Relationship between the market share of the fluoride toothpaste and dental caries experience by birth year cohort according to the Japanese national survey of oral health

Abstract

We analyzed the relationship between dental caries prevalence and the market share of fluoride toothpaste by birth year cohort. The dental caries experience was obtained from 10 Japanese national surveys of oral health over approximately 60 years. The market share of fluoride toothpaste was researched by the Lion Co. We analyzed the data by birth year cohort for 11 groups evaluated every five years. The DFT index of Japanese children stabilized during the prewar and immediate postwar generations, and then increased linearly over the next 30 years. During this period there was no relationship between changes in the DFT index and the market share of fluoride toothpaste. For those born between Showa 20 and 40 (1945 and 1965), the DFT and DMFT indices reached a plateau. A dramatic decrease in these indices was seen when there was a rapid increase in the market share of fluoride toothpaste. For children born between Showa 40 and 60 (1965 and 1985), the market share of fluoride toothpaste reached 50%, while the DFT and DMFT indices plateaued at the same time. These changes in dental caries experience were likely affected by the market share of fluoride toothpaste.