Non-fluoridated Areas Research Articles

Caries experience in rural Victorian adolescents

An oral health status survey was conducted on 818 adolescents aged 12 to 16 years in a non-fluoridated area in rural Victoria. The prevalence and severity of dental caries experience was found to increase with age. The occlusal surface was the predominant surface affected by dental caries for all age groups. Filled surfaces represented the largest component of the DMFS index and were responsible for the increasing dental caries experience with age. Fewer fissure sealants were present with increasing age and second molars were sealed less often than the first molars. Although no difference was evident in the total caries experience between those with and without access to public dental services, a statistical difference was found to exist in unmet need between these two groups. Untreated caries levels were significantly higher in health card holders. The provision of preventive and dental treatment services to this group should be a priority in the future.

Fluoride profiles in different surfaces of human permanent molar enamels from a naturally fluoridated and a non-fluoridated area

The surfaces, sites and depths of fluoride profiles of enamel from a naturally fluoridated area (West Hartlepool, WHP, 1.9 parts 10 6 F in drinking water) and a non-fluoridated area (Leeds, LDS, < 0.1 parts/10 6 F in drinking water) were examined in detail. Using a regression curve, y = ax −b , comparisons of fluoride concentrations were made at depths of 1, 3, 5, 10, 20 and 30 μm at occlusal, middle and cervical sites of buccal, lingual, mesial and distal molar enamel surfaces. In the outermost enamels (< 10 μ in depth), fluoride concentrations tended to be lower in the occlusal sites than in the cervical sites. In interior enamels (> 20 μm in depth), the fluoride concentrations of molars from WHP were statistically higher than those from LDS, while few significant differences were found in the outermost layers. In the mesio- and disto-occlusal sites of approximal surfaces, there were some significant differences in the exponential regression coefficients of fluoride profiles between the two groups of molars.

Trends in prevalence of dental fluorosis in North America

This review of the literature was undertaken to demonstrate the changing trends in the prevalence of dental fluorosis in North America. Using Dean's early work to establish a baseline for the prevalence of dental fluorosis, results of more recent prevalence surveys were used to establish a range for the occurrence of dental fluorosis today. These results suggest that the prevalence of dental fluorosis now ranges somewhere between 35% and 60% in fluoridated communities and between 20% and 45% in nonfluoridated areas, depending on the influence of different local conditions. While the increase has occurred primarily in the very mild and mild categories of dental fluorosis, there is also some evidence that the prevalence is increasing in the moderate and severe classifications as well.

Water fluoridation: current effectiveness and dental fluorosis

This paper reviewed the literature on the evidence for water fluoridation's effectiveness under current conditions of multiple fluoride use at recommended and at reduced concentrations, the extent of dental fluorosis at different fluoride concentrations, and the "halo" effect of water fluoridation. Using the relative difference in dental caries between communities with low and optimal water fluoride as an indicator, the effectiveness of water fluoridation has decreased over time as the use of other fluorides has increased. Thus the effectiveness of water fluoridation alone cannot now be determined. Compared to the early fluoridation studies, the differences in dental caries and fluorosis prevalence between fluoridated and non-fluoridated areas have markedly narrowed. Both the prevalence and severity of dental fluorosis have increased since 1945; however, the portion of fluorosis due to water fluoridation is now less (40%) than that attributed to other fluoride sources (60%). Research also suggests that the "halo" effect of community water fluoridation may result in a significantly greater intake of fluoride for people in non-fluoridated communities. This review recognized that since water fluoridation has unique advantages from the perspectives of distribution, equity, compliance and cost-effectiveness over other fluoride technologies, it remains as the fundamental base for caries prevention. The increasingly greater contribution that other sources of fluoride make to dental fluorosis suggests that these sources of fluoride, many of which are used on an elective basis, should be more closely examined for needed changes.

Review of fluoride exposures and ingestion.

