Cephalometric Evaluation of Dentofacial Features of Class III Malocclusion in Adults of Mashhad, Iran

Background and aims. Class III malocclusions are considered as one of the most complex orthodontic problems to diagnose and treat. Numerous studies have been conducted to determine the morphologic characteristics of craniofacial complex in patients with this malocclusion. The aim of this study was to determine the dentofacial characteristics of Class III malocclusion in Mashhadian adults. Materials and Methods. This cross-sectional descriptive study consisted of 114 cephalograms including 57 individuals with Class III malocclusion (28 males and 29 females with mean age of 19.28 years) as the case group, and 57 adults with uncrowded Class I occlusion (28 males and 29 females with mean age of 17.2 years) as the control group. Cephalometric evaluation was performed by measuring nine angular and nine linear measurements and the dentofacial characteristics of two groups were compared by Student’s t-test. Results. SNA angle, the distance from A point to Nasion perpendicular and the maxillary effective length was significantly lower in Class III group, while SNB and SN-Pog angles were significantly higher compared to control group. Mandibular effective length did not differ in two groups. Maxillary incisor protrusion and mandibular incisor retrusion in Class III subjects was also observed. From the vertical aspect, only mandibular plane angle showed an increase in Class III group (P < 0.05). Conclusion. Maxillary deficiency, mandibular prognathism, maxillary incisors protrusion and mandibular incisors retrusion are present in individuals with Class III malocclusion, but mandibular effective length does not differ significantly from Class I patients.