**4. Fluorides**

Fluoride as a caries-preventive agent was discovered as the side effect of fluorosis in teeth in areas with elevated levels of fluoride in the drinking water (Ten Cate, 2004). Research on the oral health effects of fluoride started around 100 years ago. For the first 50 years or so it focused on the link between water borne fluoride – both natural and artificial – and dental caries and fluorosis (Petersen, et al., 2004). It was difficult to determine small (sub-ppm) concentrations of fluoride in drinking water. Nevertheless, the early studies on fluoridation of the drinking water were convincing and initiatives were taken to add various types of fluorides to other oral hygiene products (Ten Cate, 2004). In the second half of the 20thcentury, fluoride research was focused on the development and evaluation of fluoride toothpastes and rinses and, to a lesser extent, alternatives to water fluoridation such as salt and milk fluoridation.

Fluoride mouthrinses were commonly used in school-based programs with 0.2% NaF solution weekly or fortnightly during the 1960's-1980's, but have now, to great extent, been withdrawn since most children are using fluoride toothpaste. The effect of the rinsing programs was in the range of 20-40% caries reduction (Koch & Poulsen, 2006).

The first test of a fluoride mouthrinse was conducted in the 1940s. An acidified NaF mouthrinse used three times a week, for 1 year by dental students failed to achieve a significant caries reduction, possibly because of very low fluoride concentrations. Fluoride mouthrinse received little attention until the early 1960s, when the effect was extensively evaluated in well-controlled clinical studies as well as in field trials on schoolchildren in Scandinavia, particularly in Sweden. Most of these studies and programs were based on weekly supervised rising with a neutral 0.2% NaF solution.

Drinking water is not fluoridated in Sweden, and during the early 1960s effective fluoride toothpaste had not yet become available. In addition, the standard of oral hygiene was very

confounds the investigation of the true changes in caries progression with time. The elucidation of the age-related pattern and rate of caries development in successive age cohorts will be important in informing future clinical trial design. In summary, the changes

• the relatively greater effect of fluorides in preventing caries on approximal surfaces;

These changes indicate that caries continues to be a challenge throughout life. The conduct of clinical trials of caries-preventive agents must now incorporate more sensitive diagnostic methods capable of valid and reliable measurement of caries initiation and progression in its early stages. The application of sophisticated statistical analysis which takes account of the pattern of caries attack will also help to overcome the difficulties posed by these changes in caries patterns. The application of such techniques to dental datasets which have large numbers of tooth-surface variables and multiple observations has been made possible by the

Fluoride as a caries-preventive agent was discovered as the side effect of fluorosis in teeth in areas with elevated levels of fluoride in the drinking water (Ten Cate, 2004). Research on the oral health effects of fluoride started around 100 years ago. For the first 50 years or so it focused on the link between water borne fluoride – both natural and artificial – and dental caries and fluorosis (Petersen, et al., 2004). It was difficult to determine small (sub-ppm) concentrations of fluoride in drinking water. Nevertheless, the early studies on fluoridation of the drinking water were convincing and initiatives were taken to add various types of fluorides to other oral hygiene products (Ten Cate, 2004). In the second half of the 20thcentury, fluoride research was focused on the development and evaluation of fluoride toothpastes and rinses and, to a lesser extent, alternatives to water fluoridation such as salt

Fluoride mouthrinses were commonly used in school-based programs with 0.2% NaF solution weekly or fortnightly during the 1960's-1980's, but have now, to great extent, been withdrawn since most children are using fluoride toothpaste. The effect of the rinsing

The first test of a fluoride mouthrinse was conducted in the 1940s. An acidified NaF mouthrinse used three times a week, for 1 year by dental students failed to achieve a significant caries reduction, possibly because of very low fluoride concentrations. Fluoride mouthrinse received little attention until the early 1960s, when the effect was extensively evaluated in well-controlled clinical studies as well as in field trials on schoolchildren in Scandinavia, particularly in Sweden. Most of these studies and programs were based on

Drinking water is not fluoridated in Sweden, and during the early 1960s effective fluoride toothpaste had not yet become available. In addition, the standard of oral hygiene was very

programs was in the range of 20-40% caries reduction (Koch & Poulsen, 2006).

weekly supervised rising with a neutral 0.2% NaF solution.

in caries patterns which have an impact on the design of caries clinical trials are:

increasing capacity of and accessibility to high-speed computers (Whelton, 2004).

