Prevalence of static and dynamic dental malocclusion features in subgroups of temporomandibular disorder patients: Implications for the epidemiology of the TMD-occlusion association

Objective: The hypothesis that dental malocclusions may be a risk factor for temporomandibular disorders (TMD) has been greatly debated in the literature. Whilst the association between features of dental occlusion and TMD has been proven weak, if existing, it seems that the transfer of such knowledge into clinical practice is yet to be completed. This study evaluated the prevalence of static and dynamic malocclusion features in a population of TMD patients and compared it with literature data on the general population. Method and Materials: A total of 625 consecutive TMD patients (75% female; aged 34.2 ± 6.7 years, range 25-44 years) were examined and were clustered into four groups on the basis of pain absence (ie, disk displacement and/or arthrosis without pain), or pain presence within the muscles and/or the temporomandibular joint (TMJ). As for the occlusal features, posterior crossbite, excessive overbite, anterior open bite, excessive overjet, and molar and canine asymmetry were recorded as static malocclusion findings. Medio-/laterotrusive interferences and slide length from retruded contact position (RCP) to maximum intercuspation (MI) ≥ 2 mm were also recorded as dynamic malocclusion findings. The ɸ correlation coefficient assessed the strength of the correlation between each occlusal feature and the presence of pain-related TMD condition. Results: No significant correlation was seen between the various malocclusion findings and the presence of any pain-related TMD condition, with ɸ values ranging from -0.081 to +0.043 for molar asymmetry and laterotrusive interferences, respectively. The prevalence findings in this TMD population were within the range reported from general population studies. Conclusions: In adult subjects, static or dynamic malocclusion findings show similar prevalence irrespective of the presence of any specific pain-related TMD condition. Also, the prevalence values are similar to the available data at general population level. Based on the above, general practitioners should note that occlusal features may not be considered a discriminant factor for TMD. Keywords: epidemiology, occlusion, prevalence, temporomandibular disorders