adam, Author at IAOMT Library

Particle versus mercury removal efficiency of amalgam separators.

OBJECTIVE:
The intent of this project was to evaluate the efficiency of three commercial amalgam separators based on mercury and particle removal.

METHODS:
Dental wastewater samples were collected from a 54-chair dental clinic and a one chair private dental office. Atomic absorption spectrometry was used to measure mercury, and a laser diffractometer method to determine the particle size distributions.

RESULTS:
The mercury removal efficiency of the three units ranged from 26.5 to 61.8% for the 54-chair clinic and from 80.8 to 94.7% for the one chair office. Following treatment, the particle size range of the effluent was 8.3-19.2 microm for the 54-chair office and 27.5-41.4 microm for the one-chair clinic. For particle samples based on the silver-copper and copper standards, the three amalgam separators had a particle removal efficiency ranging from 92.3 to 99.9%. The initial particle size distributions for these samples were all under 100 microm.

CONCLUSIONS:
The efficiency of the amalgam separators is influenced by the initial concentration of the dental wastewater, the physical setup of the discharge system before the dental wastewater reaches the separators, and the addition of chemicals to the dental wastewater. In addition, it is likely that assessment of efficiency based on particle removal by weight may not be as effective as removal based on concentration.

By Drummond JL, Liu Y, Wu TY, Cailas MD.|2018-07-20T00:15:18+00:00January 1st, 2002|Mercury|

Epidemiology of contact allergy in adults.

BACKGROUND:

We aimed to determine the prevalence of contact sensitization in the general population and to investigate associations with important sociodemographic and medical characteristics.

METHODS:

Within a population-based nested, case-control study in Germany, we performed patch tests with 25 standard allergens in 1141 adults (50.4% female, age median 50 years). Additional information was obtained by a dermatologic examination, a standardized interview, and blood analysis.

RESULTS:

At least one positive reaction was exhibited by 40.0% of the subjects, with reactions most frequently observed to fragrance mix (15.9%), nickel (13.1%), thimerosal (4.7%), and balsam of Peru (3.8%). Women were sensitized more often than men (50.2% vs 29.9%, OR 2.36, CI 1.84-3.03), and this was also significant for fragrance mix, nickel, turpentine, cobalt chloride, and thimerosal. Contact sensitization was more frequent in subjects who reported adverse skin reactions (53.8% vs. 32.6%; OR 2.41, CI 1.85-3.14), and this was particularly true for sensitization to nickel (45.5% vs 8.8%, OR 8.64, CI 5.67-13.17) and fragrance mix (29.0% vs 14.0%, OR 2.51, CI 1.60-3.91) and the corresponding intolerance of fashion jewelry and fragrances. Contact sensitization decreased with increasing degree of occupational training (unskilled 45.9%, apprenticeship 40.1%, technical college 40.4%, and school of engineering 12.5%; P=0.023; trend test P=0.042). Significant associations of contact sensitization and presence of allergen-specific IgE antibodies, atopic eczema, or psoriasis were not observed. Frequency estimates for the general adult population based on these findings were 28.0% for overall contact sensitization and 11.4% for fragrance mix, 9.9% for nickel, and 3.2% for thimerosal.

CONCLUSIONS:

It is concluded that contact allergy is influenced by sociodemographic parameters and plays an important role in the general population.

By Schäfer T, Böhler E, Ruhdorfer S, Weigl L, Wessner D, Filipiak B, Wichmann HE, Ring J.|2020-01-27T23:29:13+00:00January 1st, 2001|Other|

Effects of four Ni–Ti preparation techniques on root canal geometry assessed by micro computed tomography.

AIM:

The aim of this study was to compare the effects of four preparation techniques on canal volume and surface area using three-dimensionally reconstructed root canals in extracted human maxillary molars. In addition, micro CT data was used to describe morphometric parameters related to the four preparation techniques.

METHODOLOGY:

A micro computed tomography scanner was used to analyse root canals in extracted maxillary molars. Specimens were scanned before and after canals were prepared using Ni-Ti – K-Files, Lightspeed instruments, ProFile.04 and GT rotary instruments. Differences in dentine volume removed, canal straightening, the proportion of unchanged area and canal transportation were calculated using specially developed software.

RESULTS:

Instrumentation of canals increased volume and surface area. Prepared canals were significantly more rounded, had greater diameters and were straighter than unprepared canals. However, all instrumentation techniques left 35% or more of the canals’ surface area unchanged. Whilst there were significant differences between the three canal types investigated, very few differences were found with respect to instrument types.

CONCLUSIONS:

Within the limitations of the micro CT system, there were few differences between the four canal instrumentation techniques used. By contrast, a strong impact of variations of canal anatomy was demonstrated. Further studies with 3D-techniques are required to fully understand the biomechanical aspects of root canal preparation.

By Peters OA, Schönenberger K, Laib A|2019-05-24T23:06:54+00:00January 1st, 2001|Other|

Mercury toxicity and systemic elimination agents

This paper reviews the published evidence supporting amalgam toxicity and clinical techniques that facilitate mercury elimination. A literature review is provided which documents effective mercury elimination strategies to improve mercury toxicity syndromes. Considering the weight of evidence supporting mercury toxicity, it would seem prudent to select alternative dental restoration materials and consider effective mercury elimination strategies if mercury toxicity is present.

