Validity and responsiveness of EQ-5D-5L and SF-6D in patients with health complaints attributed to their amalgam fillings: a prospective cohort study of patients undergoing amalgam removal.

BACKGROUND: Evidence of health utility changes in patients who suffer from longstanding health complaints attributed to dental amalgam fillings are limited. The change in health utility outcomes enables calculating quality-adjusted life-year (QALY) and facilitates the comparison with other health conditions. The purpose of this study was to estimate the validity and responsiveness of the EQ-5D-5L and SF-6D utilities following removal of dental amalgam fillings in patients with health complaints attributed to their amalgam fillings, and examine the ability of these instruments to detect minimally important changes over time. METHODS: Patients with medically unexplained physical symptoms, which they attributed to dental amalgam restorations, were recruited to a prospective cohort study in Norway. Two health state utility instruments, EQ-5D-5L and SF-6D, as well as self-reported general health complaints (GHC-index) and visual analogue scale (EQ-VAS) were administered to all patients (n = 32) at baseline and at follow-up. The last two were used as criteria measures. Concurrent and predictive validities were examined using correlation coefficients. Responsiveness was assessed by the effect size (ES), standardized response mean (SRM), and relative efficiency. Minimally important change (MIC) was examined by distribution and anchor-based approaches. RESULTS: Concurrent validity of the EQ-5D-5L was similar to that of SF-6D utility. EQ-5D-5L was more responsive than SF-6D: the ES were 0.73 and 0.58 for EQ-5D-5L and SF-6D, respectively; SRM were 0.76 and 0.67, respectively. EQ-5D-5L was more efficient than SF-6D in detecting changes, but both were less efficient compared to criteria-based measures. The estimated MIC of EQ-5D-5L value set was 0.108 and 0.118 based on distribution and anchor-based approaches, respectively. The corresponding values for SF-6D were 0.048 and 0.064, respectively. CONCLUSIONS: In patients with health complaints attributed to dental amalgam undergoing amalgam removal, both EQ-5D-5L and SF-6D showed reasonable concurrent and predictive validity and acceptable responsiveness. The EQ-5D-5L utility appears to be more responsive compared to SF-6D. Trial registration The research was registered at ClinicalTrials.gov., NCT01682278. Registered 10 September 2012, https://clinicaltrials.gov/ct2/show/NCT01682278 .

The cytotoxic and oxidative effects of restorative materials in cultured human gingival fibroblasts.

The aim of this study was to evaluate the cytotoxic and oxidative effects of the most commonly used dental restorative materials on human gingival fibroblast cells (HGFCs). HGFCs were obtained from healthy individuals. The tested restorative materials were a microhybrid resin based composite, a compomer resin, a glass ionomer cement, and an amalgam alloy. One hundred eight cylindirical samples, 10 mm in diameter and 2 mm in height, were prepared according to ISO 10993-12:2002 specifications (n = 9 in the tested subgroups). Freshly prepared and aged samples in artificial saliva at 37 °C (7 and 21 d) were placed into well plates and incubated. Wells without dental materials were constituted as the control group. After 72 h incubation period, cytotoxicity was determined using the neutral red (NR) assay. Oxidative alterations were assessed using total antioxidant capacity (TAC) and total oxidant status (TOS) assay kits. Data were analyzed using the ANOVA and LSD post hoc tests. All tested materials led to significant decreases in the cell viability rates (33-73%) compared to the control group. Glass ionomer and resin composite were found to be more cytotoxic than amalgam alloy and compomer. The highest TAC level was observed in glass ionomer after seven-day aging and these changes prevented an increase in TOS levels. Increases in TAC levels after seven-day aging in all groups exhibited significant differences with freshly prepared samples (p < 0.05). In all material groups, TOS levels of freshly prepared samples differed statistically and significantly from samples aged for 7 and 21 d (p < 0.05). The data obtained suggested that all the tested materials exhibited cytotoxic and pro-oxidant features. Freshly prepared samples caused higher TOS levels. However, oxidant status induced by materials decreased over time.

Thinking outside the (pill) box: Does toxic metal exposure thwart antibiotic stewardship best practices?

