Correlation between temporomandibular disorders and malocclusions: A retrospective observational study-can malocclusions or previous orthodontic treatments affect Temporo-Mandibular Disorders?

Abstract

Background: The purpose of this article is to verify the possible correlation between TMD (Temporomandibular Disorders) and different types of malocclusions in adult subjects and subsequently that between TMD and previous orthodontic treatment. Materials and methods: A retrospective observational study was conducted in San Paolo e Carlo Hospital, associates of the University of Milan, for a period of 2 years (1st February 2019 – 3rd March 2020), on 374 adult patients (244 females and 130 males). The subjects underwent an intraoral examination with a gnathological assessment, in order to distinguish those who suffered from TMD and those who did not. Secondly, the patients were subjected to orthodontic examination to identify those who had previously undergone orthodontic treatment, assessing through an extraoral and intraoral examination, the dental class, the type of dental bite and the presence or absence of a midline deviation. Results: The data analysis revealed a statistically significant association between TMD and gender (p= 0.023, OR= 1.66). The association between class I, II, III malocclusions and the presence of TMD was found to be statistically significant: p<0.0001 (OR= 4.04) and that between open/deep bite and the presence of TMD too: p= 0.003 (OR= 1.89). Moreover, the correlation between midline deviation and the presence of TMD was statistically significant: p<0.0001 (OR=7.48). On the other hand, no correlation was found between TMD and previous orthodontic treatment (p= 0.918). Conclusions: The available data revealed a statistically significant association between TMD and malocclusions, related to dental class and bite and midline deviation, although the existing results in the literature are controversial regarding this association. While no statistically significant correlation was found between TMD and previous orthodontic treatment. Orthodontic therapy, therefore, by correcting occlusion anomalies, could reduce the risk of TMD incidence. Finally, longitudinal studies with adequate statistical power are needed to clarify the possible interrelationships between TMD and malocclusions.