CBCT-based assessment of temporomandibular joint morphology in adults with unilateral cleft lip and palate: a comparative study

Cleft lip and palate is one of the most common congenital craniofacial anomalies, affecting essential functions including mastication and speech. Individuals with this condition frequently exhibit altered dentofacial development, which may influence temporomandibular joint (TMJ) morphology. Although temporomandibular disorders have been reported with increased prevalence in this population, comprehensive evaluation of TMJ structural components remains limited. This study aimed to evaluate TMJ morphology in adults with unilateral cleft lip and palate (UCLP) using cone-beam computed tomography (CBCT) and compare these findings with those of noncleft individuals. This retrospective study included CBCT images from 30 adults with UCLP (aged 18–30 years) and 30 age-matched noncleft controls. Four TMJ parameters were assessed: condylar shape, articular eminence height, articular eminence inclination, and condylar length. Measurements were performed by two calibrated examiners, and reliability was assessed using intraclass correlation coefficients and kappa statistics. Within the UCLP group, measurements were compared using a Wilcoxon signed-rank test between the cleft side (CS) and noncleft side (NCS), and repeated-measures ANOVA was used to compare study groups. Chi-square tests were used for categorical variables. Excellent reliability was demonstrated (ICC: 0.892–0.991). Condylar shape distribution differed between groups; no convex condyles were observed on the CS, whereas round (43.3%) and angled/other (33.3%) morphologies predominated. Articular eminence height was significantly reduced on both the CS (5.44 ± 1.39 mm, p = 0.001) and NCS (5.77 ± 1.35 mm, p = 0.009) compared with controls. Within the UCLP group, eminence height (p = 0.004) and inclination (p = 0.001) were significantly lower on the CS. Condylar length was shorter on the CS compared with both the NCS (p < 0.001) and controls (p = 0.028). Adults with UCLP demonstrate distinct TMJ morphological alterations, including altered condylar shape, reduced articular eminence height and inclination, and shorter condylar length on the cleft-affected side. These findings suggest a potential susceptibility to temporomandibular disorders, possibly associated with asymmetrical functional loading. Early CBCT-based assessment of TMJ morphology provides a structural baseline that may assist in individualized treatment planning and long-term monitoring of patients with UCLP.