Dental amalgam exposure can elevate urinary mercury concentrations in children.

OBJECTIVES: Owing to its cost-effectiveness and operative convenience, dental amalgam remains in use as a restorative material for tooth caries in children in many countries. The aim of this study was to evaluate the relationship between dental amalgam exposure and urinary mercury (U-Hg) concentrations in children. METHODS: In this longitudinal study, 463, 367 and 348 children, 8-11 years of age, were evaluated at baseline, and at the first and second follow-up visits, respectively. The interval between each survey was 6 months. For the oral examination and urine sample, the amalgam-filled tooth surface (TS), and U-Hg and creatinine concentrations of participants were determined, and the cumulative amalgam-filled TS and cumulative creatinine-adjusted U-Hg were calculated. To assess potential covariates, socio-demographic factors, oral health behaviour and dietary factors were surveyed by questionnaire. Data were analysed by the t-test, correlation analysis and mixed-model analysis. The statistical analyses were performed using SPSS 18.0. RESULTS: Children with more than one amalgam-filled TS exhibited significantly higher creatinine-adjusted U-Hg concentrations than those without, in all three survey periods (P < 0.001). The results for the current and cumulative amalgam-filled TS significantly correlated with those for the current and cumulative creatinine-adjusted U-Hg concentration, respectively, in all surveys (P < 0.001). In the repeated-measures mixed model analysis, current and cumulative amalgam-filled TS was significantly related to current and cumulative creatinine-adjusted U-Hg concentration, respectively (P < 0.001). CONCLUSIONS: Amalgam-filled TS was significantly correlated with U-Hg concentrations in children. Therefore, dental amalgam exposure can affect the systemic mercury concentration in children.

Pharmacokinetics of fluoride in toddlers after application of 5% sodium fluoride dental varnish.

The prevalence of dental caries (tooth decay) among preschool children is increasing, driven partially by an earlier age of onset of carious lesions. The American Academy of Pediatrics recommends application of 5% sodium fluoride varnish at intervals increasing with caries risk status, as soon as teeth are present. However, the varnishes are marketed for treatment of tooth sensitivity and are regulated as medical devices rather than approved by the US Food and Drug Administration for prevention of dental caries (tooth decay). The objective of this research is to examine the safety of use in toddlers by characterizing the absorption and distribution profile of a currently marketed fluoride varnish. We measured urinary fluoride for 5 hours after application of fluoride varnish to teeth in 6 toddlers aged 12 to 15 months. Baseline levels were measured on a separate day. The urine was extracted from disposable diapers, measured by rapid diffusion, and extrapolated to plasma levels. The mean estimated plasma fluoride concentration was 13 µg/L (SD, 9 µg/L) during the baseline visit and 21 µg/L (SD, 8 µg/L) during the 5 hours after treatment. Mean estimated peak plasma fluoride after treatment was 57 µg/L (SD, 22 µg/L), and 20 µg/kg (SD, 4 µg/L) was retained on average. Retained fluoride was 253 times lower than the acute toxic dose of 5 mg/kg. Mean plasma fluoride after placement of varnish was within an SD of control levels. Occasional application of fluoride varnish following American Academy of Pediatrics guidance is safe for toddlers.

A dose-dependent relationship between mercury exposure from dental amalgams and urinary mercury levels: a further assessment of the Casa Pia Children's Dental Amalgam Trial.

Dental amalgams are a commonly used dental restorative material, and amalgams are about 50% mercury (Hg). In our study, urinary Hg levels was examined in children of age 8-18 years, with and without dental amalgam fillings, from a completed clinical trial (parent study) that was designed to evaluate the potential health consequences of prolonged exposure to Hg from dental amalgam fillings. Our study was designed to determine whether there was a significant dose-dependent correlation between increasing Hg exposure from dental amalgams and urinary Hg levels. Hg exposure depends on the size and number of teeth with dental amalgams. Overall, consistent with the results observed in the parent study, there was a statistically significant dose-dependent correlation between cumulative exposure to Hg from dental amalgams and urinary Hg levels, after covariate adjustment. Further, it was observed that urinary Hg levels increased by 18% to 52% among 8 to 18 year old individuals, respectively, with an average exposure to amalgams, in comparison to study subjects with no exposure to amalgams. The results of our study suggest that dental amalgams contribute to ongoing Hg exposure in a dose-dependent fashion.

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.

Association of environmental cadmium exposure with pediatric dental caries.

