US Pharm. 2007;32(10):52-56.

Despite improvements in the field of dentistry, dental decay remains the number one illness among children, surpassing asthma. 1 Dental professionals are striving to reach young children, especially those at high risk for dental decay, so that preventive programs can be implemented and routine oral health care can be established early. Current recommendations by the American Dental Association (ADA) and the American Academy of Pediatric Dentistry (AAPD) state that all children should have their first dental visit by age 1 year or within six months after the first tooth erupts. More and more dentists are implementing infant oral health care and anticipatory guidance programs into their practices.2 The goal is to reach parents early and give them advice in hopes of preventing dental decay in children. Anticipatory guidance counseling that occurs in the dental office frequently includes counseling parents about their child's diet, fluoride exposure, home care, oral habits, dental injury prevention, and risk of caries.3

One of the most effective agents used today to combat tooth decay is fluoride. Fluoride is a proven mainstay in preventive oral health care, and children at risk of developing dental decay should be evaluated for systemic and topical fluoride exposure by their oral health care provider.4 Children may be exposed to a variety of fluoride sources, and it is important to ensure that they are not receiving excessive or insufficient amounts of fluoride. If a child is not receiving adequate fluoride, a prescription or OTC supplement may be prescribed. For optimal prevention of decay for the developing and erupted teeth, it is recommended that children be exposed to fluoride at age six months. Supplementation in the form of tablets, mouth rinses, pastes, or gels is generally continued until age 16. Pharmacists are in the ideal position to counsel parents on their child's fluoride status, as they may be filling fluoride prescriptions frequently. They may also recommend age-appropriate toothpastes and mouth rinses containing fluoride from the readily available OTC products.

Pharmacology
Fluoride is thought to be effective in combating dental decay both systemically and topically. When ingested, almost 100% of fluoride is absorbed in the gastrointestinal (GI) tract, approximately 90% in the stomach.5 Fluoride absorption is inhibited by calcium, magnesium, and iron and is excreted primarily through the kidneys and, to a lesser extent, the sweat glands, the GI tract, and breast milk. Once ingested, the fluoride has a systemic affect on teeth before they erupt, incorporating into the matrix of developing teeth to increase the mineralization content and decrease the solubility of enamel.6 Topical effects of fluoride come from applying it directly onto teeth already erupted, thereby promoting remineralization, increasing tooth resistance to acid dissolution, and inhibiting cariogenic activity of bacteria in the mouth. Drinking fluoridated water and ingesting fluoride prescription drops, lozenges, or tablets are all ways of receiving adequate systemic fluoride with some simultaneous topical effects, while using toothpastes, gels, and mouth rinses containing fluoride exerts topical effects. It is speculated that systemic fluoride supplements may decrease caries rates by 60% and that topical application may decrease caries activity by up to 40%.5

Fluoride Overdosage
Symptoms of acute fluoride overdosage range from excessive salivation, nausea, vomiting, abdominal pain, and diarrhea to central nervous system irritability, paresthesias, tetany, convulsions, and respiratory and cardiac failure. Laboratory findings include hypocalcemia, hypoglycemia, and delayed hyperkalemia. A dose of 70 to 140 mg/kg is considered lethal.5 In cases of acute fluoride overdosage, patients should call their physician or local poison control center or go to their local emergency room. Management is aimed first at preventing the absorption of fluoride by administering calcium, which acts as a binding agent, in the form of milk, milk of magnesia, or calcium carbonate.7 Adjunctive treatment includes normalizing pH and electrocytes and general toxicity support. Extreme fluoride toxicity cases may require dialysis or hemoperfusion to remove excess fluoride from the body.7

Children suffering from chronic fluoride overdosage experience dental fluorosis, exhibited by pitting or discoloration of enamel, and osseous changes such as elevated bone density.8-10 To assess chronic fluoride overdosage and dental fluorosis, the oral health care provider must take a detailed history of past and pres­ ent fluoride intake--considering all the sources of fluor­ ide the child has been exposed to, including environmental fluoride, OTC products, and prescription supplements--and adjust the fluoride exposure to recommended levels.

