Optimal Fluoride Concentration Research Articles

Caries and Fluorosis Prevalence in Communities with Different Concentrations of Fluoride in the Water

The need to defluoridate and fluoridate the water supplies in areas with drinking water naturally containing above–optimal (≥2.5 mg/l) and suboptimal (≤0.3 mg/l) fluoride concentration and caries and fluorosis prevalence of 12–year–old schoolchildren were assessed in Italy. In the low–fluoride area, 48.4% children were caries–free (DMFT = 0) and the DMFT and DMFS were 1.5 and 2.6; in the high–fluoride area, 46.8% had a DMFT = 0 and the values of the indices were 1.4 and 1.6, respectively. Multiple logistic regression analysis showed a significant association in the caries–free status according to parents' employment status (OR = 1.2, 95% CI = 1.1–1.3) and children's sweets consumption, since children who consumed sweets at least once a day had an adjusted odds ratio of 1.8 (95% CI = 1.4–2.3) compared to those with a lower consumption. Multiple linear regression analysis showed that DMFT and DMFS were significantly higher in children with a lower socioeconomic status and in those who consumed sweets at least once a day, with the DMFS significantly associated also with the area of residence. DT and FT scores were higher in the high– and low–fluoride areas, respectively. No evidence of fluorosis was reported in 94.5 and 55.3% of children in the low– and high–fluoride areas, respectively. The Community Fluorosis Index (CFI) for all permanent teeth was significantly higher in the high–fluoride area, 0.8, than the value, 0.1, found in the low–fluoride community. Our results substantiate the difficulties in defining universal guidelines for the fluoridation or defluoridation of drinking water and the need for an epidemiological approach to the decision as to fluoridate and defluoridate the water supply.

The Risk of Fluorosis in Students Exposed to a Higher than Optimal Concentration of Fluoride in Well Water

In December 1991 the residents of the community of Rigolet, Labrador, Canada, discovered that they were exposed to higher than 2.0 ppm fluoride in the drinking water from the new town well, which became operational in December 1983. In 1993 an investigation of the occurrence of fluorosis in children exposed to the high-fluoride water during different ages of life was carried out. A dental examination for fluorosis was conducted using Pendrys' Fluorosis Risk Index. Out of 84 students in Rigolet, 74 were examined and the parents of 60 students agreed to be interviewed. Out of the 60 students, 48 lived all of their first six years of life in Rigolet. Of the 48 children with life-long residence, the odds ratio of fluorosis on enamel zones that began forming during the first year of life was 8.31 (95% CI = 1.84, 38.59) for children exposed since birth or during the first year of life relative to those exposed after 1 year of age. The odds that a child had a maxillary central incisor with fluorosis were 5.69 (95% CI = 1.34, 24.15) times higher if exposure occurred during the first yea of life compared with exposure after 1 year of age. Only those exposed to the high-fluoride water during the first year of life developed fluorosis on the mandibular central incisors. Within the limitations of this small population study, age relative to the date when the new water well became operational was a significant risk factor in development of fluorosis. The first year of life was a significant period for developing fluorosis on the mandibular and maxillary central incisors.

中国広州市のｆｌｕｏｒｉｄａｔｉｏｎ中断後のう蝕予防効果持続と歯牙フッ素症歯所有状況

In China, water fluoridation was begun in Guangdong province in Guangzhou in 1965 and in Dongguan in 1974, and was stopped in 1983 and 1986, respectively. There is at present no fluoridation being practiced in China. Both cities are located north of Hong Kong and belong to the subtropical zone (mean temperature=71.1°F). According to Minoguchi's formula, an optimal fluoride concentration is 0.6-0.7ppm. The fluoride concentration was unstable for the first 10 years, when annual fluoride concentrations ranged from 0.8ppm to 0.9ppm, higher than the optimal fluoride concentration. After that the concentration was about 0.7ppm. The fluoride concentration of drinking water in Guangzhou may have been sometimes higher than the optimal fluoride concentration. In December 1990, seven years after fluoridation was discontinued, a dental survey of schoolchildren aged 15 was made in Guangzhou, and also in Fushan (0.2ppm) as a control area. Two dentists examined dental caries and one dentist examined dental fluorosis with Dean's Index, and other enamel defects were also recorded. Subjects were 62 students in Guangzhou and 71 students in Fushan. The mean DMFT was 0.44 (SE=0.10) in Guangzhou and 2.20 (0.33) in Fushan. The percent difference was 80% (p<0.001). The prevalence rate of dental fluorosis was 21% in Guangzhou and 2.8% in Fushan and the CFI was 0.42 and 0.08, respectively. Many dark brown teeth, not caused by fluoride, were found. They may have been caused by tetracycline or exanthematous fevers. The present study proved that water fluoridation produced high caries-preventive effects and the favorable effects remained for seven years after discontinuation of water fluoridation without serious dental fluorosis in Guangzhou.

