Refining the estimate of the critical period for susceptibility to enamel fluorosis in human maxillary central incisors

Does the Transillumination Technique Using a Diagnostic White Tip Influence the Degree of Conversion of the Infiltrant Resin? A Case Report With In Vitro Insights: A New Technique to Improve the Predictability During the Application of Resin Infiltration: Transillumination Using a Diagnostic White Tip

OBJECTIVE

This study aimed to evaluate, through a case report combined with in vitro study, whether a new diagnostic white tip for the transillumination technique during resin infiltration influences the procedure and degree of conversion (DC).

MATERIALS AND METHODS

A clinical case report demonstrated resin infiltration using the transillumination technique with a new white diagnostic tip (Radii Xpert LED diagnostic tip, SDI, Bayswater, VIC, AU) along with a light-curing device to enhance aesthetic results. An in vitro study assessed the DC of two diagnostic white tips (Radii Xpert LED diagnostic tip [SDI, Bayswater, VIC, AU] and Valo Grand White Light Lens [Ultradent Prod., South Jordan, UT, USA]) compared to that achieved using conventional tips of both light-curing devices. Statistical analysis was performed using two-way ANOVA and Tukey's test (α = 0.05).

RESULTS

The clinical case achieved complete masking of the white spot lesion. In vitro, the diagnostic white tips exhibited significantly lower DC values compared to conventional tips (p = 0.001), regardless of the light-curing unit.

CONCLUSIONS

The diagnostic white tip used in the transillumination technique improves resin infiltration visibility without compromising the degree of conversion.

CLINICAL SIGNIFICANCE

The transillumination technique with the diagnostic white tip enables monitoring of resin infiltration while maintaining effective polymerization.

Salivary proteomic signatures in severe dental fluorosis

The relationship between dental fluorosis and alterations in the salivary proteome remains inadequately elucidated. This study aimed to investigate the salivary proteome and fluoride concentrations in urine and drinking water among Thai individuals afflicted with severe dental fluorosis. Thirty-seven Thai schoolchildren, aged 6-16, were stratified based on Thylstrup and Fejerskov fluorosis index scores: 10 with scores ranging from 5 to 9 (SF) and 27 with a score of 0 (NF). Urinary and water fluoride levels were determined using an ion-selective fluoride electrode. Salivary proteomic profiling was conducted via LC-MS/MS, followed by comprehensive bioinformatic analysis. Results revealed significantly elevated urinary fluoride levels in the SF group (p = 0.007), whereas water fluoride levels did not significantly differ between the two cohorts. Both groups exhibited 104 detectable salivary proteins. The NF group demonstrated notable upregulation of LENG9, whereas the SF group displayed upregulation of LDHA, UBA1, S100A9, H4C3, and LCP1, all associated with the CFTR ion channel. Moreover, the NF group uniquely expressed 36 proteins, and Gene Ontology and pathway analyses suggested a link with various aspects of immune defense. In summary, the study hypothesized that the CFTR ion channel might play a predominant role in severe fluorosis and highlighted the depletion of immune-related salivary proteins, suggesting compromised immune defense in severe fluorosis. The utility of urinary fluoride might be a reliable indicator for assessing excessive fluoride exposure.

Fluoride and its Implications on Oral Health: A Review

This article aims to review the literature about the history of fluoride, its toxicity, prevalence, prevention, diagnosis, and management in oral healthcare practice. Fluoride is the cornerstone of oral health, playing a pivotal role in oral health. Fluoride can be administered topically or systemically. Topically, it is found in toothpaste, mouth rinses, and professional treatments such as fluoride varnish. These directly shield teeth from decay and strengthen the existing enamel. Systemically, fluoride is ingested through water, foods, or supplements, benefiting tooth development, especially in children. Nevertheless, responsible fluoride use is essential. Overexposure can lead to dental fluorosis, affecting tooth aesthetics. Consulting a dentist for personalized guidance on fluoride usage can help strike the right balance between oral protection and potential side effects, ensuring a radiant and healthy smile for life.

Estimated Dietary Fluoride Intake by 24-Month-Olds from Chocolate Bars, Cookies, Infant Cereals, and Chocolate Drinks in Brazil

The use of fluoride (F) in the prevention of dental caries is established. However, a high amount of F intake during tooth development can cause dental fluorosis The aim of this study was to analyze variations in F concentrations in chocolate bars (CB), chocolate cookies (CC), infant cereals (IC), and chocolate milk drinks (CD) to determine the daily intake of F from different sources by children at the age of risk for developing dental fluorosis. Distinct brands of CB, CC, IC, and CD were analyzed. Fluoride was separated by hexamethyldisiloxane-facilitated diffusion. Analysis was made in triplicate with an F ion-specific electrode. F ingestion (mg/kg body weight) was evaluated with the suggested consumption (0.05-0.07 mg/kg/day) for children aged 24 months (12 kg). The concentrations for all the analyzed products ranged from 0.025 to 1.827 µg/g F. The mean (range) F concentrations were CB= 0.210 ± 0.205 µg/g (0.073-0.698, n = 8), CC = 0.366 ± 0.416 µg/g (0.320-1.827, n = 9), IC = 0.422 ± 0.395 µg/g (0.073-1.061, n = 5), and CD = 0.169 ± 0.170 µg/mL (0.025-0.443, n = 12). The products that had the highest concentration in the categories CB, CC, IC, and CD, respectively, were Nescau-Ball (0.698 µg/g), Passatempo (1.827 µg/g), Milnutri (1.061 µg/g), and Toddynho (0.443 µg/mL). The consumption of only one unit of Toddynho (CD) is equivalent to more than 11% of the maximum suggested daily intake for a 24-month-old child (0.07 mg/kg body weight). When one product from each category is consumed together only once a day, this consumption is equivalent to approximately 24% of the suggested daily intake of fluoride for a 24-month-old child. The presence of high levels of fluoride in certain products suggests that they play a significant role in overall fluoride intake. It is crucial to closely monitor the fluoride content of food and drinks that are consumed by children who are at risk for dental fluorosis, and for product labels to clearly display the fluoride concentrations.

Single Nucleotide Polymorphisms and Dental Fluorosis: A Systematic Review

Genetic factors contribute to susceptibility and resistance to fluoride exposure. The aim of this systematic review was to identify alleles/genotypes of single nucleotide polymorphisms (SNPs) associated with dental fluorosis (DF) and to identify them as protective or risk factors. PubMed, ScienceDirect, Cochrane Library, Scopus and Web of Science were searched for articles; the last search was performed in August 2022. Human studies that analyzed the relationship between SNPs and DF published in English were included; systematic reviews and meta-analyses were excluded. Methodological quality was graded using the Joanna Briggs Institute checklist and risk of bias was assessed using the Cochrane Collaboration's tool. Eighteen articles were included, 44% of which showed high methodological quality and data from 5,625 participants aged 6 to 75 years were analyzed. The SNPs COL1A2, ESR2, DLX1, DLX2, AMBN, TUFT1, TFIP11, miRNA17, and SOD2 were considered risk factors, and ESR1, MMP20, and ENAM were considered protective factors. In conclusion, there are alleles and genotypes of different single nucleotide polymorphisms involved in increasing or decreasing the risk of developing dental fluorosis.

