Association between mandibular plane angle and mandibular condylar head volume in adults with skeletal Class III deformity indicated for orthognathic surgery: a CBCT study

Abstract

Abstract Background Mandibular condylar morphology varies with craniofacial pattern, but the association between mandibular plane angle (MPA) and specifically defined condylar head volume in skeletally mature adults with skeletal Class III deformity remains insufficiently characterized. This study evaluated that association in patients indicated for orthognathic surgery. Methods This retrospective, cross-sectional, single-center study included 66 adults (33 males and 33 females; 18–40 years), with 22 patients each classified as hypodivergent (MPA < 26°), normodivergent (26°–38°), or hyperdivergent (> 38°). Bilateral condylar head volumes were measured on preoperative CBCT images using manual three-dimensional segmentation. Patient-level mean bilateral volume was used for unadjusted group comparisons with Welch ANOVA and Games–Howell tests. The primary analysis used a linear mixed-effects model with patient-specific random intercepts to account for bilateral correlation; MPA was analyzed continuously with adjustment for age, sex, and side. Results Mean bilateral condylar head volume was 1760.1 ± 476.9 mm³ in hypodivergent, 1448.8 ± 264.1 mm³ in normodivergent, and 983.1 ± 325.5 mm³ in hyperdivergent patients (Welch ANOVA, F(2, 40.13) = 23.24; p < 0.001); all pairwise comparisons were significant. In the mixed-effects model, each 1° increase in MPA was associated with a 31.91 mm³ decrease in condylar head volume (β = −31.91 mm³/°, 95% CI − 41.64 to − 22.18; p < 0.001). Female sex was associated with lower volume (β = −318.51 mm³, 95% CI − 484.58 to − 152.43; p < 0.001), and left-sided condyles with greater volume (β = 101.70 mm³, 95% CI 41.06 to 162.35; p = 0.001). Age was not associated with volume ( p = 0.744). Robust GEE sensitivity analysis yielded consistent findings. Conclusions Higher MPA was independently associated with smaller condylar head volume in this selected surgical Class III cohort. The cross-sectional, single-center design does not establish causality or support generalization to all individuals with skeletal Class III malocclusion.

The authors' abstract, as published at the source. BMC Oral Health, 2026 · DOI ↗