摘要：
Objective To compare the pulp chamber temperature changes of Nd:YAP laser, Nd:YAG laser and semiconductor laser with the same power during dentin hypersensitivity treatment, and to evaluate the safety of these three laser treatments for dentin hypersensitivity. Methods 50 intact third molars were collected to prepare the dentin hypersensitivity model. The samples were randomly divided into Nd:YAP laser group (n=15), Nd:YAG laser group (n=15), semiconductor laser group (n=15), and blank control group (n=5). Each experimental group was divided into three subgroups (n=5) of 0.9 W, 1.4 W, and 1.8 W according to the laser power. The experiments were conducted with the corresponding laser parameters and thermocouple thermometer was used to record the temperature changes in the pulp chamber. The control group does not do any processing. After laser irradiation, one sample was randomly taken from each group and the morphology of dentin tubules was observed by scanning electron microscopy. Results When different power lasers were used to irradiate the samples, the temperatures of the pulp chamber in each group were increased. Among them, the temperature rise of the pulp chamber was smallest in the Nd:YAP laser group, followed by the semiconductor laser group, and the temperature rise was highest in the Nd:YAG laser group, but it was still lower than 5.5 ° C that could cause pulp necrosis. Scanning electron microscopy results showed that after irradiation with different power lasers, the diameters of most dentinal tubules in the Nd:YAG laser group and the semiconductor laser group were narrowed or even melted, and the effect was better than that of the Nd:YAP laser group. Conclusion The treatment using Nd:YAP laser, Nd:YAG laser and semiconductor laser for dentin hypersensitivity will increase the temperature of the pulp chamber. However, the temperature rise is less than 5.5°Cand that will not cause irreversible damage to the pulp tissue. Nd:YAG laser and semiconductor laser have better dentinal tubule blocking effect, which is more suitable for laser dentin desensitization treatment than Nd:YAP laser.%目的 比较功率相同的Nd:YAP激光、Nd:YAG激光和半导体激光治疗牙本质过敏症时的髓腔温度变化,初步评价3种激光治疗牙本质过敏症的安全性.方法 收集完好的第三磨牙50颗,制备牙本质过敏症离体牙模型.将样本随机分为Nd:YAP激光组(n=15)、Nd:YAG激光组(n=15)、半导体激光组(n=15)、空白对照组(n=5).每个实验组又根据激光功率分为0.9 W、1.4 W及1.8 W 3个亚组,每组5个样本,实验中用对应激光参数进行照射并用热电偶测温仪记录髓腔温度变化;对照组不做任何处理.激光照射后,每组随机取1个样本并用扫描电镜观察牙本质小管形态.结果 采用不同功率激光照射牙体时,各组髓腔温度均有升高,其中Nd:YAP激光组髓腔温升最小,半导体激光组次之,Nd:YAG激光组髓腔温升最高但仍小于能够引起牙髓坏死的温度(5.5°C).扫描电镜结果显示,不同功率激光照射后,Nd:YAG激光组与半导体激光组中大部分牙本质小管管径缩窄,甚至熔融闭锁,且效果优于Nd:YAP激光组.结论 采用Nd:YAP激光、Nd:YAG激光以及半导体激光治疗牙本质过敏症时会引起髓腔温度的升高,但温升小于5.5°C,不会对牙髓组织造成不可逆性的损伤.Nd:YAG激光和半导体激光具有更好的牙本质小管封闭效果,比Nd:YAP激光更适合激光牙本质脱敏治疗.