Fractional urinary fluoride excretion and nail fluoride concentrations in normal, wasted and stunted 4-5 year-old children in Nepal

INTRODUCTION

It has been suggested that undernourished children are more likely to develop dental fluorosis. We investigated the effects of nutritional status on systemic fluoride metabolism including the proportion of ingested fluoride excreted through urine (i.e. fractional urinary fluoride excretion - FUFE) and fluoride concentration in nail clippings in children, aged 4-5 years, in Nepal.

METHODS

Nutritional status was evaluated using weight-for-age (wasting) and height-for-age (stunting) indices. Total daily fluoride intake (TDFI) was estimated from diet and toothpaste ingestion and 24 -h urine collected to assess daily urinary fluoride excretion (DUFE). FUFE was calculated by dividing DUFE by TDFI. Nail clippings (finger and toe) were collected and analysed for fluoride concentration.

RESULTS

Of the 100 children who participated, 89 provided information to assess FUFE and 51 children provided nail samples. Overall, 86.5 % of the 89 children were wasted and 39.3 % were stunted. When the samples were pooled into binary (affected and non-affected) categories, mean TDFI and mean DUFE were statistically significantly higher in the 77 wasted children (57.7 and 29.7 μg/kgbw/d, respectively) than the 12 non-wasted children (39.4 and 17.0 μg/kgbw/d, respectively). TDFI and DUFE were also statistically significantly higher in the 35 stunted children (65.1 and 34.5 μg/kgbw/d, respectively) than in the 54 non-stunted children (48.8 and 23.7 μg/kgbw/d, respectively). However, mean FUFE was similar in all groups. There were no statistically significant differences in fluoride concentration of either fingernails or toenails among the different categories of wasting, while mean fingernail fluoride concentration was statistically significantly higher in stunted (5.4 μg/g) than in non-stunted children (3.5 μg/g).

CONCLUSION

Our study found no significant effect of nutritional status on the proportion of ingested fluoride excreted in urine (and consequently the proportion retained in the body). These findings suggest that nutritional status may be less likely to be a main risk factor for the development of dental fluorosis than children's dietary habits or total fluoride intake.

Dental fluorosis prevalence in Saudi Arabia

Aim

In order to improve the understanding of dental fluorosis prevalence in Saudi Arabia and have a good idea of the quality of the studies that have been conducted, a systematic review was conducted to evaluate the prevalence of dental fluorosis among people who live in Saudi Arabia.

Methods

Online databases EMBASE and MEDLINE and the Cochrane Library were searched, without any restriction regarding age. In addition, there were no study design filters applied to the search engine. Study selection and data extraction were conducted in duplicate. Studies were included if they were conducted in Saudi Arabia on any population (adults and children) and collected dental fluorosis data. The Newcastle-Ottawa Scale (NOS) was used to assess the quality of the studies. A narrative synthesis was conducted.

Results

Seven cross-sectional studies were identified. Areas of weakness in study design/conduct were low response rates, and identification and handling of confounding factors. Statistical pooling of data was not appropriate due to substantial heterogeneity, due in part to variation in sample size, variation of water fluoridation concentration, index used, targeted population and age group. Seven studies present dental fluorosis at any level. The proportion of dental fluorosis prevalence at any level ranged from 0.00 to 0.91. Six studies explored the prevalence of dental fluorosis of aesthetic-only level of concern. The proportion of dental fluorosis in this category ranged from 0.07 to 0.76.

Conclusion

The proportion of dental fluorosis at any level ranged from 0.00 to 0.91 and fluorosis at aesthetics level ranged from 0.07 to 0.76. However, current data does not provide a complete assessment of dental fluorosis across Saudi Arabia. Existing studies are limited in terms of the population covered. The included studies had methodological flaws.

Comparative Evaluation of Antibacterial Effect of Propolis and Aloe Vera, Xylitol, and Cpp-Acp Gels on Streptococcus mutans and Lactobacillus in Vitro

Introduction

Early childhood caries is a kind of caries occurring in deciduous teeth. Bacteria are among the main factors. Antibacterial agents such as fluoride are used in both prevention and treatment, but their application in children faces limitations such as fluorosis. Therefore, novel methods of caries prevention among the children are mainly focused on the use of fluoride-free active ingredients. In this comparative study, antibacterial effects of gels containing propolis and aloe vera, fluoride, xylitol, and CPP-ACP were investigated.

Methods

This is an in vitro study. By plate well technique, plates containing gels were created in the culture medium of Streptococcus mutans and Lactobacillus, and their antibacterial impacts were evaluated by measuring the inhibition zone after 24, 48, and 72 hours. Then, different concentrations of each gel were evaluated in the same way for the antibacterial properties. For each sample, this process was iterated 3 times, where the average was declared as the final number. The collected data were entered in SPSS 24.

Results

In both bacteria, propolis gel and aloe vera had the highest zone of inhibition, followed by fluoride and xylitol in the second and third places, respectively. Different concentrations of gels are significantly different in terms of antimicrobial effect (P value ≤ 0/05). The antimicrobial effect of propolis and aloe vera gel was kept up to the concentration of 1/16. As the bacterial and gel contact time is prolonged, the antibacterial effect of different gels increases, but the difference is not statistically significant (P value = 0.109). CPP-ACP gel had no antimicrobial effect at any concentration.

Conclusion

Propolis and aloe vera gel had a greater antimicrobial effect than other gels, where such effect was observed in low concentrations. CPP-ACP gel had no antimicrobial properties.

Clinical changes in the severity of dental fluorosis: a longitudinal evaluation

BACKGROUND

Dental fluorosis (DF) has been one of the most prevalent pediatric dental conditions associated with aesthetic concern and treatment needs. This study aimed to identify the longitudinal clinical change in the severity of DF in 8-12-year-old children and its association with gender, age, severity, and tooth type.

METHODS

This observational study assessed the dental aspects of the 92 Colombian children in 2015 (mean age at beginning 9.71 years ± 1.23) and 2018 (mean age 13.69 years ± 1.41), from an area with high DF prevalence. DF was recorded in all permanent teeth by two calibrated examiners using the Thylstrup and Fejerskov Index (TFI). DF severity change (maximum-TFI-score) was analyzed with descriptive analysis at the tooth level. Associated factors were evaluated with the generalized linear model, binomial family, and logarithmic link function.

