Relationship Between Occlusal Contact and Pain Alleviation

Objectives: The purpose of this study is to investigate the effect of cerebral cortex in human being caused by clenching during stimulation of pain using MEG (Magnetoencephalography). Methods: The ethical issue was considered according to the declaration of Helsinki. Three healthy adult males were chosen. CO₂ laser stimulator was used as a stimulus of pain. The laser wavelength was 10.6 μm and the diameter of the irradiation beam was about 0.5mm. The stimulus intensity was 1.5 W in output power and the stimulus duration was 50ms. The stimulus interval of the laser beam was at random between 3 to 5 seconds. The handpiece of the laser stimulator was set at 30mm from the recipient site, central area in right carpal by using handpiece holder. Neuromagnetic activities of the cerebral cortex were recorded using a 306-channel whole-head neuromagnetometer, and the results were obtained by the averaged neuromagnetic signals in 100 times of stimulation in each rest position of mandible and intercuspal position. Results: The amplitude of peak latencies were reduced during intercuspal position, comparing with rest position of mandible. The Equivalent current dipoles (ECDs) were determined in temporal region during the rest position of mandible, the intensity of ECDs during intercuspal position became weaker. When their locations overlapped on MRI, the ECDs were located in the second sensory cortex. Conclusion: These results suggested that occlusion or biting might have a factor of pain alleviation in human.