Fluoride dentifrice ingestion and fluorosis of the permanent incisors

Topical fluoride as a cause of dental fluorosis in children

BACKGROUND

This is an update of a review first published in 2010. Use of topical fluoride has become more common over time. Excessive fluoride consumption from topical fluorides in young children could potentially lead to dental fluorosis in permanent teeth.

OBJECTIVES

To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis in permanent teeth.

SEARCH METHODS

We carried out electronic searches of the Cochrane Oral Health Trials Register, CENTRAL, MEDLINE, Embase, three other databases, and two trials registers. We searched the reference lists of relevant articles. The latest search date was 28 July 2022.

SELECTION CRITERIA

We included randomized controlled trials (RCTs), quasi-RCTs, cohort studies, case-control studies, and cross-sectional surveys comparing fluoride toothpaste, mouth rinses, gels, foams, paint-on solutions, and varnishes to a different fluoride therapy, placebo, or no intervention. Upon the introduction of topical fluorides, the target population was children under six years of age.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane and used GRADE to assess the certainty of the evidence. The primary outcome measure was the percentage prevalence of fluorosis in the permanent teeth. Two authors extracted data from all included studies. In cases where both adjusted and unadjusted risk ratios or odds ratios were reported, we used the adjusted value in the meta-analysis.

MAIN RESULTS

We included 43 studies: three RCTs, four cohort studies, 10 case-control studies, and 26 cross-sectional surveys. We judged all three RCTs, one cohort study, one case-control study, and six cross-sectional studies to have some concerns for risk of bias. We judged all other observational studies to be at high risk of bias. We grouped the studies into five comparisons. Comparison 1. Age at which children started toothbrushing with fluoride toothpaste Two cohort studies (260 children) provided very uncertain evidence regarding the association between children starting to use fluoride toothpaste for brushing at or before 12 months versus after 12 months and the development of fluorosis (risk ratio (RR) 0.98, 95% confidence interval (CI) 0.81 to 1.18; very low-certainty evidence). Similarly, evidence from one cohort study (3939 children) and two cross-sectional studies (1484 children) provided very uncertain evidence regarding the association between children starting to use fluoride toothpaste for brushing before or after the age of 24 months (RR 0.83, 95% CI 0.61 to 1.13; very low-certainty evidence) or before or after four years (odds ratio (OR) 1.60, 95% CI 0.77 to 3.35; very low-certainty evidence), respectively. Comparison 2. Frequency of toothbrushing with fluoride toothpaste Two case-control studies (258 children) provided very uncertain evidence regarding the association between children brushing less than twice per day versus twice or more per day and the development of fluorosis (OR 1.63, 95% CI 0.81 to 3.28; very low-certainty evidence). Two cross-sectional surveys (1693 children) demonstrated that brushing less than once per day versus once or more per day may be associated with a decrease in the development of fluorosis in children (OR 0.62, 95% CI 0.53 to 0.74; low-certainty evidence). Comparison 3. Amount of fluoride toothpaste used for toothbrushing Two case-control studies (258 children) provided very uncertain evidence regarding the association between children using less than half a brush of toothpaste, versus half or more of the brush, and the development of fluorosis (OR 0.77, 95% CI 0.41 to 1.46; very low-certainty evidence). The evidence from cross-sectional surveys was also very uncertain (OR 0.92, 95% CI 0.66 to 1.28; 3 studies, 2037 children; very low-certainty evidence). Comparison 4. Fluoride concentration in toothpaste There was evidence from two RCTs (1968 children) that lower fluoride concentration in the toothpaste used by children under six years of age likely reduces the risk of developing fluorosis: 550 parts per million (ppm) fluoride versus 1000 ppm (RR 0.75, 95% CI 0.57 to 0.99; moderate-certainty evidence); 440 ppm fluoride versus 1450 ppm (RR 0.72, 95% CI 0.58 to 0.89; moderate-certainty evidence). The age at which the toothbrushing commenced was 24 months and 12 months, respectively. Two case-control studies (258 children) provided very uncertain evidence regarding the association between fluoride concentrations under 1000 ppm, versus concentrations of 1000 ppm or above, and the development of fluorosis (OR 0.89, 95% CI 0.52 to 1.52; very low-certainty evidence). Comparison 5. Age at which topical fluoride varnish was applied There was evidence from one RCT (123 children) that there may be little to no difference between a fluoride varnish application before four years, versus no application, and the development of fluorosis (RR 0.77, 95% CI 0.45 to 1.31; low-certainty evidence). There was low-certainty evidence from two cross-sectional surveys (982 children) that the application of topical fluoride varnish before four years of age may be associated with the development of fluorosis in children (OR 2.18, 95% CI 1.46 to 3.25).

