2020 Volume 12 Issue 3 Pages 272-279
Purpose: The objectives of this study were to determine how changes in body and head posture during dental treatment affect condylar position, and to develop a set of standards for the patient’s posture.
Methods: Condylar position was investigated in eight subjects with normal occlusion and not suffering any stomatognathic dysfunction. This was done by measuring deviation in the anteroposterior direction and vertical direction, and an anterior jig was attached in all eight subjects. The measurement conditions were four kinds of head position (backward 10 degrees, forward 0, 10, 20 degrees from the reference position) and four kinds of body position (backward 50, 60, 70, 80 degrees from the reference position) while in the supine position and tapping on the incisal point. The measuring equipment was a jaw-tracking device, which measured the jaw three-dimensionally with six degrees of freedom. The Frankfurt plane was adopted as the reference plane for the jaw-tracking device, and Beyron’s point was used as the measurement point. The anteroposterior direction and the vertical direction were determined.
Results: A significant difference in anteroposterior direction was recognized between head positions of 0 degree and 10 degrees forward, 0 degree and 20 degrees forward, 10 degrees backwards and 20 degrees forward. A significant difference in vertical direction was recognized between head positions of 10 degrees forward and 20 degrees, 0 degree and 20 degrees forward, 10 degree backward, 10 degrees forward and 20 degrees. Changes in posture had little effect on condylar position.
Conclusions: The results of the present study suggest that the condylar position may be affected by the patient’s head and body posture. In conclusion, careful adjustment of the patient’s head and body position is needed when recording the occlusal registration or performing occlusal adjustment.
