the effects of different recycling methods on the shear bond strength of ceramic brackets

Objective: this study aimed to evaluate the effect of different recycling (also known as reconditioning) methods on the shear bond strength (sbs) of ceramic brackets.methods: fifty mechanically retentive polycrystalline ceramic brackets and 50 mandibular bicuspids were used in this study. the teeth were divided into 5 groups and bonded with new (group 1) or reconditioned brackets. the reconditioning methods were sandblasting (group 2), sandblasting + silane (group 3), hydrofluoric (hf) acid + silane (group 4), and er:yag laser (group 5). the sbs of brackets were assessed and the adhesive remnant index (ari) scores were determined. statistical analysis was performed using one-way anova, tukey, and chi-square tests at p<0.05.results: the highest sbs value was observed in brackets treated with sandblasting + silane (19.26 ± 3.30 mpa), which was comparable to both the control (19.01 ± 3.12 mpa) and sandblasting (16.98 ± 3.13 mpa) groups. treatment with hydrofluoric acid + silane (9.46 ± 3.43 mpa) and er:yag laser (9.71 ± 1.23 mpa) yielded significantly lower sbs values than the other study groups (p<0.05). the highest overall ari scores were observed in the hf acid + silane and er:yag laser group, indicating more adhesive remnants on the enamel surface.conclusions: sandblasting, with or without silane treatment, effectively restored the bond strength of ceramic brackets to almost initial values. although recycling with hydrofluoric acid + silane or er:yag laser produced lower bond strengths, they still surpassed the clinical threshold of 7.8 mpa, making them viable options for bracket reconditioning in clinical settings.