A comparative lateral cephalometric study between class III malocclusion and class I normal occlusion

الملخص EN

Background : the purpose of this retrospective study was to compare the craniofacial cephalometric measurements between Class III malocclusion and Class I normal occlusion in Iraqi adults.

Materials and methods: 30 digital true lateral cephalometric radiographs for 15 males and 15 females were selected from the files of the patients attending the Orthodontic clinic in the College of Dentistry, University of Baghdad with an edge to edge and anterior cross bite incisor relation to represent the Class III.

Another 30 digital true lateral cephalometric radiographs for 15 males and 15 females for under and postgraduate students in the same college, with Class I molar relation, ANB angle ranged between 2-4°, and overjet and overbite between 1-4 mm, were selected to represent Class I normal occlusion sample.

24 skeletal and dental measurements (14 angular and 9 linear measurements and one ratio) were measured using AutoCAD program.

Independent samples t-test was used to evaluate the classes differences in each gender.

Results and Conclusions: In comparison with Class I normal occlusion, Class III sample had: shorter posterior cranial base length and smaller saddle angle for both genders, retrognathic maxilla in males and normal in females, shorter maxillary length, prognathic mandible and chin position, longer mandibular length in females and normal in males, smaller ramus height in males, steeper mandibular plane with more obtuse gonial angle, decreased posterior facial height, normal total anterior facial height in males and decreased in females, proclined maxillary incisors as well as retroclined mandibular incisors with larger inter-incisal angle.