DENTALELLE TUTORING

Community

Definitions to Know

Incidence – The number of new cases of a disease or condition over a given time period. It is the rate at which new cases occur in a defined group (i.e. the incidence rate of lung cancer is 2.5% per year in 25- to 29-year-old Hispanic males in the US).

Compare with Prevalence – the terms are frequently confused and used interchangeably. In epidemiology of dental caries, it is important to note the denominator – people or individual teeth.

Index– A standard measure of a disease or condition. It extends from the number of individuals with a disease or condition to the number of millimeters of probing depth around a tooth with gingivitis. Common indices in dentistry are the DMF Index, which is a measure of caries, the O’Leary Plaque Index, which measures plaque/oral hygiene, and PSR (periodontal screening and report), which indicates treatment need for periodontal therapy.

Mean–The arithmetical average, a measure of central tendency together with the measures of mode (the most commonly occurring value) and median (the value in an order of numbers that is the midpoint – there are as many values above as below).

NHANES–A survey conducted by the US National Center for Health Statistics, part of the Centers for Disease Control & Prevention (commonly referred to as CDC), which investigates and publishes reports on the health and nutritional status of Americans (National Health and Nutrition Examination Survey). Currently, 5000 people are examined each year.

Prevalence–The number (%) of individuals exhibiting the disease or condition (i.e. Dental Caries, TB, Lung Cancer) in a defined group (i.e. the prevalence of dental caries is 50% in children aged 6 to 11 years). Compare with Incidence –the terms are frequently confused and used interchangeably in error.

Epidemiology

Studies conducted in the field of oral epidemiology provide information on normal biological processes and diseases of the oral cavity, identify populations at risk of oral disease or in need of more critical care, and compare regional, environmental, social, and access similarities and differences in dental care between populations.

Oral epidemiology also tests preventive interventions for controlling disease and evaluates the effectiveness and quality of interventions and dental health programs. To understand epidemiology, it is important to understand the definitions that follow:

Definitions to Consider

Prevalence: This is the number of individuals with disease (cases) in a population at a specific point in time.

Incidence: This is the number of individuals in a population who experience new disease during a specific time period.

Trends: These are the changes or differences in the prevalence or incidence of disease with respect to time, location, or socioeconomics.

Measuring Oral Diseases

In oral epidemiology, there are a number of crucial terms that will help dentists to understand how oral disease data is measured and presented. These include:

Index: This is a standard method of rating a disease in which there is a graduated, numerical scale with values corresponding to specific criteria.

Types of indices include: Nominal, which simply names conditions; Ordinal which lists conditions in order of severity; Interval or ratio, which establishes a mathematical relationship; Irreversible, which measures cumulative conditions that cannot be reversed (such as

enamel loss due to erosion) Reversible, which measures conditions that can be reversed (such as gingivitis).

Index

Valid: An index must be designed to measure the aspect of disease that it is intended to measure and correspond to clinical stages of the disease.

Reliable: An index should be reproducible and repeatable, and should provide consistent measurement at any given time under a variety of conditions.

Clear, Simple, Objective: An index should have clearly stated, unambiguous criteria with mutually exclusive categories, and should be simple enough for an examiner to memorize and score using the criteria.

Quantifiable: An index must present data that can be numerically analyzed and treated. Group status should be expressed by distribution, mean, median, or other statistical measures.

Sensitive: An index should identify small yet significant shifts in the condition studied.

Acceptable: The use of the index should not be unnecessarily painful, time-demanding, or demeaning to subjects.

DMF Index

The Decayed, Missing, Filled (DMF) index has been used for more than 70 years and is well established as the key measure of caries experience in dental epidemiology. The DMF Index is applied to the permanent dentition and is expressed as the total number of teeth or surfaces that are decayed (D), missing (M), or filled (F) in an individual. When the index is applied to teeth specifically, it is called the DMFT index, and scores per individual can range from 0 to 28 or 32, depending on whether the third molars are included in the scoring. When the index is applied only to tooth surfaces (five per posterior tooth and four per anterior tooth), it is called the DMFS index, and scores per individual can range from 0 to 128 or 148, depending on whether the third molars are included in the scoring.

When written in lowercase letters, the dmf index is a variation that is applied to the primary dentition. The caries experience for a child is expressed as the total number of teeth or surfaces that are decayed (d), missing (m), or filled (f). The dmft index expresses the number of affected teeth in primary dentition, with scores ranging from 0 to 20 for children. The dmfs index expresses the number of affected surfaces in primary dentition (five per posterior tooth and four per anterior tooth), with a score range of 0 to 88 surfaces. Because of the difficulty in distinguishing between teeth extracted due to caries and those that have naturally exfoliated, missing teeth may be ignored according to some protocols. In this case, it is called the df index.

DMFT

Calculating DMFT: The teeth not counted are unerupted teeth, congenitally missing teeth or supernumerary teeth, teeth removed for reasons other than dental caries, and primary teeth retained in the permanent dentition.

Counting the third molars is optional. When a carious lesion(s) or both carious lesion(s) and a restoration are present, the tooth is listed as a D. When a tooth has been extracted due to caries, it is listed as an M. When a permanent or temporary filling is present, or when a filling is defective but not decayed, this is counted as an F. Teeth restored for reasons other than caries are not counted as an F.

DMFS

Calculating DMFS: There are five surfaces on the posterior teeth: facial, lingual, mesial, distal, and occlusal. There are four surfaces on

anterior teeth: facial, lingual, mesial, and distal. The list of teeth not counted is the same as for DMFT calculations, and listing D, M, and F is also done in a similar way:

When a carious lesion or both a carious lesion and a restoration are present, the surface is listed as a D. When a tooth has been extracted due to caries, it is listed as an M. When a permanent or temporary filling is present, or when a filling is defective but not decayed, this surface is counted as an F. Surfaces restored for reasons other than caries are not counted as an F. The total count is 128 or 148 surfaces.