• the lower caries incidence in children,

• the slower rate of progression of caries,

• the increased use of fissure sealants.

**4. Fluorides** 

and milk fluoridation.

• the increased risk of primary caries in adults, and

low. Few schoolchildren cleaned their teeth every day. Therefore, caries prevalence among children was very high, and most children developed several new caries lesions every year. Under these conditions, the introduction of a simple preventive measure, supervised rinsing with 0.2% NaF solutions once a week, resulted in very significant caries reductions (25% to 40%) (Axelsson, 2004).

Several efforts have been made to summarize these extensive data sets through systematic reviews, such as those conducted on water fluoridation by the UK University of York Centre for Reviews and Dissemination; on fluoride ingestion and bone fractures; and on fluoride toothpastes and rinses through the Cochrane Collaboration Oral Health Group. These systematic reviews concluded that:


Although these findings are important, it must be acknowledged that a lack of fluoride does not cause dental caries (Petersen, et al., 2004).

Not all fluoride agents and treatments are equal. Different fluoride compounds, different vehicles, and vastly different concentrations have been used with different frequencies and durations of application. These variables can influence the clinical outcome with respect to caries prevention and management. The efficacy of topical fluoride in caries prevention depends on a) the concentration of fluoride used, b) the frequency and duration of application, and, to a certain extent, c) the specific fluoride compound used. The more concentrated the fluoride and the greater the frequency of application, the greater the caries reduction (Newbrum, 2001).

In recent years, an increasing number of reports have been published in which the observed caries- preventive effect of fluoride has been lower than could have been expected on the basis of the earlier literature. This is true for both systemic and topical methods such as water fluoridation, fluoridated school milk, fluoride mouthrinses and professional applications of topical fluoride including fluoride varnish applications. The current low levels of caries occurrence and the wide spread use of fluoridated toothpastes as well as other fluoride products and methods have been suggested as reasons for the reduced relative effect of water fluoridation. In the same way, the fact that people are today commonly exposed to fluoride from multiple sources is likely to dilute the effect of fluoride from any single source. The moderate usefulness of added fluoride exposure at the population level today may also be due to the fact that individually applicable fluoride regimes are most likely to reach people who least need them. The individuals whose dental health-related lifestyles are most unfavorable and who are not visiting a dentist regularly

Caries Incidence in School Children Included in

a Caries Preventive Program: A Longitudinal Study 369

Water fluoridation, where technically feasible and culturally acceptable, has substantial advantages particularly for subgroups at high risk of caries. Alternatively, fluoridated salt, which retains consumer choice, can also be recommended. WHO is currently in the process of developing guidelines for milk fluoridation programs, based on experiences from community

The proposal of salt as a vehicle for fluoride in caries prevention is attributed to Wespi (1948, 1950). In the mid-1950s, domestic salt supplemented by potassium fluoride, up to 90

The first 5-years results following consumption of fluoride-rich domestic salt were published by Marthaler and Schenardi (1962). The documented caries reduction of 32% fewer DMFSs in the permanent teeth of 7-to 9-year-old children was not statistically significant. Only with the subsequent caries data that became available from studies in Colombia (250 mg F/kg as NaF), and Hungary (250 mg F/kg as NaF) was it shown that

A prerequisite was the availability of domestic salt with a high fluoride concentration. The state of knowledge on the subject, up to the mid-1970s, was summarized by Marthaler (1978). The conclusions were that fluoride ingested via salt prevents dental caries in man, the cariostatic effect being similar to water fluoridation: The fluoride content of salt is adjusted so that urinary fluoride excretion levels are similar to those in areas with optimal

Based on the successful results of caries prevention obtained by salt fluoridation program in Switzerland, Hungary, Colombia and other countries, fluoride has been added to the table salt in Mexico from the late 1980s. The Mexican Sanitary Norm indicated that a concentration of 250 mg F/kg of salt should be added. Irigoyen (Irigoyen & Sanchez Hinojosa, 2000) reported that the caries prevalence and the treatment needs experienced in the State of Mexico population have decreased over the last decade. However, dental health is far from optimal, and the state has not achieved the low caries index observed in many developed countries. It is necessary to continue the work with caries prevention programs and to improve access to dental care services. Since there is a National Salt Fluoridation Program already established, no additional systemic sources of fluoride should be implemented; nevertheless, to continue the promotion of the use of fluoridated dentifrices, fluoride rinses and gels, fissure sealants and health education activities could be benefit to

Recent literature has revealed instances where a considerable reduction of the level of preventive efforts has not been followed by an increase in caries frequency and vice versa. This must have been due to the fact that the studied preventive methods, that had proved to be effective elsewhere, were not effective and efficient in those particular settings. Since conditions strongly determine the usefulness of caries prevention including different fluoride regimes, more research is still needed to monitor the effectiveness of caries-preventive programs and their components in variable conditions of today and tomorrow (Hausen, 2004).