Multi-antibiotic resistant (MAR) bacteria cost billions in medical care and tens of thousands of lives annually but perennial calls to limit agricultural and other misuse of antibiotics and to fund antibiotic discovery have not slowed this MAR deluge. Since mobile genetic elements (MGEs) stitch single antibiotic resistance genes into clinically significant MAR arrays, it is high time to focus on how MGEs generate MAR and how disabling them could ameliorate the MAR problem. However, to consider only antibiotics as the drivers of MAR is to miss the significant impact of exposure to non-antibiotic toxic chemicals, specifically metals, on the persistence and spread of MAR. Toxic metals were among the earliest discovered targets of plasmid-encoded resistance genes. Recent genomic epidemiology clearly demonstrated the co-prevalence of metal resistances and antibiotic multi-resistance, uniquely in humans and domestic animals. Metal resistances exploit the same, ancient "transportation infrastructure" of plasmids, transposons, and integrons that spread the antibiotic resistance genes and will continue to do so even if all antibiotic misuse were stopped today and new antibiotics were flowing from the pipeline monthly. In a key experiment with primates, continuous oral exposure to mercury (Hg) released from widely used dental amalgam fillings co-selected for MAR bacteria in the oral and fecal commensal microbiomes and, most importantly, when amalgams were replaced with non-metal fillings, MAR bacteria declined dramatically. Could that also be happening on the larger public health scale as use of amalgam restorations is curtailed or banned in many countries? This commentary covers salient past and recent findings of key metal-antibiotic resistance associations and proposes that the shift from phenotyping to genotyping in surveillance of resistance loci will allow a test of whether declining exposure to this leading source of Hg is accompanied by a decline in MAR compared to countries where amalgam is still used. If this hypothesis is correct, the limited success of antibiotic stewardship practices may be because MAR is also being driven by continuous, daily exposure to Hg, a non-antibiotic toxicant widely used in humans.

Increased mercury emissions from modern dental amalgams.

All types of dental amalgams contain mercury, which partly is emitted as mercury vapor. All types of dental amalgams corrode after being placed in the oral cavity. Modern high copper amalgams exhibit two new traits of increased instability. Firstly, when subjected to wear/polishing, droplets rich in mercury are formed on the surface, showing that mercury is not being strongly bonded to the base or alloy metals. Secondly, high copper amalgams emit substantially larger amounts of mercury vapor than the low copper amalgams used before the 1970s. High copper amalgams has been developed with focus on mechanical strength and corrosion resistance, but has been sub-optimized in other aspects, resulting in increased instability and higher emission of mercury vapor. This has not been presented to policy makers and scientists. Both low and high copper amalgams undergo a transformation process for several years after placement, resulting in a substantial reduction in mercury content, but there exist no limit for maximum allowed emission of mercury from dental amalgams. These modern high copper amalgams are nowadays totally dominating the European, US and other markets, resulting in significant emissions of mercury, not considered when judging their suitability for dental restoration.

Genetic polymorphisms of catechol-O-methyltransferase modify the neurobehavioral effects of mercury in children.

Mercury (Hg) is neurotoxic and children may be particularly susceptible to this effect. A current major challenge is identification of children who may be uniquely susceptible to Hg toxicity because of genetic disposition. This study examined the hypothesis that genetic variants of catechol-O-methyltransferase (COMT) that are reported to alter neurobehavioral functions that are also affected by Hg in adults might modify the adverse neurobehavioral effects of Hg exposure in children. Five hundred and seven children, 8-12 yr of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of Hg from dental amalgam tooth fillings. Subjects were evaluated at baseline and at seven subsequent annual intervals for neurobehavioral performance and urinary Hg levels. Following the clinical trial, genotyping assays were performed for single-nucleotide polymorphisms (SNPs) of COMT rs4680, rs4633, rs4818, and rs6269 on biological samples provided by 330 of the trial participants. Regression-modeling strategies were employed to evaluate associations between allelic status, Hg exposure, and neurobehavioral test outcomes. Similar analysis was performed using haplotypes of COMT SNPs. Among girls, few interactions for Hg exposure and COMT variants were found. In contrast, among boys, numerous gene-Hg interactions were observed between individual COMT SNPs, as well as with a common COMT haplotype affecting multiple domains of neurobehavioral function. These findings suggest increased susceptibility to the adverse neurobehavioral effects of Hg among children with common genetic variants of COMT, and may have important implications for strategies aimed at protecting children from the potential health risks associated with Hg exposure.

