Toothbrushing behavior changes among korean students pre- and post-COVID-19: lessons and policy implications

BACKGROUND/OBJECTIVES: In South Korea, the nationally funded School Oral Health Room Program has promoted children's oral hygiene practices since 1999; however, the COVID-19 pandemic disrupted these behaviors. This study investigates changes in toothbrushing practices among South Korean children aged 4-15 across before, during, and after Covid-19. METHODS: We analyzed cross-sectional data from the Korean National Health and Nutrition Examination Survey (KNHANES VIII-IX, 2018-2023), including 5,251 children aged 4-15 years. Toothbrushing behaviors were assessed across three periods: Before COVID (2018-2019), during COVID (2020-2021), and after COVID (2022-2023). Complex-samples chi-square tests and logistic regression analyses (adjusted for sex and age) were conducted. RESULTS: Brushing after lunch declined markedly across all age groups during and after the pandemic (e.g., 4-6-year-olds: 83.5% to 55.1%). In contrast, brushing before bedtime increased post-pandemic, particularly among older children (e.g., 10-12-year-olds: 59.6% to 74.2%). Brushing after breakfast declined during the pandemic with partial recovery, while brushing before breakfast showed mixed trends and after-dinner brushing decreased among older children. CONCLUSIONS: COVID-19 disrupted school-based toothbrushing, leading to reduced post-lunch brushing and increased bedtime brushing. These changes underscore the need for adaptable oral health programs that can sustain effectiveness during public health crises.