DMFT and DMFS

Calculating dmft and dmfs: For dmft, the teeth not counted are unerupted and congenitally missing teeth, and supernumerary teeth. The rules for recording d, m, and f are the same as for DMFT.

The total count is 20 teeth. For dmfs, the teeth not counted are the same as for dmft. As with DMFS, there are five surfaces on the posterior teeth and four surfaces on the anterior teeth. The total count is 88 surfaces.

Limitations of DMF Index: While DMF indices can provide powerful data and perspectives on dental caries, they can also present some limitations. For one, researchers have noted a significant amount of inter-observer bias and variability. Other criticisms include that the values do not provide any indication as to the number of teeth at risk or data that is useful in estimating treatment needs; that the indices give equal weight to missing, untreated decay, or well-restored teeth; that the indices do not account for teeth lost for reasons other than decay (such as periodontal disease); and that they do not account for sealed teeth since sealants and other cosmetic restorations did not exist in the 1930s when this method was devised.

Early Childhood Caries

1. Early Childhood Caries is defined as the presence of one or more decayed (non-cavitated or cavitated lesions), missing (due to caries) or filled tooth surfaces in any primary tooth in a preschool-age child between birth and 71 months of age. The term "Severe Early Childhood Caries" refers to "atypical" or "progressive" or "acute" or "rampant" patterns of dental caries. 

2. The Association recognizes that early childhood caries is a significant public health problem in selected populations and is also found throughout the general population. 

3. The Association urges health professionals and the public to recognize that a child's teeth are susceptible to decay as soon as they begin to erupt. Early childhood caries is an infectious disease. There are many aspects of early childhood caries; baby bottle tooth decay is recognized as one of the more severe manifestations of this syndrome. 

4. The Association urges parents and guardians, as a child's first tooth erupts, to consult with their dentist regarding: 

Scheduling the child's first dental visit. It is advantageous for the first visit to occur within six months of eruption of the first tooth and no later than 12 months of age, and receiving oral health education based on the child's developmental needs (also known as anticipatory guidance).

5. The Association urges its members to educate parents (including expectant parents) and caregivers about reducing the risk for early childhood caries:

Role of Bacteria  Because cariogenic bacteria (especially mutans streptococci) are transmitted

soon after the first teeth erupt, decreasing the mother's mutans levels may decrease the child's risk of developing ECC. The Association recommends that parents, including expectant parents, be encouraged to visit a dentist to ensure their own oral health.

NutritionInfants and young children should be provided with a balanced diet in accordance

with the Dietary Guidelines for Americans published by the U.S. Department of Agriculture and the U.S. Department of Health and Human Services.

Unrestricted, at-will consumption of liquids, beverages and foods containing fermentable carbohydrates (e.g. juice drinks, soft drinks, milk, and starches) can contribute to decay after eruption of the first tooth.

Bottle Feeding Unrestricted and at-will intake of sugary liquids during the day or while in bed should be discouraged.  Infants should finish their bedtime and naptime bottle before going to bed.

Breast Feeding Unrestricted, at-will nocturnal breastfeeding after eruption of the child's first tooth can lead to an

increased risk of caries.

Use of a Cup Children should be encouraged to drink from a cup by their first birthday. At will, frequent use of a training cup should be discouraged.

Home Care Proper oral hygiene practices, such as cleaning an infant's teeth following consumption of foods, liquids,

or medication containing fermentable carbohydrates, should be implemented by the time of the eruption of the first tooth.

A child's teeth should be periodically checked at home according to the directions of the dentist.

6. The Association urges state and local dental societies to be a resource for the medical community and public health programs (e.g. Women, Infants and Children [WIC] and Head Start). Dentistry can be instrumental in educating professionals and the public about risk factors for ECC. 

7. The Association recognizes that the unique characteristics of ECC should be considered in selecting treatment protocols. 

8. The Association, recognizing that the science surrounding early childhood caries continues to evolve, encourages research activities to study risk factors and preventive practices and should continue to seek a cure for early childhood caries.

Indices

Plaque Index (PI)

Plaque index (PI) The PI as developed by Silness and Loe assesses the thickness of plaque at the cervical margin of

the tooth (closest to the gum). Four areas, distal, facial or buccal, mesial, and lingual, are examined.

Each tooth is dried and examined visually using a mirror, an explorer, and adequate light. The explorer is passed over the cervical third to test for the presence of plaque. A disclosing agent may be used to assist evaluation. Four different scores are possible. A zero indicates no plaque present; 1 indicates a film of plaque present on the tooth; 2 represents moderate accumulation of soft deposits in the gingival pocket or on the tooth that can be seen by the naked eye; 3 represents an abundance of soft matter within the pocket or on the tooth.

Each area of each tooth is assigned a score from 0 to 3. Scores for each tooth are totaled and divided by the four surfaces scored. To determine a total PI for an individual, the scores for each tooth are totaled and divided by the number of teeth examined.

Four ratings may then be assigned: 0 = excellent, 0.1-0.9 = good, 1.0-1.9 = fair, 2.0-3.0 = poor.

Plaque Control Record

A similar system for measuring plaque is credited to O'Leary, Drake, and Naylor. This system measures plaque present, rather than plaque not present, but no attempt is made to differentiate in the quantity of plaque seen on each surface. The number of surfaces examined may be increased from four to six. When using six surfaces, they are facial (or buccal), mesio-facial, mesio-lingual, lingual, disto-lingual, and disto-facial.

To determine an individual's score, the clinician multiplies the number of surfaces with plaque by 100, and divides that by the number of tooth surfaces examined.

For example, if an individual has 26 teeth, that equals 104 surfaces. If eight surfaces are found to have plaque, then 800 is divided by 104, leaving a plaque control index of7.6%. A score under 10% is considered good.

