Fluoride…It’s Still Good!

For the generation that grew up with the benefit of healthy nutrition, daily exercise, and fluoride supplements in water, toothpaste, and tablets, it must come as a shock that their children now suffer with caries, obesity, and high blood pressure. The fluoride experience began in earnest in the 1950s with community and central water supplies being titrated for the optimal benefits of fluoride. Little by little, communities availed themselves, sometimes kicking and screaming, and the caries epidemic slowed. “Research indicates water fluoridation, the most cost effective method, has decreased the decay rate (in children) by over 50 percent.”¹
Gradually, dental insurance companies recognized the benefit of covering applications of fluoride to reduce their exposure for more costly restorative procedures, many times provided in an operating room environment. At present, there are some insurance companies which cover fluoride applications for adults in specific situations. Further, as the population ages and the baby boomers continue their search for a youthful appearance and a healthy body, maintenance of a healthy dentition is of paramount concern. Extensive crown and bridge, gingival recession, and xerostomia due to medications and/or chemotherapy are reasons to push adult fluoride applications. It is not unusual for routine hygiene appointments to end with a fluoride application to replace the smear layer of enamel removed during polishing.² Once fully educated on the continuing benefit, patients are less likely to resist.

Illustration by Cheryl Gloss

Rinse with it, brush with it, paint it on, bite into it… these are all ways of providing fluoride to your patient population. Even fluoride tray therapy is provided for many patients to use at home when increased risk elements are present. The basic cause of decay hasn’t changed: “Clinical studies have shown that caries is associated with increases in the proportions of acidogenic and aciduric (acid-tolerating) bacteria, especially mutans streptococci (S. mutans and S. sobrinus), and lactobacilli, which are capable of demineralizing enamel.”³ But ways of preventing caries are many and varied. Caught early in the demineralization phase, studies now report that surfaces can be remineralized, reducing the need to prepare and restore missing tooth structure.
Is it bacteria or acid pH that causes demineralization? S. mutans appears to favor an environment with a low pH, and within that environment it “up-regulates a number of genes that protect against acid stress.”³ So, do the bacteria increase due to the availability of sugar that is consumed, or is it the low pH after consuming sugar which increases the microfloral count? Results of a study published in BMC Oral Health 20063 report that it is the low pH “generated from sugar metabolism rather than sugar availability that led to the breakdown of microbial homeostasis in dental plaque.”³ In this study, S. mutans and L. rhamnosus numbers increased as the pH decreased to below neutral. Why is this important? Pathogenic bacteria can be targeted for reduction with antimicrobials or by inhibiting their growth through the oral environment.
Reduction in plaque acid can be accomplished by adding “fluoride containing products or other metabolic inhibitors”⁶ to improve the integrity of enamel and prevent the development of the acid environment specific to growth of caries-causing bacteria. The AAPD has stated that “fluoride is effective when combined with a healthy diet and good oral hygiene.”¹
Fluoride, then, is more than just a way to strengthen developing enamel, which was the focus in the 1940s and 1950s. As a component of saliva, it “will adsorb onto the surface of a tooth where demineralization has occurred. The presence of this fluoride in turn attracts other minerals (such as calcium), thus resulting in the formation of new tooth mineral.”⁴ The fluorapatite, which is created during remineralization, is more resistant to the acid environment. Fluoride can be delivered systemically by liquid or pills (in salt in some countries in Europe), or by being applied topically by the use of gels, rinses, toothpastes, and varnishes.

