Prevalence of Mandibular Third Molar Impaction, Associated Pathologies, and Correlation With Temporomandibular Joint...

Mandibular third molar is the most frequent impacted tooth in the oral cavity. Its presence can be associated with complications including the temporomandibular joint (TMJ) symptoms. Therefore, the present study aimed to assess the prevalence of impacted mandibular third molar (IMTM), associated pathologies, and its correlation with TMJ morphology in a hospital-based Spanish cohort.

We retrospectively reviewed existing orthopantomographs (OPGs) records, panoramic images of patients aged ≥18 with at least one IMTM who attended the Dental Hospital of the University of Barcelona (HOUB) between September 2021 and May 2023. The OPGs were assessed and interpreted by an experienced oral and maxillofacial radiologist for the type of impaction according to Winter's classification system, associated pathologies, and shape of mandibular condyle.

Out of 80 OPGs, 60% (95% confidence interval [CI]: 48.4%-70.7%) were females, and the majority 53.8% (95% CI: 42.3-64.9) were between 18 and 28 years of age. The prevalence rate of IMTM was 86.88%, with the left side commonly involved. On both sides, oval-shaped condyle and vertical IMTM were the most common, with dental caries and bone loss being the frequently observed pathologies. Sclerotic changes were depicted in 15% (95% CI: 8.2%-24.7%) of the cases on both sides of TMJ. On the other hand, no statistically significant associations were noticed between the pathologies and condyle shape (p > 0.05, Cramér's V < 0.25). Vertical and mesioangular, followed by horizontally IMTMs, were the most prevalent types of impactions, indicating nonsignificant association with condylar shape (p > 0.05, Cramér's V = 0.21-0.23).

In this hospital-based cohort, vertical IMTM and oval condylar morphology were predominant; however, condylar shape did not correlate with impaction type on panoramic radiographs. The findings are preliminary and require validation in sufficiently powered cone beam computed tomography (CBCT)-based studies with clinical TMJ assessment.