The literature on fluoride intake/ingestion was reviewed critically to determine the current exposure to fluorides for children living in non-fluoridated and fluoridated areas in North America. Fluoride from all sources except mouthrinses and professionally applied topical fluorides was considered, including ingestion from foods and beverages, as well as intake from the use of fluoride dentifrice and dietary fluoride supplements. Data from all of these sources were used to produce estimates of mean daily ingestion. Studies consistently have identified substantial variation in ingestion among individuals. These analyses demonstrated that a substantial proportion of individuals had exposure or ingestion well beyond that of the mean for each source, and often 10-20% received up to several times as much exposure as the mean. Some children probably ingest sufficient fluoride from a single source to exceed the "optimal" fluoride intake recommended from all sources, and are therefore at increased risk of fluorosis. This review highlighted the substantial variation and complexity of fluoride ingestion. Appropriate consideration of these aspects is warranted in efforts to ensure a margin of safety favoring dental caries prevention while limiting objectionable fluorosis.

天然フッ素地域と非フッ素地域からの成人のセメント質および象牙質のフッ素濃度分布

The purpose of the study was to examine the effect of water fluoride content on the fluoride profile across the entire thickness of the cementum and root dentine of human permanent anterior teeth using an abrasive micro-sampling technique (Weatherell et al. 1985). Twenty eight human permanent anterior teeth, aged from 30 to 60 years were analyzed. One group was obtained from a naturally fluoridated area (West-Hartlepool in the UK: fluoride content in drinking water 1.0-1.3 ppm) and the other from a non-fluoridated area (Leeds in the UK: fluoride content in drinking water is less than 0.1 ppm). A slice, about 300μm thick was prepared bucco-lingually on a slide of 28 human permanent anterior teeth. Each specimen was divided into 3 parts, one near thecement-enamel junction (CEJ), a second at the middle of the root dentine, and a third near the root apex. Using a thine diamond disk, parallel blocks of tissues about 1 mm wide were cut under a dissecting microscope. Layers of cementum and root dentine were abraded using abrasive micro-sampling until the pulpal surface of the root dentine was reached. Fluoride and phosphorus contents were determined for each sample. The results were as follows;1) Fluoride concentration was higher in teeth samples taken from the naturally fluoridated area (WHP) than from the non-fluoridated area (LDS).2) Average fluoride concentration and age had a positive correlation in WHP dentine middle region (r=0.79, p<0.001) and in the apex region (r=0.61, p<0.05), and in WHP cementum cervical region (r=0.67, p<0.01).3) An analysis of variance suggested that the area, age and number of years lived in the area combined with age were significant.We concluded that the WHP group had a higher fluoride concentration than the LDS group in cementum and root dentine throughout life, suggesting that topical and ingested fluoride application are effective in preventing adult root surface caries.

Aesthetic concerns of children and parents in relation to different classifications of the Tooth Surface Index of Fluorosis.

Increasing prevalence of dental fluorosis for children both from fluoridated and non-fluoridated communities are now well documented. Along with recent studies purporting possible adverse health effects from fluorides, this proven public health intervention is again being challenged. This study was undertaken to determine the prevalence of dental fluorosis for children from fluoridated and non-fluoridated areas in British Columbia. In addition, children and parents were provided with an opportunity to express concerns about the aesthetics of the child's anterior teeth. Children from representative schools in two communities were surveyed using the Tooth Surface Index of Fluorosis (TSIF). Questionnaires were sent home to parents to detail their child's use of various fluoride preventive practices and residence histories. Completed questionnaires were returned and exams were performed on 1131 children. Of those examined, 60% had dental fluorosis on at least two tooth surfaces, only 8% had scores ranging from "2" to "6", and 52% were classified with a score of "1". Parental and child ratings on the aesthetics or color of the child's teeth suggests that there are few children with aesthetic problems in the TSIF category of "1". While concerns of parents were more common, the actual source of those concerns was not assessed in the questionnaire. Not unexpectedly, children with fluorosis on anterior teeth ranging between TSIF scores of "2" to "6" appear to have increased concerns about tooth color. Data from children with confirmed residence histories from fluoridated communities suggest that the occurrence of aesthetic problems in these children is rare.

