Determination of transverse discrepancies in class II division I malocclusion & class I occlusion- a comparative study

Objectives: To evaluate the role of transverse discrepancy in the form of arch width, alveolar width andbuccolingual inclination of maxillary and mandibular posterior teeth between Class II division 1 malocclusion and Class I occlusion. Materials and Methods: Study consist of 25 subjects with Class I occlusion and 25 subjects with Class II division 1 malocclusion were selected to measure arch width & alveolar width with a standard caliper and Buccolingual inclination of maxillary and mandibular posteriors were measured with a bevel protractor. Results: Lingual tilted posterior teeth are seen in both the arches. The premolars and first molars of maxillary arch were significantly more lingually tilted (P< .05) in Class II division 1 malocclusion than in Class I occlusion, but in the mandibular arch first premolars were significantly less lingually tilted in Class II division 1 malocclusion than in Class I occlusion. No significant difference of Buccolingual inclination was found in mandibular second premolars and first molars between the two groups. No significant differences found between the groups with respect to arch width and alveolar width. Conclusions: Buccolingual inclination plays an important role in transverse discrepancy of Class II division 1 malocclusion, whereas no difference found with respect to arch width and alveolar width. Introduction Angle defined Class II malocclusion as characterized by a distal relation of the lower to the upper permanent first molar to the extent of more than one-half the width of one cusp and the maxillary incisors being protrusive 1 . The Class II malocclusion is a common malocclusion with a prevalence ranging between 5% and 29% 2-3 . Two thirds of the patients with Class II division 1 malocclusion were reported to have an associated significant skeletal discrepancy 3 . The dentoskeletal morphology of subjects exhibiting Class II malocclusion has been reported in several studies 4-6 It’s in the interesting for the orthodontist especially when formulating treatment planning to know the changes that occur in the arch form as growth or as a result of treatment per se. In the recent past many studies have carried out extensive research in class II division I malocclusion in the transverse plane of occlusion. Results of these studies are more contradictory. Few studies suggested of narrower maxillary arch width in Class II DETERMINATION OF TRANSVERSE DISCREPANCIES 3(2);2017 18 Journal Of Applied Dental and Medical Sciences 3(2);2017 malocclusion than in Class I or normal occlusion 7,8,9 . Whereas another study 10 found that there were no differences in maxillary arch width. Some deficiencies existed in these studies. To mention few, most of the studies concerning transverse problems with Class II division 1 malocclusion were limited to arch width and alveolar width, neglecting another important transverse problem, the buccolingual inclination of posterior teeth. Studies showed that buccolingual inclination of posterior teeth was important not only to interdigitate occlusion, but also to frontal esthetics. 11 Another issue is with the inclusion criteria of Class II division 1 in these studies did not consider the skeletal relationship. As transverse discrepancy in Class II malocclusion might be compensation to anteroposterior displacement of jaws 7 , the sagittal skeletal relationship should be considered in sample selection. In our study Class II division 1 malocclusion, both in dental and skeletal relationships are considered. The aim of our research is to investigate, the role of arch width,alveolar width&buccolingual inclination between class II Division 1 malocclusion and class I occlusion. Material & Methods The study was carried out in the Department Of Orthodontics and DentofacialOrthopedics, A.M.E’s Dental College and Hospital, Raichur, India. Study consisted of 50 subjects’ dental impression and lateral Cephalogram in an age group of 14-20 years, which includes 25 class II malocclusion and 25 class I occlusion. Materials used: 1. Patient’s Casts 2. Lateral Cephalogram, 3. Digital Caliper 4. Bevel protractor