Document Type : Original Article
Authors
1
Orthodontics, Faculty of Dental Medicine (For Girls), Al-Azhar University;
2
PhD Visiting Scholar ,Orthodontic Department, School of Dentistry, University of the Pacific, San Francisco, California, U.S.A.
3
Orthodontic Department, Faculty of Dental Medicine (For Girls), Al-Azhar University.
4
Orthodontics, Faculty of Dental Medicine (For Girls), Al-Azhar University.
5
Orthodontics, Director of Craniofacial Research Instrumentation Lab, University of the Pacific School of Dentistry, San Francisco, CA, USA.
Abstract
The issue of craniofacial growth has become more relevant because of the increasing interest in optimizing treatment timing in dentofacial orthopedics. Objective: The purpose of this study was to evaluate craniofacial growth changes in skeletal Class II and Class III subjects in comparison with an age and sex matched control group with normal dentoskeletal pattern. Materials and Methods: The sample was randomly collected from the files of the American Association of Orthodontists Foundation Legacy Collection (AAOF). The final sample consisted of 170 subjects; 75 skeletal Class II subjects (33 females and 42 males), 15 skeletal Class III subjects (5 females and 10 males) and 80 control subjects (38females and 42 males) with chronologic ages from 8 to 18 years old. The digital cephalometric radiographs were traced with replication using special software developed at the Craniofacial Research Instrumentation Laboratory. Cephalometric analysis of twenty skeletal and dental variables was performed. The stages in cervical vertebral maturation (CVM) were recorded from cephalometric records of Class II subjects. Results: 1) Most dentofacial measures in Class II subjects were similar to control group, with the exception of significant mandibular retrusion, higher value of wits appraisal and ANB angle, distal molar relationship, greater skeletal convexity and deficiency in mandibular length. 2) Relative to controls, Class III subjects displayed smaller anterior cranial base length, similar cranial base angle, shorter maxilla, more prominent mandible, and increases in lower anterior facial height. 3) Most of the angular and linear measurements showed no significant sex difference in Class II group. In contrast, presence of a sexual dimorphism was evident in Class III group. Conclusion: 1. The skeletal and dental components of Class II and Class III malocclusion were evident early and didn’t tend to self- correct with growth. 2. In Class II group, the adolescent growth spurt in mandibular length occurred at 12 to 13yrs of age in females and 13 to 14yrs of age in males. In both sexes, the mandibular growth peak occurred between cervical vertebral stages three and four (CS3-CS4). 3. The peak of mandibular growth in Class III group showed a later onset, longer duration, and larger amount than controls. There was a significant increase in mandibular length in Class III subjects from about 11 in females and 14 in males through 16 years of age.
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