Oral Hygiene Index

The OHI, developed by Greene, Vermillion, and Waggener, has two components, the debris index and the calculus index, and is an indication of oral cleanliness. The scores may be used singly or in combination. For scoring, the clinician divides the dentition into sextants and selects the facial (or buccal) and lingual tooth surface in each sextant that is covered with the greatest amount of debris and calculus. Twelve surfaces, therefore, will be evaluated. For this index, a surface includes half the circumference of the tooth.

Greene and Vermillion have also developed a simplified OHI in which the clinician measures only one tooth surface in each sextant, equaling only six surfaces.

Debris Index

For this index, debris is defined as soft, foreign matter consisting of bacterial plaque and food debris.

The criteria include 0, no debris or stain present; 1, debris covering not more than one-third of the tooth surface or extrinsic stain without debris; 2, debris covering between one- and two-thirds of the tooth surface; and 3, debris covering more than two-thirds of the tooth surface.

Calculus Index

Calculus, a hard calcified deposit of inorganic salts, is scored for this index with four criteria. They are 0, no calculus present; 1, supragingival calculus present covering not more than one third of the tooth surface; 2, supragingival calculus covering between one- and two-thirds of the tooth surface, or scattered subgingival calculus; and 3, supragingival calculus covering more than two-thirds of the tooth surface, or a continuous heavy band of subgingival calculus around the tooth.

To arrive at an OHI score, one first calculates the DI and CI scores by dividing the total scores for each tooth by the number of sextants. The DI and CI scores are then added to determine an OHI score. A perfect score would be 0, and the worst score possible is 12. In the simplified OHI, the worst score possible is 6.

Gingival Index

Also attributed to Loe and Silness, the GI assesses the severity of gingivitis based on color, consistency…

Each tooth is examined at the mesial, lingual, distal, and facial (or buccal) surface. A probe is used to press on the gingiva to determine its degree of firmness, and to run along the soft tissue wall adjacent to the entrance to the gingival sulcus. Four criteria are possible: 0, normal gingiva; 1, mild inflammation but no bleeding on probing; 2, moderate inflammation and bleeding on probing; 3, severe inflammation and ulceration, with a tendency for spontaneous bleeding.

Each surface is given a score, then the scores are totaled and divided by four. That number is divided by the number of teeth examined to determine the GI. Ratings are 0, = excellent; 0.1-1.0 = good; 1.1-2.0 = fair;2.1-3.0 = poor.

Periodontal Index

Developed by Russell, the PI determines the periodontal disease status of populations in epidemiologic studies. Each tooth is scored according to the condition of the surrounding tissues. On examination, each tooth is assigned a score using the following criteria:

0: Negative. Neither overt inflammation nor loss of function caused by the destruction of supporting tissue is noted. 1: Mild Gingivitis. Overt inflammation in the free gingiva is present, but does not circumscribe the tooth. 2: Gingivitis. Inflammation surrounds the tooth, but there is no apparent break in the epithelial attachment. 6: Gingivitis with pocket formation. The epithelial attachment of gum to tooth is broken. There is no interference with

normal function. The tooth is not loose or drifting. 8: Advanced destruction with loss of function. The tooth may be loose or drifting. It may sound dull on percussion and

may be depressible in the socket.

Scores for each tooth are added, and the total divided by the number of teeth examined. Scores can be interpreted as follows:

0-0.2: Clinically normal supportive tissues. 0.3-0.9: Simple gingivitis. 0.7-1.9: Beginning destructive periodontal disease. 1.6-5.0: Established destructive periodontal disease. 3.8-8.0: Terminal periodontal disease.

Gingival Bleeding

Unwaxed dental floss is used to measure a GBI, developed by Carter and Barnes. A full complement of teeth has 28 proximal areas to be examined.

Floss is passed interproximally, first on one side of the dental papilla, then on the other. The clinician curves the floss around each tooth and passes it below the gingival margin, taking care not to lacerate the gingiva. Any bleeding noted indicates the presence of disease. The numbers of bleeding areas versus proximal areas scored is recorded and used for patient motivation.

Mobility Index

The mobility index, developed by Grace and Smales, can be useful to track the amount of mobility in teeth over a period of time. Grade 0 indicates no apparent mobility.

Grade 1 is assigned to a tooth in which mobility is perceptible, but less than 1mm buccolingually.

Grade 2 mobility is between 1-2 mm, and Grade 3 mobility exceeds 2mm buccolingually or vertically.

Deans Fluorosis Index

Dean's is used to score the amount of dental fluorosis (discoloration) present on teeth. Fluorosis generally appears as a horizontal striated pattern across a tooth. Molars and bicuspids are most frequently affected, followed by upper incisors. The mandibular incisors are usually least affected. Fluorosis tends to be bilaterally symmetrical. Defects may appear as fine white or frosted lines or patches near the incisal edges or cusp tips.

A score is given based on the two teeth most affected. If the teeth are not equal in appearance, the less affected tooth is the one scored.

Normal (0): The enamel is smooth, glossy and translucent, usually a pale creamy-white color. Questionable (1): There are slight aberrations from the translucency of normal enamel. Lesions may range from

a few white flecks to occasional spots. Very mild (2): Opaque paper-white areas are visible, involving less than 25% of the facial or buccal tooth surface. Mild (3): White opacity of the enamel is more apparent than for code 2, but still covers less than 50% of the

surface. Moderate (4): Marked wear and brown stain, frequently disfiguring, is visible. Severe (5): Hypoplasia is so marked that the general form of the tooth may be altered. Pitted or worn areas and

brown stain are widespread. Teeth often have a corroded appearance. Excluded (8): Used for crowned teeth. Not recorded (9): Used for missing teeth or teeth that cannot be scored

DMFT

To assess dental caries in a population, a DMFT index is used. During a systematic examination with a mirror and explorer that includes the crown and exposed root of every primary and permanent tooth, each crown and root are assigned a number based on the result of that exam. The numbers are recorded in boxes corresponding to each tooth to provide a DMFT chart. It is recommended that care be taken to record all tooth-colored fillings, which may be difficult to detect.

