The change in dimension of the masseter muscle in rabbits after radiofrequency therapy.

PURPOSE: The objective of this study was to evaluate the change in muscle dimension after administering radiofrequency (RF) therapy. MATERIALS AND METHODS: This study used 6 male New Zealand rabbits. Groups were divided by number of applications of RF (eg, 1 to 4 points). The dimension of the masseter muscle was measured using a computerized tomogram scan before operation, and at 1, 2, 3, and 4 weeks after RF therapy was administered under the same conditions. Two horizontal cuts were selected for measurement. RESULTS: The size of the measured areas for each group at 1 week after RF therapy was significantly increased compared with the preoperative value (P< .05). When the measurements of each group at 3 and 4 weeks after RF therapy were compared with the preoperative value, they were significantly decreased (P< .05). The dimensional change was significantly different among groups at 1 and 3 weeks post RF therapy (P< .05). The swelling at 1 week after RF therapy was increased in terms of the number of RF applications. The ratio of dimension was decreased at 3 weeks after RF therapy in terms of the number of RF applications. CONCLUSION: There was an increase in muscle dimension because of swelling in the early stages of RF therapy. However, this dimension decreased at 3 weeks post-RF administration compared with the preoperative value. Therefore, it can be concluded that the change in the masseter muscle dimension was dependent on the number of RF applications.