Purpose: To elucidate the efficacy of strategies for preventing dental caries in Japanese children by examining trends over time in the prevalence of dental caries, the number of decayed, missing, or filled teeth (the DMFT index), and their association with factors affecting oral hygiene. Materials and Methods: Several national surveys performed between 1955 and 2015 were reviewed. The prevalence of dental caries in children aged 5-15 years, the DMFT index in children aged 9 or 14 years, individual consumption of added sugars and snacks, the number of dentists in Japan, and the percentage of children who received fluoride varnish were analysed. Additionally, the relative poverty rate among Japanese children was assessed. Results: The prevalence of caries and the DMFT index in Japanese children reflected the trend of individual added-sugar consumption from 1955 to 2015, and also seemed to decrease inversely with the number of dentists and the percentage of children who had received fluoride varnish since 1969. However, there seemed to be no relation to the relative poverty rate. Conclusion: The main preventive strategies for caries in Japan are to reduce sugar intake and educate school children and their caregivers about oral hygiene. Keywords: dentists, fluoride, poverty, school health, sugar