Scores

0: A zero indicates a sound crown or root, showing no evidence of either treated or untreated caries. A crown may have defects and still be recorded as 0. Defects that can be disregarded include white or chalky spots; discolored or rough spots that are not soft; stained enamel pits or fissures; dark, shiny, hard, pitted areas of moderate to severe fluorosis; or abraded areas.

1: One indicates a tooth with caries. A tooth or root with a definite cavity, undermined enamel, or detectably softened or leathery area of enamel or cementum can be designated a 1. A tooth with a temporary filling, and teeth that are sealed but decayed, are also termed 1. A 1 is not assigned to any tooth in which caries is only suspected. In cases where the crown of a tooth is entirely decayed, leaving only the root, a 1 is assigned to both crown and root. Where only the root is decayed, only the root is termed a 1. In cases where both the crown and root are involved with decay, whichever site is judged the site of origin is recorded as a 1. These criteria apply to all numbers.

2: Filled teeth, with additional decay, are termed 2. No distinction is made between primary caries which is not associated with a previous filling, and secondary caries, adjacent to an existing restoration.

3: A 3 indicates a filled tooth with no decay. If a tooth has been crowned because of previous decay, that tooth is judged a 3. When a tooth has been crowned for another reason such as aesthetics or for use as a bridge abutment, a 7 is used.

4: A 4 indicates a tooth that is missing as a result of caries. Only crowns are given 4 status. Roots of teeth that have been scored as 4 are recorded as 7 or 9. When primary teeth are missing, the score should be used only if the tooth is missing prematurely. Primary teeth missing because of normal exfoliation need no recording.

5: A permanent tooth missing for any other reason than decay is given a 5. Examples are teeth extracted for orthodontia or because of periodontal disease, teeth that are congenitally missing, or teeth missing because of trauma. The 5 is assigned to the crown, the root is given a 7 or 9. Knowledge of tooth eruption patterns is helpful to determine whether teeth are missing or not yet erupted. Clues to help in the determination include appearance of the alveolar ridge in the area in question, and caries status of other teeth in the mouth.

6: A 6 is assigned to teeth on which sealants have been placed. Teeth on which the occlusal fissure has been enlarged and a composite material placed should also be termed 6.

7: A 7 is used to indicate that the tooth is part of a fixed bridge. When a tooth has been crowned for a reason other than decay, this code is also used. Teeth that have veneers or laminates covering the facial surface are also termed 7 when there is no evidence of caries or restoration. A 7 is also used to indicate a root replaced by an implant. Teeth that have been replaced by bridge pontics are scored 4 or 5; their roots are scored 9.

8: This code is used for a space with an unerupted permanent tooth where no primary tooth is present. The category does not include missing teeth. Code 8 teeth are excluded from calculations of caries. When applied to a root, an 8 indicates the root surface is not visible in the mouth.

9: Erupted teeth that cannot be examined—because of orthodontic bands, for example—are scored a 9. When applied to a root, a 9 indicates the tooth has been extracted. The crown of that tooth would be scored a 4 or 5.

The "D" of DMFT refers to all teeth with codes 1 and 2. The "M" applies to teeth scored 4 in subjects under age 30, and teeth scored 4 or 5 in subjects over age 30. The "F" refers to teeth with code 3. Those teeth coded 6, 7, 8, 9, or T are not included in DMFT calculations.

To arrive at a DMFT score for an individual patient's mouth, three values must be determined: the number of teeth with carious lesions, the number of extracted teeth, and the number of teeth with fillings or crowns. A patient who has two areas of decay, six missing teeth and 11 filled or crowned teeth for example, has a DMFT score of19. Teeth that include both decay and fillings or crowns, are only given one point, a D. Thirteen teeth (based on a full dentition of 32) remain intact.

It is also possible to determine more detailed DMFS (decayed, missing, or filled surface) scores. As anterior teeth have four surfaces and posterior teeth have five, a full dentition of 32 teeth includes 128 surfaces. A patient with seven decayed surfaces, 20 surfaces from which teeth are missing, and 42 surfaces either filled or included in a crown, the DMFS score is 69. Fifty-nine surfaces are intact.

For primary dentition, scoring is referred to as "deft" or "defs" (decayed, extracted, or filled).

Community Periodontal Index

This index is reversible (oral hygiene) and irreversible (periodontal). The teeth are first divided into sextants, with each box representing a sextant. Teeth selection: Determined by the age of the patient. If the patient is 20 years or older then begin distal to canines. A sextant with no teeth or one

tooth, an X is marked. If only one functional tooth present, assess with adjacent sextant. Third molars are only assessed if they function in place of second molars. For children and adolescents, one tooth per sextant is evaluated: all first molars, maxillary right central incisor, and mandibular left central incisor. If designated tooth missing, mark sextant with an X.

The ball at the end of the probe functions to aid in detection and reduce the risk of over-measurement. The probe is used to determine probing depth, bleeding response, and presence of calculus. Pressure: no greater than 15-25g. Use color coded band for prompt identification.

Codes: 0 -Healthy periodontal tissues 1 - Bleeding after gentle probing 2- Supragingival or subgingival calculus or defective margin of filling or crown 3- 4mm or 5mm pocket 4- 6mm or deeper pathologic pocket

Recording: Use the 2x3 box chart. An X is marked for all missing sextants. Record only the highest code (most severe) for the designated sextant. Once a Code 4 has been assessed, there is no need to continue assessing the reaming teeth of the sextant. 

