[Highlights in the subject of low frequency-high intensity TENS (review)]

Transcutaneous electrical neural stimulation (l.f.-h.i. TENS), employed in dentistry, allows masticatory muscles relaxation, temporary clearance of muscular and periodontal proprioceptive input and even oro-facial pain relief. The mechanisms involved in this type of stimulation are not entirely clarified. According to the most recent neurophysiological researches, the authors describe several l.f.-h.i. TENS. action modalities. Some of them are well known such as the gate control theory, the endogenous antinociceptive system activation, the metabolic recovery of the muscular tissue and the unloading reflex. Other mechanisms, instead, are less known such as hypnosis and stress analgesia, exteroceptive suppression and counterirritation (DNIC). Some hypothetical mechanisms are also considered such as endogenous inhibition and sympathetic activity reduction.