脉冲激光辅助去除正畸金属托槽方法初探

Pulsed Nd：YAG laser-aided debonding for removing the metal brackets

目的 探讨脉冲Nd：YAG激光辅助去除正畸金属托槽的可行性,以期为临床提供一种优于机械性去除金属托槽的方法.方法 选择因正畸治疗拔除的50颗前磨牙,粘接托槽后根据随机数字表随机分为5组,每组10颗,实验1-4组分别接受13.0、13.5、14.0、14.5 A电流强度的激光照射,同时给予4.9 N的外力,直至托槽脱落,记录托槽脱落时间及牙髓腔内温度;剩余1组为对照组,使用持针器去除托槽.在体视显微镜下测量并计算粘接剂残留指数（adhesive remnant index,ARI）.扫描电镜观察各组釉质表面情况.结果 实验1-4组的托槽脱落时间分别为（67.70 4±7.18）、（35.90±4.28）、（24.90 ±3.76）、（6.90±2.33）s.各组间差异均有统计学意义（P〈0.01）.实验1-4组牙髓腔内温度分别升高（20.97±3.10）、（12.75±3.14）、（8.99±2.47）、（2.91±1.88）℃,各组间差异均有统计学意义（P〈0.05）.实验1-4组和对照组Arl分别为（8.55±5.02）%、（15.42±7.37）%、（5.55±3.79）%、（13.72±6.69）%和（74.36±29.44）%,两两比较显示对照组与不同实验组间差异均有统计学意义（P〈0.05）,实验1-4组间差异无统计学意义（P〉0.05）.扫描电镜下可见对照组釉面横纹已被破坏,釉质表面粗糙不平;实验组釉质表面清洁,未见划痕、弹坑样及蜂窝样改变.结论 脉冲Nd：YAG激光辅助去除正畸金属托槽是一种可行的方法;与机械法相比,脉冲Nd：YAG激光辅助去除托槽及粘接剂的过程不破坏釉质表面结构.

Objective To explore the possibility of pulsed Nd：YAG laser-aided debonding for removing orthodontic metal brackets and to compare the method with the conventional mechanical debonding method.Methods Fifty healthy premolars extracted for orthodontic purpose were randomly divided into five groups （10 teeth in each group）.There were four experimental groups and one control group.Every tooth was bonded with bracket.Laser was used to irradiate the teeth in experimental groups with different electric currents（13.0,13.5,14.0,14.5 A）.During the irradiation,the brackets received 4.9 N of force until the brackets off.The time needed for debonding and the temperature change of the pulp cavity were recorded.The teeth in control group were debonded using mechanical method.The adhesive remnant index （ARI） was calculated using stereomicroscope and imagetool software.All samples were examined with a scanning electron microscope.Results The time taken between the four groups were （67.70±7.18）,（35.90±4.28）,（24.90±3.76）,（6.90±2.33） s,highly statistical difference was found in the time needed for debonding（P〈0.01）.The temperature in the pulp cavity among the four groups were （20.97± 3.10）,（12.75±3.14）,（8.99±2.47）,（2.91±1.88） ℃,and statistical differences were found in temperature change of the pulp cavity （P 〈 0.05）.ARI of three experimental groups and the control group were （8.55±5.02）%,（15.42±7.37）%,（5.55±3.79）%,（13.72±6.69）%,and （74.36±29.44）%.The enamel surface of the control group was coarse with deep scratchs.The enamel surface was smooth and clean in the experimental groups.Conclusions Pulsed Nd：YAG laser-aided debonding for removing metal brackets was feasible.Laser-aided debonding was better than conventional mechanical debonding method.The method reduced the damage to the enamel surface.