Is Transverse Maxillary Hypoplasia a Link Between Sleep-Disordered Breathing and TMJ Derangement?

Temporomandibular disorder (TMD) and sleep-disordered breathing (SDB) tend to be comorbid conditions that negatively impact quality of life, including jaw pain and breathing function. Genome-wide association studies (GWAS) demonstrate that OSA has a causal effect on TMD. Clinical studies support that TMD-related pain and headache symptoms improve after 18 months of OSA treatment. Transverse maxillary hypoplasia (TMH) associated with nasal obstruction may contribute to both airway compromise and altered occlusal loading, predisposing individuals to TMD. Our study aims to identify TMH with nasal obstruction as one mechanism of developing TMD.

This retrospective, single-center cohort study included 358 subjects aged 18 years and older presenting with TMJ arthralgia between 2024 and 2025. Exclusion criteria included lack of MRI or CBCT imaging, systemic bone diseases, history of facial trauma, neurological disorders, and prior TMJ or orthognathic surgery. The predictor variable was group (1), no TMD symptoms (n=49), and group (2) MRI-confirmed unilateral anterior disc displacement without reduction (n=23). The primary outcome was naso-maxillary width. Secondary outcomes were maxillary angle at the pyriform rim, nasal floor width, greater palatine foramen width, and the presence of chronic nasal obstruction or prior nasal surgery. Covariates included age, sex, and BMI. Statistical analysis involved descriptive and bivariate analyses, including Fisher's exact test for categorical variables, and multivariable analyses, with P < 0.05 considered statistically significant.

Twenty-three subjects met the inclusion criteria for unilateral anterior disc displacement without reduction (ADDwoR), with a mean age of 39.6±14 years. The cohort included 2 male subjects and 1 nonbinary subject. Subjects in the ADDwoR group had a narrower naso-maxillary width of 17.4±1.6 mm compared with the control group of 20.9±1.8 mm, and a narrower nasal floor width of 18.6±1.5 mm compared with 21.7±2 mm in the controls. The maxillary angle at the pyriform aperture was 42.4±6.2 degrees compared with 48±7 degrees, while the greater palatine foramen width was narrower (23.5±2 mm vs. 25.8±2.4 mm). Chronic nasal obstruction or prior nasal surgery was more prevalent in the unilateral ADDwoR group (39.1%) than in the control group (10.2%) (OR=5.66, P=0.008). When adjusted for age, sex, and BMI, narrower naso-maxillary width, nasal floor width, maxillary angle, and greater palatine foramen width remained significantly associated with increased odds of ADDwoR (adjusted OR = 0.34).

Subjects with unilateral ADDwoR are associated with transverse maxillary hypoplasia and a higher prevalence of chronic nasal obstruction or prior nasal surgery. Transverse maxillary hypoplasia may contribute to occlusal instability and asymmetric TMJ loading, potentially aggravating unilateral ADDwoR. Combined with GWAS findings linking OSA as a causal factor for TMD, these results emphasize the need for more research in support of sleep-disordered breathing screening and intervention in ADDwoR.