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PubMedDate not supplied

Salivary mercury levels in healthy donors with and without amalgam fillings.

Dental amalgam (AMG) is the most diffused dental filling material. Since it is constituted for at least 40-45% of Hg, many questions have raised about its safe use. Hg particles from dental amalgam dissolve in saliva and, being ingested, they reach the blood stream through the intestinal mucosa. It has been demonstrated that amalgam fillings continuously release Hg vapour and that there is detectable Hg in expired and inspired air of amalgam owners. It is not yet fully accepted that AMG fillings represent the principal source of Hg for man and the aim of this study was to evaluate if the mercury level in saliva: 1) was higher within people bearing dental amalgam restorations than in people with no restorations; 2) was different between males or females; 3) increased in relation to the surface of amalgam restorations. The results showed a correlation between number of fillings and salivary Hg, between amalgam surface and salivary Hg. The Authors could finally assert that AMG fillings represented the principal source of salivary Hg in the subjects studied.

Adolescent↗
PubMed1998

Mercury in biological fluids after amalgam removal.

Dental amalgam is the major source of inorganic mercury (Hg) exposure in the general population. The objective of the present study was to obtain data on changes in Hg levels in blood, plasma, and urine following removal of all amalgam fillings during one dental session in 12 healthy subjects. The mean number of amalgam surfaces was 18 (range, 13 to 34). Frequent blood sampling and 24-hour urine collections were performed up to 115 days after amalgam removal, and in eight subjects additional samples of plasma and urine were collected up to three years after amalgam removal. A transient increase of Hg concentrations in blood and plasma was observed within 48 hours after amalgam removal. In plasma, the peak concentrations significantly exceeded the pre-removal plasma Hg levels by, on average, 32% (1.3 nmol/L; range, 0.1 to 4.2). No increase in the urinary Hg excretion rate was apparent after amalgam removal. An exponential decline of Hg was seen in all media. Sixty days after the amalgam removal, the Hg levels in blood, plasma, and urine had declined to approximately 60% of the pre-removal levels. In seven subjects, who were followed for up to three years, the half-lives of Hg in plasma and urine were calculated. In plasma, a bi-exponential model was applied, and the half-life was estimated at median 88 days (range, 21 to 121). The kinetics of Hg in urine (nmol/24 hrs) fit a mono-exponential model with a median half-life of 46 days (range, 35 to 67). It is concluded that the process of removing amalgam fillings can have a considerable impact on Hg levels in biological fluids. After removal, there was a considerable decline in the Hg levels of blood, plasma, and urine, which slowly approached those of subjects without any history of amalgam fillings.

Adult↗
PubMed1996

[Amalgam allergy and amalgam controversy].

Safety concerns regarding dental amalgam have been voiced ever since its introduction 150 years ago. As most people have amalgam fillings, the issue has received extensive coverage in the lay as well as the medical medical media. This has led to confusion about the terms amalgam allergy, mercury burden and intoxication, and amalgam disease, an understanding of which is crucial in consideration of this controversy. Allergy to amalgam is rare and should be investigated by a specialist, as diagnosis may result in a decision to remove dental amalgam. Dental amalgam is the most important source of mercury burden in the general population. Occupational exposure to mercury within established exposure limits reaches levels much higher without evidence of intoxication. However, mercury released from dental amalgam induces measurable organ effects. Amalgam disease has been introduced as a term to identify patients who typically ascribe a variety of symptoms to their amalgam fillings. Current literature lacks sound evidence of a role for amalgam in human disease other than allergy.

Body Burden↗
PubMedDate not supplied

Mercury vapor in amalgam waste discharged from dental office vacuum units.

Clinical procedures in dental offices generate quantities of waste slurry or fine particulate matter, much of which is derived from dental amalgam filling material. This mercury-containing material is discharged into waste streams via the dental office vacuum-pump system. This system also discharges large quantities of air, either into the atmosphere exterior to the office building or into the sewer system, depending on the type of equipment used. The purpose of this study was to investigate whether the discharged air contained mercury vapor.

Air Pollutants, Occupational↗
PubMed1996

No evidence of renal toxicity from amalgam fillings.

Dental amalgam continuously releases mercury. Studies of sheep [Boyd et al., Am. J. Physiol. 261 (Regulatory Integrative Comp. Physiol. 30): R1010-R1014, 1991] showed decreased renal function after placement of amalgam fillings. In this study, renal function was investigated in 10 healthy volunteers before and after amalgam removal. The subjects had an average of 18 tooth surfaces filled with amalgam, which was removed during one dental session. One week before and sixty days after removal, the glomerular filtration rate (GFR) was determined by 51Cr-EDTA clearance technique. Blood and urine samples were collected for analysis of mercury, creatinine, beta 2-microglobulin, N-acetyl-beta-glucosaminidase (NAG), and albumin 1 wk before and 1, 2, and 60 days after amalgam removal. The plasma mercury concentration increased significantly 1 day after removal. Sixty days later, significantly lower mercury levels were found in blood, plasma, and urine. The GFR values were similar before and after mercury exposure (mean 94 and 94 ml/min per 1.73 m2, respectively). No detectable effects occurred on excretion of NAG, beta 2-microglobulin, or albumin. It is concluded that no signs of renal toxicity could be found in conjunction with mercury released from amalgam fillings.

Acetylglucosaminidase↗
PubMed2001

Potential health and environmental issues of mercury-contaminated amalgamators.

