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About Masters RD, Coplan MJ, Hone BT, Dykes JE.

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So far Masters RD, Coplan MJ, Hone BT, Dykes JE. has created 994 blog entries.

Association of silicofluoride treated water with elevated blood lead.

Previous epidemiological studies have associated silicofluoride-treated community water with enhanced child blood lead parameters. Chronic, low-level dosage of silicofluoride (SiF) has never been adequately tested for health effects in humans. We report here on a statistical study of 151,225 venous blood lead (VBL) tests taken from children ages 0-6 inclusive, living in 105 communities of populations from 15,000 to 75,000. The tests are part of a sample collected by the New York State Department of Children’s Health, mostly from 1994-1998. Community fluoridation status was determined from the CDC 1992 Fluoridation Census. Covariates were assigned to each community using the 1990 U.S. Census. Blood lead measures were divided into groups based on race and age. Logistic regressions were carried out for each race/age group, as well as above and below the median of 7 covariates to test the relationship between known risk factors for lead uptake, exposure to SiF-treated water, and VBL >10 microg/dL.  RESULTS:
For every age/race group, there was a consistently significant association of SiF treated community water and elevated blood lead. Logistic regressions above and below the median value of seven covariates show an effect of silicofluoride on blood lead independent of those covariates. The highest likelihood of children having VBL> 10 microg/dL occurs when they are both exposed to SiF treated water and likely to be subject to another risk factor known to be associated with high blood lead (e.g., old housing). Results are consistent with prior analyses of surveys of children’s blood lead in Massachusetts and NHANES III. These data contradict the null hypothesis that there is no difference between the toxic effects of SiF and sodium fluoride, pointing to the need for chemical studies and comprehensive animal testing of water treated with commercial grade silicofluorides.

By |2018-07-26T16:16:23+00:00January 1st, 2000|Fluoride|

Neuropathic pain in maxillofacial osteonecrosis.

Ischemic osteonecrosis (10) is not so much a disease in its own right as it is the natural consequence of a wide variety of systemic and local factors capable of compromising marrow blood flow (Table 1).1,9 It is the condition for which the term cavitation was coined in the orthopedic literature, and it is one of a select group of interrelated diseases able to deterio·rate and hollow out medullary spaces (Fig 1)1.10: First described in 1794 in a case of septic necrosis of the femoral head, this enigmatic disease is as old as the dinosaurs, but it has been poorly understood and has such subtle radiographic changes that until recently it was seldom diagnosed before end-stage damage. 1 ).13 Contemporary research has so enhanced our understanding of its basic pathophysiology that it now bears little resemblance to the entity once known as “aseptic osteomyelitis.”

By |2018-08-25T00:37:35+00:00January 1st, 2000|Periodontal Disease|

Influence of periodontal infections on systemic health.

The influence of host factors on the pathogenesis and progression of periodontal diseases is widely recognized. Offenbacher (61) has reviewed the mechanisms by which physical, environmental and social host stresses affect and modify disease expression. Models of pathogenesis have been presented in which systemic disorders affecting neutrophil, monocyte and/or lymphocyte function result in altered production or activity of cytokines and inflammatory mediators.

By |2018-08-28T00:18:46+00:00January 1st, 1999|Other|

Dental Restorations: How long do routine dental restorations last? A systematic review.

CONCLUSIONS:
Many studies were imperfect in design. Those considered to be the most appropriate for analysis were too limited to undertake a formal statistical exploration. Therefore there remains a need for definitive randomised controlled trials of restoration longevity, of sound design and adequate power, employing standardised assessments and appropriate methods of analysis.

By |2018-07-20T00:04:23+00:00January 1st, 1999|Mercury, Other|

Effect of rubber dam on mercury exposure during amalgam removal.

It was the aim of this investigation to treat 20 volunteers with maximally 5 amalgam fillings by the same comprehensive protocol in which all removals with (n = 8) and without (n = 12) rubber dam had been performed within a few months. Nine amalgam-related parameters indicated a close matching of both groups before removal. In the group without rubber dam, mercury (Hg) levels in plasma increased significantly above preremoval values at days 1 and 3 after removal; they decreased significantly below preremoval values at day 30 in the rubber-dam group and at day 100 in both groups. Excretion rates did not increase significantly in either group, but decreased significantly at day 100 in the protected group. Peak plasma-Hg was 0.6 ng/mL on average at day one and decreased with halftimes of 3 and 43 d in subjects protected by rubber dam. The results indicated that concentrations of total mercury in plasma responded rapidly to changes in the amalgam status and reflected the actual absorption most reliably. Notably, plasma-Hg levels were sensitive enough to detect a transient attenuation of the additional exposure by using rubber dam during the removal of only a few fillings. However, being small in magnitude and lasting 100 d at best, the rubber-dam effect had minor toxicological relevance.

Occupational exposure to mercury. What is a safe level?

QUESTION:
One of my pregnant patients, a dental hygienist, uses mercury in her workplace, but appears to have no symptoms of mercury toxicity. She has heard that mercury might affect her fetus. What should I recommend to her? What is a safe level of mercury in the air for pregnant women?

ANSWER:
Testing for levels of mercury in whole blood and, preferably, urine is useful for confirming exposure. Currently, mercury vapour concentrations greater than 0.01 mg/m3 are considered unsafe. Also, women of childbearing age should avoid contact with mercury salts in the workplace.

By |2018-08-10T00:01:40+00:00January 1st, 1999|Mercury|

Water treatment with silicofluorides and lead toxicity.

