This study was conducted to discern-differences of craniofacial, dentnalveolar structure and model measurements between sex and between class lII openbite group and non-openbite group.
The sample consisted of 49 adult patients with class Iii malocclusion. 24 linear measurements, 22 angular measurements and 12 ratios were -selected in lateral cephalometry. Also, arch width, length, antericr crowding, average molar relation were measured or calculated in diagnostic model. .
The data were evaluated by t-test and multiple discriminant analysis.
The results were as follows ;
1. Most linear measurements, with the exception of MnBL and AUDH, were significantly larger in male(p<0.05). but,
intermaxillary relations and spatial position of maxilla and mandible relative to cranial base were not different for both sex. 2. With the exception of upper and lower anterior crowding, lower arch width, upper arch length, AMi3, male exhibited
significantly larger measurements in model analysis (p<0.05).
3. Size differences of maxilla and mandible between openbite and non-openbite group were not significant(p>0.05). but openbite group showed significantly increased gonial angle(p<0.05), FH-CoGo(p4. ALFH and PUDH were larger(p<0.05) in openbite group. this result served as compensation for the spatial position of mandible relative to cranial base. AUPUDH (p<0.001) and ALPLDH(p<0.05) were lower in openbite group.
upper anterior crowding was the only measurement which showed difference between openbite and non-openbite group(p<0.05).
5. For the purpose of classifying adult class lII openbite and non-openbite group, multiple discriminant analysis was done. gonial angle, ALPLDH, AUPUDH, FH-NA were included in multiple discrinunant equation. 39 cases(92.86%) were correctly classified when applied to the sample used in this study.
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