Mercury from dental amalgam: exposure and risk assessment.

There has long been an undercurrent within the dental profession of anti-amalgam sentiment, a "mercury-free" movement. To assess whether anything is or is not scientifically wrong with amalgam, one must look to the vast literature on exposure, toxicology, and risk assessment of mercury. The subject of risk assessment goes straight to the heart of the debate over whether a malgam is safe, or not, for unrestricted use in dentistry in the population at large.

Embryotoxicity assays for leached components from dental restorative materials.

BACKGROUND: Currently, there are no suitable assays available to evaluate the embryotoxicity of leached components from restorative dental materials. METHODS: The effect of the medium conditioned by composites and amalgam on mouse blastocysts in vitro was tested. The materials were also subcutaneously implanted, and the effect of the medium supplemented with serum from the host blood was evaluated in the embryotoxicity assay. The embryo implantation rate in the material-transplanted mothers was also evaluated. RESULTS: The results show that while the culture in media conditioned by amalgams did not affect blastocyst development, the medium conditioned by composites caused blastocyst degeneration and apoptosis. The development of blastocysts in a medium containing serum obtained from animals after transplantation was, however, without effect. Finally, inconsistent reduction in the implantation rate in transplanted mothers was observed. CONCLUSIONS: In this study, we provide examples of in vitro and in vivo tests that may be used to evaluate embryotoxicity for dental materials. Our results show that leached components from our composite-material induced embryotoxicity in vitro, however, no toxicity was observed when subcutaneously implanted in vivo. This highlights the necessity of integrated in vitro and in vivo tests for valuable predictive estimation of embryotoxicity for complex materials.

Hospital admissions for neurological and renal diseases among dentists and dental assistants occupationally exposed to mercury.

OBJECTIVES: For many years an amalgam containing metallic mercury, which has been associated with neurological and renal diseases, has been used in dentistry. In this nationwide study we compared hospital admissions due to neurological and renal diseases among dentists and dental assistants to admissions in controls. METHODS: This register-based cohort study included all Danish workers employed in dental clinics, general practitioners' clinics or lawyers' offices between 1964 and 2006. We compared dentists with general practitioners and lawyers, and dental assistants with medical secretaries, nurses and legal secretaries. We also compared dentists and dental assistants employed during periods with high occupational mercury exposure with dentists and dental assistants employed during periods with less mercury exposure. We followed all subjects in a nationwide register of hospital admissions. We analysed risk of neurological diseases, Parkinson's disease and renal diseases using a Cox regression model. RESULTS: The cohort consisted of 122,481 workers including 5371 dentists and 33,858 dental assistants. For neurological diseases, no association was observed for dental assistants, while for dentists an increasing risk for periods with less mercury exposure was observed. Among dental assistants, a negative association between employment length and risk of neurological disease was observed. Admissions for renal disease among dental assistants were increased during periods with less mercury exposure compared with controls. For dentists a non-significant increased risk was observed between employment length and renal disease risk. CONCLUSIONS: Our nationwide study does not indicate that occupational exposure to mercury increases the risk of hospital admissions for neurological, Parkinson's or renal diseases.

Impact of occupational exposure to elemental mercury on some antioxidative enzymes among dental staff.

OBJECTIVES: The aim of this study is to investigate the effect of elemental mercury exposure on renal function and antioxidative enzymes activity as a possible mechanism of renal affection among dental staff. METHODS: This study was performed on a group of dental staff exposed to elemental mercury (N = 32) and matched control group (N = 37). Urinary and blood level of mercury, albumin α1 microgloblin in urine, glutathione peroxidase and superoxide dismutase blood level were measured for the exposed and control group. RESULTS: Compared to the control group, urinary and blood mercury were significantly higher in the exposed group. Glutathione peroxidase and superoxide dismutase activities in blood were significantly decreased and were negatively correlated with duration of work. CONCLUSION: Oxidative stress is an important molecular mechanism for renal dysfunction in mercury exposure, manifested by decreased activities of antioxidant enzymes.

