Morphometric examination of hyoid bone position, craniocervical junction and upper cervical vertebra alignment on cone beam computed tomography images of individuals with temporomandibular joint degeneration

Objective: The temporomandibular joint, together with the connections between the cranium and cervical vertebrae, forms a complex structure called the craniocervicomandibular system (CCMS). It has been suggested that postural changes in the cervical region may be observed in individuals with temporomandibular joint disorders due to the neurovascular and musculoligamentous connections established within the CCMS. The aim of this study is to examine the morphometric changes in parameters related to hyoid bone position, craniocervical junction, and upper cervical vertebral alignment on cone beam computed tomography (CBCT) images in individuals with temporomandibular joint degeneration (TMJD) and in a control group. Method: In this study, morphometric changes related to hyoid bone position, craniocervical junction, and upper cervical vertebral alignment were examined using a total of 24 parameters in the CBCT images of 100 individuals. Results: The parameters were compared according to gender and diagnosis, and their correlation with age was examined. Statistically significant differences were found between genders in 9 of the 24 parameters and between the study and control groups in 3 parameters related to the evaluation of the craniocervical junction. When examining the correlation of parameters with age, a positive correlation was found in 4 parameters and a negative correlation in 5 parameters. Conclusion: This study aims to determine reference values for the morphometric evaluation of the CCMS on CBCT images. It is anticipated that this will contribute to the literature by aiding in determining the prognosis and treatment protocols for individuals with temporomandibular joint degeneration (TMJD) and in assessing potential postural changes. Further studies on CBCT images in different populations, among TMD subtypes, and before and after orthodontic, occlusal, and physical treatments are recommended to establish standard values.