A Critique of Topical Fluoride Methods (Dentifrices, Mouthrinses, Operator‐, and Self‐applied Gels) in an Era of Decreased Caries and Increased Fluorosis Prevalence

Within the last 20 years there has been a decrease in the caries prevalence of US schoolchildren, a change in the intraoral caries pattern, and a slowing of the progress of lesions. Simultaneously, the prevalence of enamel milder, cosmetically acceptable forms and is more noticeable in fluoride-deficient communities than those with optimal or above-optimal water fluoride concentrations. Circumstantial evidence indicates that a principal contributor to the caries decline is the extensive use of fluoride dentifrices. Conversely, although use of a fluoride dentifrice can add to the total daily amount of ingested fluoride in preschool children, there is little evidence to suggest that dentifrice ingestion is a principal factor causing the fluorosis increase. The value of fluoride methods may be assessed in relative or absolute terms. The relative, or percentage, caries reduction attributed to fluoride mouthrinses and gels appears to be a property intrinsic to the methods themselves and generally is little affected by the caries activity of the population being treated. Conversely, the absolute, or numerical, caries reduction is dependent upon the level of disease in the population. Thus, the reported caries decline reduces the number of surfaces prevented from developing caries, even though the percentage reduction remains substantially unchanged. Although inadvertent ingestion of fluoride can result from the use of mouthrinses and gels, there is little evidence to suggest that they have contributed to the fluorosis increase. When using topical methods, prudence should prevail to avoid ingestion of fluoride. Fluoride dentifrices should continue to be used routinely, and although lower potency dentifrices may be considered, the literature does not provide strong support for their need. Use of fluoride mouthrinses and gels for individual patients should be predicted upon their caries activity or risk. Use of these methods in public health programs is a matter of cost-effectiveness, which will be influenced by the caries prevalence of the target population.

Fluoride sources and dental attendance habits among adults in communities with optimal and low water fluoride concentrations

The aim of this study was to obtain data on local fluoride supply, dental attendance, and dental care habits in two sociologically similar municipalities with optimal, 1.0 ppm, and low, 0.3 ppm, water fluoride concentrations, respectively. The participants in the study were 30- to 40-year-old lifetime residents in the two municipalities: 569 individuals from the 1-ppm fluoride community and 466 from the low-fluoride community. There were no intergroup differences in the fluoride mouthrinse utilization rate of 1%. Fluoride toothpaste was much more common in the low-fluoride area. In the 1-ppm fluoride area more people drank tea, and they went more regularly to the dentist. It is suggested that dental attendance habits and various fluoride sources should be taken into account in studies evaluating the effect of fluoride in drinking water.

