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About Sheehan MC, Burke TA, Navas-Acien A, Breysse PN, McGready J, Fox MA.

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So far Sheehan MC, Burke TA, Navas-Acien A, Breysse PN, McGready J, Fox MA. has created 996 blog entries.

Global methylmercury exposure from seafood consumption and risk of developmental neurotoxicity: a systematic review.

OBJECTIVE:
To examine biomarkers of methylmercury (MeHg) intake in women and infants from seafood-consuming populations globally and characterize the comparative risk of fetal developmental neurotoxicity.

METHODS:
A search was conducted of the published literature reporting total mercury (Hg) in hair and blood in women and infants. These biomarkers are validated proxy measures of MeHg, a neurotoxin found primarily in seafood. Average and high-end biomarkers were extracted, stratified by seafood consumption context, and pooled by category. Medians for average and high-end pooled distributions were compared with the reference level established by a joint expert committee of the Food and Agriculture Organization (FAO) and the World Health Organization (WHO).

FINDINGS:
Selection criteria were met by 164 studies of women and infants from 43 countries. Pooled average biomarkers suggest an intake of MeHg several times over the FAO/WHO reference in fish-consuming riparians living near small-scale gold mining and well over the reference in consumers of marine mammals in Arctic regions. In coastal regions of south-eastern Asia, the western Pacific and the Mediterranean, average biomarkers approach the reference. Although the two former groups have a higher risk of neurotoxicity than the latter, coastal regions are home to the largest number at risk. High-end biomarkers across all categories indicate MeHg intake is in excess of the reference value.

CONCLUSION:
There is a need for policies to reduce Hg exposure among women and infants and for surveillance in high-risk populations, the majority of which live in low-and middle-income countries.

Effluent Limitation Guidelines and Standards for the Dental Category.

EPA is proposing technology-based pretreatment standards under the Clean Water Act for discharges of pollutants into publicly owned treatment works (POTWs) from existing and new dental practices that involve the discharge of dental amalgam. The proposal would require dental practices to comply with requirements for controlling the discharge of dental amalgam pollutants into POTWs based on the best available technology or best available control technology and Best Management Practices.

By |2018-07-20T18:13:26+00:00January 1st, 2014|Mercury|

Systemic allergic contact dermatitis associated with allergy to intraoral metals.

Contact (allergic) dermatitis is a skin disorder related to natural exposure to various allergens. Systemic contact dermatitis (SCD) describes a cutaneous eruption in response to systemic exposure to an allergen. The exact pathologic mechanism remains uncertain. Herein we describe a 36-year-old woman with symmetric systemic allergic contact dermatitis, unresponsive to conventional treatment, associated with dental alloy-contact hypersensitivity. We did skin patch testing and the blood lymphocyte transformation test (LTT) from the dental allergen series to assess contact allergy to restorative dental materials. On patch testing, positive allergic contact dermatitis reactions to metals occurred (nickel, potassium dichromate, and gold). Nickel hypersensitivity was confirmed by LTT, which also revealed silver-amalgam sensitization. Our case report highlights the need to consider adverse reactions to base-metal dental alloys in the differential diagnosis of cases of systemic allergic contact dermatitis.

Water fluoridation: a critical review of the physiological effects of ingested fluoride as a public health intervention.

Fluorine is the world’s 13th most abundant element and constitutes 0.08% of the Earth crust. It has the highest electronegativity of all elements. Fluoride is widely distributed in the environment, occurring in the air, soils, rocks, and water. Although fluoride is used industrially in a fluorine compound, the manufacture of ceramics, pesticides, aerosol propellants, refrigerants, glassware, and Teflon cookware, it is a generally unwanted byproduct of aluminium, fertilizer, and iron ore manufacture. The medicinal use of fluorides for the prevention of dental caries began in January 1945 when community water supplies in Grand Rapids, United States, were fluoridated to a level of 1 ppm as a dental caries prevention measure. However, water fluoridation remains a controversial public health measure. This paper reviews the human health effects of fluoride. The authors conclude that available evidence suggests that fluoride has a potential to cause major adverse human health problems, while having only a modest dental caries prevention effect. As part of efforts to reduce hazardous fluoride ingestion, the practice of artificial water fluoridation should be reconsidered globally, while industrial safety measures need to be tightened in order to reduce unethical discharge of fluoride compounds into the environment. Public health approaches for global dental caries reduction that do not involve systemic ingestion of fluoride are urgently needed.

By |2018-07-28T17:20:14+00:00January 1st, 2014|Fluoride|

Fluoride toothpaste use for young children.

To assess the effectiveness and safety of using fluoride toothpaste for young chil-dren, the Council recommended a systematic review of the evidence. The results of the review demonstrated that for children younger than 6 years, fluoride toothpaste use is effective in reducing caries. The evidence also showed that ingesting pea-sized amounts or more can lead to mild fluorosis.

An ex vivo study of arrested primary teeth caries with silver diamine fluoride therapy.

RESULTS:
Micro-CT examination revealed a superficial opaque band approximately 150μm on the arrested cavitated dentinal lesion. This band was limited in the active carious lesion. EDX examination detected a higher intensity of calcium and phosphate of 150μm in the surface zone than in the inner zone, but this zone was restricted in the active cavitated dentinal lesion. SEM examination indicated that the collagens were protected from being exposed in the arrested cavitated dentinal lesion, but were exposed in the active cavitated dentinal lesion. TEM examination suggested that remineralised hydroxyapatites were well aligned in the arrested cavitated dentinal lesion, while those in the active cavitated dentinal lesion indicated a random apatite arrangement.

