A comparative assessment of mandibular condylar position in patients with anterior disc displacement of the temporomandibular joint.
OBJECTIVE
The purpose of this study was to determine whether the position of the mandibular condyle in patients with anterior disc displacement (ADD) is different from that of a control group with normal joints using a novel method to quantify the irregular shape of the temporomandibular joint (TMJ).


METHODS
Twenty-six magnetic resonance images of TMJs with ADD were evaluated and compared with 14 normal joints. The position of the condyle was determined by using 2 different methods: 1) measuring the horizontal and vertical normalized distances in millimeters between the geometric centers of the glenoid fossa and the condyle and 2) calculating the anteroposterior joint space ratio.


RESULTS
Using the first method, the horizontal distance between the centers of the condyle and the glenoid fossa was 14.0 +/- 11.1 in the ADD group and 5.3 +/- 10.9 in the control group (P <.001). The vertical distance was 64.7 +/- 22.7 in the ADD group and 68.3 +/- 32.9 in the control group (P =.015). The ratio of the horizontal and the vertical condylar displacement in the ADD group was 2.4. Using the second method, the anteroposterior joint space ratios in the ADD group and in the control group were 1.7 +/- 0.5 and 1.2 +/- 0.4, respectively (P =.001).


CONCLUSIONS
This study found that condyles of patients with ADD were situated more posterior and superior in the fossa than those in the control group. Moreover, in the ADD group, the posterior condylar displacement was noted to be 2.4 times greater than the superior condylar displacement.
Gateno
Jaime
J
Department of Oral and Maxillofacial Surgery, Dental Branch, The University of Texas Health Science Center at Houston, Houston, TX 77030, USA.
Anderson
Paul B
PB
Xia
James J
JJ
Horng
Julie C
JC
Teichgraeber
John F
JF
Liebschner
Michael A K
MA
D000293:Adolescent; D000328:Adult; D002508:Cephalometry / Q000379:methods*; D003936:Diagnosis, Computer-Assisted; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008297:Male; D008335:Mandibular Condyle / Q000473:pathology*; D008875:Middle Aged; D012016:Reference Values; D012189:Retrospective Studies; D019224:Temporomandibular Joint Disc / Q000473:pathology*; D013705:Temporomandibular Joint Disorders / Q000473:pathology*