Corroborating with study findings from other countries, we observed a gradient by maternal educational attainment. Less educated mothers reported more dental visits due to dental caries compared with more educated mothers. We also observed a gradient by smoking status among mothers or family income. These trends continued from the third to the sixth survey. A Japanese national survey suggests that the occurrence of dental caries among young children varies across regions; dental caries were more prevalent in more rural areas such as Tohoku and Kyushu/Okinawa.24 We confirmed higher proportions of children with dental caries in these two regions compared to the Kanto area at the third survey in LSB21.