| Purpose To explore the possibility of pulsed Nd:YAG laser-aided debonding for removing orthodontic metallic brackests. Compare this method with the conventional mechanical debonding method.Methods Fifty healthy premolars extracted for orthodontic purpose were randomly divided into five groups of 10 teeth. Every tooth was bonded with bracket. Using laser to irradiate the four groups with different electric current (13.0A, 13.5A, 14.0A, 14.5A). Every group received the illumination with a fixed electric current. During the irradiation, the brackets received 500'g force, untill the brackets were debonded. To record the time that the debonding took and the temperature's change of the pulp cavity. Another group as contrast group was debonded using mechanical method. To calculate the ARI of the five groups using stereomicroscope and imagetool software. All samples were examined in a scanning electron microscope and photographs were taken.Results It was found that there was a highly statistical difference of time taken between the four groups(P＜0.01). The change of the temperature in the pulp cavity had a statistical difference between the four groups(P＜0.05). The residual resin of the five groups had a statistical difference(P＜0.05). But between the four groups received laser irradiation, there was no statistical difference(P＞0.05). Under SEM, the normal enamel surface was smooth, free, and the overlapped perikymata were clear. The enamel surface of the mechanical debonding group was coarse and was found deep scratch, honeycomb. The laser-aided debonding groups were not found scratch, honeycomb. The surface was smooth and clean.Conclusions①Pulsed Nd:YAG laser-aided debonding for removing orthodontic metallic brackets is a feasible method.②The effect of laser-aided debonding was well.③The method didn't destroy the structure of enamel and reduce the damage to enamel surface.④The study was a in vitro study, so the effect to pulp was need to do more study.
|
PDF Full Text Request