Association between infant formula feeding and dental fluorosis and caries in Australian children

Objective: The objective of this study was to evaluate associations between patterns of infant formula feeding and dental fluorosis and caries in a representative sample of Australian children. Methods: A population‐based study gathered information on fluoride exposure in early childhood. Information on infant formula feeding and fluoridation status was used to group children: three groups in nonfluoridated areas (formula nonuser, user for ≤6 months, and user for 6+ months) and four groups in fluoridated areas (nonuser, user with nonfluoridated water, user with fluoridated water for ≤6 months, and user with fluoridated water for 6+ months). Children aged 8‐13 years were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Primary tooth caries experience recorded at age 8‐9 years was extracted from clinical records. Fluorosis cases were defined as having TF 1+ on maxillary incisors. Fluorosis prevalence and primary caries experience were compared across formula user groups in multivariable regression models adjusting for other factors. Results: Total sample was 588 children. Children in fluoridated areas had higher prevalence of very mild to mild fluorosis, but lower caries experience than those in nonfluoridated areas. Among children in nonfluoridated areas, formula users for 6+ months had significantly higher prevalence of fluorosis compared with nonusers. There was no significant difference in fluorosis prevalence among the formula users in fluoridated areas. Among children in fluoridated areas, formula users with nontap water had higher caries experience. Conclusion: Infant formula use was associated with higher prevalence of fluorosis in nonfluoridated areas but not in fluoridated areas. Type of water used for reconstituting infant formula in fluoridated areas was associated with caries experience.     

Dental Caries and Dental Fluorosis Among Schoolchildren Who Were Lifelong Residents of Communities Having Either Low or Optimal Levels of Fluoride in Drinking Water

Objective : This paper reports findings for dental caries and dental fluorosis in 8–10- and 13–16-year-old schoolchildren who were lifelong residents of communities having either naturally occurring low (Broken Bow and Holdrege, NE; <0.3 ppm) or optimal (Kewanee, IL; 1 ppm) levels of fluoride in drinking water. Methods : Findings are reported for participants who received both dental caries and dental fluorosis examinations (n=495). The DMFS and TSIF indices, respectively, were used to assess dental caries and dental fluorosis. Results : The mean DMFS score adjusted for age, sealant presence, and fluoride use was significantly lower in Kewanee (1.8) than was the adjusted mean caries score in either Holdrege (2.9) or Broken Bow (3.6). Adjusted mean DMFS scores in Broken Bow and Holdrege were not statistically different. The mean percent of fluorosed tooth surfaces per person, adjusted for age and use of dietary fluoride supplements, was similar in the three communities (approximately 15%); more than 80 percent of tooth surfaces in all participants were fluorosis-free. Conclusion : Findings from the present study suggest that water fluoridation still is beneficial and that dental sealants can play a significant role in preventing dental caries. In addition, findings from this survey appear to support the premise that the difference in dental fluorosis prevalence between fluoridated and nonfluoridated communities has narrowed considerably in recent years.     

The Results of Water Fluoridation in Ireland

The visit of Dr. Trendley Dean to Dublin in the mid-1950s helped accelerate the decision to introduce water fluoridation as a public health measure in the prevention of caries in the Republic of Ireland. A challenge to the constitutional validity of the Health (Fluoridation of Water Supplies) Act 1960 failed and in 1964 the water supplies of Dublin city were fluoridated. Over the next seven to eight years all the major urban communities in the Republic of Ireland were fluoridated. Currently, 67 percent of the 3.5 million people in the country reside in fluoridated communities. Studies conducted over the last 20 years show that residents of fluoridated communities have better dental health than those in nonfluoridated communities—the mean dmft is lower in children and the number of natural teeth present in adults is higher.     

