Ceramic bracket debonding with the carbon dioxide laser.

Abstract

The conventional removal of ceramic brackets can be complicated by bracket fracture or enamel loss. To ease this ceramic bracket removal, lasers have been previously investigated for thermally softening thermally the bonding resin. This conversion of laser light to heat can also threaten the vitality of the debonded teeth. Pilot studies and computer modeling suggest that for commonly used polycrystalline brackets debonded with the carbon dioxide laser, some form of mechanical assistance is needed during the lasing process to keep the intrapulpal temperature below the 5.5 degrees C safety threshold. One type of polycrystalline bracket was bonded to lower anterior bovine incisor teeth with one type of resin adhesive. A ceramic bracket debonding plier was modified to accommodate a laser waveguide so that a tensile debonding force could be applied simultaneously during lasing. A control group and three experimental groups were tested (n = 10). The three experimental groups were debonded with the carbon dioxide laser at 20 W and a static tensile force of 3 pounds, 1.5 pounds, or 0.75 pounds. The length of lasing time for the static force to remove the bracket was measured along with the increase in intrapulpal temperature. The mean debonding times and mean increases in intrapulpal temperature for each group were: 3 pound group, 1.64 seconds and 1.80 degrees C; 1.5 pound group, 1.83 seconds and 3.01 degrees C; and 0.75 pound group, 3.42 seconds and 4.47 degrees C.