Reproducibility of natural head position in normal Chinese people
Kaiyue Tian1, Qianqian Li2, Xiaoxia Wang3
1Resident, Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China.
Introduction:
In this study, we evaluated the reproducibility of natural head position for pitch and roll acquired using 3 methods.
Methods:
The participants were 30 Chinese adults (ages, 23-28 years) who had normal occlusion with no history of orthodontic therapy, maxillofacial trauma, or surgery. The natural head position was acquired using the self-balanced, mirror, and estimated positions, which were performed in duplicate and repeated after 1 week. Three-dimensional photographs were recorded with a horizontal laser line projected onto the face. The laser lines were observed by registering the repeated 3-dimensional photographs. The roll and pitch of the head orientation were measured with a digital ruler. Reproducibility was calculated using Dahlberg's formula and the Bland-Altman method.
Results:
The reproducibility values calculated with Dahlberg's formula were 1.51°, 1.2°, and 0.99° for pitch, and 0.78°, 0.76°, and 0.41° for roll in the self-balanced, mirror, and estimated positions, respectively.
Conclusions:
The 3 methods are reproducible for both pitch and roll, and the estimated position showed the best reproducibility among these methods. This indicates that the estimated position could be used for acquiring the reference plane in preoperative planning for orthognathic surgery.