Analysis of dental amalgam fillings on primary Sjögren's syndrome: A population-based case-control study in Taiwan.

ABSTRACT: Primary Sjören's syndrome (pSS) is an autoimmune disease characterized by the inflammatory infiltrate and progressive dysfunction of salivary glands. Dental amalgam with mercury has been raised the public concerns regarding its purported mercury toxicity from dental amalgam to possible systemic inflammatory and immune reactions.In this study, a nationwide population-based database was employed to investigate the association of amalgam filling (AMF) and the risk of pSS. A retrospective case-control study was sourced from the Taiwanese National Health Insurance Research Database (NHIRD) from 2000 to 2013. Case and control groups were matched by sex, age, urbanization level, monthly income, and comorbidities using the propensity score method with a 1:1 ratio. In this study, 5848 cases and 5848 controls were included.The results demonstrated no statistically significant differences between AMF and pSS (odds ratio [OR]: 0.974, 95% confidence interval [CI] = 0.904-1.049). In addition, pSS was also not associated with AMF for women (OR: 0.743, 95% CI = 0.552-1.000) and men (OR: 1.006, 95% CI = 0.670-1.509), respectively.Taken together, evidence demonstrated that the association of AMF and pSS was inconsistent from this robust register databank.

Observance of proper mercury hygiene practices by Jordanian general dental practitioners.

OBJECTIVES: To assess the knowledge and observance of proper mercury hygiene and amalgam waste management (AWM) among Jordanian general dental practitioners (GDPs). SUBJECTS AND METHODS: Interviews were conducted with randomly selected 250 Jordanian GDPs, using a specially designed questionnaire. Out of the total of 250 GDPs, 228 (91.2%) agreed to participate. The questionnaire covered aspects related to professional information and total amalgam contact (TAC) of these practitioners. The second part focused on the degree of awareness of the protocols related to mercury hygiene and safe AWM. RESULTS: Mean TAC was 3.2+/-3.6 hours per week. Of the Jordanian practitioners, 22.6% reported no undergraduate training in amalgam safety measures. Almost a quarter of GDPs did not have proper ventilation in their clinics, around 20-25% did not use protective clothing or eye protection, 5.3% were mixing amalgam manually, and 13.9% used their bare fingers for inserting the freshly mixed amalgam. Most of unused amalgam ends up through the drain or in trash; there are no recycling facilities to be used. CONCLUSIONS: Most Jordanian GDPs do not strictly follow the mercury hygiene and AWM guidelines. Promoting the American Dental Association (ADA) guidelines through undergraduate and postgraduate training will help GDPs acquire proper attitude towards the proper hygiene practices described in these recommendations.

Mercury in dental amalgam: a risk analysis.

Mercury is a highly potent cell toxin with effects on human and animal nervous systems. Mercury vapour released from dental amalgam is the predominant source of mercury in the human adult and foetal central nervous system in populations of developed countries. Only in small populations with high consumption of methyl mercury containing fish can the contribution from fish consumption reach or surpass that of amalgam fillings. The most severe health risk is that of interference with foetal and child brain development. This effect of mercury vapour exposure has been demonstrated in animal experiments on monkeys and rats and in nerve cell cultures at nanomolar concentrations. The effect is also supported by epidemiological studies on women occupationally exposed to mercury vapour during pregnancy. However, there is no data permitting an assessment of dose-response relations for this effect in humans. In epidemiological studies on populations with occupational exposure to mercury vapour, subclinical effects on kidneys, the immune system, thyroid function, and CNS function have been observed at an exposure level equal to the upper range of the exposure range seen in amalgam bearers and measured as urine excretion rate of inorganic mercury. The cell toxic effect of mercury is likely to be based on the ability of mercury to modify protein tertiary and quaternary structure. As protein structure is genetically determined, there is ample scope for genetic polymorphism to manifest itself in varying sensitivity and reaction to mercury exposure. It is also likely that mercury exposure from dental amalgam exerts side effects like most potent pharmaceuticals. The clinical support for this assumption is reviewed. An incidence of side effects exceeding 10% is unlikely considering available epidemiological evidence. However, an incidence of 1% or below is highly probable. It is recommended that use of amalgam for dental restorations is abandoned and substituted with available less toxic material and that amalgam restorations in children and women of childbearing age should be avoided due to the potential risk of interference by mercury with brain development.

