Community Water Fluoridation⁹

The notion of fluoridating the community water supply grew out of a need to address the prevalence of dental caries in the United States in the 1940s. At that time the population was not exposed to the myriad fluoride-containing products to which the population is exposed today. One of the great disease prevention measures of all time, community water fluoridation, is a nearly ideal public health intervention because the system has the following characteristics:

Inexpensive and cost-effective

Effective (decreased caries prevalence by about 50%)

Eminently safe

Equitable (i.e., benefits the entire population on the water system)

Not dependent on client compliance (cooperative effort)

Beneficial as a topical fluoride over the client’s lifespan as long as water consumption continues

Instrumental in reducing costs for dental treatment

Not dependent on the professional services of a licensed healthcare provider

As a public health measure, community water fluoridation calls for testing of the community water supply to determine the naturally occurring level of fluoride. The level of fluoride is then adjusted through fluoridation or defluoridation to the accepted level of 0.7 to 1.2 parts per million (ppm), depending on the average maximum daily air temperature of the area. Defluoridation is necessary if the naturally occurring level of fluoride in the water exceeds the recommended level, putting the public at risk for dental fluorosis¹⁰ (chronic fluoride toxicity).

Food and Beverages

The public is exposed to a variety of fluoride-containing foodstuffs that become part of the client’s overall exposure to topical and systemic fluoride. There is considerable variation in the amount of fluoride in products routinely ingested; thorough questioning is necessary to document this information during client assessment procedures (see Chapter 10Table 10-2Figure 10-4).

Infants primarily ingest breast milk, cow’s milk, and milk-based and soy-based formulas. Fluoride levels are generally low in human breast milk (<0.01 ppm) and cow’s milk (0.05 ppm). When the formula industry recognized that milk-based formula might be reconstituted with fluoridated water, many voluntarily reduced the fluoride content in powdered formula. Formula packaging should be consulted to determine fluoride levels in the prepared powder. Ready-to-use soy-based formulas have more fluoride than do milk-based products (0.30 ppm).¹⁰

Beverages prepared from natural ingredients may be a systemic and topical source of fluoride. Raw tea leaves are high in fluoride content and contain as much as 400 ppm of fluoride. Brewed tea contains an average of 3 ppm of fluoride. This is a risk factor for dental fluorosis in cultures where children consume tea on a daily basis during tooth development (e.g., Asian Indians and Asians).¹⁰

The fluoride level in processed beverages and bottled waters varies considerably. For example, fluoride content in fruit juices and carbonated beverages ranges from <0.1 to 6.7 ppm. Differences in fluoride content in processed beverages is attributed to the variations in the fluoride levels of the water used to prepare these products.¹⁰ Although there is also variation in the fluoride content of bottled waters, these beverages generally have low fluoride concentration. Bottled waters are marketed as distilled, drinking, mineral, or natural spring waters and may be carbonated or noncarbonated. Given that consumption of tap water among U.S. children has declined and consumption of other beverages has grown, it is becoming increasingly difficult to assess clients’ fluoride exposure via fluid intake.

Other foodstuffs such as seafood products, processed baby food, and chicken may also contain substantial levels of fluoride. Prepared foods are generally processed in urban areas with fluoridated water and become additional sources of fluoride for individuals living in both fluoridated and nonfluoridated communities. Internationally, other foodstuffs are used as vehicles for delivering fluoride. In countries such as Switzerland, Jamaica, and France, fluoride is incorporated into table salt.

Prescription Supplements

Fluoride supplements in the form of drops, lozenges, or tablets can provide systemic and topical (if tablet or lozenge is sucked or chewed) fluoride to children residing in nonfluoridated communities (communities without water fluoridation or having well water with low or undetectable levels of fluoride) (Figure 31-1). The goal of supplementation is to have children in nonfluoridated communities reach a similar level of caries reduction as children living in fluoridated communities. However, considerable debate remains regarding this issue because of the following factors:

Fluoride supplementation increases risk for dental fluorosis; the risk has increased over the years owing to clients’ exposure to multiple sources of fluoride.

Clients are exposed to multiple sources of topical and ingested fluorides.

Prescriptive dosages of fluoride supplements may be improper, and supplements may be prescribed inadvertently by both dentists and pediatricians.

Fluoride supplements may be used improperly in fluoridated communities.

Fluoride supplements may be recommended for clients who use well water as their primary water source before the well water is tested to determine natural fluoride levels.

Compliance of clients or caregivers may be poor.

Figure 31-1 Example of a fluoride supplement available by prescription.

The use of prenatal fluoride supplements is not recommended for pregnant women because permanent teeth do not develop in utero.

After an evaluation of these factors, the American Dental Association (ADA) Council on Scientific Affairs published a recommended supplementation schedule (Table 31-3). Fluoride supplementation recommendations are based on client age and the level of fluoride in the primary water source. When supplementation is considered, assessment procedures should include questions about the client’s primary water source (e.g., fluoridated community water supply, nonfluoridated community water supply, well water, filtered water) and exposure to other systemic fluoride sources (see the discussion of the patient dental history in Chapter 10).

