The influence of horizontal cephalic rotation on the deviation of mandibular position
10.4047/jap.2018.10.6.401
- Author:
Naoto KATAYAMA
1
;
Kaoru KOIDE
;
Katsuyoshi KOIDE
;
Fumi MIZUHASHI
Author Information
1. Functional Occlusal Treatment, The Nippon Dental University Graduate School of Life Dentistry at Niigata, Niigata, Japan.
- Publication Type:Original Article
- Keywords:
Cephalic presentation;
Horizontal cephalic rotation;
Mandibular position;
Condylar point;
Incisal point;
Three dimensional jaw movement measurement device with six degrees of freedom
- MeSH:
Freedom;
Head;
Humans;
Jaw;
Muscles;
Occlusal Adjustment;
Temporomandibular Joint;
Tooth
- From:The Journal of Advanced Prosthodontics
2018;10(6):401-407
- CountryRepublic of Korea
- Language:English
-
Abstract:
PURPOSE: When performing an occlusal procedure, it is recommended that the patient should be sitting straight with the head in a natural position. An inappropriate mandibular position caused by an incorrect occlusal record registration or occlusal adjustment can result in damaged teeth and cause functional disorders in muscles and temporomandibular joints. The purpose of this study was to clarify the influence of horizontal cephalic rotation on mandibular position by investigating the three-dimensional positions of condylar and incisal points. MATERIALS AND METHODS: A three-dimensional jaw movement measurement device with six degrees of freedom (the WinJaw System) was used to measure condylar and incisal points. The subjects were asked to sit straight with the head in a natural position. The subjects were then instructed to rotate their head horizontally 0°, 10°, 20°, 30°, 40°, 50°and 60° in the right or left direction. RESULTS: The results indicated that horizontal cephalic rotation made the condyle on the rotating side shift forward, downward, and toward the inside, and the condyle on the counter rotating side shift backward, upward, and toward the outside. Significant differences in deviations were found for angles of rotation higher than 20°. The incisal point shifted in the forward and counterrotating directions, and significant differences were found for angles of rotation higher than 20°. CONCLUSION: The mandibular position was altered by horizontal cephalic rotations of more than 20°. It is essential to consider the possibility of deviation of the mandibular position during occlusal procedures.
