The caries status in China exhibits characteristics typically found in developing countries. About 97% carious teeth of children aged 5 are left untreated, while for children aged 12, this percentage is 89%. About 78.9%-91.7% of carious teeth (including third molars) of the middle-aged and elderly people have been left untreated. This situation has not been much improved with China's economic development, challenging China's oral health care resources [8] [9] .