Fluoridation: Turning the Tide on Dental Decay

Robert Weyant, DMD DrPHDepartment 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 20th 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 1901 - 1950

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-20th cent.• Major cause of death 1600s-1800s.

9

Caries: The Problem in the first half of the 20th 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.

• 1931 ALCOA (H.V. Churchill) joins in and fluoride is discovered as the causative agent.

15

16

H. Trendley Dean• 1931 begins to study

epid. of F-• Improves technology of

assay• Creates and index

• 1933 - Compares “High” and “Low” F- communities.

• 1939 - Compares “high” and “low” F- communities.

• 1941- Launches field investigation – “21 Cities” study.

17

Why not add it to the water…

• Gerald Cox (Pitt faculty)

• 1945 - 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: 1960-2010

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 1971-1991

DMFS

Mean Number of Missing Teeth for 12 year-old Mean Number of Missing Teeth for 12 year-old Children by Year of SurveyChildren by Year of SurveyMean Number of Missing Teeth for 12 year-old Mean Number of Missing Teeth for 12 year-old Children by Year of SurveyChildren 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, 1988-94

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