Ex Vivo Mercury Release from Dental Amalgam after 7.0-T and 1.5-T MRI.

Purpose To evaluate ex vivo mercury release from dental amalgam after 7.0-T and 1.5-T MRI. Materials and Methods The authors evaluated 60 caries-free molar or premolar teeth that had been extracted for clinical indications. Two-sided cavities were opened in each tooth and amalgam fillings applied. After 9 days, two groups of 20 randomly selected teeth were placed in 20 mL of artificial saliva immediately followed by 20 minutes of MRI exposure at 1.5 or 7.0 T. A control group of teeth was placed in artificial saliva without undergoing MRI exposure. The teeth were removed from the artificial saliva 24 hours later, and the saliva was analyzed for mercury content by using inductively coupled plasma mass spectrometry. One-way analysis of variance was used to compare the mean mercury values among the three independent groups, and the Tukey test was used for multiple comparisons of the mean values. Results The mean mercury content of the artificial saliva was 673 µg/L ± 179 in the 7.0-T MRI group, 172 µg/L ± 60 in the 1.5-T MRI group, and 141 µg/L ± 152 in the control group. The mercury content in the 7.0-T group was greater than that in both the 1.5-T group (P < .001; 95% confidence interval: 368 µg/L, 633 µg/L) and the control group (P < .001; 95% confidence interval: 416 µg/L, 648 µg/L). There was no statistically significant difference in mercury content between the 1.5-T and control groups (P = .84; 95% confidence interval: -164 µg/L, 110 µg/L). Conclusion In an ex vivo setting, mercury was released from amalgam fillings after exposure to 7.0-T MRI but not 1.5-T MRI.

New science challenges old notion that mercury dental amalgam is safe.

Mercury dental amalgam has a long history of ostensibly safe use despite its continuous release of mercury vapor. Two key studies known as the Children's Amalgam Trials are widely cited as evidence of safety. However, four recent reanalyses of one of these trials now suggest harm, particularly to boys with common genetic variants. These and other studies suggest that susceptibility to mercury toxicity differs among individuals based on multiple genes, not all of which have been identified. These studies further suggest that the levels of exposure to mercury vapor from dental amalgams may be unsafe for certain subpopulations. Moreover, a simple comparison of typical exposures versus regulatory safety standards suggests that many people receive unsafe exposures. Chronic mercury toxicity is especially insidious because symptoms are variable and nonspecific, diagnostic tests are often misunderstood, and treatments are speculative at best. Throughout the world, efforts are underway to phase down or eliminate the use of mercury dental amalgam.

Evaluation of mercury contamination in patients and water during amalgam removal.

AIM: The aim of this study was to evaluate mercury levels in wastewater and in patients during the removal of dental amalgam restorations. MATERIALS AND METHODS: To test for mercury levels, patients were tested before and after amalgam restoration removal. To test for mercury emissions, samples of constant volume of wastewater from high-speed drills were collected before and during amalgam restoration removal. RESULTS: Although the systemic mercury levels were lower than the limit of biological tolerance, all patients had increased levels after dental restorations. All samples of wastewater had increased mercury levels too. CONCLUSION: The urinary levels of mercury increased with dental amalgam removal using a high-speed drill. During the process of amalgam removal, water used for cooling the dental drill was contaminated with mercury. CLINICAL SIGNIFICANCE: The mercury released by the physical action of the drill, the replacement material and especially the final destination of the amalgam waste can increase contamination levels that can be a risk for human and environment health.

Mercury Concentration in Saliva and the Impact of Chewing: An Inductively Coupled Plasma Mass Spectrometry Study.