TABLE 31-3 Fluoride Supplements Dosage Schedule (milligrams of fluoride per day)^∗

When supplementation is recommended, it should be in consultation with the child’s pediatrician or primary medical care provider. This will prevent a child from receiving duplicate prescriptions for fluoride supplements. Given that many pediatric dentists recommend that children be seen in general dental offices as infants, there is an increased risk that a child could be given prescriptions by more than one provider. Table 31-4 describes various types of fluoride supplements and indications for their use.

TABLE 31-4 Consideration for the Use of Prescription Fluoride Supplements

Data from Levy SM, Kiritsy MC, Warren JJ: Sources of fluoride intake in children, J Public Health Dent 55:39, 1995; Newburn E: Fluorides and dental caries, Springfield, Ill, 1986 Charles C Thomas; Tate WH, Chan J: Fluoride concentration in bottled and filtered waters, Gen Dent 42:362, 1994.

Risk of Chronic Fluoride Toxicity (Dental Fluorosis)¹⁰

Dental fluorosis is the hypomineralization of the enamel that results from the chronic ingestion of fluoride that exceeds optimal levels. Dental fluorosis is detected by clinical evaluation and classified by degree (Table 31-5). Mild dental fluorosis is often difficult to identify and requires careful assessment and good lighting. Although some consider fluorosis primarily to be an aesthetic concern, in its most severe state the enamel may actually break down. This alteration in the enamel occurs during tooth formation and is therefore a risk only during the preeruptive stages of tooth development. Dental fluorosis is associated with chronic fluoride toxicity and can occur only as a result of systemic ingestion of fluoride during tooth development (Figure 31-2).

TABLE 31-5 Classification of Degree of Dental Fluorosis

Adapted from Newburn E: Fluorides and dental caries, Springfield, Ill, 1986, Charles C Thomas.

Figure 31-2 Dental fluorosis.

(From Ibsen OAC, Phelan JA: Oral pathology for the dental hygienist, ed 5, St Louis, 2009, Saunders.)

Clients cannot develop fluorosis as a result of topical fluoride exposure, even if the topical exposure is excessive (high-concentration fluoride at frequent intervals). The only way a client can develop dental fluorosis from topical fluoride is by swallowing the product during periods of tooth development, that is, changing the mechanism of fluoride action from topical to systemic. Fluorosis risk increases with ingestion of low-concentration fluoride products such as fluoride-containing dentifrices or mouth rinses. These products are of concern because they are used unsupervised by young children, have an appealing taste and appearance, are often swallowed, and may be stored within reach of small children. The administration of professionally applied, high-concentration fluoride products may initially appear to be a risk factor for dental fluorosis. Scientific evidence confirms that fluoride ingestion occurs as the result of topical treatments and that plasma levels of fluoride are elevated after the treatment. Even though fluoride concentration in professionally administered products is high, the infrequent application of these products does not result in clinically evident enamel disturbances.

Ingested Fluoride—Issues for Consideration

Community water fluoridation remains a successful public health approach and is the cornerstone of a fluoride protocol and caries management program. This systemic fluoride vehicle is available to all individuals residing in fluoridated communities, regardless of socioeconomic background or ability to access other fluoride therapies. (Consult lists of fluoridated communities available from the Department of Health.)

Debate continues regarding need for additional systemic supplementation (based on the multiple sources of fluoride children receive from processed foodstuffs, prepared beverages, and naturally occurring fluoride).

Many households use bottled water as their primary water source. Bottled waters have low fluoride concentrations and typically do not reveal fluoride content. A few bottled water manufacturers identify fluoride content on product labels. Other companies are adding fluoride and using the added fluoride as a marketing tool (e.g., “nursery water with fluoride”).

It has become common for individuals to attach water filtration devices (reverse osmosis, bubbling ozone, activated charcoal, and so on) to household water taps. Many of these water filtration systems remove significant amounts of fluoride from the water.

Persons who use well water as their primary water sources should have the water tested to determine fluoride level. Without this information, it is impossible to prescribe fluoride supplements accurately. In addition, consideration may be given to how dental hygienists and other dental providers can facilitate water testing by providing clients with testing kits and submitting specimens for testing.

Well water may contain water from various sources (with varying fluoride concentrations).

Some water supplies are poorly monitored for optimum fluoride.

There may be a systemic effect from topical fluoride preparations.

Some topical preparations, especially fluoride-containing dentifrices and oral rinses, may be swallowed, causing the client to receive both a topical and systemic exposure to fluoride. Children using fluoride products must be monitored to decrease risk for acute and chronic fluoride toxicity.

Ingested fluoride delivery, especially community water fluoridation, has a track record of success in reducing caries incidence and prevalence. Just as with other client care decisions, the scientific literature provides evidence to substantiate changes in ingested fluoride protocols.

