The study of Diode laser effect on pulp tissue

本研究的目的是探讨二极管激光对切除牙髓组织的伤口愈合效果。本实验以年轻雄性Wistar大鼠双侧上颌第一磨牙为实验对象，分为三组。第1组（对照组）在截髓表面不进行照射。第二组用输出功率为500mW、照射时间为5秒的连续波二极管激光器照射断牙髓表面。第三组用输出功率为500mW的二极管激光照射断牙髓表面，照射时间为10秒。初步试验确定了二极管激光照射的条件，高输出功率二极管激光对牙髓产生热损伤，而低输出功率二极管激光对牙髓无损伤。用纯氢氧化钙粉与无菌生理盐水混合敷设，用玻璃离子水门栓封闭龋洞，最后对标本进行组织病理学检查。14天后，两个二极管激光组均出现大量由骨样硬组织组成的钙化屏障。然而，与2组相比，3组多见于根状牙髓炎症。对照组在截肢部位形成钙化的牙本质样硬组织屏障。然而，在一些病例中，神经根髓有严重的炎症，没有形成钙化屏障。提示二极管激光照射断髓对断髓术后创面愈合有一定的促进作用。经过一系列的实验，将二极管激光应用于临床椎髓切开术，观察期内效果良好。

The purpose of this study was to examine the wound healing effect of Diode laser on the amputated pulp tissues. This experiment was conducted on the bilateral maxillary first molar teeth of young male Wistar rats, divided into three groups. In group 1 (control group), they received no irradiation on the surface of the amputated pulp. In group 2, the surface of the amputated pulp was irradiated with the continuous wave Diode laser with an output power of 500mW and an irradiation time of 5 seconds. In group 3, the surface of the amputated pulp was irradiated with Diode laser with an output power of 500mW and an irradiation time of 10 seconds.The condition of Diode laser irradiation was determined by preliminary examination that a high output power of Diode laser produced heat damage to the pulp, in contrast a low output power of that gave no damage to the pulp.All of the teeth were dressed with a pure calcium hydroxide powder mixed with sterile saline solution and the cavities were sealed with glass ionomer cement, finally histopathological examination of the specimens was performed.After 14 days, a large amount of calcified barrier consisted of bone like hard tissue was found in both Diode laser groups. However, the inflammation in radicular pulp is often found in group 3 in comparison with group 2. In control group, the calcified dentin like hard tissue barrier was formed at the amputation site. However, in some cases, severe inflammation in radicular pulp and no formation of a calcified barrier were found. These results suggested that Diode laser irradiation on the amputated pulp might be useful for wound healing after pulpotomy. After these serial experiments Diode laser was applied to the clinical pulpotomy cases, which have been good in the period of observation.