Fluoride products continue to evolve, offering more treatment options.
Ellen R. Fein, RDH
Fluoride supplements were developed prior to the incorporation of fluoride into toothpastes, mouthrinses, and concentrated gels. Since the incorporation of fluoride in home care products, it has been difficult to control the amount of fluoride ingested through outside sources, leading to a controversy over prescription dosages for patients.
Dental professionals should be aware of patients` needs for any supplemental dosages and what ingredients are in a particular brand. Some products, for example, contain sucrose, which can contribute to dental decay. Other products contain no dyes, and one is sweetened with Xylitol, which has been shown to have a noncariogenic effect on the tooth surface.
Professional applications of fluoride make the tooth surface more resistant to the acidic dissolution. Topical treatments have been introduced with acidulated phosphate fluoride (APF), stannous fluoride, or sodium fluoride in the form of rinses, foams, gels, or varnishes.
Sodium fluoride is widely used because of its favorable taste. Most studies that have been done can confirm the effectiveness of sodium fluoride solutions in preventing caries.
All types of fluoride preparations demonstrated a remarkable decrease in caries. In vitro studies confirm that fluoride uptake is increased by the duration of time of application. Richardson revealed that the application of a waterproof coating on the tooth surface to maintain the fluoride contact will increase the uptake.
Fluoride is an essential mineral that helps in the hypomineralization of teeth. Histologically, ameloblasts, which are enamel-forming cells, lay down a partially mineralized protein matrix containing fluoride. This fluoride is derived from food or water intake that gets absorbed into the system during tooth development. Teeth acquire fluoride during developmental stages.
The process begins at the dentinoenamel junction where fluoride is incorporated into the ameloblasts. These cells create the enamel matrix prior to eruption. The fluoride that is introduced becomes a layer of fluorapatite that protects the enamel surface. The fluorapatite produced is less soluble and will improve the quality of the dental tissues. The mineralization of enamel continues through systemic and topical applications.
Therefore, professional applications of fluoride should be given to children to enhance the mineralization of the tooth surface. Once the mineralization process has been completed, fluoride penetration is slower but still effective.
Fluoride products were introduced in the early 1960s to the dental field primarily as a means of prevention for children. Subsequently, drops, tablets (chewable and nonchewable), and lozenges were developed for both topical and systemic benefits. Recommendations by the American Academy of Pediatrics state that fluoride should be given to infants and children residing in areas where the drinking water has less than 0.5 mg/L of fluoride. Most of these prophylactic products were developed with a form of sodium fluoride. They contain strengths that range from 0.25 milligrams to 1.0 fluoride milligrams. Other products available contain either phosphate potassium or calcium fluoride.
Chewable tablets have a greater proficiency, because they satisfy both topical and systemic actions. It is recommended that the optimum time to take any supplement be at the hour prior to sleep. This is recommended because fluoride absorption will not be interrupted by any food intake.
The two ways to benefit from fluoride applications are topically or systemically. The uptake of fluoride is based upon the amount consumed systemically or the duration of topical exposure time. Systemic consumption of fluoride is considered highly essential for persons in areas where the water supply is not fluoridated.
The concept of a fluoride varnish was developed in the late 1960s. Mellberg, et al, used a shellac ? polyvinyl pyrolidone vinlactate and nonylphenol in a 20 percent ethanol ? as a coating after application of fluoride. Schmidt then introduced a sodium fluoride in a natural colophonium base.
Today?s formulations come in a viscous or resinous form when applied to the tooth surface. The varnish will set on contact with saliva or moisture. This process allows the fluoride to remain in contact with the enamel for a prolonged period. The fluoride varnish was viewed as a way to increase the formulation of the fluorapatite on the tooth surface, thereby minimizing the demineralization process. If the fluoride ion concentration were increased, then this would have a positive effect on sound or carious surfaces.
Duraflor, produced by Pharmascience Laboratories Inc. in Montreal, was the first approved fluoride varnish for use in the United States. Colgate has now introduced Duraphat to the U.S. market. Both products also are approved for immediate relief for patients suffering from sensitivity. In Canada and Europe, fluoride varnishes have been widely used as a topical fluoride treatment.
Fluoride varnishes have been proven to be effective in the prevention of caries. Since new recommendations suggest that early lesions not have surgical intervention, fluoride varnishes could potentially slow down or stop the process of caries. Studies have shown a 30 to 40 percent reduction in caries of permanent dentition, as well as up to 44 percent effective in primary teeth.
Fluoride varnishes help care for patients with special needs, postoperative general anesthesia cases, root caries, and people who suffer from rampant decay. This has been discussed, but more research needs to be done to emphasize this fact.
Although the action of fluoride penetration is not clearly understood, research suggests that varnishes increase the resistance of the enamel to acid demineralization. The amount of fluoride varnish typically used is about 0.3 to 0.5 milliliters, delivering approximately 3 to 6 milligrams of fluoride.
The application process is easy for both patients and practitioners. Simply isolate; remove any excess moisture; and paint on with a disposable instrument. Saliva or moisture must contact the varnish to allow for a quick set.
From a practical standpoint, fluoride varnishes have many advantages. Primarily, they are easy to apply, thereby saving valuable chair time. Polishing with a rubber cup is not needed since fluoride penetrates plaque. Fluoride varnishes should be considered for topical fluoride procedures.
Ellen R. Fein, RDH, is responsible for all national technical sales support for A.R. Medicom Inc. and Pharmascience Inc. and is available for speaking engagements. She also is an adjunct dental hygiene faculty member and works in private practice. She also is on the Editorial Board for RDH. Her e-mail address is EF2Varnish@aol.com; she can be reached by phone at (800) 435-9267, ext 40.
* Weatherall, JA, Hallsworth, AS, Robinson, C, The effects of tooth wear on the distribution of fluoride in the enamel surface of human teeth. Arch Oral Biol. 1973; 18: 1175-1189
* Isaac, S, Brudevold, F, Smith, FA, et al, Solubility rate and natural fluoride content of surface and subsurface enamel. J Dent Res. 1958; 37:254-263
* Fluoride in Dentistry. Second edition. Chapter 16, pp 291
* Clinical Practice of the Dental Hygienist. Seventh edition. Chapter 29, pp 442
* Biddy, BG, Use of fluoride in the prevention of dental caries, II. The effects of the sodium fluoride applications. JADA, 31: 317. March 1, 1944.
* Richardson, B, Fixation of topically applied fluoride in enamel. J. Dent Res 1967; 46:87-91
* Mellburg, JR, Nicholson, CR, Laakso, PV, The effect of a barrier coating on fluoride uptake by human tooth enamel. Arch Oral Biol 12:1177-1187, 1967
* DeBruyn (Fluoride Varnish - Review)