Self-Applied Dentifrices¹⁴

See Chapter 23. Other than fluoride consumed in drinking water, dentifrices are the most widely used fluoride-containing preparations. Dentifrices that carry the ADA Seal of Acceptance or the CDA Seal of Recognition provide sufficient concentrations of fluoride to facilitate enamel remineralization when applied two to three times daily (Figure 31-3). Scientific literature provides clinical evidence to substantiate the use of a fluoridated dentifrice with this frequency. Studies done to compare caries reduction indicate that brushing once a day with a fluoridated toothpaste results in a 21% reduction in dental caries, whereas brushing three times a day results in 45% fewer caries.

Figure 31-3 Sample over-the-counter dentifrices that have the American Dental Association Seal of Acceptance for dental caries prevention as well as other benefits. A, Crest ProHealth. B, Colgate Total.

(A, courtesy Procter & Gamble, Cincinnati, Ohio. B, courtesy Colgate Oral Pharmaceuticals, New york, New York.)

The majority of commercial dentifrices available in the United States contain 0.1% fluoride or 1000 ppm. Some manufacturers produce higher-strength dentifrices that contain 1500 ppm fluoride; others have marketed a pediatric toothpaste with lower levels of fluoride ranging from 250 to 550 ppm. It is important for the dental hygienist to recommend products that have undergone clinical evaluation and have documented caries-preventive ability.

Special consideration must be given when recommending fluoridated dentifrices for children under 6 years of age. The primary concern is that young children swallow dentifrice because they enjoy the taste and are not capable of (or efficient at) expectorating dentifrice from their mouths. Only 5% of children younger than 2½ years of age expectorate after brushing, and only 32% of 2½- to 4-year-olds expectorate.¹¹ This inability to expectorate results in the ingestion of an agent designed for topical use and increases dental fluorosis risk. When recommending dentifrices for young children, it is important to involve the client’s parent or caregiver and emphasize the following:

Importance of supervision when children are brushing their teeth

Delay in introduction of fluoridated toothpaste until child is 2 years of age (although this recommendation may be modified by the ADA to a smear of toothpaste for some children after 6 months of age)

Limiting toothpaste used to a smear, a pea-sized amount (0.25 mL), or enough paste to cover one quarter of the toothbrush head (depending on the age of the child).

Importance of expectorating after brushing with a fluoridated dentifrice

Avoidance of higher-concentration dentifrices and other fluoride products with children under 6 years of age

Storage of fluoridated dentifrices out of the reach of children

Toothpaste is the most widely used at-home, topical fluoride vehicle, but various other products are available for those clients whose caries risk warrants the use of additional agents (Table 31-7).

TABLE 31-7 Topical Fluorides: Self-Applied Pastes, Rinses, and Gels

Self-Applied Mouth Rinses and Gels¹⁴

Fluoride rinses and gels may be used in addition to fluoride-containing dentifrice to manage dental caries. The majority of the rinses and gels are of low- to mid-range potency and as such are administered with higher frequency. Research suggests that these fluoride products reduce caries by 30% to 35%. Table 31-7 identifies some rinses and gels available to clients. Clients should be provided with verbal and written instructions regarding home fluoride use. Care must be taken to keep oral products out of the reach of children.

Daily Fluoride Mouth Rinses

Low-potency, high-frequency fluoride rinses (0.05%) are available OTC; they have a fluoride concentration that equates to 230 ppm (Figure 31-4). These products are used daily as an adjunct to brushing with a fluoride dentifrice. Clients should be educated to use 5 mL (1 teaspoon) to 10 mL (2 teaspoons) of the rinse, to vigorously swish the rinse in the oral cavity for 1 minute, and then to thoroughly expectorate the rinse. Because there is a risk for young children to swallow fluoride rinses, this product is not recommended for children under 6 years of age. For the same reason, fluoride rinses should be stored out of the reach of young children. Low-potency, high-frequency 0.044% sodium fluoride (NaF) in an acidulated phosphate fluoride (APF) solution (e.g., OrthoWash Daily Rinse by 3M ESPE), 0.4% stable stannous fluoride (SnF₂), and 0.2% neutral NaF rinses that equate to 200 ppm are available by prescription only. These are indicated for the following:

Caries, white spot lesions, caries prevention

Dentinal hypersensitivity

Orthodontic clients

Figure 31-4 A and B, Sample of over-the-counter 0.05% sodium fluoride rinses with the American Dental Association Seal of Acceptance. C, Prescription-only 0.2% sodium fluoride rinse (for once-weekly use).

(A and B, Courtesy Colgate Oral Pharmaceuticals, New York, New York; and Chattem, Inc, Chattanooga, Tennessee. C, Courtesy Procter & Gamble, Cincinnati, Ohio.)

The 0.63% SnF2 rinse (e.g., PerioMed by 3M ESPE) is diluted per manufacturers directions and swished in the mouth twice daily for up to 4 weeks after nonsurgical periodontal therapy as an antimicrobial, to manage dentinal hypersensitivity, and to protect against root caries.

Daily Fluoride Gels and Pastes

Fluoride gels are marketed as a 0.4% SnF2 product at 1000 ppm available OTC 1.1% neutral NaF gel, 1.1 NaF toothpaste with 5% potassium nitrate, and 1.1% NaF toothpaste at 5000 ppm available by prescription only (Figure 31-5). These products are designed for daily use and are brushed on the teeth for 1 minute. If a product does not have a built-in cleaning system, then it is used after toothbrushing with a conventional fluoride dentifrice. Manufacturer instructions are as follows:

Remove oral biofilm with toothbrush, interdental aid, and tongue cleaner.

