Prevalence of temporomandibular disorders in subjects affected by Parkinson disease: A systematic review and metanalysis

Introduction: While Temporomandibular disorders (TMDs) are not typically considered a primary symptom of Parkinson disease (PD), recent studies have documented a correlation between ageing and TMDs, a cluster of conditions affecting the temporomandibular joint and surrounding musculature, thereby underscoring the potential for an increased frequency of TMDs in the ageing PD population. Objective: The purpose of this review is to systematically evaluate the existing literature on the topic and provide a comprehensive overview of the prevalence of TMDs in patients with PD. Methods: To determine eligibility, we utilised the Population (human subjects), Exposure (PD), Comparator (PD vs non-PD subjects), and Outcomes (TMD) (PECO) model. To conduct this systematic review, we searched for articles published in PubMed, Web of Science and Lilacs from the beginning until April 15, 2023. Results: Three studies were selected. All together they comprised a total of 55 828 subjects, out of which 12 629 were affected by PD or Parkinsonism, and the remaining 43 199 were non-PD subjects matched for age and sex. The study aimed to evaluate the prevalence of TMDs in subjects affected by PD. The results showed that 193/12629 (1.53%) of PD individuals presented with TMD symptoms or were diagnosed with TMD, while 260/43199 (0.6%) of non-PD subjects were diagnosed with the same. The meta-analysis showed that there was a higher TMD prevalence in PD subjects compared to non-PD subjects (RR 1.57; 95% CI: 1.30–1.89). Conclusion: The studies reviewed suggest a possible association between TMD and PD. Further research is needed to clarify the relationship between TMD and PD and to identify possible mechanisms and treatment strategies.