesion boosters, may enhance bond performance while preserving enamel integrity.<h4>Objectives</h4>To evaluate the effect of a light-cure adhesion booster on the shear bond strength (SBS) of orthodontic brackets following four enamel conditioning protocols.<h4>Materials and methods</h4>Eighty extracted premolars were divided into four groups (<i>n</i> = 20 each): Group 1-35% phosphoric acid etching; Group 2-sandblasting; Group 3-sandblasting followed by acid etching; Group 4-Er: YAG laser etching. All specimens received a light-cure adhesion booster before bracket bonding with a light-cure adhesive. The shear bond strength was measured using a universal testing machine, and adhesive remnant index (ARI) scores were evaluated under stereomicroscopy.<h4>Results</h4>One-way ANOVA revealed a significant difference among groups (<i>P</i> < 0.001). Group 4 (laser) recorded the highest SBS (27.54 MPa), followed by Group 3 (27.36 MPa), Group 1 (16.87 MPa), and Group 2 (12.88 MPa), with the sandblasting the lowest values. Tukey's <i>post hoc</i> test indicated statistically significant differences between Groups 1 vs. 3 and 4, and Groups 2 vs. 3 and 4 (<i>P</i> < 0.0001). ARI scores showed no significant intergroup differences.<h4>Conclusion</h4>The use of a light-cure adhesion booster significantly enhanced SBS across all conditioning methods. Sandblasting, followed by acid etching and laser etching, demonstrated superior performance.