Purpose: The purpose of this study was to observe the effect of the position of premature on track of mandibular incisal point during opening movement.
Methods: The changes of the track of mandibular incisal point along with the change of premature position were recorded by Arcus DigMa mandibular moving track analysis system. The relativity between the premature position and mandibular incisal point moving track on arrowy axis, vertical axis and horizontal axis was analyzed. Regression analysis was used for linear correlation between premature position and mandible opening moving track.
Results: The results showed that along with the retrusion of premature, the moving distance of mandibular incisal point tended to increase on arrowy axis, while decrease on vertical axis and lean to the contralateral side on horizontal axis. The linear regression equation of mandibular incisal point moving distance on vertical axis along with the premature position was: y=34.7095-0.1590x(1), delta=0.5549, P<0.001.
Conclusion: The position of premature influenced the track of mandibular incisal point during opening movement significantly. With the retrusion of premature, the mandible opening moving track tended to be more posterior and shifting to the contralateral side, and the opening dimension tended to decrease. There was linear correlation between premature position and mandible moving track on the vertical axis.