Abstract
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