Relationship between internal derangement of the temporomandibular joint and dentofacial morphology in women with anterior open bite.
BACKGROUND
Anterior open bite is known to be associated with internal derangement of the temporomandibular joint (TMJ). This study examined the relationships between internal derangement and dentofacial morphology in women with anterior open bite.


METHODS
Fifty-one women with anterior open bite were enrolled in this study. The sample was divided into 3 groups based on magnetic resonance imaging of bilateral TMJs: normal disk position, disk displacement with reduction, and disk displacement without reduction. One-way analysis of variance was used to compare the 3 groups with respect to the cephalometric variables, and Duncan's multiple comparisons were performed at the 95% confidence level to identify the differences among the 3 groups.


RESULTS
Internal derangement of the TMJ was much more prevalent in subjects with a more posteriorly rotated mandibular ramus, a smaller mandible, and a greater tendency for a skeletal Class II pattern, although all subjects had an anterior open bite. These patterns were more severe as the internal derangement progressed to disk displacement without reduction.


CONCLUSIONS
Some cephalometric characteristics, such as a decrease in posterior facial height, decrease in ramus height, and backward rotation and retruded position of the mandible, are associated with TMJ internal derangement in women with anterior open bite.
Byun
Eun-Sun
ES
Department of Orthodontics, College of Dentistry, Seoul National University, Korea.
Ahn
Sug-Joon
SJ
Kim
Tae-Woo
TW
D000328:Adult; D002508:Cephalometry; D005260:Female; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007180:Incisor / Q000473:pathology; D004204:Joint Dislocations / Q000473:pathology; D008279:Magnetic Resonance Imaging; D008312:Malocclusion, Angle Class II / Q000473:pathology; D008334:Mandible / Q000473:pathology; D008335:Mandibular Condyle / Q000473:pathology; D008437:Maxilla / Q000473:pathology; D024343:Open Bite / Q000473:pathology*; D012399:Rotation; D019291:Skull Base / Q000473:pathology; D019224:Temporomandibular Joint Disc / Q000473:pathology; D013705:Temporomandibular Joint Disorders / Q000473:pathology*; D014070:Tooth / Q000473:pathology; D014716:Vertical Dimension