Load tray with appropriate amount of fluoride gel.

Dry teeth with cloth or gauze.

Place loaded tray over the desired arch; hold head upright and avoid swallowing product and saliva.

Leave tray on arch for 4 minutes, then remove tray and expectorate several times.

Repeat steps for the other arch.

Do not eat or drink for 30 minutes to maintain level of ambient fluoride.

Rinse, clean, and air dry trays.

Figure 31-5 Examples of 0.4% stable stannous fluoride gels and pastes, and 1.1% sodium fluoride prescription toothpaste.

(Colgate products courtesy Colgate Oral Pharmaceuticals, New York, New York; Oral-B products courtesy Procter & Gamble, Cincinnati, Ohio.)

This daily procedure is recommended for persons with the following:

Rampant caries, root caries, root exposures

Xerostomia, particularly associated with salivary gland dysfunction or medication

Radiation therapy to the head and neck

Dentinal hypersensitivity

Special needs

Because there is a risk for young children to swallow fluoride gels, these products are not recommended for children under 6 years of age. Although there are a very limited number of studies documenting their efficacy, the ADA Council on Scientific Affairs approved OTC SnF2 gels. In addition, the U.S. Food and Drug Administration (FDA) approved SnF2 gels for sale OTC because they contain the same fluoride concentration as conventional dentifrices. Stannous gels do not contain abrasives and should not be substituted for dentifrices that achieve pellicle and extrinsic stain removal.

Neutral and acidulated NaF gels (5000 ppm) are available without abrasives and with abrasives (marketed as prescription dentifrices). These products have gained widespread use for clients with special needs. Careful client education is required when these products are recommended for unsupervised home use. The products should be used as directed in a custom tray or brushed on the teeth for 1 minute and then expectorated. Clients should be reminded that these products are available by prescription owing to their moderate levels of fluoride and therefore should be carefully stored out of the reach of children. Neutral NaF preparations are indicated if the client has porcelain, composite, titanium, or sealant materials placed in the mouth; acidulate fluorides are contraindicated when these materials are present.

Professionally Applied Fluoride (In-Office Administration)^6,13-20

Professionally applied topical fluorides solutions and gels (prescription agents) have been used successfully (Table 31-8). Although fluoride foams are also in use, little evidence exists to support their efficacy; more research is needed before they can be used with the same confidence as gels. See Figure 31-6 for additional product examples.

TABLE 31-8 Topical Fluorides: Professionally Applied Gels, Foams,^∗ Solutions, and Varnishes

Figure 31-6 Topical fluoride gels for professional applications.

Solutions, Gels, and Foams

Professionally applied fluoride products are typically delivered using a disposable tray technique, are one of the last procedures performed in the appointment sequence, and are administered by licensed dental professionals. Three high-potency, low-frequency topical fluoride systems have been approved by the FDA for in-office use. These systems contain 9000 to 25,000 ppm of fluoride and are manufactured in the form of solutions, gels, or foams, as follows:

2.0% neutral NaF2

1.23% APF (NaF with hydrofluoric acid added)

8.0% SnF2

These high-potency, low-frequency fluoride systems have a caries reduction rate of approximately 30%. Of the three products, the 1.23% APF gel system is the most widely researched and used. The 2.0% neutral NaF gel is the second most widely used and is recommended when it is inappropriate to use an acidulated product (when client has tooth-colored restorations, titanium implants, sealants, and/or dentinal hypersensitivity). The foam system lacks research to support efficacy. The 8.0% SnF2 system is rarely used owing to its limited availability and lack of stability in aqueous solution. In addition, this product has poor client acceptance because of taste, tissue irritation, gingival sloughing, and extrinsic tooth staining.

Client Selection

(Table 31-9). Although client selection criteria for this procedure will continue to change based on research evidence, key issues must be considered during identification of clients who will benefit from professionally applied fluoride therapy:

Client’s fluoride history, for example, fluoride level in the primary water supply, overall exposure to fluoride.

Demonstrated risk for developing caries. Box 31-1 summarizes the caries risk factors that make children and adults candidates for professionally applied topical fluoride treatments.

Presence of newly erupted teeth (studies indicate that teeth are most susceptible to caries formation during the first 2 years after eruption).

Client’s ability to tolerate a 4-minute topical fluoride application.

Age of the client. Extreme care should be used if in-office fluoride treatment is administered to a child under 6 years of age. Inadvertent swallowing of fluoride and the inability to effectively expectorate place the client at risk for ingesting high-potency fluoride. This could result in acute fluoride toxicity. Older adults may present the same risks as the child client. Fluoride varnish therapy is a better choice for young children at moderate to high risk for dental caries.

Physical or cognitive disabilities (e.g., inability to expectorate or understand the importance of refraining from swallowing).