飲料水中フッ素濃度と永久歯う蝕り患状況

This study deals with the prevalence of dental caries of permanent teeth and dental fluorosis among 5 th and 6th grade Japanese schoolchildren (aged 10-12), residing in 7 different communities in the Tohoku, Kanto, and Ko-Shin-Etsu districts, in relation to the differing concentrations ranging from 0.0 to 1.4ppm of fluoride in the communities' drinking water supplies.Information on dental health in school was obtained from school teachers, and data on dental habits at home were collected by a questionnaire filled out by parents.In 1987, children were examined for dental caries by three dentists, adopting the ‘Blind Recording Method’ where the dentists had no information about the communities, such as the fluoride concentration in the drinking water, and for dental fluorosis by means of Dean's index by two dentists.1, 060 children, who were continuous residents in their communities since birth, were selected for analysis. Comparing the prevalence of dental caries at a fluoride concentration of below 0.2ppm with that of above 1.0ppm, the maximum reduction rate was 69.6% in mean DMFS for 6th grade school-children.From Quantification theory (I), the highest factor was ‘fluoride concentration in the drinking water’, associated with the prevalence of dental caries of permanent teeth. The partial correlation coefficient of ‘fluoride concentration in the drinking water’ was -0.269. A secondary factor was ‘community’, and the other factors were very low. Thus, it became clear that there is an inverse relationship between the prevalence of dental caries and the fluoride concentration in the drinking water.In this study the optimal fluoride concentration in the drinking water that most effectively prevents dental caries in permanent teeth was 1.1 ppm.There was no public health problem regarding dental fluorosis, for CFI was under 0.30 at concentrations of 0.0 to 1.4ppm of fluoride in the drinking water.

Impact of source of drinking water on fluoride supplementation

The benefits of water fluoridation and systemic fluoride to public dental health are well established. The incidence of dental caries is lower in communities with an optimal concentration of fluoride in the 1 The daily intake of fluoride as a supplement provides the same benefit in communities with water fluoride levels at less than the optimal level. 2, 3 Oral fluoride supplementation is currently recommended by both the American Academy of Pediatrics 4 and the Council on Dental Therapeutics, American Dental Association. 5 The use of bottled or filtered water in the United States has increased tremendously during recent years. 6, 7 Many households and businesses use bottled or filtered water for their and cooking needs, largely because of concerns over industrial contamination of groundwater, poor quality control of municipal and leakage of lead from water pipes, as well as the increase in health awareness. Furthermore, bottled water has become a status symbol, an alternative to soft drinks and alcoholic beverages. Bottled waters may be marketed as distilled water, purified water, drinking water, mineral water, or natural spring water. They also may be carbonated (hence, sparkling) or noncarbonated. These bottled waters may serve as the major source of water for children, as well as being used to reconstitute infant formulas. Recently, several studies have focused on the fluoride content of bottled waters, 6, 8, 9 but as far as we know, no literature exists on the efficacy of filtering systems in trapping fluoride, or on the consistency of fluoride content in bottled

天然フッ素地区・北津軽における飲料水中フッ素濃度別の歯牙フッ素症発現に関する疫学的研究

An epidemiological survey on the prevalence of dental fluorosis and measurement of fluoride concentration in drinking water has been performed in natural fluoride areas, in Kitatsugaru since 1974. The region of Kitatsugaru is located at 40°45', north latitude; the annual mean temperature is 9.6°C and annual mean maximum temperature is 14.1°C. Dental fluorosis is caused by excessive intake of fluorides during calcification of teeth. Therefore, the relationship between the occurrence of dental fluorosis and fluoride concentration in the drinking water, which the subjects had been drinking since birth, was evaluated. 248 elementary school children in 3 areas, from age 6 to 9, were examined. The severity of fluorosis was examined by an experienced examiner and recorded according to the WHO classification (1971).Thirty-seven deep wells in natural fluoride areas of Kitatsugaru were divided into 7 groups, according to their fluoride concentrations (Mean±S. D.): Group I, 0.34±0.04 ppm; Group II, 0.64±0.13 ppm; Group III, 0.95±0.19 ppm; Group IV, 1.72±0.20 ppm; Group V, 2.50±0.52 ppm; Group VI, 1.01±0.95 ppm; and Group VII, 1.15±0.61 ppm. Coefficients of variation (C. V.) of fluoride concentration from Group I to V were stable within about 20%, but unstableness of C.V. was found in Group VI and VII.The moderate [MO] and severe [S] types of dental fluorosis were not found in natural fluoride areas, in Kitatsugaru. A mild type [M] of dental fluorosis was first observed in Group III and increased from 4.6 to 25.0% to the maximum level of Group V, with the increasing fluoride concentration of the water. Community fluorosis indices of each fluoride concentration group were as follows: Group III, 0.33-negative zone; Groups IV and V, 0.86 and 0.88-higher than borderline zone, respectively; Group VI, 0.25-negative zone; and Group VII, 0.50-borderline zone.The percentage of school children having nonfluoride enamel opacities was less than 5% in natural fluorides areas in Kitatsugaru. On the basis of the severity of dental fluorosis and CFI, the optimum fluoride concentration in drinking water in this area appears to be 0.9 ppm.

