Is scoliosis related to mastication muscle asymmetry and temporomandibular disorders? A cross-sectional study

Objective: Patients with adolescent idiopathic scoliosis (AIS) may face motor control problems and health disability barriers during mandibular movements and chewing. However, studies investigating the extent of these disadvantages, and possible associated factors are quite limited in patients with AIS. This study was conducted to gain a deeper perspective on the effect of AIS on temporomandibular disorders (TMD) and to contribute to the small amount of data on this subject.Methods: Twenty-nine patients with AIS and 29 age- and sex-matched asymptomatic controls participated in this cross-sectional study. Cobb's method was used to measure scoliosis curves. In both groups, the volume of the masseter muscle was determined on magnetic resonance imaging, and Helkimo and Fonseca anamnestic indexes were used to evaluate temporomandibular joint (TMJ).Results: It was observed that the TMD symptoms were higher in the AIS group (22.6- Helkimo and 1.2 - Fonseca) than the asymptomatic group (13.6 - Helkimo and 0.7 - Fonseca). There was no significant asymmetry in masseter volume in patients with AIS, however the volume of the masseter muscles was smaller in the AIS group (R = 14.6/L = 13.6) compared to the control group (R = 16.1/L = 16.2).Conclusions: The study results indicate that spinal curvatures affect the anatomical, biomechanical, and kinesiological features of the masticatory system, and individuals with AIS may experience more chewing problems than asymptomatic individuals. Examining musculoskeletal properties of masticatory system can provide information about the limitation of the TMJ in patients with AIS.