Effect of Inferior Traction on a Unilateral Condyle under Various Conditions

The methods of creating inferior traction on a unilateral condyle using bilateral and unilateral bite plates on the molars and unilateral pivot were examined. Different patterns of mandibular displacement were also examined, i. e., voluntary clenching, manual unilateral elevation of the mandible, and unilateral and bilateral myo-monitor pulse stimulation (myo-pulsing). Displacement of the condyle was measured with a computerized axiograph. Inferior traction on a condyle did not arise during voluntary clenching with the pivot or either of the bite plates. Voluntary clenching apparently caused the condyle to be pressed anterosuperiorly against the glenoid fossa. Manual unilateral elevation with the pivot created inferior traction of the condyle (1.3-1.4mm) on the pivot side but superior movement (0.9-1.0mm) also caused the condyle to be pressed against the glenoid fossa on the contralateral side. Plate side pulsing created inferior traction on the contralateral condyle without creating pressure on the pulsing side both with and without bite plates. Then non-plate side pulsing created inferior traction on the contralateral condyle without creating pressure on the pulsing side. In conclusion, unilateral myo-pulsing with the pivot or the unilateral bite plate was the most effective for creating the inferior traction effect on the contralateral condyle, while voluntary clenching was ineffective.