Hip Fractures and Fluoridation in Utah's Elderly Population

To test the effect of water fluoridated to 1 ppm on the incidence of hip fractures in the elderly. Ecological cohort. The incidence of femoral neck fractures in patients 65 years of age or older was compared in three communities in Utah, one with and two without water fluoridated to 1 ppm. All patients with hip fractures who were 65 years of age and older over a 7-year period in the three communities, excluding (1) those with revisions of hip fractures, (2) those in whom the hip fracture was anything but a first diagnosis, (3) those in whom metastatic disease was present, or (4) those in whom the fracture was a second fracture (n = 246). Rate of hospital discharge for hip fracture. The relative risk for hip fracture for women in the fluoridated area was 1.27 (95% confidence interval [CI] = 1.08 to 1.46) and for men was 1.41 (95% CI = 1.00 to 1.81) relative to the nonfluoridated areas. We found a small but significant increase in the risk of hip fracture in both men and women exposed to artificial fluoridation at 1 ppm, suggesting that low levels of fluoride may increase the risk of hip fracture in the elderly.

Hip fractures and fluoridation in Utah's elderly population

<h3>Objective.</h3> —To test the effect of water fluoridated to 1 ppm on the incidence of hip fractures in the elderly. <h3>Design.</h3> —Ecological cohort. <h3>Setting.</h3> —The incidence of femoral neck fractures in patients 65 years of age or older was compared in three communities in Utah, one with and two without water fluoridated to 1 ppm. <h3>Patients.</h3> —All patients with hip fractures who were 65 years of age and older over a 7-year period in the three communities, excluding (1) those with revisions of hip fractures, (2) those in whom the hip fracture was anything but a first diagnosis, (3) those in whom metastatic disease was present, or (4) those in whom the fracture was a second fracture (n=246). <h3>Outcome Measure.</h3> —Rate of hospital discharge for hip fracture. <h3>Results.</h3> —The relative risk for hip fracture for women in the fluoridated area was 1.27 (95% confidence interval [CI]=1.08 to 1.46) and for men was 1.41 (95% CI=1.00 to 1.81) relative to the nonfluoridated areas. <h3>Conclusions.</h3> —We found a small but significant increase in the risk of hip fracture in both men and women exposed to artificial fluoridation at 1 ppm, suggesting that low levels of fluoride may increase the risk of hip fracture in the elderly. (<i>JAMA</i>. 1992;268:746-748)

Prevalence of enamel defects/fluorosis in fluoridated and non-fluoridated areas in Ireland.

Water fluoridation was introduced in Ireland in 1964 and in recent years the availability of fluoride from other sources had increased. As part of a National Survey of Children's Health in Ireland Dean's and the DDE indices were used to determine the prevalence of enamel fluorosis/defects in 8- and 15-yr-old children in fluoridated and non-fluoridated areas. Over 94% of the children examined in all areas were regarded as having normal enamel, as defined by Dean's index, the remainder showing evidence of either questionable, very mild or mild fluorosis. Between 52% and 63% of the children had one or more teeth affected by enamel defects when measured by the DDE index. The prevalence of enamel fluorosis/defects was similar in children living in fluoridated and non-fluoridated areas but the prevalence of diffuse opacities (DDE) was higher in the fluoridated areas.

