The range of functional mandibular movement in bruxists. 4. Discussion and conclusions

A study of some kinesiological characteristics of the mandible of non-bruxist and bruxist subjects was carried out using a closed circuit television point movement tracking system. The use of incandescent light bulbs attached to the incisor teeth of the maxilla and mandible as the point movement source allowed records to be made without head restraint of the subjects examined. Records were stored on magnetic tape. Mandibular movement was studied using the vertical, lateral and anteroposterior components of movement. Two components of movement were combined electronically for all three combinations of the components and the signals produced were used to prepare envelopes of motion graphically, on an X-Y recorder, in the coronal, sagittal and horizontal planes. Qualitative analysis of envelopes of motion in three planes mutually at right angles proved useful in providing information which demonstrated trends to minor differences between non-bruxist and bruxist subjects. However, variations of patterns of movement occurred frequently enough in each test of each group to negate any possibility at present of using these techniques in the development of diagnostic procedures.