Fluoridation: Turning the Tide on Dental Decay Robert Weyant, DMD DrPH Department of Dental Public Health and Information Management University of Pittsburgh

Fluoridation: controlled addition of fluoride compound to a public water supply in order to bring its fluoride concentration to optimal One of the CDC’s Top 10 major public health achievements in 20 th c. Major factor responsible for the decline in dental caries (tooth decay). Classic example of clinical observation leading to epidemiologic investigation and community-based public health intervention.

The fluoride story

Caries: Case Definition Dental Caries is the localized destruction of dental hard tissues by acidic by- products from bacterial fermentation of dietary carbohydrates. The disease process is initiated within the bacterial biofilm. No global consensus on staging. DMFT index = severity. coronal caries root caries Bacterial Acids Diet Salivary Minerals Rx

Dental Caries Dental caries most common chronic childhood disease. Over 50% of 5- to 9-year- old children have at least one cavity or filling. Decay prevalence is 78% in 17-year-olds. Early childhood caries

Root Caries Common infectious disease in older adults. Poor rates of diagnosis and treatment. More retained teeth - more “at risk” teeth. Strong link with xerostomia Fluoride effective in prevention. Root Caries Prevalence by Age

Nutrition (baby bottles, sodas, sugars & carbohydrates) Oral Hygiene (tooth brushing, fluoride use, flossing) Access to and Use of Professional Dental Care (regular cleanings, restorative care) Caries (i.e., tooth decay, cavities) Patient’s Knowledge, Attitudes, Behavior (dental fear, mistrust, competing priorities, lack of OH knowledge, cultural expectations) Caries Process

Nutrition (baby bottles, sodas, sugars & carbohydrates) Oral Hygiene (tooth brushing, fluoride use, flossing) Caries (i.e., tooth decay, cavities) Family Functioning (parental engagement, limit- setting, attachment, communication, support from extended family, conflict, abuse and neglect) “Built Environments” (proximity to grocery stores and dental clinics, access to public transportation) Substance Abuse (tobacco, alcohol, methamphetamine) Patient’s Knowledge, Attitudes, Behavior (dental fear, mistrust, competing priorities, lack of OH knowledge, cultural expectations) Screening, Brief Intervention & Referral to Treatment (substance abuse, injury risk behavior, HIV, diabetes, obesity) Co-morbid Health Conditions (xerostomic medications, compromised immunity, chronic inflammation) Caries Process Access to and Use of Professional Dental Care (regular cleanings, restorative care) Genetics

Dental Caries: Secular Changes A big problem in need of a solution. Steady increase from 1000 AD to mid-20 th cent. Major cause of death 1600s-1800s. 9

Caries: The Problem in the first half of the 20 th Cent. typical school child developed 3-4 new carious lesions each year. commonplace for folks to get dentures as HS graduation presents or wedding gifts. 10 Caries associated facial cellulitis

WW II (Standard: 6 opposing teeth) 11 ~1 million draftees couldn’t meet standard. 40% of draftees required immediate Tx.

Fluoridation History

Fredrick McKay, DDS. 1901, Graduates Penn, moves to Colorado Springs. Notices brown staining – later called “Colorado Brown Stain”. Launches into field epid. activities.

GV Black joins the investigation 1909 Black arrives Colorado Springs. 90% of city’s locally born children had disorder. Continued investigation showed: “Mottled enamel” was a developmental defect in tooth. (no risk of mottling for healthy erupted teeth). Afflicted teeth had no decay… 1920s - A water causation theory emerged.