Dental Amalgam Fillings and Multiple Sclerosis: A Nationwide Population-Based Case-Control Study in Taiwan.

Multiple sclerosis (MS) is an inflammatory neurological disease characterized by autoimmune-mediated demyelination of the central nervous system. Genetic and environmental factors may contribute to the development of MS. This has not been confirmed yet. Dental amalgam has long been controversial in MS due to its mercury content but the toxicological implications of mercury-containing amalgam fillings (AMF) for MS remain to be elucidated. We conducted a case-control study to investigate the association between AMF and the risk of MS from the Taiwanese National Health Insurance Research Database (NHIRD). Case (n = 612) and control (n = 612) groups were matched by sex, age, urbanization level, monthly income, and Charlson comorbidity index by propensity score matched with a 1:1 ratio from 2000 to 2013. Differences between cases and controls was not statistically significant (OR: 0.82, 95% CI = 0.65-1.05). In subjects stratified by gender, MS was also not associated with AMF for women (OR: 0.743, 95% CI = 0.552-1.000) and men (OR: 1.006, 95% CI = 0.670-1.509), respectively. In summary, this Taiwanese nationwide population-based case-control study did not find an association between MS and AMF.

Association between Dental Amalgam Filling and Essential Tremor: A Nationwide Population-Based Case Control Study in Taiwan.

Essential tremor (ET) is a common neurological disorder and the most common movement disorder. Low-level occupational exposure to mercury vapor is known to be a crucial factor that increases the risk of tremor. Dental amalgam is one of the main sources of mercury in those who possess amalgam restorations. However, the relationship between ET and amalgam filling (AMF) is not quite clear. The purpose of this study was to investigate the association between AMF and the risk of ET using a population-based administrative databank. The data for this study were sourced from the Taiwanese National Health Insurance Research Database (NHIRD). A retrospective case-control study was conducted using this databank from 2000 to 2013. Case and control groups were matched by sex, age, urbanization level, monthly income, and Charlson comorbidity index using the propensity score method with a 1:1 ratio. In this study, 3008 cases and 3008 controls were included. The results from this nationwide population-based case-control study did not indicate any association between ET and AMF in Taiwan. Although the results were not significantly statistical, the findings may be worthy to be valued.

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.

Urinary porphyrin excretion in children with mercury amalgam treatment: findings from the Casa Pia Children's Dental Amalgam Trial.

Increases in the urinary concentrations of pentacarboxyl- and coproporphyrins and the appearance of the atypical precoproporphyrin have been defined in relation to mercury (Hg) body burden in animal studies, and this change in the porphyrin excretion pattern has been described as a biomarker of occupational Hg exposure and toxicity in adult human subjects. In the present studies, urinary porphyrins were determined in relation to Hg exposure in children and adolescents, 8-18 yr of age, over the 7-yr course of a clinical trial designed to evaluate the neurobehavioral and renal effects of dental amalgam in children. Subjects were randomized to either dental amalgam or composite resin treatments. Urinary porphyrins and creatinine concentrations were measured at baseline and annually in all subjects. Results were evaluated using linear regression analysis. No significant differences between treatment groups (amalgam versus composite) were found when comparing all subjects for any of the porphyrins of interest. However, incipent amalgam treatment-specific increases were observed in the mean concentrations of penta-, precopro- and coproporphyrins especially when the analyses were restricted to younger subjects (8 to 9 yr old at baseline), and these increases were most apparent during yr 2 through 3 of follow-up, the period of highest mercury exposure from amalgam treatment. Based on the mean number of amalgam fillings received by children in this group (17.8), the renal Hg concentration associated with incipient increases in urinary porphyrins was estimated to be approximately 2.7 microg/g renal cortex. This value corresponds to an observed mean urinary Hg concentration of 3.2 microg/g creatinine, which is approximately fivefold less than that at which renal damage from Hg exposure is estimated to occur in children. These findings are consistent with growing evidence supporting the sensitivity of urinary porphyrins as a biological indicator of subclinical Hg exposure in children.

