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About Leite GA, Sawan RM, Teófilo JM, Porto IM, Sousa FB, Gerlach RF

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So far Leite GA, Sawan RM, Teófilo JM, Porto IM, Sousa FB, Gerlach RF has created 1044 blog entries.

Exposure to lead exacerbates dental fluorosis.

“Aim: Our aim was to test the hypothesis that co-exposure to lead and fluoride alter the severity of enamel fluorosis. Materials and methods: Wistar rats were allocated in four groups: control, and 3 groups that received water containing 100 ppm of fluoride (F), 30 ppm of lead (Pb), or 100 ppm of F and 30 ppm of Pb (F + Pb) from the beginning of gestation. Enamel analysis and F and Pb determinations in enamel, dentine, and bone were performed in 81-day-old animals. Fluorosis was quantified using a new fluorosis index based on the identification of incisor enamel defects (white bands and white islets, representing hypomineralization, and cavities) weighted according to their severity and quantity. Hypomineralization was validated histopathologically by polarizing microscopy and microradiography. Scores were given by two blinded calibrated examiners (intra and interexaminer kappa values were 0.8 and 0.86, respectively). Results: The control and the Pb groups presented normal enamel. The F + Pb group presented more severe enamel defects compared with the F group (P < 0.0001). Conclusions: This study shows that lead exacerbates dental fluorosis in rodents, suggesting that co-exposure to lead may affect the degree of fluorosis.”

Is dental amalgam safe for humans? The opinion of the scientific committee of the European Commission.

“It was claimed by the Scientific Committee on Emerging and Newly Identified Health Risks (SCENIHR) in a report to the EU-Commission that ‘….no risks of adverse systemic effects exist and the current use of dental amalgam does not pose a risk of systemic disease…’ [1, available from: http://ec.europa.eu/health/ph_risk/committees/04_scenihr/docs/scenihr_o_016.pdf]. SCENIHR disregarded the toxicology of mercury and did not include most important scientific studies in their review. But the real scientific data show that:(a) Dental amalgam is by far the main source of human total mercury body burden. This is proven by autopsy studies which found 2-12 times more mercury in body tissues of individuals with dental amalgam. Autopsy studies are the most valuable and most important studies for examining the amalgam-caused mercury body burden.(b) These autopsy studies have shown consistently that many individuals with amalgam have toxic levels of mercury in their brains or kidneys.(c) There is no correlation between mercury levels in blood or urine, and the levels in body tissues or the severity of clinical symptoms. SCENIHR only relied on levels in urine or blood.(d) The half-life of mercury in the brain can last from several years to decades, thus mercury accumulates over time of amalgam exposure in body tissues to toxic levels. However, SCENIHR state that the half-life of mercury in the body is only ’20-90 days’.(e) Mercury vapor is about ten times more toxic than lead on human neurons and with synergistic toxicity to other metals.(f) Most studies cited by SCENIHR which conclude that amalgam fillings are safe have severe methodical flaws.”

By |2018-06-28T23:37:53+00:00January 1st, 2011|Mercury|

An assessment of bone fluoride and osteosarcoma.

“The association between fluoride and risk for osteosarcoma is controversial. The purpose of this study was to determine if bone fluoride levels are higher in individuals with osteosarcoma. Incident cases of osteosarcoma (N = 137) and tumor controls (N = 51) were identified by orthopedic physicians, and segments of tumor-adjacent bone and iliac crest bone were analyzed for fluoride content. Logistic regression adjusted for age and sex and potential confounders of osteosarcoma was used to estimate odds ratios (OR) and 95% confidence intervals (CI). There was no significant difference in bone fluoride levels between cases and controls. The OR adjusted for age, gender, and a history of broken bones was 1.33 (95% CI: 0.56-3.15). No significant association between bone fluoride levels and osteosarcoma risk was detected in our case-control study, based on controls with other tumor diagnoses. “

Embryonic exposure to thimerosal, an organomercury compound, causes abnormal early development of serotonergic neurons.