AUTHORS' CONCLUSIONS

Most evidence identified mild fluorosis as a potential adverse outcome of using topical fluoride at an early age. There is low- to very low-certainty and inconclusive evidence on the risk of having fluorosis in permanent teeth for: when a child starts receiving topical fluoride varnish application; toothbrushing with fluoride toothpaste; the amount of toothpaste used by the child; and the frequency of toothbrushing. Moderate-certainty evidence from RCTs showed that children who brushed with 1000 ppm or more fluoride toothpaste from one to two years of age until five to six years of age probably had an increased chance of developing dental fluorosis in permanent teeth. It is unethical to propose new RCTs to assess the development of dental fluorosis. However, future RCTs focusing on dental caries prevention could record children's exposure to topical fluoride sources in early life and evaluate the dental fluorosis in their permanent teeth as a long-term outcome. In the absence of these studies and methods, further research in this area will come from observational studies. Attention needs to be given to the choice of study design, bearing in mind that prospective controlled studies will be less susceptible to bias than retrospective and uncontrolled studies.

Doses of fluoride toothpaste for children up to 24 months

AIM

The aim of this study was to test the dose of fluoride toothpaste by parents for their children aged up to 24 months.

METHODS

Parents who use fluoride toothpastes for their children were asked to dose two commercially available toothpastes (A and B) with 1000 ppm fluoride each for their children as they would normally do at home. The toothpaste amounts were weighed, and as reference, the weight of an 'optimal' grain of rice-size amount of each toothpaste was used.

RESULTS

61 parents dosed a mean of 0.263 ± 0.172 g toothpaste A and 0.281 ± 0.145 g toothpaste B. The parents' mean doses were 5.9 times higher for toothpaste A and 7.2 times higher for toothpaste B than an 'optimal' grain of rice-size amount (the reference dose as recommended). The difference between parent's and reference dose was statistically significant (p < 0.001). Moreover, 39.3% of parents were not aware about conditions of use and warnings that have to be printed on the package of fluoride toothpastes.

CONCLUSION

In this study, parents significantly overdosed the toothpaste for their children. To avoid fluoride intake from toothpaste, parents can choose fluoride-free alternatives for the oral care of their infants and toddlers.

Patterns of fluoride intake from 6 to 17 years of age: The Iowa Fluoride Study

OBJECTIVES

This article reports on estimated daily fluoride intake from water, other beverages and selected foods, dentifrice, and dietary fluoride supplements by both individual sources, and all sources combined, among 787 children participating in the Iowa Fluoride Study (IFS) from 6 to 17 years of age.

METHODS

Total daily fluoride intake (mg F) and fluoride intake per kilogram bodyweight (mg F/kg bw) were estimated using responses to questionnaires sent every 3-6 months. Dietary assessments included frequencies and amounts of beverage intake for the previous week from water, milk, ready-to-drink beverages, beverages made by adding water to concentrate or powder, and selected foods with substantial water content. Descriptive statistics and bivariate and multivariable analyses with linear mixed models were used to assess associations with each of mg F and mg F/kg bw.

RESULTS

Mean combined dietary fluoride (mg F) from all sources examined in the study increased slightly with age, whereas the fluoride intake per kg bw decreased with age. Age, sex, and socioeconomic status were significantly associated with fluoride intake (mg F and mg F/kg bw). Each year increase in age was associated with a 0.02-mg increase in fluoride consumption, on average, after adjusting for the effects of covariates.

