Long-term changes in the perception of comfortable mandibular occlusal positions.

The aim of this study was to disclose, whether use of a screw jack device to set the distance between the jaws, would contribute towards a stabilization of the magnitude and position of a comfortable zone of mandibular positions or even eliminate it. Thirteen subjects participated in each of fifteen experimental sessions distributed over a 3-week period. Throughout the investigation the zone prevailed at an average width of 1-3 mm. The gap shrank 0-08 mm on average per experimental session. Although this latter value was found to be significant statistically, it can hardly be of clinical importance, considering the time needed for a total contraction of 0-8 mm to develop.