Recent Dental Caries and Treatment Patterns in US Children

This report presents dental caries and treatment patterns found in a longitudinal study of US children between 1978 and 1982 who were geographically dispersed across several fluoridated and nonfluoridated sites. The analyses include first- and fifth-grade children examined annually for four years in the National Preventive Dentistry Demonstration Program and who did not receive effective preventive procedures. The results indicate that in association with the caries decline in US children, treatment ratios increased by over 20 percent during the study period. FS/DFS ratios averaged 79 percent for the four grade/fluoridation status cohorts analyzed and were significantly higher in fluoridated than in nonfluoridated sites. The single-fissured surface was the dominant treatment or disease area observed and these surfaces tended to be restored early. In assessing tooth-surface status changes annually, tooth surfaces were more than twice as likely to change from sound to filled than from sound to decayed between yearly examinations at fluoridated sites. The lower levels of decay and higher degree of restorative care observed were not observed in lower SES and black children nearly to the extent as those for higher SES and white children in the population. The dental profession should shift its emphasis from the early restoration of fissured-surface defects to an expanded use of sealants for those with reduced decay and focus resources on a minority of the population with high caries levels who receive limited care.     

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.     

Community fluoridation status and caries experience in children

OBJECTIVE: This study compares dental caries experience in fluoridated and nonfluoridated communities. METHODS: A dental health survey designed to collect data on caries experience and treatment needs for community-specific public health planning purposes was conducted in public elementary schools during the 1996-97 school year. Oral examinations of 17,256 children were completed, representing 93 percent of children residing in 62 East Tennessee communities. RESULTS: The analysis showed that water fluoridation was significantly related to caries experience in the primary (dfs) and permanent (DMFS) dentitions and to the proportion of caries-free children in the primary and permanent dentitions. When the data were adjusted for socioeconomic status, race, and age, caries levels were 21 percent lower in the primary dentition and 25 percent lower in the permanent dentition in fluoridated communities than in nonfluoridated communities. In addition, the proportion of children who were caries free was larger in fluoridated as compared with nonfluoridated communities by 19 percent in the primary dentition and 6 percent in the permanent dentition. CONCLUSION: Although the design of the study prevented the collection of individual fluoride and residency histories, findings suggest there was substantially lower caries experience in fluoridated communities than in nonfluoridated communities.     

Adult root caries survey of two similar communities with contrasting natural water fluoride levels

For a comparative study of root caries, 502 adult lifelong residents of a naturally fluoridated community (1.6 ppm F) and 465 such residents of a nearby, comparable nonfluoridated community (0.2 ppm F) were examined. Substantially fewer carious lesions were found among adults in the fluoridated community relative to the nonfluoridated community. This was observed in virtually all age- and gender-specific groups. Given a cross-sectional design and considering only exposed root surfaces, root caries was related to age. In addition, the data from this study show that the number of root caries lesions is underestimated but that root caries prevalence is overestimated by the standard Root Caries Index (RCI). A less restrictive form of the RCI may lead to more valid estimation of root caries prevalence.     

Pattern of dental caries experience on tooth surfaces in an adult population

OBJECTIVES: To determine the pattern of caries experience across teeth and surfaces in an adult population depending on age and exposure to water fluoridation. METHODS: Between November 2002 and March 2003 a total of 973 subjects aged 17-51 years had a clinical examination using visual and tactile criteria. Subsequent to this examination, bitewing radiographs were taken and viewed separately. Approximal and occlusal surfaces of molars and premolars were examined on the radiographs. RESULTS: Caries experience was relatively low, with mean DMFS scores of 3.21, 5.12, 9.61, 13.04 and 24.35 for subjects aged 17-20, 21-25, 26-30, 31-35 and 36-51 years respectively. The first molar teeth had the greatest caries experience, and occlusal surfaces had more caries experience than approximal surfaces. Subjects with a lifetime exposure to fluoridated drinking water had significantly lower caries experience than those who had no exposure to fluoridated drinking water. CONCLUSION: This study showed that caries prevalence, although relatively low in the study population, was found predominantly in occlusal surfaces, with an increasing prevalence in approximal surfaces of posterior teeth in older subjects. Subjects with a lifetime exposure to fluoridated drinking water had a lower level of caries experience than those with no exposure to fluoridated drinking water, and this was more noticeable in approximal surfaces than occlusal surfaces.     