CONCLUSIONS

Daily mean fluoride intakes from single and combined sources were relatively stable, while the intake of fluoride per kg bw decreased from 6 to 17 years of age. Fluoridated water was the major source of ingested fluoride, contributing over 50% of total daily intake at all ages.

Predictors of Plasma Fluoride Concentrations in Children and Adolescents

Despite increasing concerns about neurotoxicity of fluoride in children, sources of fluoride exposure apart from municipal water fluoridation are poorly understood. We aimed to describe the associations of demographics, drinking water characteristics, diet, and oral health behaviors with plasma fluoride concentrations in U.S. children. We used data from 3928 6–19-year-olds from the 2013–2016 National Health and Nutrition Examination Survey. We used a 24-h dietary recall to estimate recent consumption of fluoridated tap water and select foods. We estimated the associations of fluoridated tap water, time of last dental visit, use of toothpaste, and frequency of daily tooth brushing with plasma fluoride concentrations. The participants who consumed fluoridated (≥0.7 mg/L) tap water (n = 560, 16%) versus those who did not had 36% (95% CI: 22, 51) higher plasma fluoride. Children who drank black or green tea (n = 503, 13%) had 42% higher plasma fluoride concentrations (95% CI: 27, 58) than non-tea drinkers. The intake of other foods and oral health behaviors were not associated with plasma fluoride concentrations. The consumption of fluoridated tap water and tea substantially increases plasma fluoride concentrations in children. Quantifying the contribution of diet and other sources of fluoride is critical to establishing safe target levels for municipal water fluoridation.

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.

Gastrointestinal Absorption and Renal Excretion of Fluoride After Ingestion of a High-Fluoride Dentifrice

This study aimed to evaluate the gastrointestinal absorption and renal excretion of fluoride after the ingestion of high-fluoride dentifrice. Twelve volunteers participated in this in vivo, crossover, and blinded study. In three experimental phases, the volunteers were randomly assigned to one of three treatment groups, who ingested either the following: distilled and deionized water (control), conventional dentifrice (1100 μg/g), or high-fluoride dentifrice (5000 μg/g). Both dentifrices contained fluoride in the form of NaF/SiO₂. To determine the rate of fluoride absorption, non-stimulated saliva was collected for up to 120 min after ingestion and the area under the curve of the salivary fluoride concentration was plotted as a function of time and the maximum concentration determined. All urine produced during the 24 h before and after ingestion was collected, and urinary excretion was calculated from the difference between the urinary fluoride concentrations in the two periods. A specific ion electrode coupled to an ion analyzer was used to measure fluoride concentrations. Statistical analysis was performed by ANOVA followed by Tukey's test with p set at 5%. All measured parameters were highest after the ingestion of the dentifrice with 5000 μg/g (p < 0.001), confirming that this has an increased level of bioavailable fluoride compared with the conventional dentifrice. The high-fluoride dentifrice increases the concentration of salivary fluoride, which may explain its greater anticaries effect. However, it poses a potential risk of causing dental fluorosis and so should not be used by children.

Enamel Microabrasion and Dental Bleaching on Teeth Presenting Severe-pitted Enamel Fluorosis: A Case Report

The present clinical case report describes the clinical steps of enamel microabrasion associated with dental bleaching to restore severely-pitted fluorosed teeth. The process of removing the fluorotic superficial stains started by using macroabrasion with a water-cooled fine tapered 3195 FF diamond bur. Rubber dam isolation of the operative field was used to remove the remaining enamel stains and superficial irregularities with the Opalustre microabrasive compound (6.6% hydrochloric acid associated with silicon carbide particles) followed by polishing using fluoridated paste and subsequent 2% neutral fluoride gel topical application. After one month, dental bleaching was performed using 10% carbamide peroxide in custom-formed acetate trays for two hours/day for 42 days. The association of enamel microabrasion with dental bleaching was effective for reestablishing the dental esthetics of a patient with severe dental fluorosis.

Parental views on fluoride tooth brushing and its impact on oral health: A cross-sectional study

Objective:

This study aimed to describe the current use and knowledge about fluoride toothpaste and children's oral hygiene habits among parents of Saudi children.