RESULTS

TFI scores ranged between 1 (very mild) to 6 (severe), being score 2 (41.7%) the most prevalent. After three years, 29.6% of the teeth presented score reduction, 24.1%, increased and 46.3% did not change; the significant association was related to increasing of the basal TFI = 1 score (44.2%) (RR = 9.7; 95% CI 1.7-56.5; p = 0.01) and with canines, premolars and second-permanent-molars teeth group (RR = 3.3; 95% CI 1.9-5.6; p = 0.005).

CONCLUSION

The present study based on clinical features about DF confirms the dynamic post-eruptive nature of this condition. After three years of follow-up, a considerable proportion of the teeth changed to a higher score. Furthermore, the canines, premolars, and second-permanent-molars showed a higher incidence of an increase in severity of TFI score.

Dental fluorosis in the Australian adult population

BACKGROUND

The use of fluoride involves a balance between protection against caries and risk of dental fluorosis. Prevalence and trend of dental fluorosis in the adult population are not frequently reported.

OBJECTIVE

To describe the prevalence of dental fluorosis in the Australian adult population.

METHOD

Data from the National Study of Adult Oral Health (NSAOH) 2004-06 and 2017-18 were used. Prevalence of fluorosis was reported using data from the NSAOH 2017-18. Case definitions of fluorosis were as follows: having a TF score of 2+ (TF2+) or a TF score of 3+ (TF3+) on one or more maxillary central incisors. Synthetic cohorts were constructed by year of birth allowing for time trend analysis.

RESULTS

One in ten Australian adults were found to have dental fluorosis at TF2+. The prevalence of TF3 + was low. Time trend analysis revealed an increase in the prevalence and severity of fluorosis among those born during 1970s to 1980s decade. Such prevalence declined among those who were born after measures were introduced in early 1990s to reduce exposure to discretionary fluorides.

CONCLUSION

The prevalence of dental fluorosis in the Australian adult population was found to be related to population-level changes in fluoride exposure.

Current Guidance for Fluoride Intake: Is It Appropriate?

The purpose of this report is to examine critically the appropriateness of the current guidance for fluoride intake in the population (0.05-0.07 mg F/kg bodyweight/d), consider whether changes to the current guidance are desirable, and suggest further research that will strengthen the evidence base for future decisions on guidance/advice in this area. The benefits and the risks of using fluoride particularly concern preschool children because it is at this age that excessive fluoride intake may result in dental fluorosis. Data from mostly cross-sectional studies show a wide variation in exposure and a considerable variation in the amount of fluoride ingested. Fluorosis, mostly mild, is commonly observed. For considering changes in current guidance, there is a need for more knowledge on the relationship between exposure to fluoride at an early age and the development of fluorosis. For that, prospective epidemiological studies with sufficiently large and representative samples of children are required. It is also important to study children in communities both with and without water fluoridation and to include populations where salt or milk fluoridation is used. There is also a need for professional agreement on acceptable levels of mild and moderate/severe fluorosis and a more comprehensive knowledge on the appreciation of mild fluorosis among the public.

Fluoride Revolution and Dental Caries: Evolution of Policies for Global Use

Epidemiological studies over 70 y ago provided the basis for the use of fluoride in caries prevention. They revealed the clear relation between water fluoride concentration, and therefore fluoride exposure, and prevalence and severity of dental fluorosis and dental caries. After successful trials, programs for water fluoridation were introduced, and industry developed effective fluoride-containing toothpastes and other fluoride vehicles. Reductions in caries experience were recorded in many countries, attributable to the widespread use of fluoride. This is a considerable success story; oral health for many was radically improved. While previously, water had been the only significant source of fluoride, now there are many, and this led to an increase in the occurrence of dental fluorosis. Risks identified for dental fluorosis were ingestion of fluoride-containing toothpaste, water fluoridation, fluoride tablets (which were sometimes ingested in areas with water fluoridation), and infant formula feeds. Policies were introduced to reduce excessive fluoride exposure during the period of tooth development, and these were successful in reducing dental fluorosis without compromising caries prevention. There is now a much better understanding of the public perception of dental fluorosis, with mild fluorosis being of no aesthetic concern. The advantages of water fluoridation are that it provides substantial lifelong caries prevention, is economic, and reduces health inequalities: it reaches a substantial number of people worldwide. Fluoride-containing toothpastes are by far the most important way of delivering the beneficial effect of fluoride worldwide. The preventive effects of conjoint exposure (e.g., use of fluoride toothpaste in a fluoridated area) are additive. The World Health Organization has informed member states of the benefits of the appropriate use of fluoride. Many countries have policies to maximize the benefits of fluoride, but many have yet to do so.

Exposição a fluoreto por crianças na faixa etária crítica para fluorose dentária, residentes no semiárido brasileiro

Resumo Há uma preocupação com o aumento da prevalência de fluorose dentária, que depende da dose de fluoreto (F) a que as crianças são submetidas durante a formação dos dentes. A temperatura ambiental afeta a ingestão de água e, portanto, seria importante avaliar se as crianças que vivem em uma região de clima semiárido estão expostas a uma dose excessiva de F. Assim, o objetivo do presente estudo foi determinar a dose total de F a que as crianças são expostas durante a idade crítica para a fluorose dentária, tendo dieta (água e alimentos) e dentifrício como fontes de F, em uma região de clima semiárido no Brasil. Metodologia: foram selecionadas 26 crianças com idade de 25,2 ± 9,1 meses, residentes em Feira de Santana-BA. Foram coletadas amostras de dieta-duplicada, água, produtos de escovação e dentifrícios. A concentração de F foi determinada após o devido preparo das amostras, utilizando um eletrodo específico. Resultados: a média e o desvio padrão de dose (mg F / kg / dia) em função da dieta, dentifrício e total foram, respectivamente: 0,016 ± 0,010; 0,030 ± 0,039 e 0,047 ± 0,043. Conclusões: as crianças avaliadas, residentes em uma região de clima semiárido, não estão expostas a uma dose de risco de fluorose dentária.

Timing of fluoride intake and dental fluorosis on late-erupting permanent teeth

OBJECTIVE

Very few studies have examined the relationship between timing of fluoride intake and development of dental fluorosis on late-erupting permanent teeth using period-specific fluoride intake information. This study examined this relationship using longitudinal fluoride intake information from the Iowa Fluoride Study.

METHODS

Participants' fluoride exposure and intake (birth to 10 years of age) from water, beverages, selected food products, dietary fluoride supplements, and fluoride toothpaste was collected using questionnaires sent to parents at 3- and 4- month intervals from birth to 48 months of age and every 6 months thereafter. Three trained and calibrated examiners used the Fluorosis Risk Index (FRI) categories to assess 16 late-erupting teeth among 465 study participants. A tooth was defined as having definitive fluorosis if any of the zones on that tooth had an FRI score of 2 or 3. Participants with questionable fluorosis were excluded from analyses. Descriptive and logistic regression analyses were performed to assess the importance of fluoride intake during different time periods.