Enamel defects and dental caries in 9-year-old children living in fluoridated and nonfluoridated areas of Auckland, New Zealand

Abstract – Objectives: This epidemiological study aims to investigate the developmental enamel defects and dental caries among 9‐year‐old children resident in fluoridated and nonfluoridated regions in Auckland, New Zealand. Methods: A stratified, two‐stage random selection design where strata were defined by fluoridation status, school size, and school decile. After informed consent was obtained, parents completed oral health questionnaires and children underwent dental examinations at school clinics. Results: 612 children from 38 schools participated in the study. Overall, 175 (29%) children had lived continuously in fluoridated areas, 149 (24%) had lived continuously in nonfluoridated areas, and 288 (47%) had resided intermittently in fluoridated areas. Diffuse opacities were present in 117 (19%) children and deciduous teeth dental caries was seen in 370 (60%) children. After adjustment for covariates, a strong dose–response relationship between diffuse opacity and fluoridation status was found, with children who lived continuously in fluoridated areas being 4.17 times as likely to have diffuse opacities as children who lived continuously in nonfluoridated areas (P < 0.001). Conversely, a strong protective dose–response relationship between caries experience and fluoridation status was seen, with children who lived continuously in fluoridated areas being 0.42 times as likely to have dental caries as children who lived continuously in nonfluoridated areas (P < 0.001). Conclusions: Reticulated water fluoridation in Auckland reduces the risk of dental caries but increases the risk of diffuse opacities in 9‐year‐old children. Guidelines and health‐promotion strategies that enable children to minimize their risk to diffuse opacities yet reduce their risk of dental caries should be reviewed.     

Patterns of dental caries following the cessation of water fluoridation

OBJECTIVES: To compare prevalence and incidence of caries between fluoridation-ended and still-fluoridated communities in British Columbia, Canada, from a baseline survey and after three years. METHODS: At the baseline (1993/4 academic year) and follow-up (1996/7) surveys, children were examined at their schools. Data were collected on snacking, oral hygiene, exposure to fluoride technologies, and socio-economic level. These variables were used together with D1D2MFS indices in multiple regression models. RESULTS: The prevalence of caries (assessed in 5,927 children, grades 2, 3, 8, 9) decreased over time in the fluoridation-ended community while remaining unchanged in the fluoridated community. While numbers of filled surfaces did not vary between surveys, sealed surfaces increased at both study sites. Caries incidence (assessed in 2,994 life-long residents, grades 5, 6, 11, 12) expressed in terms of D1D2MFS was not different between the still-fluoridating and fluoridation-ended communities. There were, however, differences in caries experienced when D1D2MFS components and surfaces at risk were investigated in detail. Regression models did not identify specific variables markedly affecting changes in the incidence of dental decay. CONCLUSIONS: Our results suggest a complicated pattern of disease following cessation of fluoridation. Multiple sources of fluoride besides water fluoridation have made it more difficult to detect changes in the epidemiological profile of a population with generally low caries experience, and living in an affluent setting with widely accessible dental services. There are, however, subtle differences in caries and caries treatment experience between children living in fluoridated and fluoridation-ended areas.     

Modification of occurrence of caries in children by toothbrushing and sugar exposure in fluoridated and nonfluoridated areas

Abstract A representative sample (2024 children, 7–16 years old) from fluoridated and nonfluoridated areas was studied. Structured questionnaires were used to collect data on oral health habits; caries diagnoses were made by local dentists in municipal dental clinics. In the fluoridated area a positive correlation existed between toothbrushing frequency and occurrence of dental caries. In the nonfluoridated area the correlation was negative. This difference in the effect of toothbrushing on caries was statistically significant. Sugar exposure increased the difference.     

Quantifying the diffused benefit from water fluoridation in the United States

OBJECTIVE: To estimate the total contribution of water fluoridation to caries reduction by including the benefit from the diffusion of fluoride from fluoridated communities to surrounding nonfluoridated communities via the export of bottled beverages and processed foods. METHODS: We analyzed data from the 1986-87 NIDR Children's Survey for 18,507 school children aged 6-17 years who had at least one permanent tooth and for whom a complete fluoride exposure history could be created. To measure water fluoridation exposure, we generated continuous and categorical exposure variables. Years of fluoridation exposure (YFE-continuous) measured the number of years the child lived at residences receiving fluoridated water. Lifetime fluoridation exposure (LFE-categorical) was high if the child lived at residences receiving fluoridated water more than 50% of his life and low, otherwise. We summed the proportion of state population receiving fluoridated water times the number of years the child had lived in each state and then divided this value by the child's age to measure diffusion exposure (DE). We grouped DE into three levels: low (DE<=0.25), medium (0.25=0.55). For each level of DE, we compared the age-adjusted mean DMFS for high and low LFE. In addition we used linear regression to measure the association between DMFS and YFE while controlling for DE, age, exposures to other fluoride sources, and sociodemographic variables. Reported results are significant at P<0.05. RESULTS: Comparison of mean DMFS scores found that the direct benefit of water fluoridation (DMFS(LFE=low) - DMFS(LFE=high)) was 1.44 surfaces among low DE children and 0 among high DE children. The diffused benefit (DMFS(LFE=low, DE=low) - DMFS(LFE=low, DE=high)) was 1.23 surfaces. The regression results were similar and indicated that the direct benefit would be 1.44 fewer DMFS for low DE children and the indirect benefit would be 1.09 fewer DMFS for high DE children. CONCLUSION: Failure to account for the diffusion effect may result in an underestimation of the total benefit of water fluoridation, especially in high diffusion exposure regions.     