“Even though neuronal toxicity due to organomercury compounds is well known, thimerosal, an organomercury compound, is widely used in pediatric vaccine preservation. In the present study, we examined whether embryonic exposure to thimerosal affects early development of serotonergic neurons. Thimerosal (1mg Hg/kg) was intramuscularly administered to pregnant rats on gestational day 9 (susceptible time window for development of fetal serotonergic system), and fetal serotonergic neurons were assessed at embryonic day 15 using anti-serotonin antibodies. A dramatic increase in the number of serotonergic neurons localized to the lateral portion of the caudal raphe was observed in thimerosal group (1.9-fold increase, p<0.01 compared to control). These results indicate that embryonic exposure to thimerosal affects early development of serotonergic neurons.”

Mercury exposure and risks from dental amalgam in the US population, post-2000.

“Dental amalgam is 50% metallic mercury (Hg) by weight and Hg vapour continuously evolves from in-place dental amalgam, causing increased Hg content with increasing amalgam load in urine, faeces, exhaled breath, saliva, blood, and various organs and tissues including the kidney, pituitary gland, liver, and brain. The Hg content also increases with maternal amalgam load in amniotic fluid, placenta, cord blood, meconium, various foetal tissues including liver, kidney and brain, in colostrum and breast milk. Based on 2001 to 2004 population statistics, 181.1 million Americans carry a grand total of 1.46 billion restored teeth. Children as young as 26 months were recorded as having restored teeth. Past dental practice and recently available data indicate that the majority of these restorations are composed of dental amalgam. Employing recent US population-based statistics on body weight and the frequency of dentally restored tooth surfaces, and recent research on the incremental increase in urinary Hg concentration per amalgam-filled tooth surface, estimates of Hg exposure from amalgam fillings were determined for 5 age groups of the US population. Three specific exposure scenarios were considered, each scenario incrementally reducing the number of tooth surfaces assumed to be restored with amalgam. Based on the least conservative of the scenarios evaluated, it was estimated that some 67.2 million Americans would exceed the Hg dose associated with the reference exposure level (REL) of 0.3 µg/m(3) established by the US Environmental Protection Agency; and 122.3 million Americans would exceed the dose associated with the REL of 0.03 µg/m(3) established by the California Environmental Protection Agency. Exposure estimates are consistent with previous estimates presented by Health Canada in 1995, and amount to 0.2 to 0.4 µg/day per amalgam-filled tooth surface, or 0.5 to 1 µg/day/amalgam-filled tooth, depending on age and other factors.”

Study of some biomarkers in hair of children with autism.

“Introduction
Autism is a severe developmental disorder, which involves social withdrawal, communication deficits, and stereotypic repetitive behavior. The possible etiologies that precipitate autism symptoms remain controversial in many cases, but both genetic and environmental factors have been implicated. Mercury has gained much attention for a considerable period of time before other exacerbating or protective factors were suggested. The aim of this study was to investigate the relationship between autism and the level of some metals (namely mercury, lead, and copper) or zinc as a counteracting antioxidant element.
Methods
The study recruited 32 autistic children and 32 normal controls and all of them were subjected to KID-SCID, Childhood Autism Rating Scale (CARS), Stanford Binet intelligence test, and biochemical analysis of hair samples for the level of mercury, copper, lead and zinc.
Results
There were highly significant differences between the level of these substances in the hair of children with autism compared with controls, positive correlation of CARS score with both mercury and copper, while intelligence quotient has significant negative correlation with the level of lead in the hair. The level of zinc does not correlate with either CARS score or intelligence quotient.
Conclusion
These preliminary results suggest a complementary role for the studied elements in the pathogenesis of autistic disorder, which should be considered in the management plane.”

Bone fluoride concentrations of eastern grey kangaroos (Macropus giganteus) resident near an aluminium smelter in south-eastern Australia.

“Lesions of skeletal and dental fluorosis have been described recently in eastern grey kangaroos (Macropus giganteus). The present study further examined the epidemiology of skeletal fluorosis in this species. Bone fluoride concentrations were obtained from a range of skeletal sites of animals from a high (Portland Aluminium) and a low (Cape Bridgewater) fluoride environment in Victoria, Australia. Age, but not sex, affected the mean bone fluoride concentration of kangaroos. For a given age, bone fluoride concentrations were significantly higher in kangaroos from Portland than Cape Bridgewater. Concentrations varied between skeletal sites examined, with samples containing cancellous bone having higher fluoride concentrations than those containing only cortical bone. “

By |2018-06-04T22:38:57+00:00January 1st, 2011|Fluoride|

Amoxicillin use during early childhood and fluorosis of later developing tooth zones.

