脉冲Nd:YAG激光照射对犬牙髓的影响

目的：探讨Nd：YAG激光对牙髓的安全阈值。方法：选择4条健康的本地杂种犬，先进行过敏模型制备，随机分为3组，分别给予：33J／cm^2、56J／cm^2和111J／cm^2激光照射，按照即刻、3d、7d、1个月4个时间段处死试验犬，实验牙经过固定、脱钙后，进行组织切片、光镜观察、病理分级。结果：牙髓反应均在3级以下，随激光照射能量的升高牙髓组织病理变化明显。在33～56J／cm^2之间，牙髓组织正常或反应轻微。结论：应用Nd：YAG激光进行牙齿过敏治疗时，其热效应可能对牙髓组织产生影响，33～56J／cm^2的激光能量不会对牙髓组织产生损害，能量较高将导致牙髓组织炎症，所以33～56J／cm^2的能量密度应为进行当次牙齿过敏治疗的安全阈值。

Effect of pulsed Nd:YAG laser irradiation on dog's dental pulp

AIM:To determine the threshold of Nd:YAG laser energy which would not make dental pulp injured.(METHODS):Four healthy local mongrel dogs were selected.Their teeth were prepared for sensitive models,divided into three groups randomly,and then irradiated respectively by 33 J/cm~2,56J/cm~2 and 111 J/cm~2 laser energy density.One dog was killed immediately,other dogs were sacrificed after 3,7 and 30 days.Experimental teeth were fixed,decalcified,selected and graded.RESULTS:The reactions of all dental pulp were under the 3rd grade.The higher the laser energy raised,the higher grade the dental pulp was.The dental pulp showed normal or light reaction while laser energy density was between 33 J/cm~2and 56 J/cm~2.CONCLUSION:33~56 J/cm~2 energy density will not injure the pulp tissue when Nd:YAG laser is applied to treat dental sensitivity;a higher energy will have dental pulp tissue injured.So 33~56 J/cm~2 energy density is a threshold for dental pulp tissue.