Calcium and phosphorous in teeth from children with and without cystic fibrosis

The objective of this study is to analyze the percentage of Ca and P in teeth from children with and without cystic fibrosis with respect to different variables, namely, gender, age, type of teeth, area, fluoridation of water supply, term of pregnancy, and maternal smoking and drinking habits. The method of analysis is proton-induced X-ray emission and proton-induced gamma emission on tooth-crown samples. T-test results show less Ca in the teeth of the population of CF + NT (cystic fibrosis+ nontetracycline antibiotics) than in that of NCF (noncystic fibrosis) for incisors and the total tooth population. It also shows greater Ca for incisors than for nonincisors for NCF. Teeth from urban CF + NT have less Ca than those from urban NCF. This holds for the total area population. Both Ca and P in teeth of NCF population living in fluoridated areas are greater than in those living in nonfluoridated area. Ca is depleted in the teeth of CF + NT children whose mothers smoke and P is depleted in the teeth of NCF children whose mothers drink. High and low Ca and P values for individual teeth are reported.

Dental Fluorosis and Fluoride Exposure in Western Australia

Dental fluorosis in children is reported from many locations, and its prevalence may be increasing. This study aimed to measure fluorosis in 12-year-olds in fluoridated and non-fluoridated areas of Western Australia and to relate this to exposure. School dental clinics in Perth (F- 0.8 mg/L) and the Bunbury area (F- less than 0.2 mg/L) were the sampling units. Parents provided data on residence in fluoridated areas and on use of supplements and toothpaste. Exposure to water and supplemental fluoride between birth and four years was calculated. Clinical examinations (upper left central incisor) based on the TF classifications of fluorosis (which requires teeth to be dried) were conducted for 338 children in Perth and 321 in the Bunbury region. Re-examinations (n = 50) gave a weighted kappa of 0.78. Contingency analysis estimated bivariate relationships, and multiple logistic regression estimated odds ratios (OR) for risk factors. Fluorosis prevalence in the Perth region was 0.40, and in the Bunbury region 0.33 (chi 2 = 3.69, df = 1, p = 0.055). Prevalence was 0.44 in children with fluoride exposure equivalent to optimal water fluoridation and 0.20 among those with the lowest exposure (chi 2 = 35.99, df = 1, p = 0.0001). Increasing exposure was associated with higher fluorosis prevalence and higher TF scores, but overall, 27.3% of participants had TF score 1 (barely discernible), and only 9.4% had TF score greater than or equal to 2.(ABSTRACT TRUNCATED AT 250 WORDS)

Bone cancer incidence rates in New York State: time trends and fluoridated drinking water.

Recent animal studies of the potential carcinogenicity of fluoride prompted an examination of bone cancer incidence rates. Trends in the incidence of primary bone cancers, including the incidence of osteosarcomas were examined among residents of New York State, exclusive of New York City. Average annual osteosarcoma incidence rates in fluoridated and non-fluoridated areas were also compared. Among persons less than 30 years of age at diagnosis, bone cancer incidence among males demonstrated a significant increase since 1955, while incidence among females has remained unchanged. A significant decrease in bone cancer incidence rates since 1955 was observed among both males and females age 30 years and over at time of diagnosis. Osteosarcoma incidence rates have remained essentially unchanged since 1970, among both younger and older males and females. The average annual age adjusted incidence of osteosarcomas (1976-1987) in areas served by fluoridated water supplies was not found to differ from osteosarcoma incidence rates in non-fluoridated areas. These data do not support an association between fluoride in drinking water and the occurrence of cancer of the bone.

Fluoride Intake of Infants in New Zealand

Since the fluoride (F-) intake of New Zealand infants and young children is not known, a study was designed to determine and compare the F- intake of infants, aged 11 to 13 months, residing in fluoridated (F) and non-fluoridated (NF) areas. Parents of 60 infants duplicated quantitatively and qualitatively all food and drink that the infants ingested during a three-day period. The acid-diffusible F- content in the liquid homogenate was isolated by the HMDS-HCl diffusion technique (Taves, 1968) and measured by a fluoride electrode. The ionic F- in samples of breast milk was measured directly by the electrode. In the F area, the F- content of the food and drinks of 31 subjects ranged from 0.130 to 0.679 mg/kg (mean, 0.320; SD, 0.168); in the NF areas, the F- content of the food and drinks of 29 subjects ranged from 0.036 to 0.281 mg/kg (mean, 0.095; SD, 0.053). The dietary intake ranged from 0.089 to 0.549 mg F/day (0.009-0.056 mg F/kg bw) in the F area, and from 0.038 to 0.314 mg F/day (0.004-0.038 mg F/kg bw) in the NF area. Including F- from tablets and toothpastes, total intake ranged from 0.093 to 1.299 mg F/day (0.009-0.150 mg F/kg bw) and from 0.039 to 0.720 mg F/day (0.004-0.061 mg F/kg bw) in F and NF areas, respectively. The mean dietary intake of infants in the F area was about half the recommended "optimal" range; in the NF areas, the dietary intake was five to seven times less than the optimal.(ABSTRACT TRUNCATED AT 250 WORDS)