Materials and Methods:

In this cross-sectional study, the parents of children aged 7–12 years who visited the undergraduate pediatric dental clinics at the College of Dentistry in Riyadh, Saudi Arabia were interviewed. The interview included questions to assess the parents’ level of fluoride knowledge, the dental appearance of their children, and any general dental health concerns and practices.

Results:

A total of 463 parents (women 55.5%, men 44.5%) were included. Over half (60.3%) of the participants reported that they were unhappy with the appearance of their child's teeth. Only 11.5% received high fluoride knowledge scores. The additive index for the level of fluoride knowledge was significantly lower among mothers than among fathers. The majority of the parents were not able to correctly report whether the toothpaste their children used contained fluoride. Furthermore, the majority of the respondents were unaware of the benefits of fluoride in preventing dental caries.

Conclusions:

There is a need to enhance parental knowledge regarding high fluoride intake and its harmful consequences on children's health. Both mothers and fathers should have higher levels of awareness regarding oral health promotion to maintain optimal oral health in their children.

Dental fluorosis in the Blue Mountains and Hawkesbury, New South Wales, Australia: policy implications

AIM

The aim of the present study was to determine whether the adjustment of the fluoride concentration to 1 ppm in the drinking water supplied to the Blue Mountains, New South Wales, Australia in 1993 was associated with fluorosis incidence.

METHODS

In 2003, children attending schools in the Blue Mountains and a control region (fluoridated in 1967) that had been randomly selected at baseline in 1992 were examined for dental fluorosis (maxillary central incisors only) using Dean's index. A fluoride history for each child was obtained by questionnaire. Associations between fluorosis and 58 potential explanatory variables were explored.

RESULTS

The response rate was 63%. A total of 1138 children aged from 7 to 11 years with erupted permanent central incisors were examined for dental fluorosis. Fluorosis prevalence was the same in both regions. The Community Index of Dental Fluorosis values were slightly different, but were both above 0.6, indicative of public health concern.

CONCLUSIONS

For the group as a whole, we concluded that: (a) fluorosis prevalence (0.39) in both regions was similar; and (b) the higher-than-expected prevalence and severity of fluorosis was due mainly to two factors: (a) the higher-than-optimal fluoride level in drinking water; and (b) swallowing of fluoride toothpaste in early childhood.

Mechanisms of action of fluoridated acidic liquid dentifrices against dental caries

OBJECTIVE

This study attempted to clarify the mechanisms of action of fluoridated acidic liquid dentifrices against dental caries.

DESIGN

In the in vitro leg, enamel specimens were submitted to a pH-cycling model, treated with distinct dentifrices (0, 550 μgF/g pH 4.5 and pH 7.0, 1100 or 5000 μgF/g pH 7.0) and analyzed using hardness. Alkali-soluble fluoride (F) deposition was quantified on pre-demineralized specimens treated with the dentifrices. In the clinical leg, 2-to-4-year-old children who had been using liquid dentifrices for 6 months (550 μgF/g pH 4.5 or pH 7.0 or 1100 μgF/g pH 7.0) had their plaque samples collected 5 and 60 min after the last brushing. Fluoride uptake in whole plaque was evaluated.

RESULTS

The reduction of the pH had a partial preventive effect on subsurface hardness loss only. [F] had a significant influence on the deposition of fluoride, surface and subsurface hardness loss. In vivo, the reduction of the pH was able to significantly increase plaque F uptake, leading to similar levels as those found for the neutral dentifrice containing twice [F].

CONCLUSION

The results obtained from in vitro studies whose design does not include the presence of dental plaque should be interpreted with caution.

High-fluoride toothpaste: a multicenter randomized controlled trial in adults

Objective

The aim of this single – blind, multicenter, parallel, randomized controlled trial was to evaluate the effectiveness of the application of a high-fluoride toothpaste on root caries in adults.

