脉冲Nd:YAG激光根管内照射对狗牙尖周组织的影响

Effects of irradiation in root canal with pulsed Nd:YAG laser on periradicular tissues in dogs

目的 :观察脉冲Nd :YAG激光根管内照射对狗牙尖周组织的影响。方法 :组织学切片法和超薄切片法。结果 :2 .1W ,140mJ,15Hz的脉冲Nd :YAG激光根管内照射 2 5s,对尖周组织产生了明显的损伤 ,并延缓了尖周病变的愈合。 1.2W ,80mJ ,15Hz的脉冲Nd :YAG激光根管内照射 2 5s ,对尖周组织产生的损伤明显轻于传统根管治疗 ,有利于尖周病变的愈合。结论 :合适能量的脉冲Nd :YAG激光根管内照射 。

AIM: Irradiation in root canal by pulsed Nd:YAG laser with a variety of energy parameter after pulpectomy, compared with the conventional methods, in order to observe the histological effects of periradicular tissues. METHODS: 64 teeth from 4 health Mongrel dogs (16 teeth from each dog) were randomly divided into 3 groups. The first group was as control, that is, root-canal preparation and root canal filling were performed after pulpectomy. In the other two groups, after pulpectomy and root-canal preparation, inner layer of root canal was irradiated by pulsed Nd:YAG laser with energy parameter of 1.2W (80mJ,15Hz) and 2.1W(140mJ,15Hz) respectively, and then followed by routine root canal filling. The postoperative dogs would be sacrificed by perfusion fixation in 1, 15, 30 and 60d, and the removed periradicular tissues were examined histologically with microscopy and transmission electron microscopy. RESULTS: Severe injury and delayed healing were observed in periradicular tissues by irradiation of pulsed Nd:YAG laser (2.1W,25s) in root canal. In contrast with it, irradiation in root canal by pulsed Nd:YAG laser with energy of 1.2W(80mJ,15Hz) just caused less injuries in periradicular tissues and the periradicular tissues healed rapidly, compared with the conventional root-canal therapy. CONCLUSION: The results provide evidences that irradiation in root canal by pulsed Nd:YAG laser with optimized energy parameter is safe to apply for root-canal therapy. Key worlds pulsed Nd:YAG laser; root-canal therapy; histological evaluation; transmission electron microscopy