【摘要】 目的应用Nd:YAG激光,观察在不同功率、时间等参数下,激光照射辅助去除陶瓷托槽后兔牙髓的组织学变化。方法选择新西兰长耳白兔20只,将其4颗前牙作为实验用牙齿,常规黏结陶瓷托槽。左上前牙机械去黏结,作为对照组;其余3颗牙齿采用激光去黏结,右上前牙激光能量为3W、3s(A组),左下前牙能量为2W、5s(B组),右下前牙能量为5W、2s(C组)。去黏结后5min、1d、3d、1周和1月后处死动物,每次处死4只,拔除前牙,制作兔牙髓组织切片。结果与对照组相比,经不同能量激光照射后5min,兔牙髓组织均出现轻度毛细血管扩张。1d后,A、B组出现中度毛细血管扩张;C组除有中度毛细血管扩张外,还伴有少量炎细胞浸润。3d后,B组牙髓症状消失;A组牙髓症状减轻,仍有轻度毛细血管扩张;C组有毛细血管扩张、出血,并伴有炎细胞浸润。1周后,A组毛细血管扩张减轻,基本恢复正常;C组症状仍很明显。1月后,A组牙髓症状消失,C组仍有轻度毛细血管扩张。结论采用能量为3W、3s的Nd:YAG激光去除陶瓷托槽,兔牙髓组织不会出现不可逆的组织学变化。更多还原

【Abstract】 Objective Ceramic brackets debonding by Nd:YAG laser is based on the thermal effect of laser,which may cause injury of the pulp tissue.In this study,the histological changes of pulp tissue that subjected to Nd:YAG laser irradiation with different power and time were observed.Methods 20 New Zealand rabbits were included in this study.Ceramic brackets were bonded to the 4 incisors as routine.The ceramic brackets of left upper teeth that debonded mechanically were used as control group,while the brackets of right upper,left lower and right lower incisors were debonded by laser with 3W 3s(group A),2W 5s(group B)and 5W 2s(group C)energies,respectively.The teeth were pulled out at 5 minutes,1 day,3 days,1 week and 1 month after the debonding operations.Slides prepared from the pulp tissues of the debonded teeth were used to evaluate the injury of laser.Results In comparison with the control group,pulp tissue of teeth that exposed to laser with different energy for 5 minutes showed mild capillary dilation.One day later,group A,B and C showed moderate capillary dilation,and group C also showed moderate infiltration.At 3 days,inflammation was disappeared in group B,whereas capillary dilation was found in group A.Hemorrhage and inflammation cells infiltration were found in group C.At 1 week,alleviation of capillary dilation was found in group A but not in group C.One month later,inflammation disappeared in group A,while pulp tissue in group C showed mild edema and capillary dilation.Conclusion Nd:YAG laser of high energy may cause injury of the pulp tissue during debonding.Laser energy of 3W 3s could effectively debond ceramic brackets without irreversible pulp injury.更多还原