Methods

Adult patients (n = 130, ♂ = 74, ♀ = 56; mean age ± SD: 56.9 ± 12.9) from three participating centers, diagnosed with root caries, were randomly allocated into two groups: Test (n = 64, ♂ = 37, ♀ = 27; lesions = 144; mean age: 59.0 ± 12.1; intervention: high-fluoride toothpaste with 5000 ppm F), and Control (n = 66, ♂ = 37, ♀ = 29; lesions = 160; mean age: 54.8 ± 13.5; intervention: regular-fluoride toothpaste with 1350 ppm F) groups. Clinical examinations and surface hardness scoring of the carious lesions were performed for each subject at specified time intervals (T₀ – at baseline before intervention, T₁ – at 3 months and T₂ – at 6 months after intervention). Mean surface hardness scores (HS) were calculated for each patient. Statistical analyses comprised of two-way analysis of variance and post hoc comparisons using the Bonferroni–Dunn correction.

Results

At T₀, there was no statistical difference between the two groups with regard to gender (P = 0.0682, unpaired t-test), or age (P = 0.9786, chi-squared test), and for the overall HS (Test group: HS = 3.4 ± 0.61; Control group: HS = 3.4 ± 0.66; P = 0.8757, unpaired t-test). The anova revealed significantly better HS for the test group than for the control groups (T₁: Test group: HS = 2.9 ± 0.67; Control group: HS = 3.1 ± 0.75; T₂: Test group: HS = 2.4 ± 0.81; Control group: HS = 2.8 ± 0.79; P < 0.0001). However, the interaction term time-point*group was not significant.

Conclusions

The application of a high-fluoride containing dentifrice (5000 ppm F) in adults, twice daily, significantly improves the surface hardness of otherwise untreated root caries lesions when compared with the use of regular fluoride containing (1350 ppm F) toothpastes.

Estimation of toothpaste fluoride intake in preschool children

The objective of this study was to estimate the intake of toothpaste fluoride used by children aged 2 to 6 years (n=87) treated at a hospital of a medium-sized city (Campina Grande, PB) in the Northeastern region of Brazil. Data regarding sociodemographic characteristics of families and children's toothbrushing were collected from questionnaire-based interviews with parents/guardians, and the amount of fluoride used during toothbrushing was estimated using a precision scale for assessment of the risk of dental fluorosis, considering a cutoff value of 0.07 mgF/kg body weight/day. Fluoride content in the toothpastes was analyzed using a specific fluoride electrode. Data were analyzed using descriptive and inferential statistics using the chi-square and Fisher's exact tests (α=0.05). Considering the use of the derice, the risk of fluorosis in the children was 19.5%. There was significant association (p<0.05) between the risk of fluorosis, brushing frequency, type of derice and who performed the child's oral hygiene. It was concluded that a high percentage of children in the studied sample used toothpaste inappropriately and were at risk of developing dental fluorosis.

Fluoridated toothpaste: usage and ingestion of fluoride by 4- to 6-yr-old children in England

Fluoridated toothpaste is effective for dental caries control, yet may be a risk factor for dental fluorosis. This study aimed to quantify fluoride ingestion from toothpaste by children and to investigate the effects of age, gender, and social class on the amount of fluoride ingested per toothbrushing session. Sixty-one children, 4-6 yr of age, were recruited: 38 were from low socio-economic (LSE) areas of Newcastle, UK, and 23 were from high socio-economic (HSE) areas of Newcastle, UK. All expectorated saliva, rinse water (if used), and residual toothpaste were collected after brushing at home and were analysed for fluoride. Of the children, 74% and 69% from HSE and LSE areas, respectively, claimed that they brushed twice per day. The mean (SD) weight of toothpaste dispensed was 0.67 (0.36) g. The mean (SD) amount of fluoride ingested per toothbrushing session and per day was 17.0 (14.7) and 29.3 (32.8) μg kg(-1) of body weight, respectively. Daily fluoride intake per kilogram of body weight did not differ significantly between children from LSE and HSE areas. Fluoride intake per toothbrushing session was significantly influenced by weight of toothpaste, its fluoride concentration, and the child's age. Whilst the average amount of toothpaste used per toothbrushing session was more than twice the recommended amount (of 0.25 g), only one child had a daily fluoride intake that exceeded the tolerable upper intake level of 0.1 mg kg(-1) of body weight for this age group.

