ENAMEL SURFACE-MORPHOLOGY AFTER BRACKET DEBONDING

The purpose of this study was to evaluate the shear bond strength of b rackets and the enamel morphology after using six methods for removal of adhesive after bracket debonding. A total of thirty-five recently e xtracted non-carious human premolars were used. The twin bracket Mini- Taurus was used with the Mono-Lok2 TM bonding system. Shear bond stren gth (MPa) was calculated. Immediately after the brackets were removed, the teeth were rinsed and dried, using an air-water syringe. The adhe sive remnant index was calculated and the debonded teeth with residual adhesive material attached to the enamel surface were equally sorted in seven groups of five, as follows: Group 1. The residual adhesive wa s removed with a 12-blade tungsten carbide finishing bur in a high-spe ed handpiece, using water as the coolant. Group 2. The residual adhesi ve was removed with a 12-blade tungsten carbide finishing bur in a low -speed handpiece, using water as the coolant. Group 3. The residual ad hesive was removed with an Arkansas stone: Dura-white stones for finis hing composite in a highspeed handpiece using water as the coolant. Gr oup 4. The residual adhesive was removed with an Arkansas stone: Dura- white stones for finishing composite in a low-speed handpiece, using w ater as the coolant. Group 5. The residual adhesive was removed with S of-Lex aluminum oxide discs according to manufacturer's instructions i n a low-speed handpiece, using water as the coolant. Group 6. The resi dual adhesive was removed with Enhance Composite Finishing Discs in a low-speed handpiece, using water as the coolant. In this group, the pa ste was not applied after the polishing discs. Group 7 The residual ad hesive was removed with Enhance Composite Finishing Discs and Polishin g Cups in a low-speed handpiece, using water as the coolant. Prisma-gl oss polishing paste and ultrafine polishing paste were applied accordi ng to manufacturer's instructions. After removal of the adhesive, all teeth were evaluated with the scanning electron microscope. The result s revealed a mean shear bond strength of 12.75 MPa. The higher the bon d strength, the higher the percentage of ARI. The smoothest enamel sur face was obtained when the Enhance system with the gloss polishing pas te was used; the second smoothest enamel surface was obtained when usi ng Sof-Lex discs. If the paste was not used with the Enhance system, t he obtained surface was rougher than when using Sof-Lex discs.