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NOVEMBER / DECEMBER 2014 :: 75(6)
Improving Population Health in North Carolina

Population health examines the health outcomes of groups and the disparities in health among subgroups. This issue of the NCMJ illustrates population health efforts in the areas of obesity prevention, tobacco cessation, and clean water. Articles in this issue also discuss community health needs assessments, integrated health improvement, social determinants of health, and the Healthy North Carolina 2020 program.

INVITED SIDEBAR

Preventing Dental Caries Through Community Water Fluoridation

B. Alex White, Sharon M. Gordon

N C Med J. 2014;75(6):430-431.PDF | TABLE OF CONTENTS



Heralded as 1 of the 10 greatest public health achievements of the 20th century [1], community water fluoridation is a safe, effective, and cost-effective strategy for reducing the incidence of dental caries in people of all ages. In 1949 Charlotte became the first municipality in North Carolina to adopt this preventive measure [2]; at that time, its water system was the largest in the world to adjust fluoride to the optimal level of 1 part per million. Since then, community water fluoridation has expanded; currently, 87.5% of North Carolina residents who access water from a community water system—about 63% of the state’s total population—receive the benefits of drinking fluoridated water [3]. Nationally, North Carolina ranks 18th among the states in terms of the percentage of community water systems with added fluoride [3]. A broad range of dental and nondental health organizations support community water fluoridation, including the North Carolina Department of Health and Human Service’s Division of Public Health [4].

Dental caries result from bacterial metabolism in biofilms and the interaction of these biofilms with the tooth structure [5]. All humans have this biofilm, which usually forms within 20 minutes after brushing. When the pH of this biofilm drops below 5.5, minerals in the tooth enamel—especially calcium—leach out. When the pH of the biofilm rises again, the enamel will remineralize. This cycle of demineralization and remineralization happens constantly in all people with natural teeth. When demineralization exceeds remineralization, there is a net mineral loss, which results in white spot lesions, cavitation, and potential tooth loss.

Diet has a dramatic effect on dental caries. Every time a person eats or drinks something that contains sugar or starches, the bacteria in the teeth’s biofilm convert these foods to acids, the pH of the biofilm drops below 5.5, and demineralization begins; demineralization continues until the pH rebounds above 5.5. Frequent eating, especially of starch and sugar, results in more acid in the biofilm and longer periods during which the pH of the biofilm is below 5.5. The pH of the most popular cola drinks is 2.5–3.0 [6, 7].

Community water fluoridation provides teeth with frequent, low-dose exposure to fluoride throughout life [2, 8]. This fluoride is concentrated in the biofilm and saliva, where it inhibits demineralization of enamel and enhances remineralization. Fluoride also inhibits bacterial production of acid, and it decreases the ability of bacteria to adhere to the tooth surface. Finally, fluoride that is taken during tooth development incorporates into the tooth structure, making the enamel harder and more resistant to cariogenic bacteria.

Community water fluoridation has resulted in substantial improvements in oral health. In a 2007 report [9], the National Research Council and the Institute of Medicine of the National Academies identified fluoride as a mineral that can positively influence human health; this report concluded that fluoride is essential for human life based on its role in cellular functions involving metabolic or biochemical processes. The report further stated that fluoride in drinking water has 2 beneficial effects: preventing tooth decay (dental caries) and contributing to bone mineralization and bone matrix integrity. Community water fluoridation is a method of fluoride delivery that benefits all people—regardless of age, income, educational level, or socioeconomic status.

The weight of the scientific evidence in peer-reviewed literature does not support an association between community water fluoridation and any adverse health effects or systemic disorders, including an increased risk for cancer, Down syndrome, heart disease, osteoporosis, bone fractures, immune disorders, low intelligence, renal disorders, Alzheimer disease, or allergic reactions [10]. Not only is community water fluoridation safe and effective [11], it is also cost saving [12], and it is the least expensive way to deliver the benefits of fluoride to all residents of a community [13]. For communities of more than 20,000 people, it costs about 50 cents per person per year to fluoridate the water, and every $1 invested in community water fluoridation saves approximately $38 in dental treatment costs [12].

North Carolinians who do not live in an area with fluoridated water can still benefit from fluoride. Most people obtain fluoride by brushing with a fluoride-containing toothpaste and/or by using an over-the-counter mouth rinse containing fluoride. Individuals who are at high risk for dental caries may need more fluoride than they receive through incidental exposure; they can get extra exposure through fluoride gels or varnishes, prescription fluoride tablets or mouth rinses, or high-strength fluoride toothpastes.