Groundwater quality and its health impact: An assessment of dental fluorosis in rural inhabitants of the Main Ethiopian Rift

This study aims to assess the link between fluoride content in groundwater and its impact on dental health in rural communities of the Ethiopian Rift. A total of 148 water samples were collected from two drainage basins within the Main Ethiopian Rift (MER). In the Ziway-Shala basin in particular, wells had high fluoride levels (mean: 9.4±10.5mg/L; range: 1.1 to 68 mg/L), with 48 of 50 exceeding the WHO drinking water guideline limit of 1.5mg/L. Total average daily intake of fluoride from drinking groundwater (calculated per weight unit) was also found to be six times higher than the No-Observed-Adverse-Effects-Level (NOAEL) value of 0.06 mg/kg/day. The highest fluoride levels were found in highly-alkaline (pH of 7 to 8.9) groundwater characterized by high salinity; high concentrations of sodium (Na⁺), bicarbonate (HCO₃⁻), and silica (SiO₂); and low concentrations of calcium (Ca²⁺). A progressive Ca²⁺ decrease along the groundwater flow path is associated with an increase of fluoride in the groundwater. The groundwater quality problem is also coupled with the presence of other toxic elements, such as arsenic (As) and uranium (U). The health impact of fluoride was evaluated based on clinical examination of dental fluorosis (DF) among local residents using the Thylstrup and Fejerskov index (TFI). In total, 200 rural inhabitants between the ages of 7 and 40 years old using water from 12 wells of fluoride range of 7.8-18 mg/L were examined. Signs of DF (TF score of ≥ 1) were observed in all individuals. Most of the teeth (52%) recorded TF scores of 5 and 6, followed by TF scores of 3 and 4 (30%), and 8.4% had TF scores of 7 or higher. Sixty percent of the teeth exhibited loss of the outermost enamel. Within the range of fluoride contents, we did not find any correlation between fluoride content and DF. Finally, preliminary data suggest that milk intake has contributed to reducing the severity of DF. The study highlights the apparent positive role of milk on DF, and emphasizes the importance of nutrition in management efforts to mitigate DF in the MER and other parts of the world.

Alimentary fluoride intake in preschool children

Background

The knowledge of background alimentary fluoride intake in preschool children is of utmost importance for introducing optimal and safe caries preventive measures for both individuals and communities. The aim of this study was to assess the daily fluoride intake analyzing duplicate samples of food and beverages. An attempt was made to calculate the daily intake of fluoride from food and swallowed toothpaste.

Methods

Daily alimentary fluoride intake was measured in a group of 36 children with an average age of 4.75 years and an average weight of 20.69 kg at baseline, by means of a double plate method. This was repeated after six months. Parents recorded their child's diet over 24 hours and collected duplicated portions of food and beverages received by children during this period. Pooled samples of food and beverages were weighed and solid food samples were homogenized. Fluoride was quantitatively extracted from solid food samples by a microdiffusion method using hexadecyldisiloxane and perchloric acid. The content of fluoride extracted from solid food samples, as well as fluoride in beverages, was measured potentiometrically by means of a fluoride ion selective electrode.

Results

Average daily fluoride intake at baseline was 0.389 (SD 0.054) mg per day. Six months later it was 0.378 (SD 0.084) mg per day which represents 0.020 (SD 0.010) and 0.018 (SD 0.008) mg of fluoride respectively calculated per kg bw/day.

When adding the values of unwanted fluoride intake from the toothpaste shown in the literature (0.17-1.21 mg per day) the estimate of the total daily intake of fluoride amounted to 0.554-1.594 mg/day and recalculated to the child's body weight to 0.027-0.077 mg/kg bw/day.

Conclusions

In the children studied, observed daily fluoride intake reached the threshold for safe fluoride intake. When adding the potential fluoride intake from swallowed toothpaste, alimentary intake reached the optimum range for daily fluoride intake. These results showed that in preschool children, when trying to maximize the benefit of fluoride in caries prevention and to minimize its risk, caution should be exercised when giving advice on the fluoride containing components of child's diet or prescribing fluoride supplements.