Oral Health is fundamental to general health and well-being. A healthy mouth enables and individual to speak, eat and socialize without experiencing active disease, discomfort or

trials carried out in both developed and developing countries ( Petersen, et al., 2004).

mg/kg, became available in various cantons of Switzerland.

fluoride-induced caries reductions could reach 50%.

water fluoride content (Axelsson, 2004).

the population's oral health status.

**5. Dental programs for caries prevention** 

are likely to be least exposed to fluoride, and it is not easy to provide them with any individual protection against caries. The advantage of community water fluoridation is that it reaches even the least advantaged segments of the population. If the risk for caries is high, however, water fluoridation alone cannot provide full protection against the onset of cavities (Hausen, 2004).

The WHO report is quite clear that the post-eruptive effect of sugar consumption is one of the main etiological factors for dental caries and notes in particular the damaging effects of:


A WHO/FAO analysis of the evidence on the role of diet in chronic disease recommends that free (added) sugars should remain below 10% of energy intake and the consumption of foods/drinks containing free sugars should be limited to a maximum of four times per day. For countries with high consumption levels it is recommended that national health authorities and decision-makers formulate country-specific and community-specific goals for reduction of consumption of free sugars. However, WHO also notes that many countries currently undergoing nutrition transition do not have adequate fluoride exposure. It is the responsibility of national health authorities to ensure implementation of feasible fluoride programs for their country.

First, it is clear that all countries and communities should advocate a diet low in sugars in accordance with the WHO/FAO recommendations. This has been emphasized most recently in May 2004 at the World Health Assembly by the confirmation of the WHO Global Strategy on Diet, Physical Activity and Health. Secondly, countries with excessive levels of fluoride ingestion, particularly where there is a risk of severe dental fluorosis or of skeletal fluorosis, should maintain a maximum fluoride level of 1.5 mg/l as recommended by WHO Water Quality Guidelines, although this objective is admittedly not always technically easy to achieve. Thirdly, where sugar consumption is high or increasing, the caries-preventive effects of fluorides need to be enhanced.

WHO recommends that every effort must be made to develop affordable fluoride toothpastes for use in developing countries. As a public health measure, it would be in the interest of countries to exempt these toothpastes from the duties and taxation imposed on cosmetics (Petersen, et al., 2004).

Twetman reported strong evidence for a caries-preventive effect of daily use of fluoride toothpaste compared with placebo in the young permanent dentition (PF, 24.9%), that toothpastes containing 1500 ppm of fluoride had a superior preventive effect (additional PF, 9.7%) compared with standard dentifrices of 1000 ppm of fluoride. Also, strong evidence for higher caries reductions with supervised toothbrushing compared with unsupervised brushing was founded. There was incomplete evidence regarding the effect of fluoride toothpaste in the primary dentition. This systematic review reinforces the importance of daily toothbrushing with fluoridated toothpastes for preventing dental caries, although long-term studies in age groups other than children and adolescents are still lacking (Twetman, et al., 2003).

are likely to be least exposed to fluoride, and it is not easy to provide them with any individual protection against caries. The advantage of community water fluoridation is that it reaches even the least advantaged segments of the population. If the risk for caries is high, however, water fluoridation alone cannot provide full protection against the onset of

The WHO report is quite clear that the post-eruptive effect of sugar consumption is one of the main etiological factors for dental caries and notes in particular the damaging effects of:

3. Children going to bed with a bottle of a sweetened drink or drinking at will from a

A WHO/FAO analysis of the evidence on the role of diet in chronic disease recommends that free (added) sugars should remain below 10% of energy intake and the consumption of foods/drinks containing free sugars should be limited to a maximum of four times per day. For countries with high consumption levels it is recommended that national health authorities and decision-makers formulate country-specific and community-specific goals for reduction of consumption of free sugars. However, WHO also notes that many countries currently undergoing nutrition transition do not have adequate fluoride exposure. It is the responsibility of national health authorities to ensure implementation of feasible fluoride