Decisions about starting, continuing, or stopping community water fluoridation are made at the local level, and health care professionals can play an important role in educating patients, the general public, and community leaders about the benefits of this public health measure. Resources and strategies for communicating these benefits are available from a variety of organizations, including the National Institute of Dental and Craniofacial Research, the National Institutes of Health, and the American Dental Association.

Acknowledgments
Potential conflicts of interest. B.A.W. and S.M.G. have no relevant conflicts of interest.

References
1. Centers for Disease Control and Prevention (CDC). Ten great public health achievements—United States, 1900–1999. MMWR Morb Mortal Wkly Rep. 1999;48(12):241-243.

2. North Carolina Department of Health and Human Services (DHHS), Division of Public Health, North Carolina Oral Health. Fluoride: the facts. DHHS Web site. http://www.ncdhhs.gov/dph/oralhealth/services/fluoride.htm. Accessed July 10, 2014.

3. Centers for Disease Control and Prevention (CDC). Community water fluoridation. 2012 water fluoridation statistics. CDC Web site. http://www.cdc.gov/fluoridation/statistics/2012stats.htm. Page last reviewed and updated November 22, 2013. Accessed September 16, 2014.

4. Cummings RG. Community fluoridation: position statement from the Office of the State Health Director, April 2014. North Carolina Department of Health and Human Services Web site. http://www.ncdhhs.gov/dph/oralhealth/library/includes/NCDHHS%20CWF%20position%20statement%204-25-14.pdf. Accessed July 10, 2014.

5. Takahashi N, Nyvad B. The role of bacteria in the caries process: ecological perspectives. J Dent Res. 2011;90(3):294-303.

6. Walsh LJ. Black cola drinks, oral health, and general health: an evidence-based approach. Australian Dental Association Web site. http://www.ada.org.au/app_cmslib/media/lib/0904/m163307_v1_m142700_v1_633613022505490000.pdf. Accessed September 16, 2014.

7. Jain P, Nihill P, Sobkowski J, Agustin MZ. Commercial soft drinks: pH and in vitro dissolution of enamel. Gen Dent. 2007;55(2):150-154.

8. National Institute of Dental and Craniofacial Research (NIDCR). The tooth decay process: how to reverse it and avoid a cavity. NIDCR Web site. http://www.nidcr.nih.gov/OralHealth/OralHealthInformation/ChildrensOralHealth/ToothDecayProcess.htm. Accessed July 10, 2014.

9. National Research Council, Institute of Medicine of the National Academies. Earth Materials and Health: Research Priorities for Earth Science and Public Health. Washington, DC: The National Academies Press; 2007.

10. Centers for Disease Control and Prevention (CDC). Community water fluoridation. Scientific reviews: assessing the weight of evidence. CDC Web site. http://www.cdc.gov/fluoridation/safety/systematic.htm. Page last reviewed and updated July 10, 2013. Accessed September 16, 2014.

11. Centers for Disease Control and Prevention (CDC). Community water fluoridation. Fluoridation safety. CDC Web site. http://www.cdc.gov/fluoridation/safety/index.htm. Page last reviewed and updated July 10, 2013. Accessed July 10, 2014.

12. Centers for Disease Control and Prevention (CDC). Community water fluoridation. Cost savings of community water fluoridation. CDC Web site. http://www.cdc.gov/fluoridation/factsheets/cost.htm. Page last reviewed and updated July 10, 2013. Accessed July 10, 2014.

13. Centers for Disease Control and Prevention (CDC). Community water fluoridation. Fluoridation basics. CDC Web site. http://www.cdc.gov/fluoridation/basics/index.htm. Page last reviewed and updated July 25, 2013. Accessed July 10, 2014.


B. Alex White, DDS, DrPH associate professor, Department of Health Policy and Management, UNC Gillings School of Global Public Health, University of North Carolina at Chapel Hill; associate professor, Department of Dental Ecology, School of Dentistry, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina.
Sharon M. Gordon, DDS, MPH, PhD associate dean of innovation and discovery, School of Dental Medicine, East Carolina University; chair of foundational sciences, School of Dental Medicine, East Carolina University, Greenville, North Carolina.

Address correspondence to Dr. B. Alex White, 1106-J McGavran-Greenberg Hall, 135 Dauer Dr, CB #7411, Chapel Hill, NC 27599 (alex_white@unc.edu).