RESULTS

Most dental fluorosis in the study population was mild, with only four subjects (1%) having severe fluorosis (FRI Score 3). The overall prevalence of dental fluorosis was 27.8%. Logistic regression analyses showed that fluoride intake from each of the individual years from age 2 to 8 plays an important role in determining the risk of dental fluorosis for most late-erupting permanent teeth. The strongest association for fluorosis on the late-erupting permanent teeth was with fluoride intake during the sixth year of life.

CONCLUSION

Late-erupting teeth may be susceptible to fluorosis for an extended period from about age 2 to 8. Although not as visually prominent as the maxillary central incisors, some of the late-erupting teeth are esthetically important and this should be taken into consideration when making recommendations about dosing of fluoride intake.

The association between social deprivation and the prevalence and severity of dental caries and fluorosis in populations with and without water fluoridation

BACKGROUND

To determine the association between social deprivation and the prevalence of caries (including caries lesions restricted to enamel) and enamel fluorosis in areas that are served by either fluoridated or non-fluoridated drinking water using clinical scoring, remote blinded, photographic scoring for caries and fluorosis. The study also aimed to explore the use of remote, blinded methodologies to minimize the effect of examiner bias.

METHODS

Subjects were male and female lifetime residents aged 11-13 years. Clinical assessments of caries and fluorosis were performed on permanent teeth using ICDAS and blind scoring of standardized photographs of maxillary central incisors using TF Index (with cases for fluorosis defined as TF > 0).

RESULTS

Data from 1783 subjects were available (910 Newcastle, 873 Manchester). Levels of material deprivation (Index of Multiple Deprivation) were comparable for both populations (Newcastle mean 35.22, range 2.77-78.85; Manchester mean 37.04, range 1.84-84.02). Subjects in the fluoridated population had significantly less caries experience than the non-fluoridated population when assessed by clinical scores or photographic scores across all quintiles of deprivation for white spot lesions: Newcastle mean DMFT 2.94 (clinical); 2.51 (photo), Manchester mean DMFT 4.48 (clinical); 3.44 (photo) and caries into dentine (Newcastle Mean DMFT 0.65 (clinical); 0.58 (photo), Manchester mean DMFT 1.07 (clinical); 0.98 (photo). The only exception being for the least deprived quintile for caries into dentine where there were no significant differences between the cities: Newcastle mean DMFT 0.38 (clinical); 0.36 (photo), Manchester mean DMFT 0.45 (clinical); 0.39 (photo). The odds ratio for white spot caries experience (or worse) in Manchester was 1.9 relative to Newcastle. The odds ratio for caries into dentine in Manchester was 1.8 relative to Newcastle. The odds ratio for developing fluorosis in Newcastle was 3.3 relative to Manchester.

CONCLUSIONS

Water fluoridation appears to reduce the social class gradient between deprivation and caries experience when considering caries into dentine. However, this was associated with an increased risk of developing mild fluorosis. The use of intra-oral cameras and remote scoring of photographs for caries demonstrated good potential for blinded scoring.

Alternative esthetic management of fluorosis and hypoplasia stains: blending effect obtained with resin infiltration techniques

STATEMENT OF PROBLEM

New light-polymerized resin composites optimized for rapid infiltration of enamel lesions with resin light curing monomers are commercially available today to prevent enamel lesions from further demineralization and provide a highly conservative therapy. In addition, this technique has proved to be effective treatment for blending white spot lesions because the microporosities of infiltrated lesions are filled with resin.

PURPOSE

This clinical report presents and describes cases in which the minimally invasive infiltrant resin technique was used for blending different microporous lesions, mild-to-moderate fluorosis, and hypoplasia stains related to traumatic dental injuries.

RESULTS

The fluorosis stain showed visually perceptual improvements. In the cases of hypoplasia, stains were not completely blended. However, the general clinical outcomes of these cases were considered successful and recovered the patients' self-esteem.

CONCLUSION

Based on the results obtained, it could be concluded that the resin infiltration technique shows promising results and could be considered a minimally invasive procedure for mild-to-moderate fluorosis and hypoplasia stains.

CLINICAL SIGNIFICANCE

This case study allows a better understanding of the concept of the resin infiltration technique applied in other types of porous lesions, increasing its use as a therapeutic alternative for esthetic purposes in the philosophy of minimally invasive dentistry.

Fluoride

Fluoride is a naturally occurring element with multiple implications for human health. This review discusses its metabolism and toxicity, along with the current understanding of the mechanism of action of fluoride and its role as a safe and effective agent in the prevention of dental caries. The relationship between excessive fluoride intake during periods of dental enamel formation and the development of dental fluorosis is also reviewed.

Determination of fluoride concentration in powdered milk in Iran 2010

High concentrations of fluoride (F) in powdered milk (formula milk) can have adverse health effects on the body. The F concentration in powdered milk was analysed in Iran in 2010. A total of twelve commercial brands of highly consumed powdered milk were selected to analyse the F content through the standard F ion-selective electrode method. From each brand, three samples with different production dates were selected. The means and standard deviation for F concentration in all the samples was 1·73 (sd 0·3) μg F/g. The minimum and maximum F content in powdered milk brands Humana2 and Humana3 was 1·32 (sd 0·1) and 2·36 (sd 0·3) μg F/g, respectively. The study revealed that there was no significant difference in F concentration in the samples that belonged to various dates. Humana3 had a high F concentration (with an average of 2·36 (sd 0·3) μg F/g), which can be a risk factor for increased dental fluorosis, especially when being prepared using water with a high content of F.

Evidence-based clinical recommendations regarding fluoride intake from reconstituted infant formula and enamel fluorosis: a report of the American Dental Association Council on Scientific Affairs

BACKGROUND

This article presents evidence-based clinical recommendations regarding the intake of fluoride from reconstituted infant formula and its potential association with enamel fluorosis. The recommendations were developed by an expert panel convened by the American Dental Association (ADA) Council on Scientific Affairs (CSA). The panel addressed the following question: Is consumption of infant formula reconstituted with water that contains various concentrations of fluoride by infants from birth to age 12 months associated with an increased risk of developing enamel fluorosis in the permanent dentition?

TYPES OF STUDIES REVIEWED

A panel of experts convened by the ADA CSA, in collaboration with staff of the ADA Center for Evidence-based Dentistry (CEBD), conducted a MEDLINE search to identify systematic reviews and clinical studies published since the systematic reviews were conducted that addressed the review question.

RESULTS

CEBD staff identified one systematic review and two clinical studies. The panel reviewed this evidence to develop recommendations.

CLINICAL IMPLICATIONS

The panel suggested that when dentists advise parents and caregivers of infants who consume powdered or liquid concentrate infant formula as the main source of nutrition, they can suggest the continued use of powdered or liquid concentrate infant formulas reconstituted with optimally fluoridated drinking water while being cognizant of the potential risks of enamel fluorosis development. These recommendations are presented as a resource to be considered in the clinical decision-making process. As part of the evidence-based approach to care, these clinical recommendations should be integrated with the practitioner's professional judgment and the patient's needs and preferences.