“Objectives: Amoxicillin use has been reported to be associated with developmental defects on enamel surfaces. This analysis assessed the association between amoxicillin use and fluorosis on late-erupting permanent teeth.

Methods: As part of the Iowa Fluoride Study, subjects were followed from birth to 32 months with questionnaires every 3-4 months to gather information on fluoride intake and amoxicillin use (n = 357 subjects for this analysis). Permanent tooth fluorosis on late-erupting zones was assessed by three trained dentists using the fluorosis risk index (FRI) at approximately age 13. A case was defined as fluorosis if a subject had at least two FRI classification II zone scores of 2 or 3. Chi-square tests and logistic regression were used, and relative risks (RRs) and odds ratios (ORs) were calculated.

Results: There were 113 cases and 244 controls. In bivariate analyses, amoxicillin use from 20 to 24 months significantly increased the risk of fluorosis on FRI classification II zones [44.2 percent versus 30.4 percent, [RR = 1.45, 95 percent confidence interval (CI) 1.05-2.04], but other individual time periods did not.  Multivariable logistic regression confirmed the increased risk of fluorosis for amoxicillin use from 20 to 24 months (OR = 2.92, 95 percent CI = 1.34-6.40), after controlling for otitis media, breast-feeding, and fluoride intake.

Conclusions: Amoxicillin use during early childhood could be a risk factor in the etiology of fluorosis on late-erupting permanent tooth zones, but further research is needed.”

By |2018-05-30T22:59:44+00:00January 1st, 2011|Fluoride|

The US Dental Amalgam Debate, 2010 Meeting of the FDA Dental Products Panel.

“The Food and Drug Administration (FDA) convened a meeting on December 14 and 15, 2010 to consider FDA policy regarding the safety of dental amalgam.(1-12) Dental amalgam, commonly called “silver filling” material, is composed of about 50% mercury mixed with other metals including silver, tin and copper. At the meeting, the FDA Dental Products Panel of the Medical Devices Advisory Committee considered whether a 2009 FDA rule(13) adequately addressed the health risks posed by the mercury contained in the fillings. The meeting included scientific and public testimony, as well as panel deliberation, providing a forum to present information pertinent to the dental amalgam debate.”

By |2018-03-24T20:13:44+00:00January 1st, 2011|Mercury|

Supplemental fluoride use for moderate and high caries risk adults: a systematic review.

“Objectives: Multiple systematic reviews have evaluated fluorides for caries prevention in children, but a need to review the literature regarding supplemental fluoride use in adults still remains. The purpose of this systematic review is to evaluate the research regarding professional and/or supplemental self-applied fluoride for preventing and remineralizing caries in moderate and high caries risk adults.

Methods: Utilizing multiple databases, a comprehensive search was undertaken in both foreign and English languages. Studies included were randomized control trials (RCT) or clinical trials conducted in moderate or high caries risk adult populations, evaluating self- or professionally applied fluoride with the outcomes of caries reduction/remineralization. Studies were excluded if they were in situ, in vitro, split mouth design, or with unclear outcomes specific to fluorides. A quality evaluation of the studies used a checklist of critical domains and elements for an RCT.

Results: Seventeen studies were included in the systematic review. Findings were categorized into the following groups: sodium fluoride (NaF) and amine/potassium fluoride mouthrinses of varying strengths, NaF gels and pastes, NaF varnish, and stannous fluoride. Quality evaluation scores varied from 50.2 percent to 88.9 percent.

Conclusions: The strongest studies demonstrated the following modalities as moderately effective in higher caries risk adults: low strength NaF rinses [relative risk reduction (RRR) for carious lesions: 50-148 percent]; 1.1 percent NaF pastes/gels (RRR for root lesion remineralization: 35-122 percent); fluoride varnishes [RRR for RC remineralization: 63 percent; RRR for decrease in decayed, missing, and filled surfaces: 50 percent]. Evidence regarding 1.1 percent NaF and 5 percent NaF varnishes related primarily to root caries and older adults.”

By |2018-04-30T22:28:18+00:00January 1st, 2011|Fluoride|
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