Functional changes in the temporomandibular joint mechanoreceptors associated with experimentally induced condylar resorption in rats

Objectives: To evaluate the influence of experimentally induced progressive condylar resorption (PCR) on temporomandibular joint (TMJ) mechanoreception.

Materials and methods: Twenty 13-week-old male albino Wistar rats were divided equally into control and PCR groups. A compressive force was loaded on the left TMJ of PCR group rats to induce condylar resorption. Single-unit activities of TMJ mechanoreceptors were also induced through passive jaw movement. Recording was performed for the left Gasserian ganglion at 3 days and 1 week after the establishment of PCR group. The effects of PCR on TMJ units were assessed by measuring the firing threshold, maximum instantaneous firing frequency, and average firing frequency.

Results: Compared with the control group, there were no significant differences in the firing threshold of the PCR group after 3 days. The thresholds were significantly higher 1 week after compressive force loading on the condyle. The maximum instantaneous firing frequencies and the average firing frequencies showed no significant differences after 3 days. However, these were significantly lower 1 week after compressive force loading.

Conclusions: The findings suggest that compressive force loading on the condyle may influence the function of TMJ mechanoreceptors.