Fluoride in Caries Prevention: Is the Effect Pre- or Post-eruptive?

A longitudinal study of children from ages 7 to 18 showed that, if enamel lesions were included, the overall number was the same in fluoridated and non-fluoridated areas. However, a significant reducing effect of pre-eruptive fluoride could be seen in the number of dentinal lesions in a fluoridated area, provided that fluoride was also consumed post-eruptively for a considerable period of time. A precise estimation of both pre- and post-eruptive effects was obtained when teeth were classified according to their eruption time as related to the onset of water fluoridation. About 66% of the greatest reduction in pit and fissure caries came from pre-eruptive fluoride, while in smooth surfaces, this effect was reduced to 25%. In approximal surfaces, the reduction was due half to pre- and half to post-eruptive fluoride. Post-eruptive fluoride became more important with decreasing severity of caries attack. Thus, assuming a continuing decline in dental caries, the majority of such populations will benefit most from the use of topical fluorides. However, in high-risk groups, supplementation of pre-eruptive fluoride can still be of major importance.

The effect of fluoride consumption and social class on dental caries in 8‐year‐old children

School dental service data indicate that whilst Melbourne eight-year-old children had worse dental health than similar children in the Geelong area in 1979, the situation in 1985 was the reverse. In order to investigate this, and determine the effects of socio-economic level (SEL), residential history, and fluoride history on dental caries status, 208 eight-year-old children in the Melbourne area and 209 eight-year-old children in the Geelong area were examined for dental caries. A questionnaire was administered to gain details of subjects' exposure to water and supplement fluorides. The SEL of the subjects' school was used in place of individual SEL. A high proportion (46 per cent) of Geelong subjects used a fluoride supplement at some stage, but few continued this for most of their life. Residential history was important, with 2.4 per cent of the Melbourne subjects living most of their life in a nonfluoridated area and 3.4 per cent of Geelong subjects living most of their life in a fluoridated area. There was a significant difference between the dmft in Melbourne and Geelong when only children who had lived all their life in the city in which they were examined and did not use a fluoride supplement were included. A large part of this difference is attributed to water fluoridation in Melbourne. A substantial number of children would benefit from fluoridation of the reticulated water supply in Geelong, particularly those in the lower social classes.

Prevalence of dental caries in 7–13‐yr‐old children in Morogoro District, Tanzania, in 1984, 1986, and 1988

A 4-yr mixed-longitudinal study to determine the prevalence of caries in 7-13-yr-old Tanzanian children was started in 1984. The parameters considered were age, locality, Socio-Economic Status, and sex. Locality was composed of urban (Morogoro town), rural (Morogoro District), and rural areas in the District with an average fluoride level of 0.5 ppm or more in all drinking water present. SES was established based on the occupation of the father or mother and on housing conditions. Overall, the reproducibility of the dental conditions studied (D2MT/S and D3MT/S) was high, with lower scores for the conditions including early enamel lesions (D3MT/S). The reproducibility of the SES scoring system was high (kappa = 0.96 and kappa = 0.90), but the association over the 2 yr of measurement (1984 and 1988) was weak (r = 0.50). There were no restorations found. The percentage of children with caries increased with increasing age from 12-17% at age 7 to 37% at age 13. The statistical tests (ANOVA) revealed an age effect for all conditions studied in 1984, 1986, and 1988 and a locality effect in 1988 only. The mean D3MT-scores varied between 0.15 and 0.24 at age 7 to 0.76 at age 13, while the mean D3MS-scores varied between 0.27 and 0.31 at age 7 to 1.18 at age 13. In general, the caries prevalence observed was low. Children living in naturally fluoridated rural areas had significantly lower caries scores than children in non-fluoridated areas.