TYPES OF FLUORIDE AVAILABLE

Water fluoridation began in Grand Rapids, Michigan, in 1945. While the ingestion of too much fluoride causes fluorosis, the optimal concentration in water supplies is suggested to be 0.7 and 1.2 ppm. In areas where community water is not fluoridated, school water can be supplemented, reducing decay in the population least able to afford dental care or without access to care.
Fluoride toothpastes generally available over the counter contain 0.1% (1,000 ppm) sodium monoflurophosphate and are safe for children over 6 years of age when using a pea-sized amount. Supervision is required with those under 6 years of age to reduce the possibility of ingestion. Fluoride in prescription strength toothpastes reach 1.1% (4,950 ppm) sodium fluoride. This level has been established to be safe and effective, used once daily with supervision. Fluoride toothpastes make up 95% of all toothpaste sales in the United States.⁵
Fluoride rinses contain sodium fluoride, though the over-the-counter concentration at 225 ppm common to most rinses is not as effective as prescription rinses. Children under 6 years of age should be monitored to avoid ingestion and the possibility of fluorosis. Prescription rinses are not recommended for children where public water already contains fluoride, unless there is a high risk of caries.⁵
Fluoride supplements such as tablets, lozenges, or liquids (some containing vitamins) may be prescribed where water supplies contain inadequate levels of fluoride. Dosage guidelines were established in 1994 by the ADA, the AAPD, and the AAP. Gels and foams are applied using a tray system and are indicated for children at high risk for disease, patients with xerostomia, and patients who are under treatment for head and neck cancer. These materials should remain in contact with the teeth for up to 4 minutes with no rinsing, eating, smoking, or drinking for a minimum of 30 minutes post-treatment. Gels are available for home use, but generally are at a reduced strength.
Fluoride varnish received an insurance code this year (01206) even though use of the material for caries prevention is still categorized as “off label” by the FDA. Success of the product outside the United States, in Canada, Western Europe, and Scandinavian countries where it has been used since the 1980s has increased attention and use in this country, especially in areas where children do not have access to fluoridated water supplies or regular dental care. The FDA has approved fluoride varnishes for use as cavity liners and for treating hypersensitive tooth structure, but its use for caries prevention is not contraindicated.⁶
In addition, there appears to be no evidence of fluorosis with varnish, and the material may be used with children beginning at 6 months of age. The application technique, by professionals, limits the possibility of ingestion. Because of its sticky nature, varnish remains in contact with the teeth over a longer time than gels, foams, or rinses, and should be reapplied semiannually at a minimum.⁵ The most common complaint regarding sodium-based varnishes is the color change which is temporary and can be removed by brushing. All surfaces of the teeth should be “painted” with varnish: occlusal and interproximal. Brushing the teeth or dental prophylaxis prior to application of varnish is necessary, as is drying of the teeth. Patients are advised to not brush their teeth for 4 hours post-application to allow the fluoride to penetrate the enamel. Better compliance with adult patients necessitated the development of fluoride which would not color the teeth.
Some common fluoride varnishes are DuraPhat (5% sodium fluoride) by Colgate Oral Pharmaceuticals; Duraflor (5% sodium fluoride) by  Medicom; Fluor Protector C (0.9% difluorisilane) by Ivoclar Vivadent; Cavity-Shield (5% sodium fluoride) by OMNI Preventive Care/3M ESPE, and Flor-Opal Varnish (5% sodium fluoride) by Ultradent.
Because of the success of the fluoride varnish program in Iowa, where most studies have shown a  25% to 45% reduction in the decay rate with the use of fluoride varnish, it is now the standard of care for the Title V Child Health/EPSDT program and the Title V maternal health program.⁷ Hygienists can apply the varnish under the general or public health supervision of a dentist. Protocol for the initiative and training for dental hygienists was provided through the University of Iowa College of Dentistry. Children chosen for varnish application had risk factors of plaque on deciduous incisors, carious lesions, white spot lesions, a history of decay, and low socioeconomic status.8 Applications of varnish increased from 348 in FY 2000 to 8,311 in FY 2005. Costs per application varied from $11 to $22 for a child and $10 to $20 for adults. Hygiene hourly wages ran $20 to $35 per hour.
