The study of Diode laser effect on pulp tissue

本研究旨在探讨半导体激光对离体牙髓组织的创伤愈合作用。本实验以雄性Wistar大鼠双侧上颌第一磨牙为实验材料，分为三组。第1组（对照组），离体牙髓表面不接受照射。第2组用半导体激光器照射离体牙髓表面，激光功率500mW，照射时间5s。第3组用半导体激光照射离体牙髓表面，功率500mW，照射时间10s，初步判断半导体激光照射条件为高功率半导体激光对牙髓产生热损伤，所有的牙齿都用纯氢氧化钙粉末与无菌盐水混合，用玻璃离子封闭洞14天后，两组均见大量由骨样硬组织构成的钙化屏障。但与第2组相比，第3组的根髓炎症发生率更高。对照组在离断处形成钙化的牙本质样硬组织屏障。然而，在某些情况下，根髓严重的炎症和没有钙化屏障的形成。这些结果表明，半导体激光照射离断的牙髓可能是有用的伤口愈合后，活髓切断。经过一系列实验，将半导体激光应用于临床活髓切断病例，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.