By Mercola J, Klinghardt D.|2019-05-30T21:25:51+00:00January 1st, 2001|Mercury|

Recommendations for using fluoride to prevent and control dental caries in the United States.

Widespread use of fluoride has been a major factor in the decline in the prevalence and severity of dental caries (i.e., tooth decay) in the United States and other economically developed countries. When used appropriately, fluoride is both safe and effective in preventing and controlling dental caries. All U.S. residents are likely exposed to some degree to fluoride, which is available from multiple sources. Both health-care professionals and the public have sought guidance on selecting the best way to provide and receive fluoride. During the late 1990s, CDC convened a work group to develop recommendations for using fluoride to prevent and control dental caries in the United States. This report includes these recommendations, as well as a) critical analysis of the scientific evidence regarding the efficacy and effectiveness of fluoride modalities in preventing and controlling dental caries, b) ordinal grading of the quality of the evidence, and c) assessment of the strength of each recommendation. Because frequent exposure to small amounts of fluoride each day will best reduce the risk for dental caries in all age groups, the work group recommends that all persons drink water with an optimal fluoride concentration and brush their teeth twice daily with fluoride toothpaste. For persons at high risk for dental caries, additional fluoride measures might be needed. Measured use of fluoride modalities is particularly appropriate during the time of anterior tooth enamel development (i.e., age <6 years). The recommendations in this report guide dental and other health-care providers, public health officials, policy makers, and the public in the use of fluoride to achieve maximum protection against dental caries while using resources efficiently and reducing the likelihood of enamel fluorosis. The recommendations address public health and professional practice, self-care, consumer product industries and health agencies, and further research. Adoption of these recommendations could further reduce dental caries in the United States and save public and private resources.

By Kohn WG, Maas WR, Malvitz DM, Presson SM, Shaddik KK.|2018-07-24T20:30:05+00:00January 1st, 2001|Fluoride|

Nickel allergy is found in a majority of women with chronic fatigue syndrome and muscle pain—and may be triggered by cigarette smoke and dietary nickel intake.

Two hundred and four women with chronic fatigue and muscle pain, with no signs of autoimmune disorder, received immune stimulation injections with a Staphylococcus vaccine at monthly inter-vals over 6 months. Good response was defined as a decrease by at least 50% of the total score on an observer’s rating scale. Nickel allergy was evaluated as probable if the patient had a positive history of skin hyper-sensitivity from cutaneous exposure to metal objects. The patient’s smoking habits were recorded. Fifty-two percent of the patients had a ositive history of nickel contact dermatitis. There were significantly more good responders among the non-allergic non-smokers (39%) than among the allergic smokers (6%). We also present case reports on nickel-allergic patients who apparently improved after cessation of cig-arette smoking and reducing their dietary nickel intake. Our observa-tions indicate that exposure to nickel, by dietary intake or inhalation of cigarette smoke, may trigger systemic nickel allergy and contribute to syndromes of chronic fatigue and muscle pain.

By Regland B, Zachrisson O, Stejskal V, Gottfries CG.|2018-07-30T16:39:59+00:00January 1st, 2001|Other|

Mercury and selenium concentrations in maternal and neonatal scalp hair.

Mercury and selenium concentrations were determined in scalp hair samples collected postpartum from 82 term pregnancy mothers and their neonates. Maternal mercury and selenium had median concentrations of 0.39 microg/g (range 0.1-2.13 microg/g) and 0.75 microg/g (range 0.1-3.95 microg/g), respectively, and corresponding median neonatal values were 0.24 microg/g (range 0.1-1.93 microg) and 0.52 microg/g (range (0.1-3.0 microg/g). Amalgam-based restorative dental treatment received during pregnancy by 27 mothers (Group I) was associated with significantly higher mercury concentrations in their neonates (p < 0.0001) compared to those born to 55 mothers (Group II) whose most recent history of such dental treatment was dated to periods ranging between 1 and 12 yr prior to pregnancy. In the Group I mother/neonate pairs, amalgam removal and replacement in 10 cases was associated with significantly higher mercury concentrations compared to 17 cases of new amalgam emplacement. Selenium concentrations showed no significant intergroup differences. However, the selenium/mercury molar ratio values were lowest in the Group I neonates, compared to their mothers and to the Group II mother/neonate pairs. This ratio decreased as mercury concentration increased, and this interrelation was statistically significant in both groups of mother/neonate pairs. The data from this preliminary study suggest that amalgam-based dental treatment during pregnancy is associated with higher prenatal exposure to mercury, particularly in cases of amalgam removal and replacement. The ability of a peripheral biological tissue, such as hair, to elicit such marked differences in neonatal mercury concentrations provides supporting evidence of high fetal susceptibility to this form of mercury exposure. The data are discussed in relation to the differences between maternal and fetal mercury metabolisms and to mercury-selenium metabolic intereactions in response to mercury exposure.

