Temporomandibular Joint Disorder in Parkinson's Disease Patients

Recent studies suggested that Temporomandibular joint disorder (TMD) may be more prevalent in patients with Parkinson's disease (PD), but lack international standardized clinical assessment.

This study aimed to investigate the correlation between the Diagnostic Criteria for TMD (DC/TMD) diagnosis and PD motor symptoms, and to investigate the presence of TMD in PD patients.

419 participants from the outpatient clinic of the Department of Neurology were enrolled. Patient's TMD status was diagnosed with DC/TMD. PD motor symptoms and severity were assessed by the Movement Disorder Society Unified Parkinson's Disease Rating Scale (MDS-UPDRS) part III and Modified Hoehn and Yahr scale (HY).

45.6% of PD participants were diagnosed with TMD, with Anterior Disc Displacement with Reduction being the most common TMD subtype (27.4%), followed by Degenerative Joint Disease (6.9%). Compared to PD patients without TMD, those with TMD exhibited more advanced motor dysfunction (p = 0.043). Occurrence of Pain-related TMD was correlated with bradykinesia (rho = 0.135, p = 0.006) and axial symptoms (rho = 0.125, p = 0.010), while Intra-articular joint disorder was correlated with tremor (rho = 0.097, p = 0.047). PD patients with longer disease duration were associated with higher odds of TMD diagnosis (OR = 1.064, p = 0.010).

TMD subtypes are associated with specific motor manifestations in PD: pain-related TMD correlated with bradykinesia and axial impairment, whereas intra-articular joint disorders correlated with tremor. Multidisciplinary collaboration between dentists and neurologists is essential and may benefit the management for both PD and TMD.