Although Japan has rapidly become a super-aged society, with more than one-fourth (26.8%) of the total population aged 65 years or older , a survey of dental diseases conducted in Japan in 2011 reported a decrease in the number of edentulous patients and complete denture wearers . While the results of the next survey will not be reported until 2017, this trend is expected to continue. This decrease has also been observed in other industrialized countries, and now that treatment for edentulous patients requires higher levels of expertise and technical skills than ever before, it is increasingly difficult for general dentists to fabricate complete dentures .