Blocking of periodontal afferents with anesthesia and its influence on elevator EMG activity.

The effect of anesthetic blocking of the periodontal afferents of the canine teeth was studied in order to determine its influence on any changes in the jaw elevation activity. Unilateral integrated EMG recordings were made of the masseter and anterior temporal muscles during maximal voluntary clenching in centric occlusion and laterotrusive position with canine contact. After anesthetic blocking of the periodontal afferents of one or both ipsilateral canines, a significant increase was observed of the EMG activity of both jaw elevator muscles studied, in centric occlusion as well as with canine contact. The elevator activity increase was of a greater magnitude when antagonistic canines were anesthetized. These findings thus support the hypothesis that high threshold periodontal receptors exert an inhibitory effect on jaw elevator muscular activity.

The immediate effect of the variation of anteroposterior laterotrusive contacts on the elevator EMG activity.

A unilateral maxillary splint divided into three occlusal blocks was built for eight healthy young adults. The three blocks allowed the anteroposterior location of the laterotrusive contacts to vary and to distribute the occlusal force over equivalent periodontal surfaces. The ipsilateral masseteric and temporalis electromyogram (EMG) activities were recorded with surface electrodes during maximal voluntary clenching. The elevator EMG activity with the anterior occlusal block in place was significantly lower than with the intermediate or posterior blocks. The reduction for both elevators with the intermediate block in place did not show a significant variation in comparison to the posterior block of the three blocks inserted. The elevator activity with the three occlusal blocks did not differ from that recorded with the posterior block alone. Neurophysiologic and biomechanical explanations are given related to this laterotrusive elevator muscular behavior.

Influence of stabilization occlusal splint on craniocervical relationships. Part II: Electromyographic analysis.

The aim of this study was to determine the effect of stabilization occlusal splints on electromyographic (EMG) activity of sternocleidomastoid and trapezius muscles in subjects with spasm in the mentioned muscles. A full-arch maxillary stabilization occlusal splint was made for each of the 15 subjects. In the sternocleidomastoid muscle, tonic and saliva swallowing EMG activity decreased significantly with the splint, whereas maximal clenching activity did not change. In the trapezius muscle, no significant changes were observed with the occlusal splint. The different pattern in both muscles during tonic and swallowing EMG activity with the splint is attributed to differences in the synaptic inputs to the respective motoneuron pools, suggesting that a differential modulation of the motor neuron pools may exist of both muscles, of peripheral and/or central origin.

Influence of stabilization occlusal splint on craniocervical relationships. Part I: Cephalometric analysis.

This study was conducted in order to determine the effect of an occlusal splint on craniocervical relationships, in subjects with muscle spasms in the sternocleidomastoid and trapezius muscles. A full-arch maxillary stabilization occlusal splint was made for each of the 15 subjects. Two lateral craniocervical radiographs were taken for each subject, with and without an occlusal splint. Cephalometric analysis showed that the splint caused a significant extension of the head on the cervical spine. There was also a significant decrease in the cervical spine lordosis in the first, second and third cervical segment. These cervical changes could be a compensation mechanism caused by the extension of the cranium on the upper cervical spine. The change in the curvature implies that it is necessary to periodically evaluate the changes occurring in the craniocervical relationships after the occlusal splint has been inserted.

Relationship between the tonic elevator mandibular activity and the vertical dimension during the states of vigilance and hypnosis.

The variation of the tonic EMG elevator mandibular activity was studied as well as the consequent variation of the vertical dimension in two different experimental states: those of vigilance and hypnosis. In the state of vigilance, normal values of tonic EMG activity were recorded and a space of inocclusion (X = 2.22 mm) coincident with the postural mandibular position. Under hypnosis a significant reduction of the tonic EMG activity was observed (43 to 50%), together with a great increase of the inocclusion space (X = 8.90 mm).

Physical therapy for the postsurgical TMJ patient.

The evolution of the role of the physical therapist in the treatment of dysfunction in the stomatognathic system includes involvement in oral surgery and postsurgical repair procedures of the TMJ. There is no doubt that the multidisciplinary approach to treatment is essential to the effective treatment of a surgically repaired or restructured synovial joint. The surgical and therapeutic goals are to restore the joint, as much as possible, to a friction-free, pain-free, functional range of motion. To accomplish this, the practitioner must consider the normal structure and biomechanics of ligaments and tendons; the time frame for adequate collagen fiber biosynthesis; and the effects of immobilization, controlled mobilization, and exercise on ligament repair.