Comparison between observed children's tooth brushing habits and those reported by mothers

Background

Information bias can occur in epidemiological studies and compromise scientific outcomes, especially when evaluating information given by a patient regarding their own health. The oral habits of children reported by their mothers are commonly used to evaluate tooth brushing practices and to estimate fluoride intake by children. The aim of the present study was to compare observed tooth-brushing habits of young children using fluoridated toothpaste with those reported by mothers.

Methods

A sample of 201 mothers and their children (aged 24-48 months) from Montes Claros, Brazil, took part in a cross-sectional study. At day-care centres, the mothers answered a self-administered questionnaire on their child's tooth-brushing habits. The structured questionnaire had six items with two to three possible answers. An appointment was then made with each mother/child pair at day-care centres. The participants were asked to demonstrate the tooth-brushing practice as usually performed at home. A trained examiner observed and documented the procedure. Observed tooth brushing and that reported by mothers were compared for overall agreement using Cohen's Kappa coefficient and the McNemar test.

Results

Cohen's Kappa values comparing mothers' reports and tooth brushing observed by the examiner ranged from poor-to-good (0.00-0.75). There were statistically significant differences between observed tooth brushing habits and those reported by mothers (p < 0.001). When observed by the examiner, the frequencies of dentifrice dispersed on all bristles (35.9%), children who brushed their teeth alone (33.8%) and those who did not rinse their mouths during brushing (42.0%) were higher than those reported by the mothers (12.1%, 18.9% and 6.5%, respectively; p < 0.001).

Conclusions

In general, there was low agreement between observed tooth brushing and mothers' reports. Moreover, the different methods of estimation resulted in differences in the frequencies of tooth brushing habits, indicative of reporting bias. Data regarding children's tooth-brushing habits as reported by mothers should be considered with caution in epidemiological surveys on fluoridated dentifrice use and the risk 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.

Topical fluoride as a cause of dental fluorosis in children

BACKGROUND

For many years, topical use of fluorides has gained greater popularity than systemic use of fluorides. A possible adverse effect associated with the use of topical fluoride is the development of dental fluorosis due to the ingestion of excessive fluoride by young children with developing teeth.

OBJECTIVES

To describe the relationship between the use of topical fluorides in young children and the risk of developing dental fluorosis.

SEARCH STRATEGY

Electronic search of the Cochrane Oral Health Group Trials Register, CENTRAL, MEDLINE, EMBASE, BIOSIS, Dissertation Abstracts and LILACS/BBO. Reference lists from relevant articles were searched. Date of the most recent searches: 9th March 09.

SELECTION CRITERIA

Randomised controlled trials (RCTs), quasi-RCTs, cohort studies, case-control studies and cross-sectional surveys, in which fluoride toothpastes, mouthrinses, gels, foams, paint-on solutions, and varnishes were compared to an alternative fluoride treatment, placebo or no intervention group. Children under the age of 6 years at the time topical fluorides were used.

DATA COLLECTION AND ANALYSIS

Data from all included studies were extracted by two review authors. Risk ratios for controlled, prospective studies and odds ratios for case-control studies or cross-sectional surveys were extracted or calculated. Where both adjusted and unadjusted risk ratios or odds ratios were presented, the adjusted value was included in the meta-analysis.

MAIN RESULTS

25 studies were included: 2 RCTs, 1 cohort study, 6 case-control studies and 16 cross-sectional surveys. Only one RCT was judged to be at low risk of bias. The other RCT and all observational studies were judged to be at moderate to high risk of bias. Studies were included in four intervention/exposure comparisons. A statistically significant reduction in fluorosis was found if brushing of a child's teeth with fluoride toothpaste commenced after the age of 12 months odds ratio 0.70 (random-effects: 95% confidence interval 0.57 to 0.88) (data from observational studies). Inconsistent statistically significant associations were found between starting using fluoride toothpaste/toothbrushing before or after the age of 24 months and fluorosis (data from observational studies). From the RCTs, use of higher level of fluoride was associated with an increased risk of fluorosis. No significant association between the frequency of toothbrushing or the amount of fluoride toothpaste used and fluorosis was found.

