Analysis of mechanism in reducing pain during orthodontic tooth movement by CO_2 laser

本研究旨在探讨CO2激光在正畸牙齿移动过程中的镇痛作用及其机制。在本研究中，我们分析了CO2激光对大鼠实验性牙齿运动时中枢（髓背角）和外周（牙髓、牙周韧带）神经系统的影响。结果，实验牙齿移动后，疼痛标志物c-fos升高，而CO2激光照射后髓背角处c-fos明显降低。另一方面，降钙素基因相关肽（CGRP）和PGP9无明显变化。5 . CO2激光照射后牙髓和牙周韧带。此外，通过温度测量，最高温度低于40℃，不会造成组织损伤。因此，我们认为CO2激光通过抑制中枢神经系统的c-fos神经元而不损伤外周组织来减轻实验性牙齿运动时的疼痛。

The aim of this study is to investigate the pain reducing effect and mechanism of CO2 laser during orthodontic tooth movement. In the present study, we analyzed the effect of CO2 laser in the central (medullary dorsal horn)and in the peripheral (tooth pulp, periodontal ligament)nervous system during experimental tooth movement in rats. As a result, increased c-fos known as the pain marker, was observed after experimental tooth movement, and it significantly decreased at the medullary dorsal horn after CO2 laser irradiation. On the other hand, there was no significant change in the calcitonin gene-related peptide (CGRP)and PGP9. 5 at the tooth pulp and periodontal ligament after the irradiation of CO2 laser. Furthermore, by the temperature measurements, the maximum temperatures were less than 40°C, which cannot cause tissue injury. Therefore, it is suggested that the CO2 laser reduces pain during experimental tooth movement by inhibiting c-fos neurons at the central nervous system without damaging peripheral tissue.