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

IntroductionWhile 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. ObjectiveThe 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. MethodsTo 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. ResultsThree 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). ConclusionThe 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.