Fluoride effect on the secretory-stage enamel organic extracellular matrix of mice

The formation of an ordered enamel organic extracellular matrix (EOECM) seems to be a crucial step for the proper formation of the enamel mineral phase. The ordered supramolecular structure of the EOECM in the secretory stage can be analyzed using polarizing microscopy, as it is strongly birefringent. Excessive fluoride (F) ingestion during tooth development can cause enamel fluorosis, leading to increased porosity in mature enamel. We analyzed the effects of F on the birefringence of the EOECM in the A/J, CBA, and DBA/2 strains of mice given 0, 11.25, and 45 ppm of fluoride in drinking water. In the CBA and DBA/2 strains, the 11.25 and 45 ppmF groups presented a significant decrease in optical retardation (OR) when compared with the respective 0 (CBA 11.25 ppmF p = 0.0056 and 45 ppmF p < 0.0001; DBA/2 11.25 and 45 ppmF p < 0.05). ORs in A/J 0 ppmF were significantly higher than in 45 (p < 0.0001). The enamel of the A/J strain was more severely affected by fluoride than it was in the other strains of mice and exhibited the lowest levels of fluoride in plasma, whereas its normal secretory enamel presented a significantly higher protein absorbance than it did in CBA and DBA mice (p = 0.0099 and p = 0.0025, respectively). The results showed that experimental fluorosis can alter the supramolecular organization of EOECM in the secretory stage of amelogenesis and that the susceptibility to dental fluorosis seems to be influenced by the inherent characteristics of the developing enamel.

Fluoride consumption and its impact on oral health

OBJECTIVE

The purpose of this study was to evaluate caries and dental fluorosis among Mexican preschoolers and school-aged children in a non-endemic zone for fluorosis and to measure its biological indicators.

METHODS

DMFT, DMFS, dmft, dmfs, and CDI indexes were applied. Fluoride urinary excretion and fluoride concentrations in home water, table salt, bottled water, bottled drinks, and toothpaste were determined.

RESULTS

Schoolchildren presented fluorosis (CDI = 0.96) and dental caries (DMFT = 2.64 and DMFS = 3.97). Preschoolers presented dmft = 4.85 and dmfs = 8.80. DMFT and DMFS were lower in children with mild to moderate dental fluorosis (DF). Variable fluoride concentrations were found in the analyzed products (home water = 0.18-0.44 ppm F, table salt = 0-485 ppm F, bottled water = 0.18-0.47 ppm F, juices = 0.08-1.42 ppm F, nectars = 0.07-1.30 ppm F, bottled drinks = 0.10-1.70 ppm F, toothpaste = 0-2,053 ppm F). Mean daily fluoride excretion was 422 ± 176 μg/24 h for schoolchildren and 367 ± 150 μg/24 h for preschoolers.

CONCLUSIONS

Data from our study show that, despite values of excretion within an optimal fluoride intake range, the prevalence of caries was significant in both groups, and 60% of the 11- to 12-year-old children presented with dental fluorosis. In addition, variable fluoride concentrations in products frequently consumed by children were found.

Fluoride does not inhibit enamel protease activity

Fluorosed enamel can be porous, mottled, discolored, hypomineralized, and protein-rich if the enamel matrix is not completely removed. Proteolytic processing by matrix metalloproteinase-20 (MMP20) and kallikrein-4 (KLK4) is critical for enamel formation, and homozygous mutation of either protease results in hypomineralized, protein-rich enamel. Herein, we demonstrate that the lysosomal proteinase cathepsin K is expressed in the enamel organ in a developmentally defined manner that suggests a role for cathepsin K in degrading re-absorbed enamel matrix proteins. We therefore asked if fluoride directly inhibits the activity of MMP20, KLK4, dipeptidyl peptidase I (DPPI) (an in vitro activator of KLK4), or cathepsin K. Enzyme kinetics were studied with quenched fluorescent peptides with purified enzyme in the presence of 0-10 mM NaF, and data were fit to Michaelis-Menten curves. Increasing concentrations of known inhibitors showed decreases in enzyme activity. However, concentrations of up to 10 mM NaF had no effect on KLK4, MMP20, DPPI, or cathepsin K activity. Our results show that fluoride does not directly inhibit enamel proteolytic activity.

Combined effect of fluoride and 2,3,7,8-tetrachlorodibenzo-p-dioxin on mouse dental hard tissue formation in vitro

Fluoride interferes with enamel matrix secretion and mineralization and dentin mineralization. The most toxic dioxin congener, 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), also impairs dental hard tissue formation and mineralization in vitro and in vivo. Our aim was to investigate in vitro whether the combined effect of sodium fluoride (NaF) and TCDD on dental hard tissue formation is potentiative. For this purpose, mandibular first and second molar tooth germs of E18 mouse embryos were cultured for 5-12 days with NaF and TCDD alone at various concentrations (2.5, 5, 10, 12.5, 15, and 20 μM and 5, 10, 12.5, and 15 nM, respectively) to determine the highest concentrations, which alone cause no or negligible effects. Morphological changes were studied from the whole tooth photographs and histological tissue sections. The concentrations found were 15 μM for NaF and 10 nM for TCDD. While at these concentrations, the effects of NaF and TCDD alone were barely detectable, the effect of simultaneous exposure on dentin and enamel formation was overt; mineralization of predentin to dentin and enamel matrix secretion and mineralization were impaired. Immunohistochemical analysis revealed that the combined exposure modified amelogenin expression by odontoblasts. Morphology of ameloblasts and the expression of amelogenin indicated that ameloblasts were still secretory. The results show that NaF and TCDD have potentiative, harmful effects on the formation of dental hard tissues. Since children can be exposed to subclinical levels of fluoride and dioxins during early childhood, coincidently with mineralization of the first permanent teeth, this finding may have clinical significance.

Associations between fluorosis of permanent incisors and fluoride intake from infant formula, other dietary sources and dentifrice during early childhood

OBJECTIVES

The authors describe associations between dental fluorosis and fluoride intakes, with an emphasis on intake from fluoride in infant formula.

METHODS

The authors administered periodic questionnaires to parents to assess children's early fluoride intake sources from beverages, selected foods, dentifrice and supplements. They later assessed relationships between fluorosis of the permanent maxillary incisors and fluoride intake from beverages and other sources, both for individual time points and cumulatively using area-under-the-curve (AUC) estimates. The authors determined effects associated with fluoride in reconstituted powdered infant formulas, along with risks associated with intake of fluoride from dentifrice and other sources.

