Korean J Orthod.  1989 Mar;19(1):201-218.

The cephalometric study of facial types in Class II division 1 malocclusion

• Jeon YO
• Lee KS

Abstract

This study was focused on the distribution of different facial types of the Class II division 1 malocclusion groups and skeletal characteristics of the each group and those that anteropsterior relationship of the maxilla and mandible calculated from the analysis of ANB angle and Wits appraisal was quite different from each other, as well. Cephalometric headplates of 140 persons of Class II division 1 malocclusion whose mean age was 11.2 years and 69 persons of normal occlusion whose mean age was 12.2 years were utilized as materials. Measurements were recorded, tabulated and statistically analyzed employing the tracings of the lateral cephalograms, then Class II division 1 malocclusion group was divided into 9 Types according to the angle of SNA and SNB for the anteroposterior relationship of the maxilla and mandible, another 9 Types according to the FH-NPog and SN-MP for the horizontal and vertical relationship, and the other 9 Types according to the ANB and Wits appraisal for intermaxillary relationship as well, with which was based on Mean+/- 1SD of those of normal occlusion. The result allowed the following conclusion: 1. 37.1 % of population demonstrated maxilla within normal range and retrognathic mandible to the cranial base, 30% for both maxilla and mandible within normal range, 20% for retrognathic maxilla and mandible and 12.9 % of the rest were arranged in Class II division 1 malocclusion groups. 2. Retrognathic mandible and hyperdivergent face accounted for 30.7 %, mesognathic mandible and neutrodivergent face for 29.3 %, mesognathic mandible and hyperdivergent face for 16.4 %, retrognathic mandible and neutrodivergent face for 13.6 %, mesognathic mandible and hypodivergent face for 10% of population were computed in Class II division 1 malocclusion groups. 3. It was suggested that skeletal Class II malocclusion might be due to anomaly in size and shape of cranial base, underdevelopment of mandible, retropositioning of mandible, underdevelopment of posterior face against anterior face, or any combination of these factors. 4. Population with underdevelopment and/or retropositioning of the mandible showed hyperdivergent tendency of facial profile. 5. The ANB angle and Wits appraisal did not coincide the severity of anteroposterior dysplasia in 35.7% of Class II division 1 malocclusion group each other, and this inconsistency was suggested to be related with mandibular rotation, inclination of cranial base, and anteroposterior position of the maxilla.

MeSH Terms

Humans
Malocclusion*
Mandible
Maxilla
Reference Values
Skull Base