Dental diseases, particularly dental caries (cavities) and periodontal disease, are a significant burden to society, even though they are not fatal, and represent some of the most prevalent diseases in the world [1, 2]. In Japan, the national medical cost of dental diseases in 2015 amounted to 2,829,400 million yen, which was third behind the cost of cardiovascular diseases including hypertension (5,981,800 million yen) and neoplasms such as cancer (4,125,700 million yen). In particular, the cost of dental diseases for individuals younger than 65 years of age is highest compared with other diseases. In addition, recent studies have shown that oral health may affect general health. Accordingly, public health policies, such as the Health Promotion Campaign for the Twenty-First Century (Health Japan 21) and the "8020 Campaign" to retain 20 natural teeth by 80 years of age, have been promoted in Japan. A difference in health status, such as variation of height among the population, maybe natural. However, it becomes a problem when such differences are considered Jun Aida is also the English translator for this chapter.