The potential of fluorides and sealants to deal with problems of dental decay Herschel S. Horowitz, DDS, MPH The prevalence of oral diseases in many parts of the The prospects for reducing dental decay by altering world is staggering. 1 Consequently, many countries the dietary habits of the public are equally unpromis- have, or are developing, a large cadre of professional and ing. ~’~a Diets have changed radically within the last 50 auxiliary personnel trained to deliver dental services. years in the U. S., as they surely have in other countires. The education of these persons has tended to stress skills More and more sugar is hidden in commercially pre- for reconstructing teeth and their supporting tissues after pared foods and not consciously taken from the sugar disease has occurred; teachers in most dental schools bowl. Sugar obviously plays a pervasive role in today’s seldom emphasize preventive methods. lifestyle. Getting people to change their dietary practices The potential to be able to prevent dental caries as a for the purpose of improving oral health is a difficult major oral health problem is great because, of all oral task. ~’~4 However, dental benefits are readily apparent diseases, dental caries is at present the most nearly in persons who practice dietary control of sugar, such as preventable. Three factors must be present for dental those with hereditary fructose intolerance. Although the caries to occur: (1) a susceptible host--inasmuch as any likelihood of success from a public health aspect is small, tooth will develop caries if challenged sufficiently, all restricting the frequent ingestion of sugars should con- persons with teeth must be considered susceptible; (2) tinue to be advocated. the presence in dental plaque of bacteria that can pro- Today, the most feasible way to prevent dental caries duce acids which attack the teeth; and (3) a diet suitable is to increase the tooth’s resistance to decay. The best for2’3 bacterial fermentation. individual and public health defense against dental decay Efforts to prevent dental caries have focused upon is the proper use of fluorides. But, the proper use of attempts to: (1) increase the resistance of teeth with fluorides does not preclude the need for regular dental various4-9 fluorides and adhesive pit and fissure sealants; care or educating the public about good oral hygiene (2) lower the number or reduce the cariogenic activity and dietary practices. bacteria in contact with the teeth by mechanical means Until about 10 years ago, most dental experts believed or with chemical agents; ~°-13 and (3) modify dietary that fluorides worked principally by increasing the re- practices by urging people to eat sweets, cookies and sistance of enamel to acids produced in dental plaque soft~4-~n drinks less frequently. by bacteria, es More recent research clearly shows that Dental plaque adheres tenaciously to teeth, ~7-~ but it other actions of fluoride, such as remineralization of can be removed mechanically by toothbrushing and, initial or precarious lesions and a host of antimicrobial from areas between the teeth, by the use of dental floss effects,~-~ are also important. and other cleaning devices. School-based studies, how- The mechanisms by which fluorides prevent dental ever, have shown that efforts to control plaque by daily, decay probably vary, depending upon the agent used, supervised toothbrushing and flossing for periods up to its route of administration, its concentration and fre- three years have failed to reduce the incidence of dental quency of use, and the vehicle used to deliver it. a9 More caries in children, z°’2~ Most persons cannot achieve, with than one mechanism may operate simultaneously. Per- current mechanical methods, the level of oral cleanliness haps the most important element is the frequent provi- necessary to prevent dental caries in approximal and sion=~ of low concentrations of fluoride to dental plaque. fissured tooth surfaces. It is unrealistic to believe that we can control dental caries as a public health problem Community Water Fluoridation simply by urging people to remove dental plaque fastid- Fluoride compounds are among the most common iously each day. components of the earth’s crust. Nearly all natural water 286 FLUORIDES,SEALANTS & DENTALDECAY: Horowitz sources contain a measurable quantity, which varies the average, community fluoridation currently costs according to the amount and solubility of the fluoride in about~3’34 20 ¢ per person per year to operate in the U.S. adjacent mineral deposits. Only distilled water and un- In addition, the entire community benefits from the contaminated rain and snow are completely free of procedure, regardless of socioeconomic level, educa- fluoride. tional achievement, individual motivation, or the avail- Many common foods also contain appreciable ability of dentists. No cooperative effort or direct action amounts of fluoride. Fish and tea are particularly rich need be taken by those who will benefit. Moreover, the sources. Fluoride