[Somatosensory trigeminal evoked potentials after gingival stimulation of the mental nerve. Normal values]

Somatosensory evoked potentials were recorded following unilateral stimulation of the mental nerve in the gum of 100 healthy volunteers aged between 17 and 22 years.

Responses were recorded until 100 ms with electrodes placed over the scalp (C5/C6) referenced to central frontal (Fz). In 10 subjects, simultaneous recordings were made in masticatory and facial muscles to detect possible muscle artefacts. Stimulation was effected using a specially-designed stimulator adaptable to each individual. Contralateral responses consisted of four very constant deflexions (N12, P19, N26 and P35) forming a W-shaped complex of mean duration 31.27 ms. Tables of normality were compiled for latencies and amplitudes with confidence intervals of 99.8% reliability. Constancy of deflexions, stability of response (by serial studies), and possible sexual differences were also studied. Muscle artefacts were ruled out, and the participation of the mental nerve in the genesis of the responses was confirmed.

We consider the proposed method a reliable alternative to other procedures used to obtain TEPs.