Evaluation of styloid chain calcification related to temporomandibular joint disc displacement: a retrospective cohort study

Objectives The present study aimed to evaluate any relationship between elongated styloid process (ESP) and temporomandibular joint disc displacement (TMJD). Study design: A retrospective cohort study. Setting: Dentomaxillofacial Radiology division of Erciyes University Dental Hospital. Participants: Ninety-four temporomandibular joints (TMJs) of 47 patients were allocated in this study. Intervention-disease: Two experienced dentomaxillofacial radiologists have interpreted all CBCT and MR images. Patients who referred with TMJ disorders were classified according to temporomandibular joint's disc status as normal disc position (ND), displacement with reduction (DWR) and displacement without reduction (DWoR). Methods Main outcome measures: Interpretation of styloid chain calcification pattern and styloid processes length measured linearly on reconstructed sagittal slices of CBCT. Randomization: Cone beam computed tomography (CBCT) and magnetic resonance (MR) images of 154 patients who were admitted between September 1, 2012 and September 1, 2019. Only 47 of them fulfilled the study requirements. Blinding: Single blind of the outcome measurements and interpretations of MR images. Results Total 94 TMJs of 47 patients disc status groups were analyzed and defined as DWoR (n = 25), DWR (n = 32), and ND (n = 37). On multivariate analysis, no statistical significant differences were found between groups in terms of styloid process lengths. Mean SP length and standard deviation of disc status groups (DWoR, DWR, and ND) are 35.5 (+/- 9.8) mm, 34.6 (+/- 9.2) mm, and 38.3 (+/- 8.9) mm, respectively. When patients were grouped individually according to their post-MRI diagnosis, the mean styloid process length in the non-temporomandibular joint disc displacement (non-TMJD) patients (47.9 +/- 10.8) was significantly higher than the TMJD patients (36.1 +/- 9.3). In this study, there is no intervention to cause any harm or side effects. Conclusion Our results indicate that styloid-stylohyoid syndrome may be misdiagnosed with temporomandibular joint disorder (TMD)