Thermographic assessment of reversible inferior alveolar nerve deficit

The purpose of this study was to investigate thermography's potential as a diagnostic alternative for evaluating neurosensory deficits of the inferior alveolar nerve. Electronic thermography was used to evaluate the alterations in facial thermal patterns attendant to a conduction defect of the inferior alveolar nerve induced in 12 subjects using 2% lidocaine. The rates of onset and duration of sensory block, as visualized by thermography, were related to the results of conventional neurosensory testing. Comparison of the rate of response change within each measurement system revealed that changes in facial skin temperature manifest the induced deficit earlier than discriminative tests. Also, the prolonged elevation of thermal asymmetry suggested that electronic thermography has the ability to detect subtle changes in nerve function that are not discernible by physical neurosensory tests relying on patient response. Although cutaneous temperature increases were highest in the field of observation near the sensory distribution of the mental nerve, an inexplicable warming of the contralateral side of the face and neck was also observed. These attendant findings emphasize the need for further studies on the pathophysiologic mechanisms of facial thermal changes to better understand thermography's diagnostic accuracy and clinical utility for monitoring inferior alveolar nerve dysfunction.