Effects of CO₂ laser irradiation of the gingiva during tooth movement

Patients often feel pain or discomfort in response to orthodontic force. It was hypothesized that CO₂ laser irradiation may reduce the early responses to nociceptive stimuli during tooth movement. The distribution of Fos-immunoreactive (Fos-IR) neurons in the medullary dorsal horn of rats was evaluated. Two hrs after tooth movement, Fos-IR neurons in the ipsilateral part of the medullary dorsal horn increased significantly. CO₂ laser irradiation to the gingiva just after tooth movement caused a significant decrease of Fos-IR neurons. PGP 9.5- and CGRP-positive nerve fibers were observed in the PDL of all study groups. The maximum temperature below the mucosa during CO₂ laser irradiation was less than 40°C. It was suggested that CO₂ laser irradiation reduced the early responses to nociceptive stimuli during tooth movement and might not have adverse effects on periodontal tissue.