The Association Between Enamel Fluorosis and Dental Caries in U.S. Schoolchildren

BackgroundThe authors assessed the association between enamel fluorosis and dental caries to determine if there is any beneficial effect of enamel fluorosis in U.S. schoolchildren.

MethodsThe authors used data from a National Institute of Dental Research survey of the oral health of U.S. children conducted in 1986 and 1987 to determine the prevalence of caries and mean decayed, missing or filled surfaces on permanent maxillary right first molars in children 7 to 17 years of age who had a history of a single residence. (To date, this is the only national oral health data set in the United States with detailed information on fluoride exposures.) They examined the association between enamel fluorosis and caries using logistic regression analysis, controlling for potential confounders in communities with water at or above optimal fluoridation levels and in communities with nonfluoridated or suboptimally fluoridated water.ResultsPermanent maxillary right first molars with fluorosis consistently had lower levels of caries experience than did normal molars. Adjusted odds ratios for caries prevalence in molars with fluorosis were 0.71 (95 percent confidence interval [CI], 0.56–0.89) in communities with nonfluoridated or suboptimally fluoridated water and 0.89 (95 percent CI, 0.74–1.06) in communities with water at or above optimal fluoridation levels.ConclusionThis study's findings suggest that molars with fluorosis are more resistant to caries than are molars without fluorosis.Clinical ImplicationsThe results highlight the need for those considering policies regarding reduction in fluoride exposure to take into consideration the caries-preventive benefits associated with milder forms of enamel fluorosis.     

Caries in permanent dentition and social class of children participating in public dental care in fluoridated and nonfluoridated areas

Abstract A random sample of 7-16-year-old children (n= 2778) who visited municipal dental clinics in fluoridated and nonfluoridated areas was studied. Structured questionnaires were used to collect data on social class and fluoride exposure; caries diagnoses were made by local dentists in municipal dental clinics. Children from the highest social class had the lowest caries frequency in both fluoridated and nonfluoridated areas. Differences between middle and lower class children were small. Water fluoridation had a similar effect in all social classes.     

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.     

Caries frequency in permanent teeth before and after discontinuation of water fluoridation in Kuopio, Finland

Abstract– The piped water of Kuopio, Finland, was fluoridated in 1959. Owing to strong opposition by different civic groups, water fluoridation was stopped at the end of 1992. Objectives: The aim of this study was to examine the consequences of the discontinuation on dental health. Methods: In 1992 and 1995, independent random samples of all children aged 6, 9, 12 and 15 years were drawn from Kuopio and Jyväskylä, a nearby low fluoride town whose distribution of demographic and socio-economic characteristics was fairly similar to Kuopio's. The total number of subjects examined was 550 in 1992 and 1198 in 1995. Caries was registered clinically and radiographically by the same two calibrated dentists in both towns. Results: In 1992, the mean DMFS values were lower in the fluoridated town for the two older age groups, the percentage differences for 12- and 15-year-olds being 37% and 29%, respectively. For the two younger age groups no meaningful differences could be found. In 1995, the only difference with possible clinical significance was found in the 15-year-olds in favor of the fluoridated town (18%). In 1995, a decline in caries was seen in the two older age groups in the nonfluoridated town. In spite of discontinued water fluoridation, no indication of an increasing trend of caries could be found in Kuopio. The mean numbers of fluoride varnish and sealant applications decreased sharply in both towns between 1992 and 1995. In spite of that caries declined. Conclusions: These findings suggest that the decline of caries has little to do with professional preventive measures performed in dental clinics.     