In a study published in the February 2006 Journal of Dental Research and the Journal of the International Association of Dental Research, 376 children from 6 to 44 months of age were separated into 3 groups: those receiving varnish twice a year; those receiving varnish once a year; and children receiving no varnish at all; 280 children completed the study. Results showed that the group receiving no varnish at all were more than 2 times as likely to develop caries than the group which had one application per year, and more than 4 times more likely to develop caries than the group which received varnish applications at 6-month intervals.
In addition, while varnish has been used on older children with permanent teeth, according to the investigators, this is the first study which shows that fluoride varnish can prevent decay in deciduous teeth. Dr. Jane Weintraub, principal investigator of the study, states that results indicate that very young children benefit not only from the varnish application, they benefit from seeing the doctor by one year of age.⁸
While fluoride varnish has been around for over 20 years, many dentists still do not consider the material part of their routine patient care regimen, choosing instead to apply fluoride by trays or rinses. In 1996, The Washington Dental Service (WDS) began reimbursement for varnish applications in an effort to determine if reimbursement would increase the use of varnish in dental offices. In 1995, 532 random dentists completed a survey on how they controlled caries within their practice. At this time, no dentist was aware that reimbursement would occur the following year. In 1997, the same dentists completed another survey with similar focus. After reimbursement began, the survey reported that 44% of dentists in Washington State were using fluoride varnish. Those not reporting usage indicated “lack of awareness, lack of convincing cost benefit ratio, patients’ rejection and low caries risk among young adult patients.”⁹ Reimbursement for the service does not automatically increase its use.
Varnish study research and published results have been so positive that Delta Dental of Michigan recently gave the Michigan Department of Community of Health (MDCH) a grant of $250,000 to begin a varnish program covering approximately 22,000 children enrolled in Head Start and Early Head Start statewide. The focus of the initiative is to prevent or reduce dental caries in children from birth to age 5, before they start school. By the third grade, one in 10 children have pain, swelling, or infection from dental disease. The program named Varnish! Michigan aims to reduce decay in this population from 48% to 60%.¹⁰
A study in Sweden published in the 2006 Evidence-based Dentistry11 separated adolescent children into 3 groups with a control. Group 1 received semi-annual applications of varnish for 3 years (6 total applications); Group 2 received 3 applications, 3 times a year all in one week (9 total applications); Group 3 received 8 monthly applications each year (24 total applications). The control group received no fluoride varnish at all. Results indicated that the control group had developed between 3.05 and 3.37 lesions; Group 1 between 0.95 and 1.67 lesions; Group 2 between 1.4 and 1.89 lesions. Group 3 with 8 monthly applications (during months in the school year) had significantly reduced incidence of lesions of between 0.54 and 1.26. Participants were from different caries risk areas.
During 1999 and 2000, at the University of Florida in Gainesville, a study of children from 3 to 5 years of age was conducted over a period of 9 months; 222 children were divided into 2 groups: the first received fluoride varnish at 4-month intervals, and the other group received fluoride gel. At the end of 9 months, 80% of the varnish group experienced remineralization compared with 37% of the gel group. Dr. Jaana Autio-Gold, assistant professor of Dentistry, reported the varnish was “more beneficial than the gel and reduced the need for fillings.”¹² In addition, fluoride circulating in the bloodstream after varnish applications is at a lower level than with other topical treatments. There is less nausea because less is swallowed. A study lasting a longer time period is anticipated.

FLUOROSIS

CONCLUSION

While concentrating on children is essential, decay is not just a children’s disease. Adults with recession, sensitivity, and xerostomia either chemically induced or age related, can benefit from fluoride as well. The baby boomer population, driven to “age slowly,” will continue to seek out ways to maintain or enhance their lives and will want good aesthetics as well. Fluoridated water and fluoride applications as part of routine office visits will increase the available salivary fluoride, reducing disease and tooth loss. Any way you look at it, fluoride is still good.

Ms. Cary lives in North Georgia and continues her consulting with “Creative Solutions.” She can be reached at janicecary@etcmail.com.

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