Shades of John Snow… McKay to Oakley, Idaho. Stains occurred when new pipeline build. McKay to Bauxite, Arkansas. A tale of two towns ALCOA (H.V. Churchill) joins in and fluoride is discovered as the causative agent. 15

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H. Trendley Dean 1931 begins to study epid. of F- Improves technology of assay Creates and index Compares “High” and “Low” F- communities Compares “high” and “low” F- communities Launches field investigation – “21 Cities” study. 17

Why not add it to the water… Gerald Cox (Pitt faculty) A plan was developed. Short term obsv. study – health effects. Intervention trial. Grand Rapids – Muskegon. Newburgh – Kinston. Branford - Sarnia. Evanston – Oak Park. 18 Caries reduction ~50% Fluorosis – 10% Mild to Moderate

Fluoride growth in US and Global Status

Current fluoridation status of US public water systems 88% US on public water supply Percent public water supply 10 highest and 10 lowest states. 59% of US population receives fluoridated water

F- Biological Mechanisms Post Eruptive (ongoing, daily) Remineralizes enamel. Inhibits glycolysis. Pre Eruptive (early childhood) Some reduction of enamel solubility. Water Fluoridation Toothpaste Rinses Post-natal tablets and drops Water fluoridation

Fluoridation Process and Practices

Dosage Air Temperature Dependent Range 0.7 – 1.2 ppm. Maximum Contamination Level (EPA) 4 ppm.

Fluoride and Caries: Fluoride is everywhere Water Toothpaste (1960s) Processed foods Soft drinks Mouthrinses Varnishes Tablets Caries is different Less prevalent Less severe Slower Concentrating in fewer/poor people

25 Decrease of about 70-80% in caries

Age specific caries rates DMFS

Mean Number of Missing Teeth for 12 year-old Children by Year of Survey

Caries Trends (developed nations) Historically - disease of high-income countries (and high income individuals). Recent changes (late 20th c) showed dramatic decreases in caries prevalence in many developed nations. Caries in 12 y/o

Caries Trends (developing nations) Trend is less clear in “middle” and “low” income nations. Function of diet, health infrastructure, and economy. Caries in 12 y/o

Changes in Coronal Caries: Post Fluoride Disease is now on occlusal surfaces (>80%). Disease is concentrating in poor. 25% of population has 75% of disease. Slower progression.

Percentage of Children Aged 2-4 years Who Have Ever Had Tooth Decay Source: NHANES III, Family Income

Fluoride and Politics Falls under “police powers” of the states. Mandatory in 8 states. Connecticut (1965), Georgia (1973), Illinois (1967), Michigan (1968), Minnesota (1967), Nebraska (1973), Ohio (1969), and South Dakota (1969). Most states use local control at community level. Historically local referenda pass only 25% of the time. 21 states meet HP 2010 of at least 75% of pop. with F- water. 32

Antifluoridationists Extra-scientific self- organizing group not interested in the traditional scientific process, but goes around it directly to the public to bring up sensational, unsubstantiated claims. Cancer Downs Syndrome Kidney Problems IQ problems Dementia All cause mortality Congenital Malformations

Systematic Reviews of Safety and Efficacy BMJ (2000) Australian MRC (2007) Water fluoridation beneficial in reducing decay. Insufficient evidence of adverse effects other than fluorosis.

Benefits: Prevalence 214 studies. Decrease 14.6% (range -5% to 64%).

Benefits: Severity Mean difference DMFT 2.25 (range 0.5 to 4.4).

Harm: Fluorosis Dose dependent association.

Harm: Bone Fracture Studies of >10 yrs = fluoride protective.

Harm: Cancer 26 studies 24 no association 1 positive (more cancer) 1 negative (less cancer) Bassin Study Osteosarcoma 5.6 / 1 million (incidence) males 2.0 > females Finding OR 5.16 (1.7 – 16.2) (males at age 7) No association for females Age-specific Fluoride Exposure in Drinking Water and Osteosarcoma (United States) (Bassin et al., 2006 )

Harm: Toxicity Acute fatal poisoning (adults). 2.5 to 5 grams in 2 to 4 hours. Acute fatal poisoning (10 kg child). 320 mg in 2 to 4 hours. Acute fatal poisoning in 3 yo child, 435 mg in approx. 3 hours. Short-term nausea in primary school following ingestion of 93 to 375 ppm H2O- symptoms appeared within 30 minutes,

CDC Continues to recommend. Effectiveness now 15-20%. Still most cost-effective approach. $0.50/person/yr. Avg savings = $38.00/yr. Reduces disparity. Fluorosis 7-16%.

The End Questions? 42