AUTHORS' CONCLUSIONS

There should be a balanced consideration between the benefits of topical fluorides in caries prevention and the risk of the development of fluorosis. Most of the available evidence focuses on mild fluorosis. There is weak unreliable evidence that starting the use of fluoride toothpaste in children under 12 months of age may be associated with an increased risk of fluorosis. The evidence for its use between the age of 12 and 24 months is equivocal. If the risk of fluorosis is of concern, the fluoride level of toothpaste for young children (under 6 years of age) is recommended to be lower than 1000 parts per million (ppm).More evidence with low risk of bias is needed. Future trials assessing the effectiveness of different types of topical fluorides (including toothpastes, gels, varnishes and mouthrinses) or different concentrations or both should ensure that they include an adequate follow-up period in order to collect data on potential fluorosis. As it is unethical to propose RCTs to assess fluorosis itself, it is acknowledged that further observational studies will be undertaken in this area. However, attention needs to be given to the choice of study design, bearing in mind that prospective, controlled studies will be less susceptible to bias than retrospective and/or uncontrolled studies.

A literature review of aesthetic perceptions of dental fluorosis and relationships with psychosocial aspects/oral health-related quality of life

Aesthetic perceptions and oral health-related quality of life concerning dental fluorosis have been assessed in several studies during the past two decades. However, no comprehensive review article summarizing the studies investigating this issue has been published.

OBJECTIVE

To assess the relationships between perceptions of dental appearance/oral health-related quality of life (OHRQoL) and dental fluorosis.

METHODS

The PubMed database was searched using the Medical Subject Headings (MeSH) for English-language studies from 1985 to March 2009. Thirty-five articles qualified for inclusion and then were classified into three categories based on the type of study approach: (i) respondent review of photographs and assessment concerning satisfaction/acceptance, (ii) respondent assessment of study subject's teeth concerning satisfaction/acceptance, and (iii) respondent assessments of the psychosocial/OHRQoL impact.

RESULTS

There were varied results from earlier studies focused on satisfaction/acceptance of very mild to mild fluorosis. More recent studies with methodological improvements to assess impact on quality of life clearly showed that mild fluorosis was not a concern. Furthermore, mild fluorosis was sometimes associated with improved OHRQoL. Severe fluorosis was consistently reported to have negative effects on OHRQoL.

CONCLUSION

Because dental fluorosis in the United States and other nations without high levels of naturally-occurring fluoride is mild or very mild, with little impact on OHRQoL, dental professionals should emphasize the appropriate use of fluorides for caries prevention and preventing moderate/severe fluorosis.

Comparison of a dietary survey and the duplicate plate method for determining dietary fluoride ingested by young children: a pilot study

BACKGROUND

Investigators have attempted to establish the diet's contribution to the total body burden of fluoride in response to a reported trend towards an increase in fluoride intake.

AIM

The aim of this study was to compare the suitability of two methods to collect dietary data for fluoride intake assessment.

DESIGN

Assessments were made in 12 children using the duplicate plate and dietary diary methods following a randomized cross-over design. Foods and beverages were analysed for fluoride, and total fluoride intake per day was calculated. Results from each method were compared.

RESULTS

Mean beverage fluoride intake was estimated at 316 +/- 120 and 422 +/- 195 microg/day utilizing the diary and duplicate plate methods, respectively. Mean food fluoride intake was estimated at 188 +/- 48 microg/day using the diary, whereas it was 130 +/- 41 microg using the duplicate plate method. Total fluoride intake was 504 +/- 138 and 552 +/- 192 microg/day utilizing the diary and duplicate methods. Large variations in daily fluoride intake from both beverages and food were observed between and within children.

CONCLUSIONS

Both methods had inherent shortcomings and sources of error. The duplicate method was more labour intensive and costly; however, the diary method required a large number of assumptions. A combination of both methods seems to be most suitable to obtain reliable data.

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.