By Razagui IB, Haswell SJ.|2018-07-30T16:24:58+00:00January 1st, 2001|Mercury|

Epidemiology of contact allergy in adults

BACKGROUND:

We aimed to determine the prevalence of contact sensitization in the general population and to investigate associations with important sociodemographic and medical characteristics.

METHODS:

Within a population-based nested, case-control study in Germany, we performed patch tests with 25 standard allergens in 1141 adults (50.4% female, age median 50 years). Additional information was obtained by a dermatologic examination, a standardized interview, and blood analysis.

RESULTS:

At least one positive reaction was exhibited by 40.0% of the subjects, with reactions most frequently observed to fragrance mix (15.9%), nickel (13.1%), thimerosal (4.7%), and balsam of Peru (3.8%). Women were sensitized more often than men (50.2% vs 29.9%, OR 2.36, CI 1.84-3.03), and this was also significant for fragrance mix, nickel, turpentine, cobalt chloride, and thimerosal. Contact sensitization was more frequent in subjects who reported adverse skin reactions (53.8% vs. 32.6%; OR 2.41, CI 1.85-3.14), and this was particularly true for sensitization to nickel (45.5% vs 8.8%, OR 8.64, CI 5.67-13.17) and fragrance mix (29.0% vs 14.0%, OR 2.51, CI 1.60-3.91) and the corresponding intolerance of fashion jewelry and fragrances. Contact sensitization decreased with increasing degree of occupational training (unskilled 45.9%, apprenticeship 40.1%, technical college 40.4%, and school of engineering 12.5%; P=0.023; trend test P=0.042). Significant associations of contact sensitization and presence of allergen-specific IgE antibodies, atopic eczema, or psoriasis were not observed. Frequency estimates for the general adult population based on these findings were 28.0% for overall contact sensitization and 11.4% for fragrance mix, 9.9% for nickel, and 3.2% for thimerosal.

CONCLUSIONS:

It is concluded that contact allergy is influenced by sociodemographic parameters and plays an important role in the general population.

By Schäfer T, Böhler E, Ruhdorfer S, Weigl L, Wessner D, Filipiak B, Wichmann HE, Ring J.|2020-01-26T18:07:49+00:00January 1st, 2001|Other|

Osteonecrosis as a complication of treating acute lymphoblastic leukemia in children: a report from the Children’s Cancer Group.

Purpose:

To determine the incidence, risk factors, and morbidity for osteonecrosis (ON) in children with acute lymphoblastic leukemia (ALL) treated with intensive chemotherapy including multiple, prolonged courses of corticosteroid.

PATIENTS AND METHODS:

The occurrence of symptomatic ON was investigated retrospectively in 1, 409 children ages 1 to 20 years old receiving therapy for high-risk ALL on Children’s Cancer Group (CCG) protocol CCG-1882.

RESULTS:

ON was diagnosed in 111 patients (9.3% +/- 0.9%, 3-year life-table incidence). The incidence was higher for older children (> or = 10 years: 14.2% +/- 1.3% v < 10 years: 0.9% +/- 0.4%; P: <.0001), especially females 10 to 15 years old and males 16 to 20 years old (19.2% +/- 2.3% and 20.7% +/- 4.7%, respectively). In patients 10 to 20 years old, the incidence of ON was higher for females versus males (17.4% +/- 2.1% v 11.7% +/- 1.6%, respectively; P: =.03) and for patients randomized to receive two 21-day dexamethasone courses versus one course (23.2% +/- 4.8% v 16.4% +/- 4.3%, respectively; P: =.27). Among ethnic groups, whites had the highest incidence and blacks the lowest, with other groups intermediate (16.7% +/- 1.4% v 3.3% +/- 2.3% v 6.7% +/- 2.2%, respectively; P: =.003). There was no difference in event-free survival in patients with or without ON. ON was diagnosed within 3 years of starting ALL therapy in all but one patient, involved weight-bearing joint(s) in 94% of patients, and was multifocal in 74% of patients. Symptoms of pain and/or immobility were chronic in 84% of patients, with 24% having undergone an orthopedic procedure and an additional 15% considered candidates for surgery in the future.

CONCLUSION:

Children ages 10 to 20 years who receive intensive ALL therapy, including multiple courses of corticosteroid, are at significant risk for developing ON.

By Mattano Jr LA, Sather HN, Trigg ME, Nachman JB.|2018-08-27T23:46:11+00:00January 1st, 2000|Other|

Mercury-induced nummular dermatitis.

We report 2 cases of relapsing nummular dermatitis according to mercury sensitivity, which was confirmed by patch testing. Removal of the amalgam from dental metal alloys markedly improved their skin eruptions. One of the patients, a dentist, experienced exacerbation of the eruptions on his lower legs after handling dental amalgam. Hypersensitivity to haptens such as metals is possibly involved in, at least in some patients, the pathogenesis of nummular dermatitis.

By Adachi A, Horikawab T, Takashimac T, Ichihashib M.|2018-07-18T15:44:26+00:00January 1st, 2000|Mercury|

adam

About Drummond JL, Liu Y, Wu TY, Cailas MD.