BACKGROUND: Although animal experiments have shown that cadmium exposure results in severe dental caries, limited epidemiologic data are available on this issue. OBJECTIVES: We aimed to examine the relationship between environmental cadmium exposure and dental caries in children 6-12 years of age. METHODS: We analyzed cross-sectional data, including urine cadmium concentrations and counts of decayed or filled tooth surfaces, from the Third National Health and Nutrition Examination Survey. We used logistic and zero-inflated negative binomial (ZINB) regression to estimate the association between urine cadmium concentrations and caries experience, adjusting these analyses for potential confounders including environmental tobacco smoke (ETS). RESULTS: Urine cadmium concentrations ranged from 0.01 to 3.38 ng/mL. Approximately 56% of children had experienced caries in their deciduous teeth, and almost 30% had been affected by caries in their permanent dentition. An interquartile range (IQR) increase in creatinine-corrected cadmium concentrations (0.21 microg/g creatinine) corresponded to a 16% increase in the odds of having experienced caries in deciduous teeth [prevalence odds ratio (OR)=1.16; 95% confidence interval (CI), 0.96-1.40]. This association was statistically significant in children with low ETS exposure (prevalence OR=1.30; 95% CI, 1.01-1.67). The results from the ZINB regression indicated that, among children with any caries history in their deciduous teeth, an IQR increase in cadmium was associated with 17% increase in the number of decayed or filled surfaces. We observed no association between cadmium and caries experience in permanent teeth. CONCLUSIONS: Environmental cadmium exposure may be associated with increased risk of dental caries in deciduous teeth of children.

[Fluoride metabolism in children and caries prevention]. / Osobennosti obmena ftoridov u detei pri profilaktike kariesa.

Basal mineral elements content in superficial dental enamel layers and daily urine fluoride excretion have been investigated in children using water with various level of this trace element. The investigation was carried out before and after sodium fluoride intake in the doses 1.1-1.6 mg/day. The results give evidence that differential approach to dental caries prevention with fluoride is required.

Caries increment in children and urinary catecholamines: findings at one-year.

This one-year follow-up study investigates the relationship between urinary catecholamine levels and dental caries increment in 314 children, boys and girls, ages six to eight years. Dental caries was recorded clinically and radiographically and oral hygiene was evaluated by recording the dental plaque. A 24-hour urine sample was collected for each subject, in a year interval, and a representative sample was analyzed by the HPLC technique to assay the catecholamine content. Socioeconomic factors such as parental age, education, and profession were recorded by a questionnaire distributed to the parents. Of the examined children, forty-four (16 boys and 28 girls) did not develop new dental caries and constituted the Caries-Free group. Two New Caries groups, A and B, of forty-four children each (16 boys and 28 girls) were matched by age and sex. Differences were tested in the quantitative and qualitative data by the paired t-test and the chi 2 test, respectively, while a regression analysis was applied to measure the effects of norepinephrine and dopamine on epinephrine. The logistic multiple-regression analysis was used to test, in the entire population, the impact of catecholamines and other related factors on the probability of a subject's developing new dental caries. The 95 percent probability was used. The results showed statistically significant differences in epinephrine and norepinephrine values between Caries-Free and New Caries group A in both examinations. Also, significant differences were found between Caries-Free and New Caries group B in epinephrine and norepinephrine at the first examination, while at the second examination the difference was significant only in epinephrine. The data provide evidence, therefore, that an emotionally stressful state can be an etiologic factor of dental caries.

Caries experience, oral health status and urine fluoride excretion in children in some localities in the Czech Republic.

Two studies on caries experience and oral health status in 12-year-old-children were conducted in a five year period (1993-1998). The examination was completed by analysing the urinary fluoride excretion of the examined children. The DMFT was recorded. The F-selective electrode was used for the analysis of the urinary fluoride concentration. The percentage of caries-free children decreased between 1993-1998. Caries experience rose in most of the localities. The highest caries experience expressed by DMFT was found in Tábor where it reached 5 per person. The urinary fluoride excretion ranged from the lowest level, found in Strakonice (0.478 mg/l), to the highest which was in Ostrava (0.660 mg/l) in 1998. F-concentrations in all other localities were between these extremes (both in 1993 and 1998). Oral health and fluoride exposure from the environment varied considerably which implies the necessity to implement individual precautions in oral care and prevention at a local level.

The effect of sucrose diet of rat dams on the dentine apposition and dental caries of their pups.

