Displacement of the glenoid fossa: a cephalometric evaluation of growth during treatment.

Pretreatment and posttreatment lateral cephalograms of 175 orthodontically treated patients were evaluated to determine the change in position of articulare. The sample was arbitrarily subdivided according to the direction of facial growth during treatment (vertical, V; horizontal, H; intermediate, H/V) measured at pogonion. The cephalograms were superimposed on anterior cranial base and a Cartesian coordinate system was devised to measure changes in the position of articulare over time. The results clearly show that articulare is displaced posteriorly and inferiorly during craniofacial development with treatment. Significant differences in the amount of displacement were noted between groups. Patients with vertical growth patterns showed significantly greater posterior displacement of articulare than patients with horizontal growth patterns. Because articulare represents the point of intersection of the temporal bone and the neck of the condyle, this investigation suggests that the temporal bone and glenoid fossa are displaced posteriorly during facial development with treatment and that the amount of displacement can affect mandibular position.