Debonding of ceramic orthodontic brackets (polycrystalline alumina, Unitek/3M, and sapphire, A Company/Johnson & Johnson) from the enamel surface aided by CO2 and YAG laser heating was investigated. The torque forces needed to debond polycrystalline alumina brackets on molar teeth were lowered by a factor of 27 when the brackets were illuminated for 2 s with a focused CO2 laser beam of 14 W (Fig. 1). When the same brackets were bonded to incisors and tested in the same conditions, we found a 16 times lower debonding force than without the laser. Illumination of the monocrystalline brackets for 2 s with a CO2 laser setting of 7 W produced a fourfold reduction of the debonding force. When identical power settings were applied to the polycrystalline brackets, only a small reduction in the debonding force was observed.
© 1990 Optical Society of AmericaPDF Article