Evaluation of the Hyoid Bone Position Based on the Hyoid Triangle in Patients With Different Skeletal Patterns: A...

We aimed to compare the hyoid bone triangle among individuals with Class I, II, and III skeletal patterns, considering different facial growth patterns.

A total of 296 patients were included in the study. Skeletal patterns were classified using the A Point-Nasion-B Point (ANB) angle and Wit's appraisal, while the Bjork angle and Jarabak index were employed to categorize facial growth patterns (vertical, horizontal, and normal). Hyoid triangle measurements-based on two facial parameters (C3-H and H-RGn) and one cervical vertebral parameter (C3-RGn)-were compared across skeletal classes and facial growth patterns.

Patients were classified into vertical (n = 143), horizontal (n = 80), and normal (n = 73) growth patterns. Significant differences in hyoid triangle measurements were observed across skeletal classes within each growth pattern. In the vertical group, mean C3-RGn was 71.90 ± 9.28 mm in Class I versus 65.40 ± 9.45 mm in Class II (p = 0.027). In the horizontal group, Class III exhibited significantly higher values than Class II for C3-H (34.19 ± 6.55 vs. 30.16 ± 4.18 mm, p = 0.050), H-RGn (93.13 ± 9.96 vs. 37.45 ± 6.02 mm, p = 0.007), and C3-RGn (76.56 ± 14.25 vs. 66.77 ± 9.11 mm, p = 0.008). In the normal group, Class III showed higher H-RGn (39.77 ± 7.72 vs. 33.57 ± 6.39 mm, p = 0.015) and C3-RGn (72.88 ± 11.27 vs. 63.89 ± 8.60 mm, p = 0.030) compared to Class II.

Class II patients tend to have a more posterior hyoid bone position, except in normal growth patterns, where the hyoid position is relatively more anterior. Vertical growth patterns in Class II patients are associated with a lower hyoid bone position.