Scoring: The patient(s) are classified into treatment needs based on the highest code recorded. 0 - No need for treatment (Code 0) I - Oral hygiene instruction (Code 1) II -OHI + scaling and root planing, including elimination of plaque-retentive margins (Codes 2 & 3) III - I + II + complex periodontal therapy that may include surgical intervention and/or deep scaling and root planing with local anesthetic (Code 4)

FLUORIDE

History

In the 1930s, dental scientists documented that the occurrence and severity of tooth decay was lower among people whose water supplies contained higher levels of natural fluoride. Extensive studies followed and discovered that fluoride, when present in the mouth, can become concentrated in plaque and saliva, helping to prevent the breakdown of enamel minerals.

In 1945, the city of Grand Rapids, Michigan, added fluoride to its municipal water system. Community water fluoridation—adjusting the amount of fluoride in an area's water supply to a level that helps to prevent tooth decay and promote oral health—had begun. Since then, numerous scientific studies and comprehensive reviews have continually recognized fluoridation as an effective way to prevent tooth decay.

Benefits

Water fluoridation prevents tooth decay mainly by providing teeth with frequent contact with low levels of fluoride throughout each day and throughout life. Even today, with other available sources of fluoride, studies show that water fluoridation reduces tooth decay by about 25 percent over a person's lifetime.

Community water fluoridation is not only safe and effective, but it is also cost-saving and the least expensive way to deliver the benefits of fluoride to all residents of a community. For larger communities of more than 20,000 people, it costs about 50 cents per person to fluoridate the water. It is also cost-effective because every $1 invested in this preventive measure yields approximately $38 savings in dental treatment costs.

This method of fluoride delivery benefits all people―regardless of age, income, education, or socioeconomic status. A person's income and ability to get routine dental care are not barriers since all residents of a community can enjoy fluoride's protective benefits just by drinking tap water and consuming foods and beverages prepared with it.

Fluoride from other sources prevents tooth decay as well, whether from toothpaste, mouth rinses, professionally applied fluoride treatments, or prescription fluoride supplements. These methods of delivering fluoride, however, are more costly than water fluoridation and require a conscious decision to use them.

Safety

Drinking water safety is defined and determined by federal, state, and local regulations. The main federal law that ensures the quality of Americans' drinking water is the Safe Drinking Water Act (SDWA). Under SDWA, the U.S. Environmental Protection Agency (EPA) sets standards for drinking water quality and oversees the states, localities, and water suppliers that implement those standards.

CDC promotes effective public health practices, such as community water fluoridation. It is not CDC's task to determine what levels of fluoride in water are safe, yet our understanding about the safety of fluoridation is guided by federal regulations, comprehensive reviews by expert panels, and individual studies.

Discovery of the decay-preventing effects of naturally occurring fluoride in water led to the start of community water fluoridation in 1945. For more than 65 years, water fluoridation has undergone extensive scientific studies and reviews to assess its public health benefits and risks.

For many years, panels of experts from different health and scientific fields have provided strong evidence that water fluoridation is safe and effective.

Fluorosis

The proper amount of fluoride helps prevent and control tooth decay. Fluoride ingested during tooth development can also result in a range of changes in tooth enamel. Because dental fluorosis is a condition that occurs when teeth are forming, only children aged 8 years old or younger are at risk. Children older than 8 years, adolescents, and adults are not susceptible to dental fluorosis.

Dental fluorosis occurs among some people in all communities, even in communities that do not fluoridate or have a low natural concentration of fluoride in their drinking water. Everyone is encouraged to know what steps can be taken to reduce the occurrence of dental fluorosis.

The safety of fluoride in drinking water at levels recommended for preventing tooth decay has been affirmed by numerous scientific and professional groups. Scientists have found a lack of evidence to show an association between water fluoridation and a negative impact on people, plants, or animals.

Three additives—sodium fluoride, sodium fluorosilicate, and fluorosilicic acid—may be used to adjust the natural fluoride levels in water to concentrations that prevent or control tooth decay.

Infants and Fluorosis

The proper amount of fluoride from infancy through old age helps prevent and control tooth decay. Community water fluoridation is a widely accepted practice for preventing and controlling tooth decay by adjusting the concentration of fluoride in the public water supply.

Fluoride intake from water and other fluoride sources, such as toothpaste and mouth rinses, during the ages when teeth are forming (from birth through age 8) also can result in changes in the appearance of the tooth's surface called dental fluorosis. In the United States, the majority of dental fluorosis is mild and appears as white spots that are barely noticeable and difficult for anyone except a dental health care professional to see.

Recent evidence suggests that mixing powdered or liquid infant formula concentrate with fluoridated water on a regular basis may increase the chance of a child developing the faint, white markings of very mild or mild enamel fluorosis.

You can use fluoridated water for preparing infant formula. However, if your child is exclusively consuming infant formula reconstituted with fluoridated water, there may be an increased chance for mild dental fluorosis. To lessen this chance, parents can use low-fluoride bottled water some of the time to mix infant formula; these bottled waters are labeled as de-ionized, purified, demineralized, or distilled.

Scientific Reviews to Consider

Reviews of scientific literature are an important resource to judge the safety of community water fluoridation. Scientific reviews are helpful because they—

Consider evidence from published studies on a subject. Use carefully-designed methods to critically examine scientific evidence. Use national and international panels of experts in various health and scientific

disciplines. This includes experts that may come from fields outside of oral health; such as, medicine, biophysics, chemistry, toxicological pathology, and epidemiology.

Judge the quality of individual studies and summarize the strength of the entire body of evidence.

Identify and summarize research gaps and make recommendations for further research. Scientific and public health organizations have conducted scientific reviews about

fluoridation during the past two decades. These reviews provide compelling evidence that community water fluoridation is a safe and effective method for reducing tooth decay across all ages.

