1 Assistant Professor, Department of Pediatric dentistry, Faculty of dentistry, Qazvin University of medical sciences ,Qazvin, Iran

2 Associate Professor, orthodontics department, Dental branch ,Islamic Azad University, Tehran ,Iran



Background and aim: Knowledge of arch width characteristics in different malocclusion types such as Class II/2 malocclusion have considerable implications in orthodontic diagnosis and treatment planning. The purpose of this study was to compare the transverse dimensions of the dental arches in an Iranian plaster cast samples with Class II division 2 (II/2) malocclusion and class I malocclsion.
Materials and methods: In this case-control study, maxillary and mandibular intercanine (IC) and intermolar (IM) arch widths measured and recorded from 26 subjects with Class II/2 malocclusion. The data were compared with 26 control subjects with class I malocclsion.
Results: In the Class II/2 group, the IC widths and IM widths in both arches were less than those in the control sample. Howeverstatistically significant difference was found only in maxillary IM width (p=0.001).
Conclusion: The findings indicated that although both maxillary and mandibular arches are narrower in Class II/2 patientsbut posterior segment of maxilla is the site which is mostly affected by the Class II/2 etiologic factors.