Mercury, which is found in dental amalgams, is considered to be the most toxic non-radioactive element. However, the health policies of different countries have not reached a consensus on the use and safety of amalgam. This study aims to investigate the effect of amalgam restorations on mercury concentration in saliva, as well as the effect of restoration number, surface number, and chewing on this concentration. A total of 86 participants were included in this study (an equal number for the study and control groups). The number of amalgam restorations and their surfaces were recorded. While both unstimulated and stimulated saliva were collected from the study group, only unstimulated saliva was collected from the control group. The effect of chewing on mercury concentration was examined in the study group with unstimulated and stimulated saliva specimens using inductively coupled plasma mass spectrometry device. Mercury concentration in the unstimulated saliva was found to be higher in the study group compared to the control group (p= 0.000). As the number of amalgam restorations and the number of amalgam restoration surfaces increased, the mercury concentration in the saliva increased (p= 0.015 and p= 0.021, respectively). There was no statistically significant difference between mercury levels in the unstimulated saliva and the stimulated saliva (p=0.316). Chewing presented an insignificant difference in mercury concentration. Given this surprising result, the effect of chewing on mercury concentrations should be explored more extensively in future research.

Staining of dentin from amalgam corrosion is induced by demineralization.

PURPOSE: To evaluate the effect of artificial demineralization upon color change of dentin in contact with dental amalgam. METHODS: Sound human molars (n = 34) were embedded in resin and coronal enamel was removed. Dentin was exposed to artificial caries gel (pH 5.5) at 37 degrees C for 12 weeks (n = 24). Non-demineralized teeth served as controls (n = the 10). A dispersive high-Cu amalgam or conventional low-Cu amalgam was condensed onto dentin surfaces of all groups. After 10 weeks storage in saline, amalgam was removed and teeth were cut into three slices. Surfaces were inspected under optical microscopy and photographed. RESULTS: Penetration of black pigments was observed in dentin underneath both high-Cu and low-Cu amalgams in demineralized specimens. Black deposits were unevenly distributed and observed predominantly in dentin near to pulp horns. Discoloration was not limited to outer demineralized dentin but extended beyond this zone. Evenly distributed bluish-green discoloration was observed underneath all high-Cu amalgam specimens independent of demineralization.

Improper waste disposal of silver-mercury amalgam.

The objective of this work was to estimate the quantity of mercury residue present in dental amalgam that is generated and discarded in the city of Manaus (Amazon-Brazil). For this purpose, the locations of amalgam usage (10 public and 31 private dental clinics), the method by which the residue is discarded (14 clinics improper disposal), and the analysis of total mercury in the sediment of the controlled landfill (2.68-3 µgHg/g), were described. It was concluded that: there are dental clinics in the city that discard mercury residue into the common waste disposal system, which contravenes health safety standards.

[Fetal and perinatal exposure to mercury and selenium: baseline evaluation of a cohort of children in Friuli Venezia Giulia, Italy]. / Esposizione fetale e perinatale a mercurio e selenio: valutazione alla baseline di una coorte di bambini del Friuli Venezia Giulia.

OBJECTIVE: neurotoxicity of prenatal exposure to high concentrations of mercury (Hg) is well known; however, the doseresponse relationship at low exposure levels has not been quantified yet. This article illustrates the measurement of prenatal exposure to Hg and the pathway of exposure through the diet in Friuli Venezia Giulia, Italy. DESIGN: description of a prospective cohort at the baseline. SETTING AND PARTICIPANTS: 242 mother- infant pairs living in Friuli Venezia Giulia were enrolled between 1999 and 2001. MAIN OUTCOME MEASURES: We measured the concentrations of Hg in the hair of mothers and children and of Hg and selenium (Se) in breast milk. The diet during pregnancy was estimated through a food frequency questionnaire (FFQ) with a detailed section regarding fish. We calculated the correlations between Hg and Se in the biological samples and estimated the association between Hg concentrations and fish consumption. RESULTS: in general, Hg levels in hair and milk were positively associated with the consumption of fish from the lagoon of Grado and Marano. However, they were low in comparison with those of other fish-eating populations and below theWHO alert limits, likely because of the small consumption of fish among pregnant women, estimated from the FFQ. The concentration of Se in milk was also smaller than that reported in other international studies. CONCLUSION: in Friuli Venezia Giulia, fetal and perinatal Hg exposure is low. The children of the cohort will be followed- up at school age to measure possible neurodevelopmental effects of such low exposures to Hg.