Fluoride Toothpaste

FormConcentrations of fluoride in toothpaste sold in the United States range from 1,000–1,500 ppm.

UseMost people report brushing their teeth at least once per day, but more frequent use can offer additional protection. Fluoride in toothpaste is taken up directly by the dental plaque and demineralized enamel and also increases the concentration of fluoride in saliva.

AvailabilityFluoride toothpaste is available over-the-counter and makes up more than 95% of toothpaste sales in the United States.

RecommendationsFor most people (children, adolescents, and adults) brushing at least twice a day with a fluoride toothpaste—when you get up in the morning and before going to bed—is recommended.

Advice for ParentsFor children aged 6 years and younger, some simple recommendations are advised to reduce the risk of dental fluorosis.

Supervise brushing to discourage swallowing toothpaste. Place only a small pea-size amount of fluoride toothpaste on your child's toothbrush. Seek advice from a dentist or other health care professional before introducing fluoride toothpaste to children

under 2 years of age.

Fluoride Mouthwash

FormFluoride mouth rinse is a concentrated solution intended for daily or weekly use. The most common fluoride compound used in mouth rinse is sodium fluoride. Over-the-counter solutions of 0.05% sodium fluoride (230 ppm fluoride) for daily rinsing are available for use by persons older than 6 years of age. Solutions of 0.20% sodium fluoride (920 ppm fluoride) are used in supervised, school-based weekly rinsing programs. Other concentrations also are available.

UseRinses are used daily or weekly for a prescribed amount of time. The fluoride from mouth rinse is retained in dental plaque and saliva to help prevent tooth decay.

AvailabilityMouth rinses intended for home use can be purchased over-the-counter. Higher strength mouth rinses for those at high risk of tooth decay must be prescribed by a dentist or physician.

RecommendationsChildren younger than 6 years of age should not use fluoride mouth rinse without consultation with a dentist or other health care provider because dental fluorosis could occur if such mouth rinses are repeatedly swallowed. Because fluoride mouth rinse has resulted in only limited reductions in tooth decay among schoolchildren, especially as their exposure to other sources of fluoride has increased, its use should be targeted to individuals or groups at high risk for decay.

Fluoride Supplements

Form Tablets, lozenges, or liquids (including fluoride-vitamin preparations) are available. Most

supplements contain sodium fluoride as the active ingredient. Tablets and lozenges are manufactured with 1.0, 0.5, or 0.25 mg fluoride.

Use Fluoride supplements can be prescribed for children at high risk for tooth decay and whose primary

drinking water has a low fluoride concentration. To maximize the topical effect of fluoride, tablets and lozenges are intended to be chewed or sucked for 1–2 minutes before being swallowed.

Availability All fluoride supplements must be prescribed by a dentist or physician. Recommendations For children aged less than 6 years, the dentist, physician, or other health care provider should

weigh the risk for tooth decay without fluoride supplements, the decay prevention offered by supplements, and the potential for dental fluorosis. Consideration of the child's other sources of fluoride, especially drinking water, is essential in determining this balance. Parents and caregivers should be informed of both the benefit of protection against tooth decay and the possibility of dental fluorosis.

Fluoride Gel and Foam

FormFluoride gel is often formulated to be highly acidic (pH of approximately 3.0). Products available in the United States include gel of acidulated phosphate fluoride (1.23% [12,300 ppm] fluoride), gel or foam of sodium fluoride (0.9% [9,040 ppm] fluoride), and self-applied (i.e., home use) gel of sodium fluoride (0.5% [5,000 ppm] fluoride) or stannous fluoride (0.15% [1,000 ppm] fluoride).

UseIn a dental office, fluoride gel is applied for 1–4 minutes. Home use follows instructions provided on the prescription.

AvailabilityMost fluoride gel and foam applications are delivered in a dental office by a dental professional. These higher strength products, if used in the home, must be prescribed by a dentist or physician.

RecommendationsBecause these applications are relatively infrequent, generally at 3 to 12–month intervals, fluoride gel poses little risk for dental fluorosis, even among patients younger than 6 years of age. Routine use of professionally applied fluoride gel or foam likely provides little benefit to persons not at high risk for tooth decay, especially those who drink fluoridated water and brush daily with fluoride toothpaste.

Fluoride Varnish

FormVarnishes are available as sodium fluoride (2.26% [22,600 ppm] fluoride) or difluorsilane (0.1% [1,000 ppm] fluoride) preparations.

UseHigh-concentration fluoride varnish is painted by dental or other health care professionals directly onto the teeth. Fluoride varnish is not intended to adhere permanently; this method holds a high concentration of fluoride in a small amount of material in close contact with the teeth for many hours. Varnishes must be reapplied at regular intervals with at least 2 applications per year required for effectiveness.

AvailabilityAll fluoride varnish must be applied by a dentist or other health care provider.

RecommendationsNo published evidence indicates that professionally applied fluoride varnish is a risk factor for dental fluorosis, even among children younger than 6 years of age. Proper application technique reduces the possibility that a patient will swallow varnish during its application and limits the total amount of fluoride swallowed as the varnish wears off the teeth over several hours.

Although it is not currently cleared for marketing by the Food and Drug Administration (FDA) as an anti-caries agent, fluoride varnish has been widely used for this purpose in Canada and Europe since the 1970s. Studies conducted in Canada and Europe have reported that fluoride varnish is as effective in preventing tooth decay as professionally applied fluoride gel.

Water Fluoridation

Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay. Fluoridated water has fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride. Fluoridated water operates on tooth surfaces: in the mouth it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.

Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.01 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. A 1994 World Health Organization expert committee suggested a level of fluoride from 0.5 to 1.0 mg/L (milligrams per litre), depending on climate. Bottled water typically has unknown fluoride levels, and some domestic water filters remove some or all fluoride.