First, it is clear that all countries and communities should advocate a diet low in sugars in accordance with the WHO/FAO recommendations. This has been emphasized most recently in May 2004 at the World Health Assembly by the confirmation of the WHO Global Strategy on Diet, Physical Activity and Health. Secondly, countries with excessive levels of fluoride ingestion, particularly where there is a risk of severe dental fluorosis or of skeletal fluorosis, should maintain a maximum fluoride level of 1.5 mg/l as recommended by WHO Water Quality Guidelines, although this objective is admittedly not always technically easy to achieve. Thirdly, where sugar consumption is high or increasing, the caries-preventive

WHO recommends that every effort must be made to develop affordable fluoride toothpastes for use in developing countries. As a public health measure, it would be in the interest of countries to exempt these toothpastes from the duties and taxation imposed on

Twetman reported strong evidence for a caries-preventive effect of daily use of fluoride toothpaste compared with placebo in the young permanent dentition (PF, 24.9%), that toothpastes containing 1500 ppm of fluoride had a superior preventive effect (additional PF, 9.7%) compared with standard dentifrices of 1000 ppm of fluoride. Also, strong evidence for higher caries reductions with supervised toothbrushing compared with unsupervised brushing was founded. There was incomplete evidence regarding the effect of fluoride toothpaste in the primary dentition. This systematic review reinforces the importance of daily toothbrushing with fluoridated toothpastes for preventing dental caries, although long-term studies in age groups other than children and adolescents are still lacking

cavities (Hausen, 2004).

bottle during the day.

programs for their country.

effects of fluorides need to be enhanced.

cosmetics (Petersen, et al., 2004).

(Twetman, et al., 2003).

1. Refined or processed foods in general. 2. The consumption of sugary soft drinks. Water fluoridation, where technically feasible and culturally acceptable, has substantial advantages particularly for subgroups at high risk of caries. Alternatively, fluoridated salt, which retains consumer choice, can also be recommended. WHO is currently in the process of developing guidelines for milk fluoridation programs, based on experiences from community trials carried out in both developed and developing countries ( Petersen, et al., 2004).

The proposal of salt as a vehicle for fluoride in caries prevention is attributed to Wespi (1948, 1950). In the mid-1950s, domestic salt supplemented by potassium fluoride, up to 90 mg/kg, became available in various cantons of Switzerland.

The first 5-years results following consumption of fluoride-rich domestic salt were published by Marthaler and Schenardi (1962). The documented caries reduction of 32% fewer DMFSs in the permanent teeth of 7-to 9-year-old children was not statistically significant. Only with the subsequent caries data that became available from studies in Colombia (250 mg F/kg as NaF), and Hungary (250 mg F/kg as NaF) was it shown that fluoride-induced caries reductions could reach 50%.

A prerequisite was the availability of domestic salt with a high fluoride concentration. The state of knowledge on the subject, up to the mid-1970s, was summarized by Marthaler (1978). The conclusions were that fluoride ingested via salt prevents dental caries in man, the cariostatic effect being similar to water fluoridation: The fluoride content of salt is adjusted so that urinary fluoride excretion levels are similar to those in areas with optimal water fluoride content (Axelsson, 2004).

Based on the successful results of caries prevention obtained by salt fluoridation program in Switzerland, Hungary, Colombia and other countries, fluoride has been added to the table salt in Mexico from the late 1980s. The Mexican Sanitary Norm indicated that a concentration of 250 mg F/kg of salt should be added. Irigoyen (Irigoyen & Sanchez Hinojosa, 2000) reported that the caries prevalence and the treatment needs experienced in the State of Mexico population have decreased over the last decade. However, dental health is far from optimal, and the state has not achieved the low caries index observed in many developed countries. It is necessary to continue the work with caries prevention programs and to improve access to dental care services. Since there is a National Salt Fluoridation Program already established, no additional systemic sources of fluoride should be implemented; nevertheless, to continue the promotion of the use of fluoridated dentifrices, fluoride rinses and gels, fissure sealants and health education activities could be benefit to the population's oral health status.

Recent literature has revealed instances where a considerable reduction of the level of preventive efforts has not been followed by an increase in caries frequency and vice versa. This must have been due to the fact that the studied preventive methods, that had proved to be effective elsewhere, were not effective and efficient in those particular settings. Since conditions strongly determine the usefulness of caries prevention including different fluoride regimes, more research is still needed to monitor the effectiveness of caries-preventive programs and their components in variable conditions of today and tomorrow (Hausen, 2004).
