Journal of AdvancedMedical and Dental Sciences Research

Introduction: A flat Curve of Spee is one of the essential criteria for the treatment in orthodontics. Growth and development of orofacial structures mainly contributes for the development of the Curve of Spee. Aim:To evaluate the pre and post treatment depth of the curve of Spee (COS) and Mandibular Dental Height (MDH) in Class I and Class II malocclusions. The intention was to assess the contribution of MDH to the depth and flattening of the COS. Materials and Methods: This retrospective study consisted of 45 cases of Angle’s Class I, Class II Division 1 and Class II Division 2 malocclusions with comprehensive clinical data, pre and post-treatment study models (SM) and lateral cephalograms (LC). On pre and post- treatment SM, depth of the COS was measured on both sides. Similarly, the depth of the COS was measured on LC, by proportioned MDH from incisal edge of the mandibular central incisor (I-MP), distobuccal cusp tip of the mandibular second molar (M2-MP) and the deepest point of the COS (S-MP) to the Mandibular plane (MP). Paired t-test and correlation coefficient were calculated to analyze the depth of the COS and MDH. Results: On pre treatment SM, deepest value was observed in Class II Division 2 (Mean2.587 mm) than Class I (1.967mm) and Class II Division 1 malocclusion (1.467mm). The depth of the COS was almost similar on both sides (p-0.906), but the significant changes were noted between pre and post-treatment groups (p< 0.001).On pretreatment LC, anterior MDH (I-MP) was significantly contributed to depth of the COS than posterior MDH (M2-MP). In post treatment, the leveling of depth of the COS was significantly contributed by M2 –MP/S-MP( p<0.05). Conclusion: The anterior MDH caused a significant effect on the depth of the COS, but the leveling of COS was substantially contributed by M2-MP/S-MP. Key words: Angle’s Malocclusion, Anterior and Posterior Dental Height, Depth of Curve of Spee.