Dental caries remain a major public health concern in most industrialized countries, affecting 60–90% of schoolchildren and the vast majority of adults. Water fluoridation prevents cavities in both children and adults, with studies estimating an 18–40% reduction in cavities when water fluoridation is used by children who already have access to toothpaste and other sources of fluoride. Studies suggest that the use of water fluoridation particular in industrialized countries may be unnecessary for caries prevention, because topical fluorides (such as in toothpaste) are widely used and caries has become low.

Although water fluoridation can cause dental fluorosis, which can alter the appearance of developing teeth or enamel fluorosis, most of this is mild and usually not considered to be of aesthetic or public-health concern. There is no clear evidence of other adverse effects from water fluoridation. Studies on adverse effects have been mostly of low quality. Fluoride's effects depend on the total daily intake of fluoride from all sources. Drinking water is typically the largest source; other methods of fluoride therapy include fluoridation of toothpaste, salt, and milk. Water fluoridation, when feasible and culturally acceptable, has substantial advantages, especially for subgroups at high risk.

The U.S. Centers for Disease Control listed water fluoridation as one of the ten great public health achievements of the 20th century; in contrast, most European countries have experienced substantial declines in tooth decay without its use, primarily due to the introduction of fluoride toothpaste in the 1970s. Fluoridation may be more justified in the U.S. because of socioeconomic inequalities in dental health and dental care. Public water fluoridation was first practiced in the USA, and has been introduced to many other countries to varying degrees with many countries having water that is naturally fluoridated to recommended levels and others, such as in Europe, using fluoridated salts as an alternative source of fluoride

The Goal

The goal of water fluoridation is to prevent tooth decay by adjusting the concentration of fluoride in public water supplies. Tooth decay (dental caries) is one of the most prevalent chronic diseases worldwide. Although it is rarely life-threatening, tooth decay can cause pain and impair eating, speaking, facial appearance, and acceptance into society, and it greatly affects the quality of life of children, particularly those of low socioeconomic status. 

In most industrialized countries, tooth decay affects 60–90% of schoolchildren and the vast majority of adults; although the problem appears to be less in Africa's developing countries, it is expected to increase in several countries there because of changing diet and inadequate fluoride exposure. In the U.S., minorities and the poor both have higher rates of decayed and missing teeth, and their children have less dental care. Once a cavity occurs, the tooth's fate is that of repeated restorations, with estimates for the median life of an amalgam tooth filling ranging from 9 to 14 years. Oral disease is the fourth most expensive disease to treat. The motivation for fluoridation of salt or water is similar to that of iodized salt for the prevention of mental retardation and goiter.

The goal of water fluoridation is to prevent a chronic disease whose burdens particularly fall on children and on the poor. Its use presents a conflict between the common good and individual rights. It is controversial, and opposition to it has been based on ethical, legal, safety, and efficacy grounds.

Health and dental organizations worldwide have endorsed its safety and effectiveness. Its use began in 1945, following studies of children in a region where higher levels of fluoride occur naturally in the water.Researchers discovered that moderate fluoridation prevents tooth decay, and as of 2004 about 400 million people worldwide received fluoridated water.

Types

Fluoridation does not affect the appearance, taste, or smell of drinking water. It is normally accomplished by adding one of three compounds to the water: sodium fluoride, fluorosilicic acid, or sodium fluorosilicate.

Sodium fluoride (NaF) was the first compound used and is the reference standard. It is a white, odorless powder or crystal; the crystalline form is preferred if manual handling is used, as it minimizes dust. It is more expensive than the other compounds, but is easily handled and is usually used by smaller utility companies.

Fluorosilicic acid (H2SiF6) is an inexpensive liquid by-product of phosphate fertilizer manufacture. It comes in varying strengths, typically 23–25%; because it contains so much water, shipping can be expensive. It is also known as hexafluorosilicic, hexafluosilicic, hydrofluosilicic, and silicofluoric acid.

Sodium fluorosilicate (Na2SiF6) is the sodium salt of fluorosilicic acid. It is a powder or very fine crystal that is easier to ship than fluorosilicic acid. It is also known as sodium silicofluoride.

In the Water

Fluoride naturally occurring in water can be above, at, or below recommended levels. Rivers and lakes generally contain fluoride levels less than 0.5 mg/L, but groundwater, particularly in volcanic or mountainous areas, can contain as much as 50 mg/L. Higher concentrations of fluorine are found in alkaline volcanic, hydrothermal, sedimentary, and other rocks derived from highly evolved magmas and hydrothermal solutions, and this fluorine dissolves into nearby water as fluoride. In most drinking waters, over 95% of total fluoride is the F− ion, with the magnesium–fluoride complex (MgF+) being the next most common.

Because fluoride levels in water are usually controlled by the solubility of fluorite (CaF2), high natural fluoride levels are associated with calcium-deficient, alkaline, and soft waters. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. It can be accomplished by percolating water through granular beds of activated alumina, bone meal, bone char, or tricalcium phosphate; by coagulation with alum; or by precipitation with lime.

Pitcher or faucet-mounted water filters do not alter fluoride; the more-expensive reverse osmosis filters remove 65–95% of fluoride, and distillation filters remove all fluoride. U.S. regulations for bottled water do not require disclosing fluoride content, so the effect of always drinking it is not known. Surveys of bottled water in Cleveland and in Iowa found that most contained well below optimal fluoride levels; a survey in São Paulo, Brazil, found large variations of fluoride, with many bottles exceeding recommended limits and disagreeing with their labels.

Effectiveness

Water fluoridation effectively reduces cavities in both children and adults: earlier studies showed that water fluoridation reduced childhood cavities by fifty to sixty percent, but more recent studies show lower reductions (18–40%) likely due to increasing use of fluoride from other sources, notably toothpaste, and also the 'halo effect' of food and drink that is made in fluoridated areas and consumed in unfluoridated ones.

