PREVALÊNCIA DO CÔNDILO MANDIBULAR BÍFIDO AVALIADO POR EXAME DE RESSONÂNCIA MAGNÉTICA

Abstract

Bifid mandibular condyle (BMC) is a rare and low-incidence alteration in the population. The bifidity of the condyle can determine the formation of a medial and a lateral head, or an anterior and a posterior head. Generally, the diagnosis of BMC is based on imaging rather than clinical evidence. The present study aimed to evaluate the prevalence of individuals with BMC and establish an imaging classification through magnetic resonance imaging (MRI) of the temporomandibular joints (TMJs). An observational, cross-sectional and retrospective study was developed. Data collection was performed on patients submitted to bilateral MRI examination of TMJs, from January to December, in 2018. The sample consisted of MRI scans of 1,153 individuals, evaluated bilaterally, totalizing 2,306 TMJ imaging records. The selected exams were evaluated in parasagittal and paracoronal sections, in open and closed mouth positions. After analyzing and classifying the BMCs, they were associated with gender, affected side, positioning of the articular disc, double or single mandibular fossae, presence of effusion, degenerative and morphological alterations. In addition, the sulcus depth and distance between the bifid heads were measured. In the sample, 77.88% (898) were female and 22.11% (255) were male. The prevalence of BMC was 0.6% (07 individuals). There was a higher prevalence of BMC with mediolateral orientation (0.52%) compared to anteroposterior orientation (0.09%). As for the affected side, 06 individuals had unilateral BMC (85.7%), with bilateral BMC being rarer (14.2%). Five individuals and five corresponding TMJs (62.5%) were diagnosed with BMC associated with articular disc displacement with reduction. Therefore, the prevalence of BMC in this population was low. Furthermore, based on the results of this research, it was possible to establish an imaging classification and to characterize the BMC imaging in terms of the exact orientation of the bifid heads, types of articular disc displacement, presence of effusion, degenerative and morphological changes.