TABLE 31-9 Clinical Recommendations for the Use of Professionally Applied Topical Fluoride

Caries Risk Level	Age	Recommendation
Low
No incipient or cavitated primary or secondary carious lesions during the last 3 years and no factor that may increase caries risk∗	All age groups	May not receive additional benefitFluoridated water and fluoride toothpastes may provide adequate caries prevention
Moderate
No incipient or cavitated primary or secondary carious lesions during the last 3 years, but at least one factor that may increase caries risk∗	<6 years of age	Fluoride varnish applications at 6-month intervals
Either of the following: One or two incipient or cavitated primary or secondary carious lesions during the last 3 years No incipient or cavitated primary or secondary carious lesions during the last 3 years, but at least one factor that may increase caries risk∗	6 years of age or older	Fluoride varnish or fluoride gel applications at 6-month intervals
High
Any incipient or cavitated primary or secondary carious lesions during the last 3 years Presence of multiple factors that may increase caries risk∗ Low socioeconomic status† Suboptimal fluoride exposure Xerostomia‡	<6 years of age	Fluoride varnish applications at 3- to 6-month intervals
Three or more incipient or cavitated primary or secondary carious lesions during the last 3 years Presence of multiple factors that may increase caries risk∗ Suboptimal fluoride exposure Xerostomia‡	6 years of age or older	Fluoride varnish applications at 3- to 6-month intervals Fluoride varnish or fluoride gel applications at 3- to 6-month intervals may provide additional caries prevention benefit for those 6-18 years of age

∗ Factors increasing risk of developing caries also may include, but are not limited to, high titers of cariogenic bacteria, poor oral hygiene, prolonged nursing (bottle or breast), poor family dental health, developmental or acquired defects, genetic abnormality of teeth, many multisurface restorations, chemotherapy or radiation therapy, drug or alcohol abuse, irregular dental care, cariogenic diet, active orthodontic treatment, presence of exposed root surfaces, restoration overhangs and open margins, and physical or mental disability with inability to perform proper oral healthcare

† On the basis of findings from population studies, groups with low socioeconomic status have been found to have increased risk of developing caries. In children too young for their risk to be based on caries history, low socioeconomic status should be considered as a caries risk factor.

‡ Medication-, radiation-, or disease-induced xerostomia.

Adapted from American Dental Association Council on Scientific Affairs: Professionally applied topical fluoride: evidence-based clinical recommendations, J Dent Educ 71:393, 2007.

BOX 31-1 Client Selection for Professionally Applied Fluoride Treatments—Risk Factors^∗

• Caries risk factors that may indicate a need for a professionally applied topical fluoride include the following: new carious lesions on previously sound surfaces; dental caries experience in the previous 2 to 3 years

• Secondary lesions associated with restoration margins

• High levels of cariogenic bacteria

• Poor family oral health status

• Irregular professional dental care

• Enamel defects, white spots, exposed roots

• Cariogenic diet

• Wearing of orthodontic appliances

• Compromised salivary flow (e.g., from medical conditions, stress, medications)

• Radiation therapy

• Age-related conditions (e.g., hypersensitivity)

• Medical conditions (e.g., Sjögren’s syndrome, eating disorders); physical or cognitive disabilities

• For children and infants, poor dental caries status of the caregiver and siblings and low socioeconomic status

^∗ Individuals who are at low risk for dental caries may have no additional benefit from professionally applied fluoride therapy, particularly if they use a fluoride toothpaste and drink fluoridated water.

Tray Selection

Fluoride gel and foam products may be applied with a variety of techniques; however, the use of stock trays is most common (Figure 31-7). Advantages of the tray technique for professionally applied fluoride treatments are as follows:

Entire dentition can be treated simultaneously

Effective contact between fluoride and teeth

Little soft-tissue contact

Less dilution and contamination of fluoride with saliva

Client comfort

Reduced potential for fluoride ingestion (also maximized with use of foam product)

Time and cost effectiveness

Figure 31-7 Dual-arch trays.

(Courtesy Dental Hygienist News, funded by an educational grant from Procter & Gamble, Cincinnati, Ohio, and published by Harfst Associates, Inc, Troy, Michigan.)

Fluoride delivery trays are marketed by several manufacturers. Tray design and fit are critical to optimize the anticaries efficacy of the treatment and prevent ingestion of these high-potency products. When selecting trays for fluoride delivery, criteria include the ability of the tray to create a distal dam to prevent flow of fluoride out the posterior border, anatomic arch fit, anterior vertical coverage, posterior vertical coverage, ease of use, and tray features that promote client comfort.

Product Selection

Once the need for a professionally applied topical fluoride treatment is determined, the dental hygienist selects the type of high-potency fluoride for this procedure. Issues to consider when selecting a product include the following:

Fluoride gel versus foam products. Evolution of in-office fluoride products went from solutions to gels to thixotropic gels to foams. Gels were initially developed for ease of application and use of fluoride trays. However, cellulose added to gels to increase viscosity inhibited the fluoride to flow into protected areas. To overcome this problem, thixotropic gels were developed; these gels flow under pressure but remain viscous when not under pressure. Both professionally applied APF and neutral NaF products are available in thixotropic gels.

