effect of surface treatment on enamel cracks after orthodontic bracket debonding: er,cr:ysgg laser-etching versus acid-etching

Objectives: this study sought to compare enamel cracks after orthodontic bracket debonding in the surfaces prepared with erbium, chromium: yttrium-scandium-gallium-garnet (er,cr:ysgg) laser and the conventional acid-etching technique.materials and methods: this in-vitro experimental study was conducted on 60 sound human premolars extracted for orthodontic purposes. the teeth were randomly divided into two groups (n=30). the teeth in group a were etched with 37% phosphoric acid gel, while the teeth in group b were subjected to er,cr:ysgg laser irradiation (gold handpiece, mz8 tip, 50hz, 4.5w, 60µs, 80% water and 60% air). orthodontic brackets were bonded to the enamel surfaces and were then debonded in both groups. the samples were inspected under a stereomicroscope at ×38 magnification to assess the number and length of enamel cracks before bonding and after debonding. independent-samples t-test was used to compare the frequency of enamel cracks in the two groups. levene’s test was applied to assess the equality of variances.results: no significant difference was noted in the frequency or length of enamel cracks between the two groups after debonding (p>0.05).conclusions: despite the same results of the frequency and length of enamel cracks in the two groups and by considering the side effects of acid-etching (demineralization and formation of white spot lesions), er,cr:ysgg laser may be used as an alternative to acid-etching for enamel surface preparation prior to bracket bonding.