Nd:YAG激光对猴牙牙髓的影响

目的：观察Nd：YAG激光对猴牙牙髓的影响，比较牙面涂布60g／L美蓝和经常规硝酸银脱敏后对激光照射效果的影响情况。方法：以1592、3185、4777mJ／mm^23种能量水平的Nd：YAG激光照射3只猴的30个牙面，用组织病理学方法观察牙髓变化情况。结果：1592mJ／mm^2照射组，不论牙面经何种处理，牙髓反应均与对照组相似，为0级；3185mJ／mm^2照射组，牙髓出现轻度改变；大能量、高频率的4777mJ／mm^2照射则出现广泛性成牙本质细胞变性、坏死。照射面色素的存在增加了激光对牙髓的刺激，氨硝酸银加丁香油酚还原成银沉淀，隔绝了外界刺激对牙本质和牙髓的影响，同样参数的Nd：YAG激光造成的牙髓损害在3组中最小。结论：大能量Nd：YAG激光可造成牙髓组织损伤性反应，照射面经不同的处理可影响Nd：YAG激光的照射效果。

The effects of Nd:YAG laser on dental pulp of rhesus monkeys

Objective: To observe the effects of Nd:YAG laser on dental pulp of rhesus monkeys and compare the effects between methylene blue and silver nitrate on laser irradiation. Methods: 27 teeth of 3 monkeys were irradiated respectively by 1 592 mJ/mm 2 ,3 185 mJ/mm 2 or 4 777 mJ/mm 2 Nd:YAG laser. Befor irridiation 9 teeth were treated with methylene blue on the surfaces and 9 treated with silver nitrate.The other 3 teeth were used as controll.One hour after irradiation,pulp samples were obtained and observed with histological examination. Results: No harmful response was observed in the dental pulp following laser irradiation at 1 592 mJ/mm 3 no matter what teatment of occlusional surfaces. Mild change were observed in the pulp irradiated with the laser at 3 185 mJ/mm 2. Severe damages were found in the 4 777 mJ/mm 2 laser treated group.Methylene blue could enhance pulp damage but silver nitrate could minish the damage by isolating tooth surface from laser beam. Conclusion: Great output energy of Nd:YAG laser may cause damaging effects on dental pulp and the use of absorption dye onto the surface of teeth may enhance the effect of laser irradiation.