Professional-strength foam-based products were developed to address the risks associated with using high-potency, low-frequency fluoride products. With foam products, 75% less fluoride is used, dramatically reducing the risk of acute fluoride toxicity. APF foam products deliver the same fluoride concentration as APF gels, but limited research exists to support their use over the gel system. Both professionally applied APF and neutral NaF are available in foam-based products.

APF versus neutral NaF products. Efficacy of APF products has been documented in controlled clinical trials. Neutral NaF products were developed because repeated exposure to APF products may etch restorative and preventive materials that contain porcelain, composite, titanium, glass, or similar materials (e.g., tooth-colored restorative materials, filled sealants).

○ Neutral NaF gels that are routinely used for in-office fluoride treatment have not had their caries reduction abilities evaluated via scientific studies. The solution form of this concentration of neutral NaF has been evaluated and found to reduce caries incidence.

○ To decide between APF and neutral NaF products, the dental hygienist considers the client profile identified during risk assessment. Although APF is the most widely used professionally applied fluoride agent, the presence of restorative or preventive dental materials that may be damaged by APF products contraindicates its use. When these materials are present intraorally, the dental hygienist selects a neutral NaF product. If a neutral NaF product is not available, then it is important to protect at-risk dental materials with petrolatum or a varnish before the fluoride treatment.

○ pH of APF products. Fluoride uptake of APF products is influenced by the pH of the product; a pH of 4.0 enhances fluoride uptake. Very slight elevations in the pH of APF products have a significant impact on the enamel-fluoride uptake. When APF products are used, it is the clinician’s responsibility to check pH level and determine if the product is effective.

Procedures for Application Using the Tray Technique

The procedural steps for professionally applied topical fluoride begin with the client and product selection as outlined in the previous section. Sequence for administration using the tray technique is described in Procedure 31-1.

Procedure 31-1 PROFESSIONALLY APPLIED TOPICAL FLUORIDE USING THE TRAY TECHNIQUE FOR IN-OFFICE FLUORIDE TREATMENT (GEL OR FOAM)

EQUIPMENT

Mouth mirror	Timer
Cotton forceps	Saliva ejector
Fluoride tray(s)	2 × 2 gauze
Cotton rolls	Tissues
1.23% acidulated phosphate fluoride (APF) or 2.0% sodium fluoride gel	2-oz cup Personal protective barriers and equipment barriers
Air syringe

STEPS

1. Assemble equipment (Figure 31-8).

2. Seat client in upright position. Reiterate benefits and obtain informed consent (Figure 31-9).

3. Try tray of appropriate size. Complete dentition must be covered, including areas of recession (Figure 31-10).

4. Load fluoride gel into trays: 2 mL maximum per tray for small children; 4 mL maximum per tray for large children (>44 lb), 2.5 mL maximum per tray for adults (Figure 31-11).

5. Isolate teeth with cotton rolls. Dry with air syringe (Figure 31-12).

6. Insert both trays in mouth (Figures 31-13 and 31-14).

7. Press tray against teeth, and ask client to close mouth and bite gently on trays or cotton rolls (Figure 31-15).

8. Place saliva ejector over mandibular tray. Set timer for 4 minutes. Never leave client unattended during procedure (Figure 31-16).

9. Tilt chin down to remove trays (Figure 31-17).

10. Ask client to expectorate; suction excess fluoride from the mouth with saliva ejector (Figure 31-18).

11. Instruct client not to eat, drink, or rinse for 30 minutes.

12. Record service in client’s chart under “services rendered”; e.g., “Applied topical APF fluoride gel to existing teeth for 4 minutes. Used stock trays to apply approx. 2 to 2.5 mL of 1.23% APF (insert brand name). Client consented to procedure; no complications or adverse reactions during treatment. Client instructed not to eat or drink for 30 minutes.”

Varnish^6,14-20

Fluoride varnishes are lacquers containing 5% NaF in a colophony/rosin base. The varnish system enables the delivery of an increased concentration of fluoride to the outer surface of the tooth and also prolongs fluoride exposure on the tooth surface for safe and effective caries control (Figure 31-19). In the United States the FDA has approved these products as medical devices for use only as cavity liners and for the treatment of hypersensitive teeth. The FDA considers caries prevention a drug claim. For the FDA to approve varnishes as a caries prevention agent, manufacturers would have to conduct clinical trials that meet ADA standards and submit evidence that this product should be approved as a therapeutic, anticaries agent.

Because of numerous clinical studies and successful use of fluoride varnishes in other countries, fluoride varnishes dispensed in unit doses have become a standard of care, albeit off-label, in the following situations:

For infants, toddlers, children, and adults at moderate to high risk for dental caries

For reversing demineralization and white spot areas

When longer fluoride contact is desired

For control of dentinal hypersensitivity

For persons with special needs

For persons with severe gag reflexes who cannot tolerate trays filled with gel or foam

European studies that evaluated the ability of fluoride varnish to reduce caries on permanent teeth reported reductions of 18% to 77%. A preliminary U.S. study that assessed the ability of fluoride varnish to remineralize initial carious lesions in primary teeth reported an 80% reversal of lesions. Both the ADA and the American Academy of Pediatric Dentistry support the use of fluoride varnish within a caries prevention program.

