Thermography for the clinical assessment of inferior alveolar nerve deficit: a pilot study

Neurosensory deficit is a major complication encountered in maxillofacial surgery. This study assessed the ability of electronic thermography to identify inferior alveolar nerve deficits in a pilot clinical study. The study population comprised six patients with inferior alveolar nerve deficit and 12 normal subjects. Frontally projected facial thermograms were taken on 18 subjects and measured using an Agema 870 unit and thermal image computer. Mathematical analysis of thermal measurements included temperature and delta T calculations of the anatomic zone over the mental region of the face. Results included (1) high levels of thermal symmetry of the chin in normal subjects (delta T = 0.1 degree C, standard deviation = 0.1 degree C); (2) low levels of thermal symmetry in patients with inferior alveolar nerve deficits (delta T = +0.5 degree C, standard deviation = 0.2 degree C); (3) statistically significant differences in delta T values (t = 4.82, P > .001) in patients with inferior alveolar nerve deficit; and (4) absolute temperature variations of the mental region in both groups. This pilot study demonstrated thermal asymmetry in patients with inferior alveolar nerve deficit and suggests that electronic thermography has promise as a simple, objective, noninvasive method for evaluating nerve deficits. However, more extensive studies are needed before thermographic procedures are accepted clinically.