Association of articular eminence inclination and glenoid fossa roof thickness with sagittal skeletal classes: a CBCT study

This study aimed to evaluate the association between skeletal sagittal relationship (based on ANB angle) and temporomandibular joint (TMJ) morphology by assessing bilateral articular eminence inclination (AEI) and glenoid fossa roof thickness, and to determine right-left symmetry patterns in these parameters.

CBCT images of 123 individuals were analyzed. Skeletal classification was performed using ANB angle and participants were distributed equally into Skeletal Class I, II, and III (n = 41 each). AEI was measured bilaterally on sagittal TMJ sections relative to the Frankfort horizontal plane, and glenoid fossa roof thickness was recorded bilaterally. Side-to-side differences were evaluated using paired tests. Intergroup comparisons were performed across skeletal classes, and right-left associations were assessed using correlation analyses.

The cohort had a mean age of 40.1 ± 18.0 years (range: 11-84), with no significant differences across skeletal classes for age (p = 0.535) or sex distribution (p = 0.156). Right and left AEI showed a strong positive correlation (r = 0.764, p < 0.001), while glenoid fossa roof thickness demonstrated a moderate correlation between sides (ρ = 0.440, p < 0.001). The right AEI (48.0 ± 12.4°) was significantly higher than the left (46.4 ± 12.7°) (p = 0.033). No significant differences in AEI or glenoid fossa roof thickness were detected among skeletal classes, although left AEI tended to be lower in Class III (p = 0.082).

TMJ measurements demonstrated high bilateral association with a small but significant right-left difference in AEI. Skeletal sagittal relationship, as determined by the ANB angle, was not significantly associated with AEI or glenoid fossa roof thickness in this sample.