A 2000 systematic review found that water fluoridation was statistically associated with a decreased proportion of children with cavities (the median of mean decreases was 14.6%, the range −5 to 64%), and with a decrease in decayed, missing, and filled primary teeth (the median of mean decreases was 2.25 teeth, the range 0.5–4.4 teeth), which is roughly equivalent to preventing 40% of cavities. The review found that the evidence was of moderate quality: few studies attempted to reduce observer bias, control for confounding factors, report variance measures, or use appropriate analysis. Although no major differences between natural and artificial fluoridation were apparent, the evidence was inadequate for a conclusion about any differences. Fluoride also prevents cavities in adults of all ages. There are fewer studies in adults however, and the design of water fluoridation studies in adults is inferior to that of studies of self- or clinically applied fluoride.

A 2007 meta-analysis found that water fluoridation prevented an estimated 27% of cavities in adults (95% confidence interval [CI] 19–34%), about the same fraction as prevented by exposure to any delivery method of fluoride (29% average, 95% CI: 16–42%). A 2002 systematic review found strong evidence that water fluoridation is effective at reducing overall tooth decay in communities.

Most countries in Europe have experienced substantial declines in cavities without the use of water fluoridation. For example, in Finland and Germany, tooth decay rates remained stable or continued to decline after water fluoridation stopped. Fluoridation may be useful in the U.S. because unlike most European countries, the U.S. does not have school-based dental care, many children do not visit a dentist regularly, and for many U.S. children water fluoridation is the prime source of exposure to fluoride. The effectiveness of water fluoridation can vary according to circumstances such as whether preventive dental care is free to all children.

Some studies suggest that fluoridation reduces oral health inequalities between the rich and poor, but the evidence is limited. There is anecdotal but not scientific evidence that fluoride allows more time for dental treatment by slowing the progression of tooth decay, and that it simplifies treatment by causing most cavities to occur in pits and fissures of teeth.

Fluorosis

Fluoride's adverse effects depend on total fluoride dosage from all sources. At the commonly recommended dosage, the only clear adverse effect is dental fluorosis, which can alter the appearance of children's teeth during tooth development; this is mostly mild and is unlikely to represent any real effect on aesthetic appearance or on public health. 

The critical period of exposure is between ages one and four years, with the risk ending around age eight. Fluorosis can be prevented by monitoring all sources of fluoride, with fluoridated water directly or indirectly responsible for an estimated 40% of risk and other sources, notably toothpaste, responsible for the remaining 60%.[57] Compared to water naturally fluoridated at 0.4 mg/L, fluoridation to 1 mg/L is estimated to cause additional fluorosis in one of every 6 people (95% CI 4–21 people), and to cause additional fluorosis of aesthetic concern in one of every 22 people (95% CI 13.6–∞ people).

Here, aesthetic concern is a term used in a standardized scale based on what adolescents would find unacceptable, as measured by a 1996 study of British 14-year-olds. In many industrialized countries the prevalence of fluorosis is increasing even in unfluoridated communities, mostly because of fluoride from swallowed toothpaste. 

A 2009 systematic review indicated that fluorosis is associated with consumption of infant formula or of water added to reconstitute the formula, that the evidence was distorted by publication bias, and that the evidence that the formula's fluoride caused the fluorosis was weak. In the U.S. the decline in tooth decay was accompanied by increased fluorosis in both fluoridated and unfluoridated communities; accordingly, fluoride has been reduced in various ways worldwide in infant formulas, children's toothpaste, water, and fluoride-supplement schedules.

Safety

Fluoridation has little effect on risk of bone fracture (broken bones); it may result in slightly lower fracture risk than either excessively high levels of fluoridation or no fluoridation.[10] There is no clear association between fluoridation and cancer or deaths due to cancer, both for cancer in general and also specifically for bone cancer and osteosarcoma. Other adverse effects lack sufficient evidence to reach a confident conclusion. A Finnish study published in 1997 showed that fear that water is fluoridated may have a psychological effect with a large variety of symptoms, regardless of whether the water is actually fluoridated.

Fluoride can occur naturally in water in concentrations well above recommended levels, which can have several long-term adverse effects, including severe dental fluorosis, skeletal fluorosis, and weakened bones. The World Health Organization recommends a guideline maximum fluoride value of 1.5 mg/L as a level at which fluorosis should be minimal. In rare cases improper implementation of water fluoridation can result in over fluoridation that causes outbreaks of acute fluoride poisoning, with symptoms that include nausea, vomiting, and diarrhea. Three such outbreaks were reported in the U.S. between 1991 and 1998, caused by fluoride concentrations as high as 220 mg/L; in the 1992 Alaska outbreak, 262 people became ill and one person died. In 2010, approximately 60 gallons of fluoride were released into the water supply in Asheboro, North Carolina in 90 minutes—an amount that was intended to be released in a 24-hour period.[61]

Like other common water additives such as chlorine, hydrofluosilicic acid and sodium silicofluoride decrease pH and cause a small increase of corrosiveness, but this problem is easily addressed by increasing the pH. Although it has been hypothesized that hydrofluosilicic acid and sodium silicofluoride might increase human lead uptake from water, a 2006 statistical analysis did not support concerns that these chemicals cause higher blood lead concentrations in children. Trace levels of arsenic and lead may be present in fluoride compounds added to water, but no credible evidence exists that their presence is of concern: concentrations are below measurement limits.

The effect of water fluoridation on the natural environment has been investigated, and no adverse effects have been established. Issues studied have included fluoride concentrations in groundwater and downstream rivers; lawns, gardens, and plants; consumption of plants grown in fluoridated water; air emissions; and equipment noise.