Malocclusion among children in Vietnam: Prevalence and associations with different habits.

Background: This study aimed to measure the prevalence of malocclusion and identify associated factors among elementary school students in Vietnam. Method: A cross-sectional study was conducted from March to December 2022 at six primary schools located in the province of Thai Binh, Vietnam. A total of 873 students were recruited for research purposes. Students were classified into normal, malocclusion classes I, II and III. Bad habits were examined. Multivariate logistic regression was used to detect associations. Results: The prevalence of malocclusion was 60.7 %; 19.0 % had Class I, 31.0 % had Class II and 10.7 % had Class III. Having finger sucking habit was associated with Class I malocclusion (OR: 3.28), and Class II malocclusion (OR: 3.22). Having lip biting habit was related to a higher odds of having Class II malocclusion (OR = 4.37) Class III malocclusion (OR = 6.83). Having tongue thrusting habit was associated with higher odds of having Class I (OR: 5.25), and Class II malocclusion (OR: 6.42). Mouth breathing was related to a higher likelihood of having Class II malocclusion (OR = 2.71). Having early loss of deciduous teeth was associated with a higher odds of having Class III malocclusion (OR = 3.83). Conclusion: Findings showed high prevalence of malocclusion, mostly class II, in elementary students in Vietnam. Bad habits such as finger sucking, biting the lower lip, tongue thrusting, mouth breathing, and early loss of deciduous teeth play important roles in developing malocclusion, which should be considered in the development of interventions.