1. Ha MY. A study on the changes in consumers' awareness and the rate of scaling in each region after its coverage by the national health insurance scheme. Seongnam: Unpublished master's thesis, Dankook University; 2015.
2. National Health Insurance Service, Health Insurance Review &Assessment Service:Annual health insurance statistical yearbook 2015; 2016. Retrieved October 16, 2016, from <uri>http://www.nhis.or.kr/bbs7/boards/B0039/21843</uri>
3. Lee BJ. Professional oral health management program used toothpick method. J Korean Dent Assoc 2009;47:272-281.
4. Public health aspects of periodontal diseases in Europe
5. The long-term effect of a plaque control program on tooth mortality, caries and periodontal disease in adults. Results after 30 years of maintenance