Fluoride Exposure Through Drinking Water
The most common and easy way for a child to receive systemic fluoride is through drinking water. Throughout the country, most municipal water treatment centers add fluoride to the community water during the water treatment process. It is thought that the fluoride level must be at least 1 part per million (ppm) to be efficacious in preventing dental decay.11 Children who live in fluoridated communities and drink the tap water in their homes on a daily basis have added protection against tooth decay. Parents can also be advised to use it while cooking at home or mixing formula for infants.

Children living in rural areas in homes with water supplied by a private or public groundwater well, however, may need their water tested to evaluate the fluoride concentration present.12 Home water-testing kits are readily available from municipal water facilities or state environmental protection agencies and can be performed at the request of the child's dentist or pediatrician. If the fluoride content is revealed to be less than 1 ppm, then a systemic fluoride prescription is recommended and can be prescribed by the provider. If these children attend school or daycare in a fluoridated community, they are considered protected if they are drinking the water while at school on weekdays. They may be advised to drink fluoridated bottled water on the weekends and may not require additional systemic fluoride supplementation. Alternatively, these children may also be prescribed systemic fluoride supplements to take on weekends only.

For children living in fluoridated-water communities, drinking tap water that is filtered through the refrigerator or other commercial filtering products is recommended; fluoride is not removed through most filtering processes.

Bottled Water Containing Fluoride
A relatively new product found on the shelves of most grocery stores and pharmacies today is bottled water containing fluoride. It should be noted that not all bottled water contains fluoride; the labeling must state that fluoride has been added. This is usually done on colorful labels marketed toward children and infants. The fluoride is added with the express purpose of preventing dental decay and is now manufactured by most major bottled-water brands. Dental professionals are now recommending that parents of children living in communities without fluoridated water purchase this bottled water and have their child drink it daily. Theoretically, consuming this bottled water daily will have the same protective benefit as drinking the home water in a fluoridated community thus avoiding the need for prescription supplements.

Prescription Systemic Fluoride
Supplemental fluoride may be prescribed in the form of drops, lozenges, or chewable tablets. The dosing for fluoride is dependent on the child's age and the home water fluoride content ( Table 1).13 Prescription fluoride products are dosed as "mg of fluoride ion." However, pharmacists may see the health care provider writing the prescription stating the fluoride dosage as "mg sodium fluoride." Dispensing the correct dosage can be accomplished using the simple conversion factor of 2.2 mg sodium fluoride equaling 1.0 mg fluoride ion.





The myriad of available oral systemic fluoride supplements is listed in Table 2. Supplemental fluoride is available in lozenges as 1 mg fluoride ion (equal to 2.2 mg sodium fluoride). Tablets are typically manufactured as 0.25, 0.5, and 1.0 mg fluoride ion (equal to 0.55, 1.1, and 2.2 mg sodium fluoride, respectively). Children older than 4 years should be instructed to suck on one lozenge or chew one tablet for one to two minutes before swallowing each night at bedtime. Children aged 4 years or younger should be prescribed liquid fluoride drops. Dosed as 0.125, 0.25, and 0.5 mg fluoride ion (equal to 0.275, 0.55, and 1.1 mg sodium fluoride, respectively), the drops should be given once daily much like a multivitamin.




In addition to the products that contain fluoride only, there are also many prescription multivitamin drops and tablet preparations available that consist of a variety of vitamins in different combinations, including vitamins A, D, E, C, and B; folic acid; iron; and fluoride (Table 3). The health care provider may prescribe these products if the child is in need of multivitamin and fluoride supplementation concomitantly.




Topical Fluoride
Fluoridated toothpaste is the most common source of topical fluoride and should be used twice daily when brushing. Children younger than 2 years should not use fluoridated toothpaste to avoid possible toxicity.14 Parents can brush with a toothbrush wet with water or they may choose to use toothpaste without fluoride. Children older than 2 years should use a small smear of fluoridated toothpaste no larger than the size of a green pea on their brush; toothpaste marketed for adults or children can be used, as long as it bears the ADA Seal of Acceptance (Figure 1).