Prevalence of dental caries and dental fluorosis in areas with negligible, optimal, and above-optimal fluoride concentrations in drinking water

The prevalence of dental caries and dental fluorosis was assessed in 1,123 children aged 8 to 16 years who were lifelong residents of areas with negligible, optimal, and above-optimal concentrations of natural fluoride in drinking water. Caries prevalence in the optimal fluoride area was 38.1% lower than it was in the negligible fluoride area, and, in the higher-than-optimal fluoride areas, even greater caries protection was evident. Caries protection was compromised in children with severe fluorosis. Findings do not support the contention that definite increases in the prevalence of fluorosis are occurring in communities with negligible and optimal water-fluoride concentrations because of increased total fluoride consumption from various sources.

The availability of fluoride chemical supplies

The availability of adequate supplies of fluoride chemicals is a critical factor in consistently maintaining the optimal fluoride concentration in water supply systems. The most recent shortage of fluoride chemicals occurred in 1982. The factors precipitating and contributing to periodic fluoride chemical shortages are discussed and recommendations for preventing future shortages are outlined.

Thirty years of fluoridation: a review

Fluoride contributes to stability of both teeth and bones and to reduction of caries, especially if ingested before eruption of teeth. Reduction of caries continues at about 60% in persons drinking fluoridated water only as long as fluoride washes over teeth. One-half the population of the US does not have access to water with an optimal fluoride concentration of about 1 mg/L. Misinformation about fluoridation contributes to reluctance of communities to supplement the natural but inadequate fluoride of those water supplies. Fluoridation of water has no positive or negative effect on incidence or mortality rates due to cancer, heart disease, intracranial lesions, nephritis, cirrhosis, mongoloid births, or from all causes together. The collective decision to increase the natural fluoride content of water supplies is not an infringement of civil rights, nor does it establish a precedent in the binding sense of the law. Supplemental fluoride in water makes it available to all members of the community in a safe, practical, economical and reliable manner. Fluoridation saves money in dental costs and time lost from work. Fluoridation is an appropriate action of government in promoting the health and welfare of society.

A new method for assessing the prevalence of dental fluorosis—the Tooth Surface Index of Fluorosis

A new index for measuring the prevalence of dental fluorosis, the Tooth Surface Index of Fluorosis (TSIF), was used to assess the condition in the permanent teeth of 807 children, aged 8 to 16, who had resided all their lives in one of seven Illinois communities with an optimal concentration of fluoride in its water or with 2, 3, or 4 times the optimal concentration. Fluorosis was absent in 84.5% of all tooth surfaces examined in the community with optimal fluoride. In contract, only 31.9% of tooth surfaces had no fluorosis in the community with 4-times the optimal fluoride level. In the optimal fluoride area, 79% of facial surfaces of maxillary anterior teeth, which are esthetically conspicuous, had no fluorosis, whereas only 15.8% of these surfaces in the 4-times optimal area were unaffected. The percentages of all tooth surfaces affected by fluorosis characterized by staining, pitting, or both were 1%, 8%, 19%, and 38%, respectively, in communities with 1-, 2-, 3-, and 4- times optimal fluoride. Differences in fluorosis based on maximum score for all tooth surfaces in a child were statistically significant (an extended chi 2 statistic) among all communities. First molars and incisors in children 8 to 10 years old were affected by more fluorosis than were the same teeth in children 13 to 16 years old. These teeth had been erupted for about 5 years longer in the older age group. The difference might result from abrasion or remineralization of these teeth in the older children or from greater consumption of fluoride by the younger children during tooth development.(ABSTRACT TRUNCATED AT 250 WORDS)

Prevalence of Dental Caries and Dental Fluorosis in Areas with Optimal and Above-Optimal Water Fluoride Concentrations

The prevalence of dental caries and dental fluorosis was assessed among 807 schoolchildren in four areas of Illinois where the respective water supplies contained natural fluoride at concentrations of 1, 2, 3, and 4 times the recommended optimal for the geographic area. Mean caries scores in all three above-optimal fluoride areas were significantly lower than in the optimal area. The prevalence of dental fluorosis was characteristically low in the optimal fluoride area. Substantial increases in fluorosis occurred in the above-optimal fluoride areas, with the condition being most pronounced in the 4-times optimal area.

