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.