Current Perception Thresholds of the Facial and Intra-oral Areas in Healthy Young Adults

Objectives: To determine the normal range of the current perception threshold (CPT) of the facial skin and intraoral mucosa, innervated by the maxillary and mandibular branches of the trigeminal nerve, and to compare the characteristics of the CPTs between and within these areas in healthy young adults.
Methods: The CPTs were measured in 24 healthy subjects (16 women, 8 men; mean age, 25.9 ± 5.5 years) by applying electrical stimulation at 2,000, 250, and 5 Hz to the infraorbital and mental skin of the facial area, the gingival mucosa of the maxillary and mandibular anterior teeth, the palatal mucosa, and the dorsal surface of the tongue on the right side.
Results: There were no significant differences in the CPTs between the facial infraorbital skin and maxillary anterior gingiva, nor between the infraorbital skin and palatal mucosa at the three stimulation frequencies. The CPTs of the mandibular anterior gingiva and tongue dorsum were lower than those of the facial mental skin at all three frequencies. The CPTs of the tongue dorsum were the lowest among the intraoral test sites, but the difference was significant only between the tongue dorsum and mandibular anterior gingiva at the 5 Hz stimulation.
Conclusions: In healthy adults, the facial and intraoral areas had different CPTs. This study provides guidance for further studies evaluating the neurosensory function of the facial and intraoral areas in healthy and diseased subjects.