Determination of optimal fluoride concentration in drinking water in an area in India with dental fluorosis.

The present study was made to determine the optimal fluoride concentration in drinking water in a fluorotic zone. The area under study was divided in four parts on the basis of fluorides present in drinking water. A sample of 1320 persons was examinmed, where prevalence of dental fluorosis varied from 3.8% to 65.4% depending on the fluoride concentration in drinking water. Statistically significant increase in the prevalence of dental fluorosis was found (a) with the rise in fluoride in drinking water, (b) with the rise in age, peak being found at 15--19 years age group and (c) amongst the bona fide residents of the area. A significant positive correlation was found between fluoride in drinking water and Community Fluorosis Index. While determining the optimal level of fluoride in drinking water, values obtained were 1.05 parts/10(6), 0.8 parts/10(6) and 0.34 part/10(6), respectively, by different formulae in a fluorotic zone of western Indian.

Fluoride Supplementation: Revised Dosage Schedule

Since the previous Committee on Nutrition statement on fluoride was issued in 19721, the value of providing fluoride supplements to help prevent dental caries has been supported by a growing body of experimental evidence.2 This statement has been prepared to recommend a new dosage schedule that decreases the dosage of fluoride in infancy and that is better adjusted to the concentration of fluoride in the drinking water. Health authorities agree that, in communities where the fluoride concentration of the water is suboptimal, the most effective and inexpensive means of reducing dental decay is by adjusting the community water supply to an optimal fluoride concentration. In the absence of a fluoridated central water supply, alternative means of fluoride supplementation should be used. Fluoride in tablets, drops, lozenges, or in combination with vitamins can serve this purpose and have been shown to be effective.2 However, the success of these forms of fluoride supplementation depends on whether parents are sufficiently motivated to supervise the regular, daily intake of fluoride supplements by their children from shortly after birth until about 16 years of age. It should be emphasized that fluoride administration is strictly supplemental; it is intended to increase fluoride intake in approximately the amount that would be obtained from fluids in optimally fluoridated communities. Fluoride intake is primarily from water and liquid foods made with fluoridated water. There is relatively little fluoride in most foods3-5; exceptions are certain seafoods. Dosage In establishing an optimal dosage regimen for fluoride supplements, the age of the child and the existing fluoride concentration in the water supply are the two major considerations.

Epidemiological Study of Appearance of Dental Fluorosis Related to Fluoride Concentrations in Drinking Water in Kitatsugaru, Japan

The aim of this study was to determine the optimum fluoride levels in drinking water for minimizing dental caries with maximum safety in Kitatsugaru area (north latitude 41°), Japan. The fluoride concentrations of drinking water in this area ranged from 0.3 to 3.2 ppm and the mean annual temparature was 9.6°C (49.3°F). The fluoride concentrations of drinking water were divided into six groups related to wells in the districts, i. e., group I, 0.31-0.38 ppm; group II, 0.52-0.63 ppm; group III, 0.82-0.95 ppm; group IV, 1.01-1.56 ppm; group V, 1.74-1.96 ppm; and group VI, 2.90-3.18 ppm. Community fluorosis index (CFI) and caries incidence in relation to groups of water fluoride concentrations were evaluated. 387 school children aged 6 to 12 years were given an oral examination. Of these 358 had resided in the area from birth and had used community well water continuously.In the Kitatsugaru area, dental fluorosis and nonfluoride enamel opacities were present in 39.1 per cent and 6.7 per cent of the children, respectively. The CFI of this area was 0.68, which is higher than borderline. When water fluoride concentrations and their CFI were compared, there was a marked distribution of CFI ranging from 0.02-1.95 from the lowest (0.31-0.38) to the highest group (2.90-3.18). Community fluorosis indices of the water groups were as follows: Group I, 0.02; Group II, 1.53; Group III, 0.14; Group IV, 0.47; Group V, 096; Group VI, 1.95. It is evident that frequency and degree of dental fluorosis increase with increase with increasing fluoride concentration of the water except in Group II. This indicates that the higher CFI values of Group II was due to the variation of fluoride concentration in the drinking water because of re-boring the well.There was a statistically significant difference (P<0.01) in caries prevalence and incidence in each water group (Group I-VI) when compared with the control district (Matsuo: F<0.1 ppm). The results obtained in this study suggest that the optimal fluoride concentration for caries prevention in this area would be 0.8-0.9 ppm. Furthermore, epidemiological findings in this study suggests that the occurrence of dental fluorosis might be affected by the transient influence of fluoride at the time of the initial calcification of enamel rather than to continuous influence during enamel formation.