Mouth rinses containing high-strength fluoride may also be implemented, particularly in high-risk children; commonly used products may be found in Table 4. OTC mouth rinses that contain fluoride must bear the ADA Seal of Acceptance and may be used once daily at bedtime after brushing and flossing in children older than 4 years who can expectorate reliably. Similarly, there are a few fluoridated mouth rinses available by prescription only. Fluoridated mouth rinses, both OTC and prescription, are unsafe in children who cannot expectorate reliably due to toxicity issues.15 Mouth rinses have optimal effect if patients rinse for one minute, then expectorate; nothing else should be taken by mouth for at least 30 minutes afterward.





Fluoride-containing gels and creams are available OTC or by prescription and are reserved for children with high cavities rates and children undergoing active orthodontic treatment who may have appliances in their mouths such as retainers or braces (Table 4). Best used at bedtime immediately after brushing and flossing, fluoride gels and creams should be brushed on for approximately one minute before fully expectorating. Further, nothing should be taken by mouth for at least 30 minutes after the fluoride exposure to ensure optimal efficacy.

The Pharmacist's Role
While fluoride is a very safe and effective drug to prevent cavities, it is crucial to understand its toxicity limits to prevent harm to children who have access to fluoride in the home in the form of toothpastes, mouth rinses, gels, creams, or prescriptions. With such a variety of ways to deliver fluoride and help prevent tooth decay, the pharmacist can play in integral role in counseling parents to ensure that their children are receiving adequate fluoride. It is important that the pharmacist counsel parents on the proper use of fluoridated water and OTC and prescription products to secure the greatest benefits of fluoride while avoiding overdosage. The ultimate goal is to have a generation of children with the right amount of fluoride exposure so that they may have little to no caries activity, leading to happier dental visits for everyone.

References

1. Centers for Disease Control and Prevention. Progress reviews for healthy people 2000: oral health. Briefing book materials: disparity charts. December 1999. Available at: www.cdc.gov/nchs/about/otheract/hp2000/oralhealth/oralhealth.htm.

2. Ramos-Gomez FJ. Clinical considerations for an early infant oral health care program. Compend Contin Educ Dent. 2005;26:17-23.

3. Lee JY, Bouwens TJ, et al. Examining the cost-effectiveness of early dental visits. Pediatr Dent. 2006;28:102-105.

4. American Academy of Pediatric Dentistry Councils on Clinical and Scientific Affairs. Reference Manual. Pediatr Dent . 2007;28:29-30.

5. Drug Facts and Comparisons 4.0. Fluoride. Available at: www.efactsweb.com. Accessed June 20, 2007.

6. Limeback H. A re-examination of the pre-eruptive and post-eruptive mechanism of the anti-caries effects of fluoride: is there any anti-caries benefit from swallowing fluoride? Community Dent Oral Epidemiol. 1999;27:62-71.

7. McIvorME. Acute fluoride toxicity: pathophysiology and management. Drug Saf. 1990;5:79-85.

8. Levy SM, Warren JJ, Broffitt B, Kanellis MJ. Associations between dental fluorosis of the permanent and primary dentitions. J Public Health Dent. 2006;66:180-185.

9. Hallanger Johnson JE, Kearns AE, et al. Fluoride-related bone disease associated with habitual tea consumption. Mayo Clin Proc. 2007;82:719-724.

10. Tamer MN, Kale Koroglu B, et al. Osteosclerosis due to endemic fluorosis. Sci Total Environ. 2007;373:43-48.

11. Committee on Fluoride in Drinking Water, National Research Council. Fluoride in Drinking Water: A Scientific Review of EPA's Standards. The National Academies Press; 2006.

12. Horowitz HS. The role of dietary fluoride supplements in caries prevention. J Public Health Dent. 1999;59:205-210.

13. American Dental Association. Fluoride and fluoridation. Available at: www.ada.org/public/topics/fluoride. Accessed June 20, 2007.

14. Adair SM, Piscitelli WP, McKnight-Hanes C. Comparison of the use of a child and adult dentifrice by a sample of preschool children. Pediatr Dent. 1997;19:99-103.

15. Adair SM. The role of fluoride mouthrinses in the control of dental caries: a brief review. Pediatr Dent. 1998;20:101-104.

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