RESULTS

Considering only fluoride intake from ages 3 to 9 months, the authors found that participants with fluorosis (97 percent of which was mild) had significantly greater cumulative fluoride intake (AUC) from reconstituted powdered infant formula and other beverages with added water than did those without fluorosis. Considering only intake from ages 16 to 36 months, participants with fluorosis had significantly higher fluoride intake from water by itself and dentifrice than did those without fluorosis. In a model combining both the 3- to 9-months and 16- to 36-months age groups, the significant variables were fluoride intake from reconstituted powder concentrate formula (by participants at ages 3-9 months), other beverages with added water (also by participants at ages 3-9 months) and dentifrice (by participants at ages 16-36 months).

CONCLUSIONS

Greater fluoride intakes from reconstituted powdered formulas (when participants were aged 3-9 months) and other water-added beverages (when participants were aged 3-9 months) increased fluorosis risk, as did higher dentifrice intake by participants when aged 16 to 36 months.

CLINICAL IMPLICATIONS

Results suggest that prevalence of mild dental fluorosis could be reduced by avoiding ingestion of large quantities of fluoride from reconstituted powdered concentrate infant formula and fluoridated dentifrice.

Prevalence of dental fluorosis in children taking part in an oral health programme including fluoride tablet supplements from the age of 2 years

AIM

To investigate the prevalence of dental fluorosis in children who had participated in an oral health programme between the ages 2-5 years, including fluoride tablets from the age of 2 years.

DESIGN

The study group consisted of 135 10- to 11-year-old children who had participated in the programme, including parent education, tooth-brushing instruction and prescribed fluoride tablets (0.25 mg NaF) (2-3 years: 1 tablet/day; 3-5 years: 2 tablets/day). The prevalence of dental fluorosis in the study group was compared with that in a nonintervention reference group consisting of 129 children of the same ages. The analysis was based on photos of the permanent maxillary front teeth using the Thylstrup & Fejerskov (TF) Index.

RESULTS

No statistically significant difference in prevalence of dental fluorosis was seen between the two groups. Forty-three percent of the children in the study group and 38% in the reference group had fluorosis, the majority of a mild nature (TF-score 1). None had a TF score above 2. The pattern was the same after correction for parent reported intake of tablets at 3 and 5 years of age.

CONCLUSION

Introduction of fluoride tablets at the age of 2 years did not result in increased prevalence of dental fluorosis.

How much toothpaste should a child under the age of 6 years use?

AIM

To discuss current concepts in the use of fluoride and to determine how much fluoride is sufficient for caries prevention but also how much is too much. Use of fluoride by young children is a balance between maximising caries efficacy and minimising the risk of fluorosis.

METHODS

Review of the current literature. This review considers the importance of amount, concentration and dose of fluoride applied from toothpaste and the implications for risk and benefit.

RESULTS

Dental fluorosis is dependent on local fluoride levels in the extra cellular fluid surrounding the tooth during its development. These fluoride levels are determined by the plasma concentration that in turn is a function of the daily intake of fluoride. Fluoride released from bone during remodelling may also contribute to fluoride levels in the tissue. There is evidence to suggest that the effects of fluoride resulting in fluorosis prior to eruption of the tooth are cumulative and dependent on the amount and duration of exposure rather than a specific window of vulnerability. In contrast to dilution of ingested fluoride in the large volume of plasma, dilution of toothpaste in oral fluids is relatively small. Hence, for a given dose of fluoride, higher fluoride levels can be achieved in the oral environment using small amounts of toothpaste with higher fluoride concentrations rather than larger amounts with lower fluoride concentrations.

CONCLUSION

It is concluded that for young children fluoride ingestion needs to be carefully controlled during the first six years of life and the best balance between risk and efficacy might be achieved by using small amounts of high fluoride toothpaste under close supervision from parents.

Fluoride intake from drinking water and dentifrice by children living in a tropical area of Brazil

Objective:

To assess fluoride (F^-) intake from water and toothpaste by children aged 18 to 36 months and to monitor the F^- concentrations in the drinking water system in a tropical city of Brazil.

Methods:

Children (n=58) aged 18-36 months, all lifetime residents of Penedo, state of Alagoas, Brazil, participated in this study. Water F^- analyses were carried out in 7 different occasions at least a week apart. For 2 days all the water drunk by each child was accounted for. Fluoride intake from water for each child was estimated using the mean F^- concentration of water in 7 different occasions. Fluoride intake from toothpaste was estimated by subtracting the recovered post-brushing F^- from the original amount placed in the toothbrush. The F^- intake from water and toothpaste was estimated by dividing the total amount of F^- ingested by the weight of each child.

Results:

The mean F^- concentration in the drinking water was 0.94 ppm (mean range 0.78-1.1 ppm), which is above the 0.7 ppm recommended for this area of Brazil. Mean total F^- intake from water and toothpaste was 0.128 mg F^-/Kg Body Weight/day. The daily means of F^- intake from water and toothpaste were 0.021 and 0.107 mg F^-/Kg Body Weight, respectively. Ninety six percent of children showed F^- intake above 0.07 mg F^-/Kg Body Weight/day.

Conclusions:

Children in Penedo are at risk for developing dental fluorosis due to high F^- intake from fluoridated toothpastes. Water fluoridation showed low contribution to the total F^- intake. However, high water F^- concentrations in the water indicate the need of surveillance of the artificial water fluoridation system.

Changing risk factors for fluorosis among South Australian children

BACKGROUND

Research in the last decade has shown changing exposure patterns to discretionary fluorides and declining prevalence of fluorosis among South Australian children, raising the question of how risk factors for fluorosis have changed.

OBJECTIVE

To examine and compare risk factors for fluorosis among representative samples of South Australian children in 1992/1993 and 2002/2003.

METHODS

Similar sampling strategies and data collection methods were employed in the Child Fluoride Study (CFS) Marks 1 (1992/1993) and 2 (2002/2003). Participants in each CFS round were examined for fluorosis using the Thylstrup and Fejerskov (TF) Index. Exposure history was collected for fluoride in water, toothpaste, fluoride supplements and infant formula, allowing for a fluorosis risk assessment analysis. Data were re-weighted to represent the child population at each time. Changes in prevalence of fluorosis, defined as having a TF score of 1+ on maxillary central incisors, fluoride exposure and risk factors between the two rounds were evaluated.

RESULT

A total of 375 and 677 children participated in the 1992/1993 and 2002/2003 rounds respectively. Prevalence of fluorosis declined significantly from 45.3% to 25.9%. Reduced use of fluoride supplements and increased use of 400-550-ppm children F toothpaste were the most substantial fluoride exposure changes. Early toothpaste use, residence in fluoridated areas and fluoride supplement use were the risk factors in 1992/1993. Early toothpaste use and fluoride supplement use were not risk factors, leaving fluoridated water as the only risk factor among the common variables in 2002/2003. In an analysis stratified by the type of fluoridated toothpaste in 2002/2003, the large amount of toothpaste used was a risk factor in those who used 1000-ppm fluoridated toothpaste, and eating/licking toothpaste when toothpaste use started was a risk factor among children who used either 1000-ppm or 400-550-ppm fluoridated toothpaste.