Effects of prostaglandins and catecholamines on rat spleen adenylate cyclase in vitro

The results reported here show some characteristics of adenylate cyclase (EC 4.6.1.1) derived from homogenates of rat spleen, and describe the in vitro stimulation of this enzyme by prostaglandins, nucleotides, and F − under conditions where cyclic nucleotide degradative pathways are effectively inhibited. Particulate fractions from rat spleen homogenates contain high adenylate cyclase activities, and the highest specific activity is recovered in a particulate fraction prepared by low speed (1200 × g) centrifugation. Activity found in all particulate fractions is stimulated by fluoride, prostaglandins E 1 and E 2, catecholamines, and purine nucleotides. No stimulation is caused by prostaglandins F 1α and F 2α. Stimulation by prostaglandin E 1 or E 2 is augmented by GTP and other purine nucleotides, and stimulation by the combination of GTP and prostaglandin E 1 is equal to that caused by optimal fluoride concentrations. Stimulation c caused by L-isoproterenol is additive to that caused by GTP but is not increased by GTP.

Further studies on the remineralization of human carious dentine in vitro

Recently published work has shown the effectiveness of a buffered fluoride solution saturated with solid brushite in the remineralization of sections of carious dentine in vitro. The present work confirms that the optimum fluoride concentration is between 5–20 ppm and describes the rapid collapse of the remineralization system when the initial fluoride concentration is raised to 100 ppm. X-ray diffraction analysis of remineralized carious dentine revealed only the presence of relatively well-crystallised apatite, indicating that hydroxyapatite is the mineral deposited in the tissue. Within the optimum fluoride concentration range, the solid phase of the remineralization fluid persists as brushite and in the absence of tooth sections the fluid is stable for at least 8 days.

The prevalence of dental caries, enamel opacities and enamel hypoplasia in Ugandans

An epidemiological survey on the prevalence of dental caries, enamel opacities and enamel hypoplasia was conducted on 1399 persons in four districts in Uganda with fluoride in the drinking water varying from 0.11 to 3.00 ppm. The dental caries experience was found to be very low (0.0–0.9 DMF-T per person in the 5–9 yr age group and 0.4–2.8 DMF-T per person in the age group ∗> 40 yr ). The expected inverse relationship between the prevalence of dental caries and the fluoride content of the drinking water was demonstrated. The optimum fluoride concentration in the drinking water in Uganda was calculated to be approximately 0.6 ppm F. The dental caries experience was higher in Asians than in Africans and higher in the primary than in the permanent dentition. The prevalence of non-fluoride enamel opacities and hypoplasia was found to be lower in high-fluoride areas in comparison with low-fluoride areas. The importance of the immediate introduction of preventive measures is stressed.

The prevalence of dental fluorosis in the people of Uganda

An epidemiological survey on the prevalence of dental fluorosis was performed in 4 districts in Uganda. 1399 persons in 13 areas with fluoride concentrations in the drinking water, varying from 0.11 to 3.00 ppm, were examined. The community index of dental fluorosis ( F ci) varied from 0.04 in low-fluoride areas to 1.74 in high-fluoride areas. The severity of dental fluorosis was found to be higher among Africans than among Asians, and higher in males than in females. The distribution of severity indices for permanent teeth ( F ti) showed the following ranking of the teeth in decreasing order of severity: premolars, second molars, upper incisors, canines, first molars and lower incisors. On the basis of the severity of dental fluorosis and the average mean maximum temperature the optimum fluoride concentration in drinking water in Uganda is considered to be 0.6 ppm F.