The following fluoride varnishes are available in the United States (see Figure 31-8):

5% NaF (2.26% fluoride or 22,600 ppm (e.g., Duraphat, Duraflor, Vanish, Fluoridex)

1% difluorosilane (0.1% fluoride or 1000 ppm (e.g., Fluor Protector)

Figure 31-8

Figure 31-9

Figure 31-10

Figure 31-11

Figure 31-12

Figure 31-13

Figure 31-14

Figure 31-15

Figure 31-16

Figure 31-17

Figure 31-18

Figure 31-19 A and B, Examples of unit-dose 5% sodium fluoride varnish. C, Fluoride varnish on central incisors.

(A, Courtesy Colgate Oral Pharmaceuticals, New York, New York. B, Courtesy 3M ESPE, St Paul, Minnesota.)

Varnish products have a higher concentration of fluoride than gels or foams, but because varnish is painted on as a thin layer, an overall smaller amount of fluoride is used (<7 mg of varnish versus 30 mg of gel for a child).

Safety of Fluoride Varnish

To date there are no documented incidents of acute or chronic fluoride toxicity as a result of using fluoride varnish. The rapid drying characteristic of fluoride varnishes seems to prevent ingestion and to minimize risk for a toxic dose. The release of fluoride after placement peaks early and then drops dramatically. Plasma levels of fluoride after varnish applications are similar to those experienced after the use of an OTC fluoridated toothpaste. Ingestion of high doses of fluoride is reduced with varnish use. The varnish breaks down over a period of several days, so ingestion occurs slowly over a period of time, reducing the likelihood of acute fluoride toxicity. Because the varnish contains colophony/rosin, it should not be used on persons with a known sensitivity to this material. Fluoride varnish also should not be used in the presence of ulcerative gingivitis, stomatitis, or large open lesions.⁶

Frequency of Fluoride Varnish Application.⁶

Some providers support application every 3 to 6 months, determined by the client’s caries risk. Procedure 31-2 outlines the steps for fluoride varnish therapy. Application is safe, effective, and fast, and client acceptance is satisfactory.

Procedure 31-2 PROFESSIONALLY APPLIED SODIUM FLUORIDE VARNISH USING THE PAINT-ON TECHNIQUE

EQUIPMENT

Mouth mirror

5% Sodium fluoride varnish (unit dosage)

Cotton-tip applicators or syringe applicator

Paper cup

Personal protective barriers and equipment barriers

STEPS

1. Select unit dose fluoride varnish product; gather equipment and supplies for application.

2. Provide client with information about procedure; reiterate benefits. Obtain informed consent.

3. Unless an oral prophylaxis has been performed at the same appointment, have client cleanse teeth with toothbrush.

4. Recline client for ergonomic access to oral cavity.

5. Wipe application area with gauze or cotton rolls and insert a saliva ejector. Can be applied in the presence of saliva and without a saliva ejector.

6. Using a cotton-tip, brush, or syringe-style applicator, apply 0.3 to 0.5 mL of varnish (unit dose) to clinical crown of teeth: application time is 1 to 3 minutes.

7. Dental floss may be used to draw the varnish interproximally.

8. Allow client to rinse on completion of procedure.

9. Remind client to avoid eating hard foods, drinking hot or alcoholic beverages, brushing, and flossing until the next day or at least for 4 to 6 hours after application. Drink through a straw for the first few hours after application.

10. Record service in client’s record under “Services Rendered,” e.g., “Applied 0.3 mL of 5% (22,600 ppm) sodium fluoride varnish (insert brand name) per tooth. Client consented to this procedure; no complications or adverse reactions during treatment. Client instructed to keep varnish on the teeth for at least 4 to 6 hours or preferably until the next day. Client told to drink through a straw and avoid hard foods, alcoholic and hot beverages, brushing, and flossing until preferably the next day to prolong the varnish treatment. Varnish can be removed the next day with toothbrushing and interdental cleaning.”

Professionally Applied Fluorides: Issues and Controversies

The scientific literature highlights the following key issues and controversies regarding use of professionally applied fluoride products:

Use of an SnF2-APF combination dual-rinse system as a substitute for a professionally applied topical fluoride delivered via the tray technique. This two-part system is marketed as a 0.31% APF solution and a 1.64% SnF₂ solution. The two solutions are used one at a time or mixed together. The total recommended rinsing time is 2 minutes, and the fluoride exposure is 1500 to 3000 ppm. Some dental professionals choose this procedure because it takes less time and equipment than the tray technique or paint-on varnish technique, because it is less labor intensive, and because clients find it more tolerable than fluoride trays.

Despite its use in some offices, there are no rigorous studies to substantiate the use of a dual, sequential fluoride rinse system. Contemporary standards of practice require that dental hygienists make client care decisions based on scientific evidence. The SnF₂-APF combination dual rinse does not meet this standard.

