Biblioteca Virtual en Salud

It is the aim of this study to observe the distribution of various facial types in class III malocclusion and to characterize the craniofacial features of the very facial types. Cephalometric headplates of a hundred and ten persons showing bilateral class III malocclusion whose mean age was 12.51 years and sixty nine persons of normal occlusion whose mean age was 12.23 years were measured and statistically analyzed. The following summary and conclusions were drawn. 1. Affording the bases for SNA and SNB, 35.45% of sample showed normally positioned maxilla and protruded mandible, 30.00% for retruded maxilla and normally positioned mandible, 15.45% for retruded maxilla and protruded mandible, 10.90% for both maxilla and mandible within normal range and 8.20% for miscellaneous types were arranged in class III malocclusion. 2. 52.72% of sample showed neutrodivergent, 35.45% for hyperdivergent and 11.81% manifested hypodivergent mandible in class III malocclusion. 3. Providing the bases for facial and mandibular planes, 33.63% of sample showed prognathic and neutrodivergent, 20.90% for mesognathic and hyperdivergent, 17.27% for prognathic and hyperdivergent and 15.45% for mesognathic and neutrodivergent were arranged in class III malocclusion. 4. The class III malocclusion brought out shorter cranial base, smaller saddle angle, and larger articular and gonial angle. It showed retropositioned maxilla and forward positioned mandible in spite of no significant differences in linear measurements of mandible. Anterior lower facial height was significantly larger in class III malocclusion, while posterior total facial and anterior total facial heights exhibited no significant differences. 5. It is suggested class III malocclusion was attributed to shorter cranial base, smaller saddle angle, maxillary deficiency and/or retrusion, mandibular excess and/or protrusion, excessive vertical growth of the anterior lower face, and their complex as well.