The purpose was to examine whether a sucrose diet in rat dams reduces dentine apposition and enhances dental caries in their pups. Sprague-Dawley rat pups were randomized into four groups on the day of birth. During the lactation period three dams received a standard rodent diet and three a diet containing 41% sucrose. At the age of 3 weeks the pups were weaned and given an intraperitoneal injection of oxytetracycline hydrochloride. During the experimental period, half of the pups of control dams received a sucrose diet (Cnt-Suc pups) and half of the pups of sucrose dams received a standard diet (Suc-Cnt pups). The pups in the other halves received the same diet as given to their dams during lactation (Cnt-Cnt and Suc-Suc pups). Urine samples were collected from dams and pups during the test periods. After 4 weeks the pups were killed, their blood was collected and their jaws sectioned sagittally. Dentine apposition was determined planimetrically and dental caries using Schiffs staining. Ca, K and Na of serum and urine were measured flame photometrically and P using an ultraviolet method. The lactational sucrose diet was associated with decreased P and Na excretion in the dams, and also with reduced dentine apposition in their pups. Reduced dentine apposition and induced Ca excretion with decreased P, K and Na excretions were observed in Suc-Suc pups and Cnt-Suc pups during the experiment period. Fewer intact teeth with more enamel and dentinal caries lesions occurred in sucrose-exposed groups (Suc-Cnt, Cnt-Suc and Suc-Suc pups). It was concluded that the sucrose diet given to dams during lactation changed the function of the pulp dentine complex of their pups leading to reduced dentinogenesis, but also predisposed to a reduction of dentinogenesis in pups during the experimental period and enhanced the occurrence of dental caries.

Urinary catecholamine levels in children with and without dental caries.

Urinary catecholamines have been used to measure emotionally stressful states which may affect the development of dental caries. This study investigates the hypothesis that children with and without dental caries do not differ significantly in the mean values of urinary catecholamines such as epinephrine, norepinephrine, and dopamine. As a test of this hypothesis, 314 children, males and females, aged from 6 to 8 years, were included in the study. Dental caries were recorded clinically and radiographically, and oral hygiene was evaluated by the recording of dental plaque. A 24-hour urine sample was collected for each subject, and a representative sample (25 mL) was analyzed by the HPLC technique to assay the catecholamine content. Socioeconomic factors such as parental age, education, and profession were recorded by a questionnaire distributed to the parents. Of the examined children, 38 (14 males and 24 females) were free of dental caries and constituted the case group. Two control groups, A and B, of 38 children each (14 males and 24 females) with dental caries were matched by age and gender. Differences in the quantitative and qualitative data were tested by the paired t test and the X2-test, respectively, while a regression analysis was applied to measure the effects of norepinephrine and dopamine on epinephrine. The logistic multiple-regression analysis was used to test, in the entire population, the impact of catecholamines and other related factors on the probability of subjects' developing dental caries. The 95% probability was used. The results showed statistically significant differences in epinephrine values between the case group and control groups A and B. The data suggest, therefore, that children with emotionally stressful states have higher probability of developing dental caries.

[Caries occurrence in schoolchildren of the canton of Glarus in 1974 to 1992: the effect of the use of fluoridated salt]. / Kariesbefall bei Schülern des Kantons Glarus in den Jahren 1974 bis 1992: Wirkung der Salzfluoridierung.

Between 1974 and 1976, fluoridated salt (250 ppm F) was introduced in the Swiss Canton of Glarus and has been used since by the bakeries and most households (domestic salt) in the Canton. Caries prevalence in schoolchildren of this Canton declined from 1974 to 1992 by 80 to 85%. As an example, 12-year-old children had 6.5 DMFT in 1974, but only 1.1 in 1992. In 1992, most DF sites were fissures and pits and most of them filled. Caries prevalence in primary teeth (dmft) decreased by 49 to 66% in the age groups 7, 8 and 9, and most of the reduction had occurred before 1983. In 1974, the average fluoride concentration in urine amounted to 0.36 ppm; between 1979 and 1992 it increased from 0.74 to 0.86 ppm. 46 to 60% of the bread samples contained between 3 to 9 ppm F; this bread had obviously been produced with fluoridated salt. Salt fluoridation contributed to caries decline until up to 1987, while subsequent caries reductions in permanent teeth must have been caused by other factors. In comparison to other Swiss data the caries prevalence of pupils in the Canton of Glarus was low in 1992.