脉冲Nd:YAG激光用于狗牙活髓切断术的实验研究

Experimental study on the effects of a pulsed Nd∶YAG laser irradiation on the pulp tissues following pulpotomy in dog

目的：观察脉冲Ｎｄ∶ＹＡＧ激光照射狗牙活髓切断术后断面的牙髓组织愈合情况。方法：动物分成３组，每组５个牙。一组对照，一组切髓后激光照射断面，条件４０Ｈｚ、６０ｍＪ（２．４Ｗ），另一组切髓后激光照射断面，条件为４０Ｈｚ、４０ｍＪ（１．６Ｗ）。各组均用盖髓剂盖髓。分别于３、１５、４５ｄ处死动物，组织切片光镜观察。结果：能量参数为４０Ｈｚ、６０ｍＪ（２．４Ｗ）、照射时间５ｓ的Ｎｄ∶ＹＡＧ激光对切髓术后牙髓组织具有良好的促进愈合作用，牙髓炎性反应小、牙本质桥形成良好。而能量参数为４０Ｈｚ、４０ｍＪ（１．６Ｗ）、照射时间１０ｓ的激光照射断髓面，对牙髓组织则产生不可逆转的损伤作用。结论：一定能量的Ｎｄ∶ＹＡＧ激光对切髓术有促进愈合作用。激光对牙髓组织的损伤程度更多取决于激光照射时间，而非输出功率。应用脉冲Ｎｄ∶ＹＡＧ激光切髓时。

Objective: To investigate the histological effects of a pulsed Nd∶YAG laser irradiation on the wounds healing of dog pulps after mechanical pulpotomy.Methods:Pulpotomy and pulsed Nd∶YAG laser irradiation with different energy and exposure time on the exposed pulp tissues were performed in 3 dogs. Afterwards, the pulps were examined with histological technics. Results: 5 s irradiation at 40 Hz, 60 mJ(2.4 W) promoted the pulp wound healing and complete hard tissue bridges formation with less pulpal inflammation in all the dogs in this group. 10 s irradiation at 40 Hz, 40 mJ (1.6 W) caused unreversible pulp damage.Conclusion:Within certain energy parameters, pulsed Nd∶YAG laser may promote the pulp wound healing. The extent of the pulpal injury seemes to depend more on the exposure time than on the output power.