[Metric analysis of temporomandibular joint in asymptomatic persons by magnetic resonance imaging].

AIM: The objective of this study was to investigate the prevalence of anterior disk displacement and condyle position in volunteers free from clinical symptoms and signs of temporomandibular disorders. MATERIAL AND METHODS: Bilateral parasagittal T1-weighted magnetic resonance images of temporomandibular joints (TMJ) in 25 asymptomatic volunteers (age range 21-27, mean 23.4 years; 18 (72%) female and 7 (28%) male) were analyzed and metric measurements of disk and condyle position were investigated. Metric analysis of the position and relationship between the disk and the condyles were described using Kurita et al. method of measuring relative and absolute distances of reference points. On statistical data analysis, the left and right TMJs of each person were presented as two separate entities. The methods of nonparametric statistics were used. RESULTS: Anterior disk displacement was found in 5 (20%) asymptomatic volunteers (four of them female). Anterior displacement with unilateral reduction and anterior displacement without reduction unilaterally was present in two subjects each, whereas one volunteer had anterior displacement without reduction bilaterally. There was no difference in the calculated position of condyle between joints with and without disk displacement (Kruskal-Wallis test, p < 0.05). DISCUSSION: This study evaluated the prevalence of asymptomatic anterior disk displacement in symptom-free healthy volunteers and the condyle position in the glenoid fossa. Displaced disk is the main cause of temporomandibular pain; however, studies in asymptomatic volunteers also suggest it to be an anatomic variant. The relationship between dorsocranially positioned condyle and anteriorly displaced temporomandibular joint disk is a controversial issue. Metric analyses were only made in parasagittal plane. CONCLUSION: There was difference in the calculated disk position between joints with and without disk displacement, but this study found no difference in the calculated condyle positions according to the presence or absence of disk displacement.