Toxic metals like lead, manganese, copper and cadmium damage neurons and deregulate neurotransmitters like serotonin and dopamine (which are essential to normal impulse control and learning). Earlier studies show that — controlling for socio‐economic and demographic factors — environmental pollution with lead is a highly significant risk factor in predicting higher rates of crime, attention deficit disorder or hyperactivity, and learning disabilities. Exposure and uptake of lead has been associated with industrial pollution, leaded paint and plumbing systems in old housing, lead residues in soil, dietary habits (such as shortages of calcium and iron), and demographic factors (such as poverty, stress, and minority ethnicity). We report here on an additional “risk co‐factor” making lead and other toxic metals in the environment more dangerous to local residents: the use of silicofluorides as agents in water treatment. The two chemicals in question — fluosilicic acid and sodium silicofluoride — are toxins that, despite claims to the contrary, do not dissociate completely and change water chemistry when used under normal water treatment practices. As a result, water treatment with siliconfluorides apparently functions to increase the cellular uptake of lead. Data from lead screening of over 280,000 children in Massachusetts indicates that silicofluoride usage is associated with significant increases in average lead in children’s blood as well as percentage of children with blood lead in excess of 10μg/dL. Consistent with the hypothesized role of silicofluorides as enhancing uptake of lead whatever the source of exposure, children are especially at risk for higher blood lead in those communities with more old housing or lead in excess of 15 ppb in first draw water samples where silicofluorides are also in use. Preliminary findings from county‐level data in Georgia confirm that silicofluoride usage is associated with higher levels of lead in children’s blood. In both Massachusetts and Georgia, moreover, behaviors associated with lead nurotoxicity are more frequent in communities using silicofluorides than in comparable localities that do not use these chemicals. Because there has been insufficient animal or human testing of silicofluoride treated water, further study of the effect of silicofluorides is needed to clarify the extent to which these chemicals are risk co‐factors for lead uptake and the hazardous effects it produces.

By |2018-08-09T23:38:16+00:00January 1st, 1999|Fluoride|

Psychometric evidence that dental amalgam mercury may be an etiological factor in schizophrenia

Scores on the Minnesota Multiphasic Personality Inventory-2 (MMPI-2), the Million Clinical Multiaxial Inventory-II (MCM-II), and Symptom Check List – 90 (SCL-90) were compared before dental amalgam removal of eight schizophrenia patients to scores six months after amalgam removal. Significant improvement was found in forty-one of the sixty-one component scales of the MMPI-2 and twelve of the twenty subscales including schizophrenia, hysteria, paranoia, and anger. Sixteen of the twenty-five diagnostic scales improved significantly in the MCMI-II including schizoid, anxiety disorders, thought disorders, and bipolar symptoms. Four of nine dimensions improved significantly in the SCL-90 including depression, psychoticism, and obsessive-compulsiive. Because dental amalgam mercury can enter the brain and affect neurotransmitters, the authors hypothesize that removal of the mercury-laden fillings may have contributed to the improved mental health.

By |2020-04-01T22:17:47+00:00January 1st, 1999|Mercury|

Pharmacological and toxicological effects of aluminofluoride complexes.

Laboratory investigations have often used aluminofluoride complexes for stimulation of various guanine nucleotide binding proteins. These complexes form spontaneously in aqueous solutions containing fluoride and traces of aluminum and appear to act as phosphate analogs. In view of the ubiquity of phosphate in cell metabolism and together with the dramatic increase in the amount of reactive aluminum now found in ecosystems, aluminofluoride complexes represent a strong potential danger for living organisms including humans. Although the possibility of pathophysiological consequences of their long-term action are not yet fully recognized, the pharmacological and toxicological effects of aluminofluoride complexes on animal and human cells, tissues, and organs are identified and summarized in this review.

By |2018-07-31T21:54:31+00:00January 1st, 1999|Fluoride|

Ischemic osteonecrosis under fixed partial denture pontics: radiographic and microscopic features in 38 patients with chronic pain.

STATEMENT OF PROBLEM:

Previous studies have identified focal areas of alveolar tenderness, elevated mucosal temperature, radiographic abnormality, and increased radioisotope uptake or “hot spots” within the quadrant of pain in most patients with chronic, idiopathic facial pain (phantom pain, atypical facial neuralgia, and atypical facial pain).

PURPOSE:

This retrospective investigation radiographically and microscopically evaluated intramedullary bone in a certain subset of patients with histories of endodontics, extraction, and fixed partial denture placement in an area of “idiopathic” pain.

MATERIAL AND METHODS:

Patients from 12 of the United States were identified through tissue samples, histories, and radiographs submitted to a national biopsy service. Imaging tests, coagulation tests, and microscopic features were reviewed. Of 38 consecutive idiopathic facial pain patients, 32 were women.

RESULTS:

Approximately 90% of subpontic bone demonstrated either ischemic osteonecrosis (68%), chronic osteomyelitis (21%), or a combination (11%). More than 84% of the patients had abnormal radiographic changes in subpontic bone, and 5 of 9 (56%) patients who underwent radioisotope bone scan revealed hot spots in the region. Of the 14 patients who had laboratory testing for coagulation disorders, 71% were positive for thrombophilia, hypofibrinolysis, or both (normal: 2% to 7%). Ten pain-free patients with abnormal subpontic bone on radiographs were also reviewed.

CONCLUSIONS:

Intraosseous ischemia and chronic inflammation were suggested as a pathoetiologic mechanism for at least some patients with atypical facial pain. These conditions were also offered as an explanation for poor healing of extraction sockets and positive radioisotope scans.

By |2018-08-24T21:05:33+00:00January 1st, 1999|Other|
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