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.

Parental knowledge and practice on childhood caries prevention in northern Vietnam.

This study was conducted to describe the knowledge and practices on dental caries prevention among parents of preschool children in Vietnam and identify associated factors. A cross-sectional study was conducted in three preschools in Northern Vietnam in 2020. A total of 316 parents of preschool children were randomly recruited. Knowledge and practices regarding early dental caries prevention were asked by using a structured questionnaire. Multivariate Tobit regression was used to examine factors associated with knowledge and practice scores. Results showed four aspects of knowledge that had the lowest proportion of parents having correct responses included timing of complete primary tooth replacement (12.3%), benefits of undergoing regular dental examination (31.7%), technique for brushing a child's teeth (33.9%), and duration for brushing (36.7%). The knowledge of parents was moderately low at 6.3/12 (SD = 2.3). The practices of parents were moderately good with the mean practice score at 6.1/9 (SD = 2.0). The proportion of parents taking children for regular checkups (56.2%) and replacing toothbrush every 3 months (53.7%) were the lowest. Information source, occupation, education and perceived necessity of oral care were found to be associated with parents' knowledge and practices. To conclude, parents had moderate levels of knowledge and practices regarding early dental caries prevention in preschool children. Further studies and interventions should be performed to improve parental knowledge and practices that could enhance the oral health of children.

Histopathological Alterations in the Livers of Chronic Hepatitis Patients Exposed to Agent Orange/Dioxin in Vietnam.

We investigated changes in some laboratory indices and the liver histology of chronic hepatitis patients who were exposed to dioxin. In 2014, we collected liver biopsy samples for histopathological examination from 33 chronic hepatitis patients living around the Da Nang Airbase, which is a dioxin-contaminated area due to the herbicide spraying in Vietnam. Dioxin exposure was measured by its levels in the blood. METAVIR classification was used to clarify the liver fibrosis stage. Laboratory tests included ten biochemical and six hematological indices that were measured in the blood. A regression linear model and binary logistic regression were used for data analysis. The observed alterations in the liver at the histological level mainly comprised hydropic degenerative hepatocytes, lymphocytes and polynuclear leukocytes surrounding the liver cells and granular and lipoic degeneration. In addition, increased TCDD levels were associated with increasing aminotransferase (AST), alanine aminotransferase, protein and total bilirubin levels and liver fibrosis stage. Similarly, increased TEQ-PCDD/Fs levels were associated with higher levels of AST and protein and liver fibrosis stage. In conclusion, dioxin exposure altered the liver histology and increased some biochemical marker indices and the liver fibrosis stage of chronic hepatitis patients living in dioxin-contaminated areas in Da Nang, Vietnam.