Depth of curve of spee in different classes of angle’s malocclusions on dental cast of orthodontic patients treated at jimma medical center dental clinic orthodontic unit, Ethiopia

Abstract

BACKGROUND - Curve of spee is important for balanced occlusion and functional occlusion, it also serves to enhance three dimensional freedom of movement of mandible. In addition, the Curves are associated with esthetics of the face and are contributing to an esthetically satisfying smile. Curve of Spee has a biomechanical function during food processing by increasing the crush shear ratio between the posterior teeth and the efficiency of Occlusal forces during mastication. Flattening the curve of Spee should be one of the goals of orthodontic treatment as correction of overbite often involves leveling the curve of Spee by anterior intrusion, posterior extrusion, or a combination of these actions. There are different opinions about the development of the curve of Spee, so it is important to know in which type of malocclusion this curve is more severe. OBJECTIVE – to assess curve of spee in Angle Class I, II & III malocclusion in Jimma medical center dental clinic, Ethiopia Method- 2 year hospital based retrospective cross sectional study design was conducted on dental casts of Orthodontic patients in the dental clinic from August 13 to Augusts 20, 2022 who fulfilled the inclusion criteria. One hundred twenty nine casts were chosen, and divided into 3 groups (n=129) according to Angle dental malocclusion classification. The depth of curve of Spee was measured on left and right sides of mandibular dental models and mean values were used as depth of curve of Spee. Data was analyzed by statistical package for social science (SPSS) version 20.0. Descriptive statistics was applied for the analysis of socio-demographic related characteristics of the study participants, patients related characteristics including such as mean, standard deviation (SD), medians and percentiles. ANOVA was used on Stata software to compare the mean depth of curve of spee between the different Classes of Angle’s Malocclusion Result: The depth of COS was found as deepest in Class II malocclusion (2.50±0.94mm) and was relative flat in Class I malocclusion (1.62±0.69mm) and there is significant difference between class I and class II, class II and class III mean score of depth of curve of Spee at 5% level of significance. However, there is no significant difference between class I and class III mean score of depth of curve of Spee at 5% level of significance. Conclusion: Since the depth of curve of Spee is increased in Class II malocclusions, this factor should be considered in diagnosis & treatment planning.