The effect of a 16% carbamide peroxide gel on mercury and silver ion release from admixed and spherical dental amalgams.

AIM: The aim of this study was to investigate the effect of 16 percent carbamide peroxide gel on mercury and silver ions released from admixed and spherical dental amalgams. METHODS AND MATERIALS: A total of 96 amalgam discs were prepared from two different types and brands of dental amalgam (admixed and spherical). The samples were stored at room temperature in glass tubes containing distilled water for 24 hours. The specimens were then polished and again immersed in distilled water at room temperature and stored for one month. Samples of both types of dental amalgam were treated with carbamide peroxide 16 percent gel (Nite White, Discus Dental, Inc., Culver City, CA, USA) for 14 and 28 hours (experimental group) and compared to samples not exposed to the bleaching agent but stored continuously in distilled water. Mercury and silver levels of each solution were measured using the VAV-440 analyzer system. RESULTS: Mercury and silver ions released from the experimental group were significantly greater than from the control group (p<0.001). There was no significant difference between the mean levels of mercury and silver ions in the two kinds of amalgams after treatment with 16 percent carbamide peroxide (p=0.119 for mercury and p=0.199 for silver). Increasing the storage time in the carbamide peroxide gel from 14 to 28 hours did not result in significant changes in the amount of ions released (p=0.329 for mercury and p=0.082 for silver). Also, the interaction effect between amalgam particles' shape (admixed and spherical) versus storage time (14 versus 28 hours) was not statistically significant (p=0.901 for mercury and p=0.951 for silver). CONCLUSION: Treatment with 16 percent carbamide peroxide gel increased mercury and silver ions released from admixed and spherical amalgams, compared to samples in the control group, but the difference between the two amalgams was not statistically significant. CLINICAL SIGNIFICANCE: The amount of mercury and silver ions released from high-copper dental amalgams during bleaching with 16 percent carbamide peroxide is in the safe range of mercury intake for patients.

[Mercury exposure and dentists' health status in two regions of centrall Morocco: descriptive cross-sectional survey]. / Exposition au mercure et état de santé des médecins dentistes de deux régions du centre du Maroc: enquête transversale descriptive.

INTRODUCTION: mercury exposure is recognized as a worldwide public health concern. However, the effect of long-term exposure to low-doses of this heavy metal is still subject to debate. Due to the use of mercury in dental amalgam, dental health care professionals are chronically exposed to low-doses of this metal. In this context, we have conducted a descriptive cross-sectional survey among liberal dentists in two regions of the center of Morocco. In parallel, the global health status of participants was investigated to assess the relevance of a subsequent etiological survey. METHODS: data were collected through a self-reported questionnaire. Occupational exposure of dentists to mercury was evaluated based on their use of dental amalgam. Moreover, the other common factors increasing the background pollution or inducing exposure peaks were also investigated. On the other hand, smoking, vaccination, fish consumption, and the number of dental amalgam in mouth were considered as non-occupational exposure sources. Finally, the self-reported global health problems of participants were collected. RESULTS: 192 dentists were included in the present study. Seventy-six percent (76.04%) of them declared using dental amalgam in their practice. Moreover, the presence of dental amalgam in mouth was identified as the main non-occupational source of exposure to mercury (63.45% of participants). Finally, most of participants (46.35%) have expressed neuropsychological complaints. CONCLUSION: altogether, our results revealed a real mercury exposure in the studied population. Thus, effective preventive measures should be promoted to minimize the mercury exposure in dental offices. Moreover, an etiological study will be of great interest to reveal the impact of mercury exposure in this population.

Forensic study of mechanical properties of dental restoration after burial in mangrove environment.