CONCLUSION

Introduction of the 400-550-ppm F toothpaste and use of smaller amount of toothpaste restricted risk associated with early toothpaste use. Less use and possibly a stricter fluoride supplements regimen also restricted fluorosis risk. Periodic monitoring of risk of fluorosis is required to adjust guidelines for fluoride use in caries prevention.

Prospective study of the association between fluoride intake and dental fluorosis in permanent teeth

OBJECTIVE

To evaluate the relationship between fluoride intake and dental fluorosis in permanent central incisors and first molars.

METHODS

Fluoride intake (mg F/kg body weight/day) from diet, dentifrice and both combined was determined on a single occasion in 1998 among children aged 19-39 months living in two fluoridated Brazilian communities (0.6-0.8 ppm F). Six years later, when the permanent teeth of these children had erupted (central incisors and first molars), 49 children aged 7-9 years [20 girls (40.8%) and 29 boys (58.2%)] were evaluated for dental fluorosis. To test the association between fluorosis and fluoride intake, children were dichotomized into two groups, cases (children with dental fluorosis on at least two teeth, TFI > or =1) and noncases (children without dental fluorosis, TFI = 0).

RESULTS

Among the case group (n = 29), median fluoride doses from diet, dentifrice and combined were 0.031, 0.050 and 0.083 mg F/kg/day, respectively. Among the noncase group (n = 20), median fluoride doses were 0.029, 0.049, 0.084 mg F/kg/day, respectively. There was no association between dental fluorosis in permanent teeth and fluoride intake from diet, dentifrice and combined (p > 0.05).

CONCLUSIONS

There was no difference between children with and without fluorosis in the permanent central incisors and first molars regarding fluoride intake. However, this study has limitations that must be recognized: fluoride intake was only measured once, and there were no children in the sample with severe degrees of dental fluorosis.

Dental fluorosis prevalence and severity using Dean's index based on six teeth and on 28 teeth

To contrast the sensitivity, specificity, and positive-negative predictive values between dental fluorosis prevalence scored on 28 (DF28) and on six permanent teeth (DF6), we undertook a cross-sectional study on 1,538 adolescents (12 and 15 years old) residing in Hidalgo State, Mexico, a naturally fluoridated (>0.7 ppm) area at an elevated altitude (>2,500 m above sea level). Dental fluorosis was scored using Deans modified index. Using the scores obtained for all teeth present (DF28) as a gold standard, we calculated the sensitivity, specificity, positive-negative predictive values, and receiver operating characteristic and concordance index pertaining to the scores based on six teeth (upper incisors and canines). DF28 fluorosis prevalence was 81.7%; based on DF6, it was 58.7% (23% difference). Among 12 year olds, the difference between DF28 and DF6 was 20.1% (84.5 vs. 64.4%); among 15 year olds, it was 25.4% (79.4 vs. 54%). Among girls, it was 23.2% (81.1 vs. 57.9%) and among boys, 22.8% (82.2 vs. 59.4%). The fluorosis community indices were 1.75 (DF28) and 1.11 (DF6). All positive predictive values reached 100% while negative predictive values were below 45%. Concordance between DF28 and DF6 was 53.9%, and kappa coefficient was 0.40. Partial scoring of fluorosis based on esthetically important permanent teeth underestimated prevalence, compared to full-mouth scoring. The decision to use an abridged Dean's index protocol must take into account the number of teeth examined, and which specific teeth are examined, to appraise the benefit of reduced data collection effort against possible information loss.

Aesthetic management of severely fluorosed incisors in an adolescent female

BACKGROUND

Dental fluorosis is a condition of enamel hypomineralization due to the effects of excessive fluoride on ameloblasts during enamel formation. Delayed degradation of enamel matrix proteins or inhibited protein removal results in impaired and incomplete crystal growth, producing hypomineralized and porous enamel. Severely fluorosed teeth may undergo post-eruptive surface breakdown and post-eruptive dark brown to black staining.

METHODS

A 13 year old girl presented with severely discoloured maxillary central incisors. Initial aesthetic management of these teeth was conservative, including in-office tooth whitening, microabrasion and take-home whitening.

RESULTS

Dark brown to black staining of the teeth was reduced successfully without the need for gross mechanical preparation of the enamel. Further improvement of aesthetics was achieved with composite veneers.

CONCLUSIONS

Conservative treatment options such as tooth whitening and microabrasion can dramatically improve severely discoloured fluorosed teeth. This can provide a satisfactory interim outcome or minimize the removal of discoloured enamel and dentine prior to the provision of composite veneers. The use of casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) may enhance remineralization and decrease postoperative sensitivity following tooth whitening and microabrasion procedures in hypomineralized teeth.

Fluoride intake by children at risk for the development of dental fluorosis: comparison of regular dentifrices and flavoured dentifrices for children

The aim of the present study was to determine fluoride intake by children at risk of dental fluorosis according to the type of dentifrice used. Forty-two volunteers aged between 20 and 30 months, from 2 kindergartens, were supervised while brushing their teeth with regular dentifrices (nominally 1,500 ppm F) and dentifrices flavoured for children (nominally 1,100 ppm F), brushing 3 times with each type in random order to minimize bias. The amount of fluoride ingested was determined by subtracting the weight of dentifrice recovered from the weight used and calculating the mean of the 3 brushings. Fluoride was analyzed with specific electrodes. Parents were asked how often the children brushed their teeth and the daily tooth brushing frequency was used to calculate the daily fluoride intake. The average fluoride intake using regular dentifrices and those flavoured for children was 0.567 +/- 0.300 and 0.630 +/- 0.320 mg F/day, respectively, corresponding to doses of 0.046 +/- 0.023 and 0.051 +/- 0.026 mg F/kg/day (p > 0.05). Fluoride intake was slightly higher with the use of dentifrices flavoured for children. Moreover, the dose to which children were exposed with either type of dentifrice was very close to that which is considered the limit (0.05-0.07 mg F/kg/day).

Life-course epidemiology: concepts and theoretical models and its relevance to chronic oral conditions

Etiological models that predominantly emphasize current adult life styles, such as smoking, diet and lack of exercise have recently been seriously challenged by a growing body of evidence that disturbed early growth and development, childhood infection, poor nutrition, and social and psychosocial disadvantage across the life-course affect chronic disease risk, including chronic oral disease. This relatively new area of research is called life-course epidemiology. The life-course framework for investigating the aetiology and natural history of chronic disease proposes that advantages and disadvantages are accumulated throughout life generating differentials in health along the life-course, but most importantly later in life. Furthermore, its dynamic framework brings together the effects of intrinsic factors (individual resources) with extrinsic factors (environmental factors). The aim of this paper is to give an overview of this new epidemiological approach and to discuss how the life-course framework has been applied to chronic oral conditions.

