Overjet as a Predictor of Skeletal Base Discrepancy among Nigerians with Malocclusion

Abstract

Background: Overjet is an invaluable tool in the clinical assessment of orthodontic patients. In contrast to other clinical assessment tools, which are largely subjective in nature, overjet is an objective measureable tool that can be readily obtained from the patient's mouth or study models, provided the latter are properly oriented from a static record of the patient's occlusion. This study aimed to assess prediction of sagittal skeletal base discrepancy using overjet in the three classes of malocclusion among a sub-set of Nigerians.
Method: A cross sectional study of 120 subjects in subsets of 40, each for the three classes of malocclusion was carried out. Overjet was measured from the study cast and a wax record of subjects' occlusion. A lateral cephalometric radiograph was taken for all subjects. The ANB angle and Wits appraisal using three reference planes was also obtained for all subjects.
Results: When the class of malocclusion was not considered, overjet had good correlation with the ANB angle and Wits appraisal irrespective of the reference planes used to obtain it (ñ=0.733; 0.687; 0.724;0.703)p<0.01. In the three classes however, high correlation was found only in class III malocclusion(ñ=0.789; 659;0.664;0.603)p<0.01. Linear regression analysis also showed overjet to be a good predictor of sagittal skeletal base discrepancy.
Conclusion: Overjet is a good predictor of skeletal base discrepancy among people with class I and III malocclusion in this environment.