Comparison of static teeth exposure in different postures and its influencing factors of orthognathic surgery patients.

Objectives: This study aimed to explore the differences and influencing factors of static teeth exposure in different postures of orthognathic surgery patients.

Methods: A total of 148 patients were collected before or after orthognathic surgery. Photographs were taken in the upright and supine positions, and the static teeth exposure values were measured to compare whether the difference among different positions was statistically significant. The patients were classified in accordance with gender, presence or absence of orthodontic brackets, measurement time (preoperative or postoperative), and maxillary movement direction (forward or backward), and the difference of static teeth exposure was compared. The correlation between the difference of static teeth exposure and age was analyzed.

Results: The diffe-rence of static teeth exposure between the two positions was 0.99 mm±0.95 mm, which was statistically significant (P=0.000). A statistical difference in the difference of static exposure was observed between female and male (P<0.05). No statistical difference in the difference of static exposure was observed among orthodontic brackets, preoperative or postoperative time points, and maxillary movement direction. In addition, no significant correlation was found between the difference of static teeth exposure and age (r=-0.087, P=0.291).

Conclusions: Compared with the upright position, the static exposure of teeth increased by approximately 0.99 mm in the supine position. The difference of static exposure under different postures was greater in males than in females. Furthermore, orthodontic bracket, maxillary surgery, maxillary movement direction, and age had no effect on the difference of static teeth exposure in different postures.