Effects of toothbrush size and dentifrice type/brand on pea-sized and larger amounts of dentifrice

PURPOSE

To assess the effects of toothbrush size and dentifrice type/brand on amounts of dentifrice being placed when trying to replicate pictures with different amounts of dentifrice, including a pea-sized amount.

METHODS

This laboratory trial used one researcher to repeatedly dispense five dentifrice products on three different child-sized toothbrushes using a standard procedure. Two sets of drawings, depicting the recommended pea-sized and larger amounts, were used as guides in an effort to place the same amount each time. Data were analysed using ANOVA.

RESULTS

Amounts of dentifrice placed on the two larger toothbrushes were significantly greater than those placed on the smallest toothbrush (p < 0.0001). The amounts placed on the two larger toothbrushes with similar brushing areas but different shapes were not significantly different from each other. The effect of dentifrice type/brand varied in each analysis. For pea-sized amounts, one of 10 pairwise comparisons was significant. For amounts larger than pea-sized, another pair of the 10 pairwise comparisons was significant. However, there was no significant effect of dentifrice type/brand when considering both pea-sized and larger amounts together in the same analysis.

CONCLUSIONS

Toothbrush size significantly affected the amount of dentifrice placed for both pea-sized and larger amounts. The amounts placed on larger size toothbrushes were greater than on the smaller size toothbrush. No consistent effects of selected dentifrices were found.

The prevalence of dental fluorosis in relation to water or salt fluoridation and reported use of fluoride toothpaste in school-age children

AIM

To compare prevalence of dental fluorosis (DF) in permanent teeth in children whose domestic water supply was fluoridated since birth with that in a community where fluoridated salt was available. A second aim was to analyse the relationship between DF prevalence and reported use of fluoride toothpaste in early childhood.

STUDY DESIGN

Cross-sectional study.

METHODS

A representative, random sample of 12-year-old children was examined in water fluoridated Dublin (Ireland) and non-water fluoridated Freiburg (Germany), where fluoridated salt was available. DF was recorded using the Dean's Index. The child's early experience of toothpaste use was recorded using a questionnaire.

RESULTS

377 children in Dublin and 322 children in Freiburg were examined. In Dublin 11.7% of the whole sample had a 'Questionable' level of DF, 9.8% had 'Very Mild', 3.7% had 'Mild' and 0.3% had 'Moderate' fluorosis. The corresponding percentages in Freiburg for all children were 10.9%, 4.0%, 3.4% and 0%. The results suggest that children in Dublin started brushing their teeth at an older age than in Freiburg, but no difference in DF levels was found between 'early' and 'late' users.

STATISTICS

Fisher's test revealed that the difference in DF levels between the two populations was statistically significant (p=0.03).

CONCLUSIONS

The prevalence of aesthetically important DF ('Mild' and 'Moderate') was low and similar in both communities and considerably lower than the expected level at water fluoridation concentrations of 1 ppm. However, the prevalence of 'Very Mild' fluorosis was twice as frequent in Dublin than in Freiburg.

Fluoride ingestion from toothpaste and diet in 1- to 3-year-old Brazilian children

OBJECTIVE

This study estimated the total daily fluoride intake of 1- to 3-year-old children from diet and dentifrice. The constituents of the diet were divided into solids, water, milk, and other beverages, which were analyzed separately. The correlation between fingernail fluoride concentrations and the total daily fluoride intake by children was also investigated.

METHODS

Thirty-three children, living in a fluoridated area, participated in the study. Fluoride intake from diet was monitored by the 'duplicate plate' method, investigating the different constituents of the diet. Fluoride ingested from dentifrice was determined by subtracting the amount of fluoride recovered after brushing from the amount originally placed onto the child's toothbrush. Fingernails were clipped and collected on three occasions. Fluoride was analyzed with the ion-specific electrode, after hexamethyldisiloxane-facilitated diffusion. Data were tested by anova and Tukey's post hoc tests, Student's t-tests and linear regression (P < 0.05).

RESULTS

Mean (+/-SD) fluoride intake from diet and dentifrice was 0.025 +/- 0.013 and 0.106 +/- 0.085 mg/kg body weight/day, respectively, totaling 0.130 mg/kg body weight/day. A strong positive correlation (r = 0.971, P < 0.0001) was seen between the amount of dentifrice loaded onto the brush (0.49 +/- 0.30 g) and the amount of fluoride ingested during each tooth brushing (0.59 +/- 0.45 mg). Among the constituents of the diet, water and milk had a significantly higher contribution to the fluoride intake (0.18 +/- 0.11 mg/day, P < 0.0001), when compared with solids (0.07 +/- 0.05 mg/day) and other beverages (0.07 +/- 0.04 mg/day). Mean (+/-SD) fingernail fluoride concentration on the three dates of collection was 3.11 +/- 1.14, 2.22 +/- 1.47 and 3.53 +/- 1.40 mug F/g. There was no significant correlation between fingernail fluoride concentration and the total fluoride intake.

CONCLUSIONS

Most of the children are exposed to a daily fluoride intake above the suggested threshold for dental fluorosis. The dentifrice alone is responsible for an average of 81.5% of the daily fluoride intake, while among the constituents of the diet, water and milk are the most important contributors. In addition, small variations in daily fluoride intake cannot be detected in fingernails.

Timing of fluoride intake in relation to development of fluorosis on maxillary central incisors

OBJECTIVES

Several studies have focused on the timing of fluoride intake relative to the development of dental fluorosis. This study reports the relationships of fluoride intake during the first 48 months of life with fluorosis on early-erupting permanent teeth.

METHODS

Subjects were followed from birth to 48 months with questionnaires every 3-4 months. Questionnaires gathered data on intakes from water, diet, supplements, and dentifrice to estimate total fluoride intake. Early-erupting permanent teeth of 579 subjects were assessed for fluorosis using the Fluorosis Risk Index (FRI) at approximately age 9. Fluorosis cases were defined as having FRI definitive or severe fluorosis on both maxillary central incisors. Individuals with FRI questionable fluorosis were excluded. The importance of fluoride intake during different time periods was assessed using t-tests and logistic regression.

RESULTS

One hundred and thirty-nine (24%) subjects had fluorosis on both maxillary central incisors. Mean fluoride intake per unit body weight (bw) ranged from 0.040 to 0.057 mg/kg bw, with higher intake during earlier time periods and relative stability after 16 months. In bivariate analyses, fluoride intakes during each of the first 4 years were individually significantly related to fluorosis on maxillary central incisors, with the first year most important (P < 0.01), followed by the second (P < 0.01), third (P < 0.01), and fourth year (P = 0.03). Multivariable logistic regression analyses showed that, after controlling only for the first year, the later years individually were still statistically significant. When all four time periods were in the model, the first (P < 0.01) and second years (P = 0.04) were still significant, but the third (P = 0.32) and fourth (P = 0.82) were not.

CONCLUSIONS

The first two years of life were most important to fluorosis development in permanent maxillary central incisors; however, this study also suggests the importance of other individual years.