Korean J Orthod.  1979 Dec;9(1):85-98.

A roentgenocephalometric study on mandibular prognatnism

• Lee KS

Abstract

This investigation was designed to compare the craniofacial and dental morphology of class III malocclusion with that of normal occlusin in children, and to determine the incidence of various class III craniofacial skeletal patterns. The material selected for this study consister in standard pateral cephalograms of eighty two Korean children, forty one boys and forty one girls, aged 10 through 12 years, having class III maloccluaion, and forty two Korean children, twenty boys and twenty two girls, with normal occlusion in the same age. Using the tracings of the standard lateral cephalograms, various angular and linear measurements were recorded, tabulated and statistically analyzed, and then normal range of those of normal occlusion. The followion characteristics of the craniofacial and dental morphology of class III malocclusion were observed. 1. The cranial base length of class III malocclusion was smaller than that of normal occlusion, and the small saddle angle was a characteristic figure of class III malocclucion. 2. Maxillary length of class III malocclusion was smaller than that of normal occlusion, and point A was retropositioned relative to cranial base but not PNS in class III malocclusion. Maxillary base inclination was not significantly different between the two, but occlusal plane to palatal plane was small in class III malocciusion. 3. The mandibular body length shown no difference between the two, but the mandibular body positioned anteriorly relative to cranial base in class III malocclusion. Ramus height, gonial angle, and mandibular effecctive length were large in class III malocclusion. Mandibular plane angle and joint angle had no difference between the two, and occlusal plane to mandibular plane angle was large in class III malocclusion. 4. Maxillary incisor inclination was not significantly different between class III malocclusion and normal occlusion, but mandibular incisors positioned and inclined lingually and consrquently interincisal angle was latge in class III malocclusion. 5. Class III malocclusion was dividid into six categories of craniofacial skeletal pattern. The most common class III pattern was found to be one in which the normal range of prognathism while the mandible was within this range was approximately one fifth of the class III sample.

MeSH Terms

Child
Dental Occlusion
Female
Humans
Incidence
Incisor
Joints
Malocclusion
Mandible
Prognathism
Reference Values
Skull Base