Enamel surface characteristics on removal of bonded orthodontic brackets

Thirty-six premolars which were scheduled for routine extraction were bracketed with either N or G system adhesives. After one week the brackets were removed and the residual adhesive removed by low-speed green stone, a hand scaler, or an ultrasonic scaler. Half the teeth were given a final pumice, and then all were extracted. The SEM was used to evaluate the enamel surface, and quantitative assessments were made for the area covered with retained adhesive and for damage to the surface. All three removal techniques left appreciable amounts of retained adhesive 20 to 60 per cent coverage for G and 55 to 75 per cent for N adhesive. All detectable adhesive was removed by final pumicing. The detectably roughened area was over 50 per cent for the green stone treatment for both materials and appeared to introduce unnecessary roughness. The hand scaler and the particular ultrasonic scaler used in this study did not severely roughen the enamel for either material and appeared to be effective for initial adhesive removal. All three techniques introduced occasional gouges 10 to 20 micrometer in depth which could not be removed. All other roughness was generally smoothed by final pumicing. Thus, pumicing is a necessary final step with all removal procedures studied.