Conducting research in the field of forensic sciences with methodologies that simulate situations found in the day-to-day practice of a given field of expertise is relevant insofar as this approach can produce results that are as close as possible to reality. In this context, the present study provided situations based on burial in a mangrove environment to estimate the changes in the mechanical properties (Knoop microhardness, roughness and color) of dental restorations utilizing silver amalgam, composite resin and glass ionomer cement over the time of burial. The silver amalgam showed a significant increase in surface roughness and a reduction in Knoop microhardness. Composite resin showed a statistically significant increase in color variation, and the glass ionomer cement showed significant increases in color variation and Knoop microhardness. These results allowed us to conclude that teeth restored with silver amalgam, composite resin and glass ionomer cement submitted to burial in mangrove environments produce different changes in surface roughness, Knoop microhardness and color properties depending on the time of burial to which the victims were submitted. These proprieties could help the forensic sciences to estimate time intervals for burial in mangrove environments.

Human exposure to mercury in the vicinity of chlor-alkali plant.

The main objectives of our study were to estimate the impact of a mercury cell chlor-alkali (MCCA) complex in Rosignano Solvay (Tuscany, Italy) on the local environment and to assess mercury exposure of inhabitants living near the plant. Measurement campaigns of atmospheric Hg near the MCCA plant showed that the impact of the emitted Hg from the industry on the terrestrial environment is restricted to a close surrounding area. Total gaseous mercury concentrations in ambient air of inhabited area around the MCCA plant were in the range of 8.0-8.7 ng/m3 in summer and 2.8-4.2 ng/m3 in winter. Peaks of up to 100 ng/m3 were observed at particular meteorological conditions. Background levels of 2 ng/m3 were reached within a radius of 3 km from the plant. Reactive gaseous mercury emissions from the plant constituted around 4.2% of total gaseous mercury and total particulate mercury emission constituted around 1.0% of total gaseous mercury emitted. Analysis of local vegetables and soil samples showed relatively low concentrations of total mercury (30.1-2919 microgHg/kg DW in the soil; <0.05-111 microgHg/kg DW in vegetables) and methylmercury (0.02-3.88 microgHg/kg DW in the soil; 0.03-1.18 microgHg/kg DW in vegetables). Locally caught marine fish and fresh marine fish from the local market had concentrations of total Hg from 0.049 to 2.48 microgHg/g FW, of which 37-100% were in the form of methylmercury. 19% of analysed fish exceeded 1.0 microgHg/g FW level, which is a limit set by the European Union law on Hg concentrations in edible marine species for tuna, swordfish and shark, while 39% of analysed fish exceeded the limit of 0.5 microgHg/g FW set for all other edible marine species. Risk assessment performed by calculating ratio of probable daily intake (PDI) and provisional tolerable daily intake (PTDI) for mercury species for various exposure pathways showed no risks to human health for elemental and inorganic mercury, except for some individuals with higher number of amalgam fillings, while PDI/PTDI ratio for methylmercury and total mercury exceeded the toxicologically tolerable value due to the potential consumption of contaminated marine fish.

Neuropsychological function in school-age children with low mercury exposures.

The EPA reference dose for methylmercury (MeHg) was established using data from populations with greater exposures than those typical of the US. Few data are available on potential adverse health effects at lower levels. We examined relationships between hair mercury (Hg) levels and neuropsychological outcomes in a population of US children. This study included data from 355 children ages 6-10 enrolled in the New England Children's Amalgam Trial. Data on total hair Hg levels, sociodemographic information and neuropsychological function were collected. We evaluated associations between hair Hg and neuropsychological test scores with linear regression methods and used generalized additive models to determine the shape of associations that departed from linearity. Models controlled for relevant covariates, including the potential beneficial effects of consuming fish. In adjusted models, we observed no significant linear relationships between hair Hg level and any test score. Significant departures from linearity were identified for WIAT Math Reasoning and WRAMVA Visual-Motor Composite scores. The association was positive for hair Hg levels below 0.5 microg/g and negative for levels between 0.5 and 1.0 microg/g. Overall, test scores of children with hair Hg levels 1.0 microg/g appeared to be lower than those of children with levels < 1.0 microg/g, but few children had levels in this upper range and these differences did not reach statistical significance. Hair Hg levels below 1.0 microg/g in US school-age children were not adversely related to neuropsychological function.

