The effects of TMJ symptoms on skeletal morphology in orthodontic patients with TMJ disc displacement.
OBJECTIVE
The aim of this study was to investigate the effects of temporomandibular joint (TMJ) symptoms on skeletal morphologies of orthodontic patients with TMJ disc displacement (DD).


METHODS
The sample consisted of 197 women seeking orthodontic treatment. The subjects were divided into two groups according to the presence of TMJ symptoms: the presence and absence of TMJ symptoms. Each group was sub-divided into three groups based on magnetic resonance images of bilateral TMJs: bilateral normal disc position (BN), bilateral disc displacement with reduction (DDR) and bilateral disc displacement without reduction (DDNR). Seventeen variables from lateral cephalograms were analyzed by two-way analysis of variance to identify differences in skeletal morphologies with respect to TMJ symptoms and TMJ DD status.


RESULTS
Patients with TMJ DD were more likely to have short ramus height, short mandibular body length and backward positioning of the ramus and mandible. These skeletal morphologies became more severe as TMJ DD progressed to DDNR. However, the skeletal morphologies associated with TMJ DD were not significantly different between symptomatic and asymptomatic patients. As a result, patients with TMJ DD had backward positioning and clockwise rotation compared to those with bilateral normal TMJs, irrespective of the presence of TMJ symptom.


CONCLUSIONS
This study suggests that TMJ DD is associated with altered skeletal morphology, but TMJ symptoms do not significantly influence the relationships between TMJ DD and skeletal morphology.
Dental Research Institute and Department of Orthodontics, School of Dentistry, Seoul National University , Seoul , Korea (ROK).
Da-Mi
DM
Jeon
Woo-Sun
WS
Jung
Su-Jung
SJ
Mah
Tae-Woo
TW
Kim
Sug-Joon
SJ
Ahn
D000328:Adult; D059925:Anatomic Landmarks / Q000473:pathology; D002508:Cephalometry / Q000379:methods; D005146:Facial Asymmetry / Q000150:complications; D005260:Female; D006801:Humans; D004204:Joint Dislocations / Q000473:pathology; D008279:Magnetic Resonance Imaging / Q000379:methods; D008310:Malocclusion / Q000150:complications*; D008334:Mandible / Q000473:pathology; D024343:Open Bite / Q000150:complications; D063173:Retrognathia / Q000150:complications; D012399:Rotation; D013704:Temporomandibular Joint / Q000473:pathology*; D019224:Temporomandibular Joint Disc / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000150:complications / Q000175:diagnosis*; D014716:Vertical Dimension; D055815:Young Adult
TMJ; disc displacement; orthodontic patients; skeletal morphology; symptom