GaAlAs Laser Therapy in Dentin Hypersensitivity and Histopathological Changes of the Dental Pulp Tissues

近年来的研究显示了二极管激光照射治疗牙本质过敏的效果。然而，系统的影响仍未得到解决。因此，疾病照射的条件和适应症没有详细定义，这降低了激光治疗疼痛的临床可靠性。本研究通过观察激光照射后牙髓组织的病理变化，探讨其作用机制。采用Ga-Al-As二极管激光器（< λ >: 830nm, Osada Electric Co.），用探针直接接触雄性Wistar大鼠第一磨牙咬合面，以30mW连续照射60秒和90秒。照射2周后处死大鼠，光镜下常规检查牙髓组织。在患者同意的情况下，对牙本质过敏患者进行临床检查。实验表明；1)本研究中辐照组与未辐照组牙髓组织的组织病理学外观未见差异。由于激光照射后疼痛的消失会使牙髓组织发生一定的组织学变化，未来的超微结构研究将会发现这些变化。2) 61例临床试验中，疗效显著者10例（16%），有效者29例（48%），无效者22例（36%）。虽然激光照射产生了立竿见影的效果，但在一些病例中疼痛又复发了。这一不确定的临床结果提示进一步研究牙本质过敏信息以获得更高的临床可靠性。

Recent studies have shown the effects of diode laser irradiation in treatment for dentin hypersensitivities. However,the system of the effects still remains unsolved. The conditions and indications of irradiation in the diseases are, therefore, not defined in detail, which decreases clinical reliability of the laser therapy for pain.The study was designed to examine histopathological change of dental pulp tissue by laser irradiation to know the mechanism of the effects.Continuous irradiation at 30mW was performed for 60 and 90 seconds under direct contact of a probe to occlusal surface of the first molars of male Wistar rats by using Ga-Al-As diode laser(<lambda>: 830nm, Osada Electric Co.). The rats were sacrificed 2 weeks after irradiation and the pulp tissues were routinely examined histopathologically under light microscope. Clinical examination also done on the patients having hypersensitive dentinunder their consents.Experiments indicate ; 1) No differences were detected in histopathological appearance of pulp tissues between irradiated and non-irradiated groups in this study. Since loss of pain by laser irradiation may give some histological change to pulp tissue, ultratine structure investigation would find the changes in future. 2) In clinical experiment, of 61 cases, the findings showing remarkable effective, effective, and non-effective were 10(16%), 29(48%), and 22(36%) cases, respectively. Though the laser irradiation yielded immediate effect, pain returned in some cases. This uncertain clinical results suggested further study on informations of dentin hypersensitivity to get higher clinical reliability.