Concentration of mercury, cadmium, and lead in breast milk from Norwegian mothers: Association with dietary habits, amalgam and other factors.

Mercury (Hg), cadmium (Cd), and lead (Pb) are of great concern for food safety and infants are especially sensitive to exposure to the maternal body burden. We quantified these elements in breast milk from Norwegian mothers and determined their association with dietary habits, maternal amalgam fillings, and smoking. Breast milk (n = 300) from the Norwegian Human Milk Study (HUMIS) was analyzed using triple quadrupole inductively coupled plasma mass spectrometry, after an acidic decomposition using microwave technique. We used multiple linear regression to examine predictors of Hg and Cd in breast milk, and logistic regression to test predictors of Pb above the quantification limit. The median breast milk concentrations (minimum - maximum) were 0.20 µg Hg/kg (<0.058-0.89), 0.057 µg Cd/kg (0.017-1.2), and <0.67 µg Pb/kg (<0.2-7.5). Cadmium showed no significant relation with any exposure variable investigated. Lead was associated with intake of liver and kidneys from game. For Hg concentration in breast milk, number of amalgam fillings and high fish consumption were significant predictors (p < 0.001). We detected a significant association (p < 0.01) between Hg in breast milk and maternal consumption of Atlantic halibut, lean fish, mussels and scallops and lifetime consumption of crab. Seafood intake alone explained 10% of variance, while together with amalgam explained 46% of variance in Hg concentration in breast milk. Our findings emphasize the importance of following consumer advice with respect to fish and seafood and points to amalgam as an important source for Hg exposure.

Assessment of some elements in human permanent healthy teeth, their dependence on number of metallic amalgam fillings, and interelements relationships.

In this study, 60 human permanent healthy teeth (without filling) were collected postmortem and analyzed using flame atomic absorption spectrometry (FAAS), cold vapor atomic absorption spectrometry (CVAAS), hydride generation atomic absorption spectrometry (HGAAS), and electrothermal atomic absorption spectrometry (ETAAS) for the determination of Ca, Hg, Se, Cu, and Ag. The concentration of these elements was assessed in carious and noncarious teeth, different tooth groups, with age and with number of amalgam fillings. A negative correlation was found between Ca and the number of amalgam fillings, and significant negative correlations were found between Ca and three other metals (Hg, Ag, and Cu) that indicate the possibility of substitutions of Ca by three other metals. Significant positive correlations were found among the number of amalgam fillings and Hg, Ag, Cu and Se showed metal concentration in permanent healthy teeth were affected by the presence of the number of amalgam filling. In addition, significant positive correlations between Hg and Ag, Hg and Cu, and Ag and Cu proved the suspicion that the Hg content in permanent healthy teeth was mainly found because of the influence of amalgam filling, not from other sources. Moreover, the significant positive correlation between Hg-Se and Ag-Se showed the formation of mercuric selenide and silver selenide complexes as part of a natural mechanism of detoxification. Consequently, the permanent healthy teeth would be considered as a bioindicator for the accumulation of long-term exposure of Hg and Ag.

Mercury Amalgam Diffusion in Human Teeth Probed Using Femtosecond LIBS.