also is found in fowl and other meats improvement in dental health continues for life if con- and in such cereals as rye, wheat, and rice. In fact, sumption of fluoridated water continues, a~’~9 A recent fluoride is present in so many foods that some is prob- report shows that lifelong consumption of fluoridated ably ingested at every meal. water also significantly lowers the prevalence of root Because naturally occurring water-borne fluoride is surface~° caries in older persons. not always present in a concentration sufficient to pro- Although the benefits of community fluoridation are duce dental benefits, the natural level should be ad- truly impressive, the procedure is not a panacea for justed. The process of adjusting the amount of fluoride dental caries. Unfortunately, its implementation is lim- in a community’s water to an optimal concentration for ited to areas with central water supplies. Moreover, other the prevention of dental caries is known as community methods of preventing decay are still necessary for par- water fluoridation. Because the original water is likely to ticularly susceptible persons living in fluoridated com- contain some fluoride already, a key word in this defi- munities, and obviously, the use of fluoridated water is nition is adjustment. not a license for unrestricted consumption of confections Fluoridation of community water supplies is the least between meals or for abandoning oral hygiene proce- expensive and most effective way to provide fluoride to dures. a°-32 large groups of people, Optimal adjustment of the Published estimates show that 185 million persons fluoride concentration of community water supplies living in 6,470 communities in 40 countries drink water should be the foundation for all programs of dental with an optimally adjusted fluoride concentration. ~1 An- health because this public health method is nearly ideal. other 39 million persons living in 4,096 communities in First and foremost, community fluoridation is highly 39 countries consume drinking water with naturally 3~’~4 effective. Hundreds of studies done throughout the occurring amounts of fluoride at optimal or greater world have shown that children who consume optimally concentrations. Nineteen of these 39 countries also have fluoridated water from birth have from 50-70% less communities with controlled fluoridation. Thus, there dental decay than they would have experienced without are at least 60 countries in the world with adjusted or fluoridation. As an example of the benefits produced natural fluoridation, serving more than 10,000 commun- after fluoridation, Table I shows comparative DMFtooth ities and 224 million persons. ~1 The Republic of Ireland scores for 12- to 16-year-old children in Grand Rapids, implemented legislation for national fluoridation in the MI before and after 15 years of community water fluor- early 1960s. Approximately 112 million U.S. citizens idation. (one-half the total population) live in communities served by fluoridated water supplies or by water that Table 1. Average number of DMFteeth in 12- to 16-year-old contains optimal or greater concentrations of fluoride as children in Grand Rapids before and after 15 years of com- a natural constituent. The municipal water supplies in munity water fluoridation. Hong Kong and Singapore are fluoridated. Thirty million DMFTeeth persons in 85 communities in the Soviet Union consume fluoridated water. 1944-45 1959 Abundant data show that fluoridated water not only Before After 15 Percentage acts systemically during tooth formation to produce Age fluoridation years difference enamel more resistant to dental caries but also acts 12 8.07 3.47 57.0 directly as a topically applied agent. Therefore, the pro- 13 9.73 3.58 63.2 cedure benefits both children and adults. 14 10.94 5.38 50.8 Studies of the effects of fluoridation in young children 15 12.48 6.22 50.2 16 13.50 7.03 47.9 prove that the procedure effectively reduces the preva- lence42-44 of dental caries in primary teeth by about 40%. Marthaler has shown that consumption of fluoridated Consumption of fluoridated water is eminently water should begin at birth to provide maximal protec- safe. 3a’a4 No other health measure has been analyzed tion44 to primary teeth. more critically than the fluoridation of city water sup- Many studies have confirmed the finding that fluori- plies. The procedure is also inexpensive and greatly dation reduces the prevalence of dental caries in per- reduces the per capita costs of dental treatment. 3s-37 On manent teeth by an average of about 60%.aa-a~ However, PEDIATRICDENTISTRY:Volume 4, Number 4 287 Percent Inhibition the benefits are not uniformly conferred to all tooth (DMFteeth) surfaces. Approximal and other smooth tooth surfaces are protected to a far greater extent than are pit and 4+-+6 fissure surfaces. Using data from several studies, 60- Marthaler 44 has shown rather conclusively that maximal caries protection to permanent teeth occurs only when children begin to consume water at birth.