A NEW TECHNIQUE FOR THE CONTROLLED REMOVAL OF MOTTLED ENAMEL - MEASUREMENT OF ENAMEL LOSS

Aim To describe and investigate a simple, effective new method for con trolled removal of unsightly, malformed surface enamel. Subjects and m ethods 22 mottled incisor teeth were chosen from a group of 12 patient s, aged 9-15 years. One half of the labial surface of the tooth was co vered with a layer of unfilled bis-GMA resin so that it remained unaff ected by the procedure. The other half was treated by etching the enam el with 35% phosphoric acid for 30 seconds, washing and drying. The fr osted, etched enamel was removed with a composite finishing bur (Jet 7 901) running dry in an air turbine, until a shiny enamel surface reapp eared. The enamel was then smoothed with a pumice and water slurry in a slow-rotating rubber prophylaxis cup. The bis-GMA resin was peeled o ff, and an elastomeric impression of the tooth (now with one half of i ts labial surface treated, and the other untreated) was taken. The tre atment of the remainder of the labial aspect was then completed. The t hickness of the mid-labial enamel removed was measured directly from t he impression by surface imaging, using a confocal microscope. Results The mean thickness of enamel removed was 164 mu m (SD +/- 85 mu m). C onclusions This technique results in equivalent amounts of enamel remo val to that claimed for other more complex and time-consuming methods.