Assessment of symphysis morphology as a predictor of the direction of mandibular growth.
The purpose of this study was to determine whether symphysis morphology could be used as a predictor of the direction of mandibular growth and to assess growth changes of the symphysis. Cross-sectional data included lateral cephalometric radiographs of 115 adults (58 women, 57 men) with the longitudinal sample a subset of 62 subjects (30 females, 32 males) at four age groups. The direction of mandibular growth was evaluated with seven cephalometric measurements that included Y-axis, SN to mandibular plane, palatal plane to mandibular plane, gonial angle, sum of saddle, articulare and gonial angles, percentage lower facial height, and posterior/anterior face height. The mandibular symphyseal dimensions studied were height, depth, ratio (height/depth), and angle. Symphysis morphology was found to be associated with the direction of mandibular growth, especially in male subjects with symphysis ratio having the strongest relationship. A mandible with an anterior growth direction was associated with a small height, large depth, small ratio, and large angle of the symphysis. Conversely, a posterior growth direction was associated with a large height, small depth, large ratio, and small angle of the symphysis. Symphysis dimensions continued to change until adulthood with male subjects having a greater and later occurring change compared with female subjects.
Aki
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Department of Orthodontics, University of Oklahoma College of Dentistry, Oklahoma City.
Nanda
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Currier
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GF
Nanda
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SK
D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001824:Body Constitution; D002508:Cephalometry; D002648:Child; D002675:Child, Preschool; D002680:Chin / Q000033:anatomy & histology*; D003430:Cross-Sectional Studies; D005260:Female; D005544:Forecasting; D006801:Humans; D008297:Male; D008334:Mandible / Q000033:anatomy & histology / Q000254:growth & development*; D011237:Predictive Value of Tests; D012016:Reference Values; D012727:Sex Characteristics