In this work the diffusion of mercury and other elements from amalgam tooth restorations through the surrounding dental tissue (dentin) was evaluated using femtosecond laser-induced breakdown spectroscopy (fs-LIBS). To achieve this, seven deciduous and eight permanent extracted human molar teeth with occlusal amalgam restorations were half-sectioned and analyzed using pulses from a femtosecond laser. The measurements were performed from the amalgam restoration along the amalgam/dentin interface to the apical direction. It was possible to observe the presence of metallic elements (silver, mercury, copper and tin) emission lines, as well as dental constituent ones, providing fingerprints of each material and comparable data for checking the consistence of the results. It was also shown that the elements penetration depth values in each tooth are usually similar and consistent, for both deciduous and permanent teeth, indicating that all the metals diffuse into the dentin by the same mechanism. We propose that this diffusion mechanism is mainly through liquid dragging inside the dentin tubules. The mercury diffused further in permanent teeth than in deciduous teeth, probably due to the longer diffusion times due to the age of the restorations. It was possible to conclude that the proposed femtosecond-LIBS system can detect the presence of metals in the dental tissue, among the tooth constituent elements, and map the distribution of endogenous and exogenous chemical elements, with a spatial resolution that can be brought under 100 µm.

Effect of smokeless tobacco on surface roughness of dental restorations.

CLINICAL RELEVANCE: Surface alterations of dental restorations can result in increased plaque biofilm. This leads to increased risk of premature restoration failure. Smokeless tobacco, in common use by some US military personnel, represents a potential source for surface alteration. If smokeless tobacco causes an untoward effect, selection of a more resistant restorative material could increase restoration longevity, thus minimizing lost work time and costs associated with replacement of failed restorations. PURPOSE: Comparatively assess the effect of smokeless tobacco/salivary substitute mixture on altering surface roughness of amalgam, composite resin, and resin modified glass ionomer (RMGI) restorations. MATERIALS AND METHODS: Sixty cubic restorations (3 groups of 20) were fabricated using a 4 mm by 3 mm Teflon mold. One examiner assessed the restorations at time points representing zero days, one day, one week, 2 weeks, one month, and 3 months. The data obtained were collected using a surface profilometer, measured in micrometers. Data were statistically analyzed using 2-way analysis of variance (ANOVA) test. A difference was significant if P< .05. RESULTS: Confidence levels with a 95% overall rating received a clinically acceptable classification. The 2-way ANOVA test detected significant differences between baseline, one day, one week, 2 weeks, one month, and 3-month data for surface roughness (P<.05). With respect to time and restoration type, results proved statistically significant with P<.0001. All restorations were statistically significant with respect to change in surface roughness with RMGIs showing the greatest surface roughness alteration. CONCLUSION: Smokeless tobacco mixed with a salivary substitute altered restoration surface roughness over time. Resin-modified glass isonomer restorations demonstrate the greatest alteration of surface roughness, with amalgam restorations showing the least. Amalgam remains the preferential restorative material in patients who use smokeless tobacco.

Placement and replacement rates of amalgam and composite restorations on posterior teeth in a military population.

OBJECTIVE: Replacement rates of direct dental restorations have been reported to be 37% to 70%, occupying a large proportion of a general dentist's time. Variations in the rate of initial placement and replacement of direct dental restorations may be associated with material placed (amalgam or composite), age, caries risk of the patient, and other factors. The purpose of this research was to clarify where the majority of patient care time is spent as a restorative Army dentist regarding either the initial placement or replacement of failed restorations; and how the location, caries risk, and material used (amalgam or composite) affects replacement rates. METHODS: This retrospective cross-sectional study gathered data from 600 randomly selected military patient dental records. All paper records were reviewed and cross checked with the digital record and digital x-ray databases. Record review was limited to all direct dental restorations placed in the posterior dentition within the past 2 years (March 2011 to March 2013). Statistical analysis was accomplished using chi-square tests and logistic regression analyses. RESULTS: Of the 600 charts reviewed, 525 were male, 75 were female, with an average age of 26 years (SD=6), ranging from 17 to 54 years. A third of the patients were classified as high, moderate, and low caries risk, respectively. The total number of posterior direct dental restorations placed was 2,117. Initial restorations totaled 1,429 (67.5%), and replacement restorations placed totaled 688 (32.5%). Four hundred forty-one of the 688 direct dental restorations replaced were amalgam (64%), the 247 remaining direct restorations replaced were composite (36%). Mandibular first molar dental restorations were replaced the most often (23.1%) while mandibular first premolar restorations were replaced the least often (0.9%). Older patients were more likely to have replacement of an existing restoration. CONCLUSIONS: Military dentists spend about one-third (32.5%) of their time replacing existing direct dental restorations. The majority of direct dental restorations placed and replaced were amalgam. No significant difference was found between composite and amalgam restorations. Location was shown to be significant with first molars and second molar restorations failing with the highest frequency. There was no significant difference found between male and female patients. As patient's age increased, the number of replacement restorations also increased.

