Demirjian method and Willems method to study the dental age of adolescents in Shanghai before and after 10 years

Background: The aim of this study was to assess whether the difference in dental ages between 2009 to 2011 and 2021 is affected by environmental factors such as environmental pollution, floating population, and dietary habits.Materials and methods: Demirjian and Willems dental age estimation methods were conducted for a Han population of children aged 8 to 14 in Shanghai, China. A total of 1259 digital panoramic radiographs of children aged 8.00-14.99 were estimated. All digital panoramic radiographs were estimated using the Demirjian and Willems methods. Data collected in 2009 to 2011 and 2021 were statistically analysed by paired t-tests.Results: The results show that the Demirjian method overestimates 2009 to 2011 and underestimates 2021 the children's chronological age. When using the Willems method, the age of males was overestimated and the age of females was underes-timated from 2009 to 2011, and it was underestimated for both genders in 2021.Conclusions: In conclusion, the difference in dental ages between 2009 to 2011 and 2021 was statistically significant. Factors such as environment and dietary habits have been found to be affected by dental development. However, there are disputes among some researchers about the exact factors, so it is suggested to further study the effects of environmental factors on tooth development.