BACKGROUND: Dental amalgamators may become contaminated internally with metallic mercury. This contamination may result from mercury leakage from capsules during trituration or from the long-term accrual from microscopic exterior contaminants that result from the industrial assembly process. The potential health risk to dental personnel from this contamination is unknown. METHODS: The authors assessed used amalgamators from the federal service inventory for the amounts of mercury vapor levels, as well as the visual presence of mercury contamination. They evaluated these amalgamators for potential mercury vapor health risk, using established National Institute for Occupational Safety and Health methods and American Conference of Governmental Industrial Hygienists standards. RESULTS: Ten of the 11 amalgamators assessed had measurable mercury vapor levels. Four amalgamators were found to have internal static mercury vapor levels above Occupational Safety and Health Administration ceiling limit thresholds. During a simulated worst-case clinical use protocol, the authors found that no amalgamators produced mercury vapor in the breathing space of dental personnel that exceeded established time-weighted federal mercury vapor limits. CONCLUSIONS: Amalgamators may be contaminated internally with metallic mercury. Although the authors detected mercury vapor from these units during aggressive, simulated clinical use, dilution factors combined with room air exchange were found to keep health risks below established federal safety thresholds. CLINICAL IMPLICATIONS: Dental personnel should be aware that amalgamators may be contaminated with mercury and produce minute amounts of mercury vapor. These contaminated amalgamators may require disposal as environmentally hazardous waste.

Air Pollution, Indoor↗
PubMed1990

[Mercury--is it a respiratory tract allergen?].

Mercury is a well-known allergen in dermato-allergology, often manifesting as delayed type hypersensitivity contact eczema. Immediate hypersensitivity reactions (urticaria, anaphylactic shock) have also been described for this allergen, most frequently seen in patients with the delayed type contact eczema. To our knowledge this allergen has not been implicated in production of respiratory symptoms. We describe a patient who had aggravation of asthma by mercury contained in dental amalgam. When the dental amalgam was removed there was a great improvement in his asthma. This observation suggests that mercury in the form of dental amalgam may also be an allergen of the respiratory tract, which should not be surprising, bearing in mind the work that shows the existence of mercury vapours from dental amalgam.

Adult↗
PubMed2004

The amalgam-free dental school.

OBJECTIVES: To review the change in teaching of Restorative Dentistry at Nijmegen dental school over the period 1986 to the present. KEY POINTS: In 1986, class I and II resin composite restorations were included in the pre-clinical program. However, these courses still started with class I and II amalgam restorations. From 1990 on, the number of amalgam restorations placed in the clinic gradually decreased while the number of resin composite restorations increased. Meanwhile, resin composite had become the first choice for treatment of primary caries (class I and class II) lesions. Finally in 1994, the pre-clinical training started with resin composite restorations before dental amalgam was taught and the advantage of a minimal preparation was further emphasized. Since 2001 the teaching of dental amalgam ceased at the dental school. This was not an abrupt change but the result of a long transitional stage during which it was gradually substituted by resin composite. This step-by-step introduction allowed the acceptance of composite resin by the staff as an alternative for dental amalgam in posterior restorations. As in 2001 students placed only 2.5 amalgam restorations before graduation, it was decided to stop with the pre-clinical training program. CONCLUSIONS: The introduction of resin composites meant an important change in teaching restorative dentistry at Nijmegen dental school. It was not just a change in materials and techniques but also a change in treatment philosophy. The reduced need for preparation and the strengthening effect on the remaining tooth were the principal reasons for the shift from dental amalgam to adhesive dentistry with resin composite at Nijmegen dental school.

Composite Resins↗
PubMed1993

[Mercury vapors from premeasured amalgam capsules].

12 dental amalgam capsules were tested for mercury leakage during trituration, storage, and disposal. The pertinent measurements were taken using two different measuring systems, both of which were based on the principle of optical absorption. While the results were excellent for half of the encapsulated products, some were deficient with respect to impermeability or safe handling. Five products cannot be recommended for regular use in the dental office. Overall, dental amalgam capsules of the latest product generations release lower mercury vapors; however, there are always exceptions, which is why periodical checks are recommended to protect the dentist and his or her team from avoidable exposure to mercury vapors.

Capsules↗
PubMed2003

Mercury generation potential from dental waste amalgam.

OBJECTIVE: The main objective of this study was to quantify the total amount of amalgam used in dental offices in the state of Illinois and to estimate the fractions of amalgam waste material generated during dental procedures. A second objective was to estimate the fractions of non-contact, contact, and tooth retained amalgam through an in vitro study. METHODS: The collection system consisted of containers placed in six dental offices and clinics to collect the material from the in-line trap (contact amalgam) and the excess dental amalgam not placed into the oral cavity (non-contact amalgam). In order to have comparable results, the data was adjusted by the number of dental chairs being used and the number of working days. RESULTS: The range for the non-contact amalgam was from 0 to 102 g, and for the contact amalgam, from 2 to 16 g. The median estimate of non-contact amalgam generated from the 6 dental offices was 421 mg/day/chair, whereas the median estimate of contact amalgam was 64 mg/day/chair. For the in vitro study, 40 one and two surface amalgams (bicuspids and molars), was distributed as follows, 46+/-20% in the tooth, 43+/-19% as non-contact amalgam, and 11+/-4% as contact amalgam. CONCLUSIONS: Based on survey data from the ADA concerning the number of working days per year, the number of practicing dentists, a 50%, by weight, mercury content in amalgam, and the generation estimates from this project, it was estimated that the practicing dentists in the State of Illinois (6455) have the potential to generate 947 kg of non-contact mercury per year, which is recyclable, and 144 kg of contact mercury which has the potential to be discarded in the environment, or be partially recycled. If this approach is applied to the total population of practicing dentist in the United States (123,641), then 18,159 kg of recyclable, non-contact mercury may be generated per year, whereas 2763 kg of contact mercury may be discarded in the environment, or be partially recycled.

Dental Amalgam↗