Sex determination ; Mandible ; Mandibular flexure ; Measurement ; Korean
Abstract
In this study, cephalometric radiographs were taken with 241 Korean adults older than 20 years, and mandibles and crania were measured with anthrophological methods on cephalometric radiogrphs. It was tried to identify sex differences, especially in the mandibular flexure. The relation between mandibular flexure and mandibular growth pattern was investigated. And the relations between mandibular flexure and antegonial notch, between mandibular flexure and gonial angle were investigated. The results were as follows.
1. Sex differences are significant in all measurements except gonial angle (p <.05). Men are larger than women in maximum cranial length, maximum cranial height, mandibular ramus height, mandibualr body lenght, the depth of mandibular flexure, ramus depth on occlusal plane, and the depth of antegonial notch.
Women are larger than men in cranial base angle, and the height of mandibular flexure.
2. Mandibular flexure tends to be deeper when gonial angle becomes lower, mandibular ramus becomes longer, and antegonial notch becomes deeper and as SNB becomes larger, so mandibular body length becomes larger and as cranial base angle does, so mandibular body length, mandibular ramus height and SNB does.
3. As mandibular plane angle becomes larger, so cranial base angle and gonial angle become larger and as mandibular plane angle does, so maximum cranial height and SNB become smaller.
4. As maximum cranial lenght becomes larger, so mandibular body length, mandibular ramus height and SNB become larger and as maximum cranial height does, so mandibular body length and mandibular ramus height does but gonial angle becomes smaller.
5. The accuracy of sex determination is 71.3 % for male, 56.8 % for female if it is regarded as male when mandibular flexure is deeper than 2 mm, and as female when less than 2 mm.
In conclusion, sex difference of mandibular flexure is significant, but sex determination accuracy using mandibular flexure is not accurate as previous sex determination methods. Mandibular flexure is thought to be related to masticatory muscles and mandibular growth pattern.