Marketing and use of professionally applied APF gel and foam products for 1 minute rather than 4 minutes. Many manufacturers have successfully marketed 1-minute 1.23% APF gel and foam products. These products have become popular owing to the reduced time required for administration. No clinical studies of caries inhibition substantiate leaving the gel in contact with the teeth for just 1 minute. Fluoride uptake by the enamel is limited when fluoride contact is reduced to 1 minute. In addition, there is no difference in the concentration of products marketed as 1-minute products versus those marketed as 4-minute products. No scientific evidence substantiates a reduction in fluoride exposure time. Limited data exist to clearly support the delivery of fluoride via foam.

Whether a professional fluoride treatment is required after extrinsic stain removal (selective polishing) procedures. Many commercially available prophylaxis pastes contain fluoride. There is no existing clinical evidence to suggest that fluoride-containing pastes improve caries protection. These pastes should not be used in place of professionally applied fluoride therapy. Some clinical evidence supports that fluoride lost when enamel is removed during selective polishing may be replaced by the fluoride in prophylaxis pastes. Although this may be the case, additional studies are needed to determine if the ingredients in prophylaxis pastes restrict the bioavailability of the fluoride. Before adjusting clinical protocols, dental hygienists should consult the literature for evidence that such a change is warranted.

Risk of Acute Fluoride Toxicity²¹

Acute toxicity from the rapid ingestion of a topical fluoride agent within a very short period of time may yield a mild systemic reaction (stomach upset) to death. Many factors influence the toxicity of fluoride compounds (e.g., route of administration, client age and weight, and rate of absorption). When fluoride is swallowed, it reacts with stomach acids; the reaction product is hydrogen fluoride (HF). HF is very irritating, and initial abdominal reactions can occur after a relatively small amount of higher concentration product is swallowed.

Symptoms

Initial symptoms of acute fluoride toxicity are nausea, gastrointestinal pain, and vomiting. If sufficient quantities of fluoride are ingested, these initial symptoms may be followed by muscular weakness and spasms that occur as a result of fluoride combining with blood calcium ions. Toxic doses of fluoride affect major body systems as follows:

Gastrointestinal: abdominal pain and cramps, nausea, vomiting, diarrhea

Neurologic: paresthesia, tetany, central nervous system depression, and coma

Cardiovascular: weak pulse, pallor, hypotension, shock, cardiac irregularities, and cardiac failure

Emergency Management

The initial treatment goal for fluoride toxicity is to reduce the amount of fluoride available for absorption from the gastrointestinal tract. Depending on the amount of fluoride ingested, initial emergency response in the dental office should be followed by medical treatment. Box 31-2 outlines treatment procedures for acute fluoride toxicity.

BOX 31-2 Management of Acute Fluoride Toxicity

• Induce vomiting by administering an emetic, such as ipecac syrup (this should occur only if the client has a gag reflex, is conscious, and is not convulsing).

• Next, administer a fluoride-binding liquid orally: 1% calcium chloride or calcium gluconate, milk of magnesia, or milk.

• While client is receiving attention, second person should activate emergency medical services (EMS); client should be transported to hospital as soon as possible.

• Support respiration and circulation if necessary. Response by emergency personnel is dependent on severity of symptoms.

• Supportive therapies include:

○ Calcium gluconate for muscle tremors or tetany

○ Endotracheal intubation, followed by gastric lavage with a calcium-containing solution or activated charcoal

○ Establishing an airway

○ Intravenous feeding to restore blood volume and electrolytes and reverse effects of vomiting and diarrhea and to maintain urine flow

○ Maintaining cardiovascular circulation and monitoring

○ Blood monitoring for plasma fluoride levels, hyperkalemia, hypocalcemia, pH

○ Intravenous calcium replacement, glucose administration, oxygen, artificial respiration, or other supportive therapies

• If the client responds favorably, supportive therapies are continued until normal mental alertness, vital signs, and serum chemistry profile are achieved.

The amount of fluoride that will cause a toxic reaction or result in a lethal dose is based on a variety of factors described earlier. Terms used to describe how much fluoride can be tolerated by a client are the safely tolerated dose (STD) and the certainly lethal dose (CLD):

The CLD is the amount of fluoride that will result in client death; 5 to 10 g of sodium fluoride is considered a CLD for a 70-kg adult.

STD is the amount of fluoride that can be ingested without causing serious acute toxicity; it is approximately one quarter the CLD.

Prevention of Fluoride Toxicity

Although fluoride products have evident therapeutic benefits, their use and storage must be monitored. In the home setting, caution must be taken regarding the use and storage of even low-dose fluoride products. Oral care professionals must educate clients (and parents or caregivers) regarding the safe use of fluorides. In addition, dental professionals must exercise extreme caution when using high-potency prescription products that contain the highest concentrations of fluoride available. To safely use professional-strength fluoride products, it is essential that the dental hygienist carefully select clients for this therapy and know the following:

Fluoride concentration of the products being used

Amount of fluoride contained in the unit packaging (e.g., bottles, tubes, pillows)

Amount used in the treatment (e.g., infant, child, or adult dose)

How the amount provided relates to the CLD