Predictive Factors of Sagittal Overjet

Abstract

Background: Sagittal overjet (SOJ) causes significant aesthetical and functional disturbances. Many possible influencing factors have been studied, however, it is not clear yet which factors explain SOJ. Aim: To investigate the extent to which the factors tongue force, mouth breathing, tongue-thrusting, Angle classification, gender, or age, predict SOJ in Dutch children aged 7-13, with and without SOJ. Method: Data on the studied variables were collected from 56 children aged 7-13. To evaluate whether those variables could predict mean SOJ, a multiple regression analysis was performed. To evaluate whether they could predict having increased SOJ, a logistic regression analysis was performed. Results: Mean age was 9 years, 57% of the subjects had increased SOJ. Mean SOJ of the complete sample was 3.41 mm. The multiple regression analysis could not demonstrate a significant effect of the variables included in the study on mean SOJ; all variables could not explain a significant amount of variance in mean SOJ. The logistic regression could not demonstrate that the predictors as a set reliably distinguished between having or not having increased SOJ. Only age made a significant contribution to prediction: when age is raised by one year, children are 1.5 more times likely to have increased SOJ. Conclusion: In this study, SOJ cannot be explained by tongue force in extension, mouth breathing, tongue-thrusting, Angle classification, or gender in various Dutch children aged 7-13. Age can partially predict having increased SOJ in this sample. Implications: The results should be interpreted with care; children with SOJ should still be checked and if necessary treated for mouth habits. Recommendations: It would be interesting to study other factors that could cause SOJ, or to study whether SOJ decreases after unlearning possible influencing mouth habits.