The higher prevalence of developmental defects of enamel in the dioxin-affected region than non-dioxin-affected region: result from a cross-sectional study in Vietnam
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Developmental defects of enamel (DDE) are induced and regulated by several factors including genetics and the environment. There is evidence showing that dioxin in polluted areas has a strong effect on the health and development of teeth. However, there has been no study on DDE in the dioxin-affected regions in Vietnam. To identify the effect of dioxin on the prevalence of DDE in studied areas in Vietnam, a cross-sectional study was conducted in 2200 adults in the A Luoi district in the Thua Thien Hue province (the dioxin-affected region) and in the Kim Bang district in the Ha Nam province (dioxin-unaffected region) in 2015. All subjects were interviewed using a structured questionnaire and their teeth were examined and scored for enamel defects based on the 1992 FDI criteria. The defected teeth were then photographed. Our results showed that the DDE rate in A Luoi was 20.5% when measured as mouth prevalence and 5.8% when measured as tooth prevalence, while the rates in Kim Bang were 10.4 and 2.32% for mouth and tooth prevalence, respectively. Demarcated opacities were predominated in both districts (45.5% in A Luoi and 52.2% in Kim Bang). The DDE rate of the anterior teeth group was higher than that of the posterior teeth group. Most lesions presented on the buccal surface of the tooth. Overall, the DDE prevalence in the dioxin-affected region was 2.2 times higher than that in non-dioxin-affected region in the studied regions in Vietnam.
KeywordsDevelopmental defects of enamel Dioxin Hypoplasia Demarcated opacity Diffuse opacity
We would like to express our deepest gratitude to those people who did not stop in providing their moral support all throughout our study, especially the participants. To the teachers in the 10 80 Committee who created an opportunity for us to carry out this study. To all of you at the commune health stations (A Ngo, Hong Thuong, Hong Van, Huong Lam, Dong Son, Kim Binh, Nhat Tuu, and Hoang Tay), who helped us to complete this study. We also would like to thank our colleagues, especially Dr. Kushi Kushekhar and Dr. Anna Mari Lone (Centre for Molecular Medicine Norway, Nordic EMBL Partnership, University of Oslo and Oslo University Hospital, Norway) for critical reading and checking to improve the revised manuscript. Dinh-Toi Chu is a researcher under the SCIENTIA FELLOWS programme co-funded by Faculty of Medicine, University of Oslo and the EU Seventh Framework Programme (FP7) Marie S. Curie scheme – People: Cofunding of Regional, National and International Programmes (COFUND), grant agreement no. 609020.
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest.
All study protocols were approved by Hanoi Medical University Ethical Committee and have therefore been performed in accordance with the ethical standards laid down in the 1964 Declaration of Helsinki and its later amendments.
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