CONCLUSIONS:
A highly remineralised zone rich in calcium and phosphate was found on the arrested cavitated dentinal lesion of primary teeth with an SDF application. The collagens were protected from being exposed in the arrested cavitated dentinal lesion.

CLINICAL SIGNIFICANCE:
Clinical SDF application positively influences dentine remineralisation.

By |2018-07-26T16:44:38+00:00January 1st, 2014|Fluoride|

Study of high levels indoor air mercury contamination from mercury amalgam use in dentistry.

This paper describes and discusses the recent investigations, regarding mercury vapours level in air, carried out at 18 dental sites in Pakistan and other countries. It is evident from the data of 42 dental sites in 17 countries, including, selected dental sites in five main cities of Pakistan, described and discussed in this paper that at most dental sites in many countries including Pakistan, the indoor mercury vapours levels exceed far above the permissible limit, recommended for safe physical and mental health. At these sites, public, in general, and the medical, paramedical staff and vulnerable population, in particular, are at most serious risk to health resulting from exposure to toxic and hazardous mercury.

By |2018-07-24T14:28:54+00:00January 1st, 2014|Mercury|

Carbon coated implants as a new solution for metal allergy in early-onset scoliosis: A case report and review of the literature.

STUDY DESIGN:

Retrospective case report.

OBJECTIVE:

To report the first known case of immunological camouflage of a metal spinal implant with carbon coating.

SUMMARY OF BACKGROUND DATA:

Metal sensitivity is common and is a consideration when choosing orthopedic implants in susceptible individuals. The sensitivity often is to nickel, cobalt, or chromium, and titanium is used as a safe alternative. However, when the allergy is also to titanium, solutions may be much more difficult. This case describes an innovative solution to a complex metal allergy that includes titanium in a child requiring spinal instrumentation for early-onset scoliosis.

METHODS:

At age 6 years 7 months, the patient underwent an uncomplicated placement of bilateral posterior Vertical Expandable Prosthetic Titanium Ribs (VEPTRs; Synthes, Inc., West Chester, PA). At that time, there were no known metal allergies. At 3 weeks, the right side had become erythematous and had serosanguineous drainage. It briefly improved after each of 2 surgical debridements and a course of intravenous antibiotics, but within 6 weeks of the index procedure, the pain was still worsening. A titanium allergy was suspected and blood was sent for allergy testing. A test confirmed hypersensitivity to titanium, niobium, molybdenum, iron, and aluminum, among others. The remaining rod was removed. An in vivo trial for tolerance to high-grade stainless-steel implants was done. The implant was removed after 2 weeks because of systemic symptoms that occurred.

RESULTS:

A plasma-spray, carbon-coated VEPTR rod was designed. A rod sample was inserted into the patient’s forearm for trial. After 3 months, there was no appreciable reaction. Carbon-coated VEPTRs were placed without complications. The patient has undergone multiple lengthening using the carbon-coated VEPTRs.

CONCLUSIONS:

In the rare patient with multiple allergies, choosing orthopedic implants can be challenging. An innovative carbon coating was applied by plasma spray to the VEPTR system, with good results.

By |2020-01-11T03:48:20+00:00January 1st, 2014|Other|

The infection hypothesis revisited: oral infection and cardiovascular disease.

Oral infections have been associated with an increased risk for myocardial infarction (MI) and other cardiovascular diseases (CVD). Conversely, low, regular alcohol consumption is associated with a lower association of CVD. The objective was to test the novel hypothesis that oral infections are modified by regular alcohol drinking which has the effect of lowering the incidence of MI’s. The effect has been observed where tooth extractions where carried out due to infections and compared with extractions unconnected to infections. Oral infections and in particular periodontal infections impose an infectious load on the health in many people. In its advanced forms (periodontal pockets ≥ 6mm) periodontitis affects ∼10-15% of adults. The infection runs a chronic course with exacerbations. The bacteria cause local infection destructive to the supporting tissues of the teeth and have been detected in systemic diseases through bacterial products and bacteria entering the circulation. The often persistent, long term history of chronic periodontal infection in individuals is a challenge to the immune system. Over 700 oral bacteria and other microorganisms have been identified, many of which are virulent. Control of the level of oral microbiota is through well known oral hygiene measures. Alcohol by being bactericidal is a factor that may reduce the bacterial level in the oral cavity. If this effect truly exists, it should be observed through reduction of infections in the mouth. Tooth extraction is the ultimate consequence of periodontal and dental infections and a reduction of tooth extraction due to infections should therefore be observed. The hypothesis was tested using the screening data of the Oslo II-study in a cross sectional analysis. The Oslo-study included men aged 48-67 years. The main finding was that the effect of a drinking pattern of 2-7 times per week reduced the risk of MI among men who had a history of tooth extractions due to infections versus tooth extraction for other causes or no extractions. This hypothesis supports an explanation as to why oral infection is a weaker independent risk factor for CVD in some studies. It also gives an indication of the reason for an added benefit by a regular drinking pattern as part of the Mediterranean diet. The important consequence of this hypothesis is the added importance of optimal oral hygiene for the prevention of CVD as well as for the benefit of good oral health.

By |2019-06-08T03:10:41+00:00January 1st, 2014|Other|
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