Comparison the site of bond failure and enamel damages between different debonding methods of metal brackets

Abstract

Background and Aim: Enamel damage during debonding process of orthodontic brackets in one of concerns in fixed orthodontic treatment. The purpose of this study was to compare the enamel micro-cracks characteristics and adhesive remnant scores(ARI) before and after debonding the metal orthodontic brackets between five different techniques. Methods: In this, in vitro investigation two hundred recently extracted human premolars were randomly divided into five groups. After bonding the brackets, they were removed through one of the following methods: How plier, bracket removal plier, ligature cutter plier, crown remover and ultrasonic scaler. The number, lengths and direction of the enamel cracks were examined by stereomicroscope. The adhesive remnant index and the number of pronounced cracks were also compared. Results: In all groups the number and length of the cracks increased significantly during debonding (P<0.001). The highest and lowest difference in number and length of the microcracks was belonged to arch crown and ultarsonic respectively (P=0.017). No significant difference was observed in ARI index between the groups (P=0.282). If arranged according to ARI scores length and number of the cracks increased significantly in all scores except in “ARI 0” (P<0.001). After debonding, mixed type had the highest frequency (78.5%) and no specimens were observed with horizontal crack. Conclusions: Debonding of orthodontic brackets has the potential of increasing the number and length of enamel microcracks. Debonding with ultrasonic appliance is recommended as a less harmful method.