A radiographic method of estimating surface area of amalgam restorations.

UNLABELLED: Mercury released from the surface of amalgam fillings has been linked to a variety of disorders, but without proof of correlation. Studies use surface counts to estimate this variable, but large-scale studies would require a tool to rapidly and accurately assess restoration surface area. OBJECTIVES: This study investigated digital analysis of conventional dental radiographs as a means of estimating amalgam surface area. METHODS: Amalgam fillings were placed in 40 typodont teeth, the surface areas of the restorations were determined by measuring standardized photomicrographs of each surface. The teeth were radiographed, and area of the radiographic image of the restorations was measured. Data were used to produce expressions to estimate actual area from radiographic area. RESULTS: Regression analyses showed that surface area estimation from radiographic area was more accurate than estimation from surface counts. The accuracy of the surface area count was further improved by combining the radiographic area with a photographic occlusal area measurement or surface count, the latter giving the highest correlation. CONCLUSIONS: This study demonstrated that two-dimensional dental radiographs may be used to estimate surface area of amalgam restorations.

Decrease of trace elements in erythrocytes and plasma after removal of dental amalgam and other metal alloys.

The objective of this study was to determine the concentration changes of 13 elements in erythrocytes and plasma after the removal of dental amalgam and other metal alloys. Blood samples from 250 patients were collected, separated into erythrocytes and plasma, and analyzed by inductively coupled plasma-mass spectrometry. The 250 patients were divided into 3 groups (Negative, Zero, and Positive) depending on their estimation of quality of life in an earlier study. Magnesium in plasma, selenium and mercury in plasma, and erythrocytes showed decreased concentrations after amalgam removal in all groups (p < 0.05). Titanium in plasma, copper in plasma, and erythrocytes and zinc in plasma exhibited decreased concentrations after amalgam removal in the Negative and Positive groups (p < 0.05). Silver in plasma and gold in erythrocytes decreased in the Zero and Positive groups after amalgam removal (p < 0.05). Copper in erythrocytes and silver and gold in plasma showed higher concentrations after amalgam removal in the Negative compared to the Positive group (p < 0.05), suggesting that patients in the Negative group excrete metals slowly. Moreover, the cobalt levels in plasma were lowest in the Negative group and only this group showed a significant increase in vitamin B12 levels in blood after amalgam removal.

Evaluating amalgam separators using an international standard.

BACKGROUND: Most amalgam particles generated during placement and removal of amalgam restorations are captured by chair-side traps and suction system traps and filters. Particles not captured can end up in the wastewater discharged from the dental office. Environmental initiatives to reduce the discharge of mercury-containing products such as dental amalgam waste into the environment have sparked interest in the use of amalgam separators. METHODS: The authors used International Organization for Standardization (ISO) Standard 11,143 for Amalgam Separators in a laboratory test to evaluate the amalgam removal efficiency of 13 commercially available amalgam separators and two commercially available filtration devices not marketed as amalgam separators but that have the potential to be used as such. RESULTS: All 13 amalgam separators and the two filtration devices exceeded the ISO Standard 11,143 requirement of 95 percent amalgam removal efficiency. The authors found statistical differences in the efficiency of the separators and filtration devices. No differences were found between the "empty" and "full" conditions for each separator. CONCLUSION AND CLINICAL IMPLICATIONS: This laboratory evaluation shows that amalgam separators and the filtration devices removed at least 97.05 percent of the amalgam in samples with particle-size distribution as specified in ISO Standard 11,143.