Caries incidence and costs of prevention programs.

Data on caries increments and costs of prevention programs are presented as background information for participants in the workshop. Estimates of annual caries increments were derived from control groups in clinical trials, epidemiologic studies, and national surveys. Cost data were obtained from dental public health directors, program administrators, fluoridation engineers, and water plant operators in different parts of the US. Caries incidence data are reported for age groups: 5-17 years (fluoridated and nonfluoridated areas), 18-44 years, 45-64 years, and 65 and over. Program costs include direct costs primarily and do not allow for program inefficiencies, nor have they attempted to include social costs. All cost data are expressed in 1988 dollars. Direct program costs are included for community water fluoridation, fluoride supplements, fluoride mouthrinses, school fluoridation, and sealant programs. For professionally and self-applied fluoride programs, only material and salary costs are included because total costs could not be located in the literature nor obtained from program directors. All factors and necessary assumptions included in the cost assessments are described.

Effectiveness of school water fluoridation and dietary fluoride supplements in school-aged children.

School water fluoridation and school-based fluoride tablet programs both have been shown in many studies to be effective in preventing dental caries. These studies indicate that school water fluoridation reduces dental decay by approximately 40 percent and school-based fluoride tablet programs by about 30 percent. However, nearly all the studies were done when the prevalence of caries among US schoolchildren was greater than it is today, which makes it difficult to assess their current effectiveness. Data from dental surveys of school-aged children conducted during the past 30 years indicate that overall caries prevalence has declined by more than 75 percent and that of approximal tooth surfaces by more than 90 percent. Recent national data indicate the difference in caries prevalence between children with lifetime residence in either fluoridated or nonfluoridated areas has also diminished, which raises questions about the cost effectiveness of initiating school-based fluoride programs for all areas. There are still groups of children, however, seriously affected by dental caries. It is safe to assume that implementation of school water fluoridation or fluoride tablet programs will result in traditionally reported benefits among these children. Ongoing school-based fluoride programs should not be discontinued until it is known what impact their cessation will have on dental disease.

Effectiveness of water fluoridation.

The efficacy of communal water fluoridation in reducing dental caries has been reviewed based on surveys conducted in the last decade of caries prevalence in fluoridated and nonfluoridated communities in the United States as well as in Australia, Britain, Canada, Ireland, and New Zealand. The efficacy is greatest for the deciduous dentition, with a range of 30-60 percent less caries in fluoridated communities. In the mixed dentition (ages 8 to 12), the efficacy is more variable, about 20-40 percent less caries. In adolescents (ages 14-17), it is about 15-35 percent less caries. Current data on caries prevalence in adults and seniors are extremely limited and include several populations living in communities with higher than optimal fluoride levels. For these adults and seniors, a range of 15-35 percent less caries would also apply. Viewed in toto, the current data for children, adolescents, adults and seniors show a consistently and substantially lower caries prevalence in fluoridated communities. For an accurate measurement of the efficacy of water fluoridation in reducing dental caries, it is essential that only persons with a record of continuous or long-term residency in fluoridated versus nonfluoridated areas be included in such assessments. Because of the high geographic mobility in our society and the widespread use of fluoride dentifrices, supplements, and other topical fluoride agents, such comparisons are becoming more difficult to conduct. Accordingly, the effectiveness (rather than the efficacy) of water fluoridation has decreased as the benefits of other forms of fluoride have spread to communities lacking optimal water fluoridation.