Difference between revisions of "Trigeminal Nervous System Segmentation"

'''Bruxism''' is usually believed to be related to musculoskeletal pain, such as pain from TMDs, but also to muscular-tensive headache. Few studies have actually tried to fully describe the pain associated with bruxism examining the neurobiological and physiological characteristics of the mandibular muscles. There are some clinical cases in the literature and small studies suggesting that some drugs related to dopaminergic, serotonergic, and adrenergic systems, can both suppress and exacerbate bruxism. Most of the pharmacological studies mentioned before indicate that several classes of medications can affect muscle activity related to bruxism without having any effect on Orofacial Pain (OP: Orofacial pain)<ref>{{cita libro  

  }}</ref>. It seems that the ‘sensitization’ of the trigeminal nociception system, the facilitation effect on the mandibular reflesxs, and the hyper-excitability of CNS are neurophysiopathogenetic phenomena that are related to pain in the craniofacial district. At the same time, the recovery cycle of the torpedo period shows the level of neuronal excitability of the trigeminal system, and it could be a valid method of testing the excitability of the nervous system.  

The recovery cycle of the masseteric reflection reflex (_rc MIR: recovery cycle Masseteric Inhibitory Reflex) has been studied by generating pairs of stimuli with identical characteristics provided percutaneously by an electrical stimulator positioned on the patient’s face in the emergency area of the mental nerves (<translate>Figure</translate> 8).

Stimulation was carried out with a square-wave electrical stimulation that was 2.5 times the inhibitory reflection threshold, which was able to evoke a distinct _rc MIR, composed of the two silent periods called ‘exteroceptive suppression’ to distinguish them from separate mechanical Silent Periods (SPs); these can be recognized in a first silent period called ES ₁ (Exteroceptive Suppression ₁) and a second silent period named ES ₂ (Exteroceptive Suppression ₂) interspersed by the resumption of the activity EMG (Interposed IA Activity). The first stimulus (S1) is considered to be conditioning and the second (S2) a stimulation test. The interstimulus range to verify the presence of a neural hyperexcitability between S1 and S2 has been set at 150 ms. In our studies, healthy subjects were instructed to tighten their teeth to produce the maximum EMG activity and maintain it for at least 3 seconds with the help of visual and sound feedback. After 60 seconds of rest, the subject repeated the contraction. The EMG signal was recorded in direct  mode and mediated mode. The disposition of the recorder electrodes must be the same as for the registration of the _b Root, jaw jerk, and SP. The parameters of the preamplifier will have to be set in 50 ms per division, 100 mV per division, and the filter bandwidth of 50 Hz–1 kHz.

[[File:Laser test.jpg|thumb|'''<translate>Figure</translate> 9:''' Preparation of the subject to laser stimulation to evoke nociceptive evoked potentials and masseteric inhibitory reflexes.]]