[A CBCT study on the inclination of the maxillary occlusal plane and related measurements in adolescent skeletal ClassⅠand ClassⅡpatients with normal vertical angles]

To analyze the differences and correlations in the inclination of the maxillary anterior and posterior occlusal planes, mandibular plane angle, mandibular angles(total angle, upper angle, lower angle), and lower facial height between adolescent patients with skeletal Class Ⅰ and skeletal Class Ⅱ normodivergent facial patterns based on CBCT, so as to provide a reference for orthodontic diagnosis and treatment of these two groups of patients.

A total of 37 adolescent patients with skeletal Class Ⅰ normodivergent facial pattern and 37 with skeletal Class Ⅱ normodivergent facial pattern who received orthodontic treatment at Suzhou Stomatological Hospital from January 2023 to December 2023 were selected. CBCT scanning and Dolphin Imaging 11.95 software were used to reconstruct lateral cephalograms. The inclinations of the maxillary anterior occlusal plane and posterior occlusal plane, as well as the total mandibular angle, upper mandibular angle, lower mandibular angle, lower facial height, mandibular plane angle(MP-FH), SNA angle, SNB angle, and ANB angle were measured.

The inclinations of the maxillary anterior and posterior occlusal planes in the skeletal Class Ⅱ group were significantly greater than those in the skeletal Class Ⅰ group(P＜0.01); the total mandibular angle, lower mandibular angle, lower facial height, and mandibular plane angle in the skeletal Class Ⅱ group were significantly larger than those in the skeletal Class Ⅰ group(P＜0.05); the SNA angle in the skeletal Class Ⅱ group was larger (P＜0.05), while the SNB angle was smaller (P＜0.01). In both groups, the inclinations of the maxillary anterior and posterior occlusal planes were positively correlated with the lower facial height and mandibular plane angle, with statistically significant correlations(P＜0.05); they were negatively correlated with the SNA angle and SNB angle, and positively correlated with the ANB angle, among which the correlations in the skeletal Class Ⅱ group were statistically significant (P＜0.05).

The inclinations of the maxillary anterior and posterior occlusal planes are related to the sagittal and vertical skeletal facial patterns; they are positively correlated with the mandibular plane angle, lower facial height, and ANB angle, which negatively correlates with the SNA angle and SNB angle.