Dental offices/clinics are facing tough competition in Japan. The number of dental clinics in Japan is 68872(Dec 2017) and it is 10000 more than total number of convenience stores in Japan. Then, there are more than 100 thousand dentists and there are 29 dental schools in Japan.
There are plenty of dental clinics in Japan but the dental expenses are not increasing at all and less children are facing problems against tooth decays.
Therefore dental clinics are more concentrating on prevention against tooth periodontal disease and trying to improve their facilities and the services.
By the way, Japanese who has medical insurance and age is between 6 and 69 pays 30% of the bill. Which means 70% of the expense is covered by state. It is less than European nations but you can expect high quality of service.