The geodemographic distribution of caries experience in neighboring fluoridated and nonfluoridated populations

OBJECTIVE: This study compares the geodemographic distribution of caries experience in neighboring fluoridated and nonfluoridated populations. METHODS: All 5-year-old children living in fluoridated (N=1,422) and nonfluoridated (N=4,779) areas of Cheshire, UK, were examined by trained and calibrated examiners. The Target Market level of the Super Profiles geodemographic classification was used to produce market penetration ranking reports for caries experience. The same area types were compared in fluoridated and nonfluoridated populations. Lorenz curves and Gini coefficients were generated from the outputs of the penetration rankings. RESULTS: There was a 12.4 percent difference in prevalence and a 29.4 percent difference in dmft between fluoridated (dmft>0=32.4%, dmft=1.01) and nonfluoridated (dmft>0=37.0%, dmft=1.43) areas. The area types at the top of both penetration rankings were deprived in nature and those at the bottom were affluent. The Gini coefficients in each area were 22.7 and 23.7 percent. CONCLUSIONS: The results demonstrate that water fluoridation is effective at preventing dental disease after controlling for confounding factors. In both populations the majority of disease was not confined to a small number of deprived area types. This undermines the contention that a targeted approach to caries prevention is a practical option.     

The Pre-and Posteruptive Effects of Fluoride in the Caries Decline

The widespread availability of fluoride from many sources is accepted as a major reason for the caries decline among children in developed countries. There is still controversy, however, about its principal mode of action. This article reviews the evidence on fluoride's preeruptive and posteruptive effects, and suggests reasons for its continuing role in the caries decline. Early fluoridation studies accepted that fluoride acted preruptively through incorporation into developing enamel; but further research could not explain why fluoride levels were not clearly higher in enamel exposed to fluoride, nor why there were no clear correlations between caries experience and enamel fluoride concentration. Instead, considerable evidence suggests that fluoride acts mainly, though not entirely, through posteruptive remineralization of demineralized enamel. Caries experience has declined in nonfluoridated as well as in fluoridated areas, though DMF scores are still consistently lower in fluoridated areas. Posteruptive remineralization effects are seen from fluoridated drinking water as well as with fluoride from other sources. The continuing caries decline, beyond the level suggested by early fluoridation field trials, can be attributed either to more efficient remineralization or to long-term, intraoral ecological change, or to both.     

Relationship of caries with socioeconomic status in 14-year-old children from communities with different fluoride histories

Abstract The aim of this study was to describe the caries prevalence of 14-yr-old children living in two fluoridated communities, a non-fluoridated community, and a community that discontinued fluoridation 5 yr before the children were examined and to relate the caries prevalence to socio-economic status. Clinical examinations were completed on 413 children of whom 227 had been continuously resident in their towns. Children living in the fluoridated communities had significantly lower mean CMFT and DMFS scores than those in the non-fluoridated town. The children from the town that had discontinued fluoridation 5 yr earlier had mean DMFT and DMFS score that occupied an intermediate position. The differences were greater when only the continuous residents were examined. There were significant differences in the mean DMFT and DMFS when comparing socioeconomic status and fluoridation of the water supply. No interaction effect was demonstrated between these two factors.     

Caries incidence and increments in Adelaide nursing home residents

The objective of The Adelaide Dental Study of Nursing Homes was to quantify coronal and root caries incidence and increments in residents of Adelaide nursing homes. A longitudinal design was used to conduct dental inspections, completed by calibrated dental examiners, for residents of 7 randomly selected nursing homes at both baseline and at one‐year follow‐up. The nursing home residents in this study were very functionally dependent, medically compromised, cognitively impaired and behaviorally difficult older adults. The coronal caries surface incidence was 64.4% and root caries surface incidence was 48.5%. There were 72.1% of residents who had coronal and/or root cartes increments between baseline and one‐year. The coronal and root caries increments in these residents were high (adjusted caries increment = 2.5 coronal and 1.0 root surfaces), and were many times greater than that reported from a longitudinal study of community‐dwelling older adults in Adelaide. Residents with eating and nutritional problems developed high levels of new caries. Both coronal and root caries incidence and increments were high in these nursing home residents over the one‐year follow‐up period.