A prospective study of prenatal mercury exposure from maternal dental amalgams and autism severity.

Dental amalgams containing 50% mercury (Hg) have been used in dentistry for the last 150 years, and Hg exposure during key developmental periods was associated with autism spectrum disorders (ASDs). This study examined increased Hg exposure from maternal dental amalgams during pregnancy among 100 qualifying participants born between 1990-1999 and diagnosed with DSM-IV autism (severe) or ASD (mild). Logistic regression analysis (age, gender, race, and region of residency adjusted) by quintile of maternal dental amalgams during pregnancy revealed the ratio of autism:ASD (severe:mild) were about 1 (no effect) for < or =5 amalgams and increased for > or =6 amalgams. Subjects with > or =6 amalgams were 3.2-fold significantly more likely to be diagnosed with autism (severe) in comparison to ASD (mild) than subjects with < or =5 amalgams. Dental amalgam policies should consider Hg exposure in women before and during the child-bearing age and the possibility of subsequent fetal exposure and adverse outcomes.

Dental devices: classification of dental amalgam, reclassification of dental mercury, designation of special controls for dental amalgam, mercury, and amalgam alloy. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule classifying dental amalgam into class II, reclassifying dental mercury from class I to class II, and designating a special control to support the class II classifications of these two devices, as well as the current class II classification of amalgam alloy. The three devices are now classified in a single regulation. The special control for the devices is a guidance document entitled, "Class II Special Controls Guidance Document: Dental Amalgam, Mercury, and Amalgam Alloy." This action is being taken to establish sufficient regulatory controls to provide reasonable assurance of the safety and effectiveness of these devices. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the guidance document that will serve as the special control for the devices.

[Mercury impregnation in dentists and dental assistants in Monastir city, Tunisia]. / L'imprégnation mercurielle des dentistes et de leurs assistants dans la ville de Monastir, Tunisie.

INTRODUCTION: The property of mercury to amalgamate with other metals is used to create a material for filling teeth. This material remains the cheapest and most efficient in tooth restoration. Mercurial toxicity has been documented since Antiquity but the metal remains widely used in some countries. This study compared mercury impregnation in dentists and dental assistants in Monastir (Tunisia) to another population not exposed professionally. SUBJECTS AND METHODS: A cross-sectional study was made on 52 dentists and dental assistants working in private offices and in the stomatology unit of the Monastir teaching hospital, with a control group of 52 physicians and nurses working in the Monastir Fattouma Bourguiba hospital. The groups were paired according to age and gender. The study lasted three months. A questionnaire investigated the socioprofessional features of the study population, non professional mercury exposure, work environment, the various amalgam handling and preparation techniques, and preventive hygiene measures. Urinary and salivary sampling was performed so as to prevent any accidental mercurial contamination. Mercury level was assessed by atomic absorption spectroscopy in an automatic sampler, urine creatinine with Jaffé's colorimetric reaction. The results of mercury level assessment were expressed in microg/g of creatinine, salivary mercury in mug/l. The statistical analysis was made with the Epi.info 6 software. Khi(2) and Fisher tests were used to compare qualitative variables. The ANOVA test was used to compare averages with a statistic significance threshold at 0.05. RESULTS: Sixty-one percent of individuals with risk exposure worked in a dental clinic. Bruxism and onychophagia were more important in the control group with a significant statistical difference (respectively, p=0.01 and p<0.0001). The urinary and salivary mercury levels were significantly increased in the exposed group, with respective values of 20.4+/-42.4microg/g of creatinine and 10.6+/-13.02microg/l versus 0.04+/-0.3microg/g of creatinine and 0microg/l in the control group. Disposing of amalgam waste was inadequate in 94% of the cases. The variation of mercury in urine was significantly influenced by the presence of fabric curtains (p=0.04). Eating lunch at meals at the work place was also linked to a significant increase of mercury levels in urine (p=0.04). The storage mode of mercury in open containers was a significant factor for variation of mercury level (p=0.03). DISCUSSION: Most dentists' private offices in Monastir do not comply or comply weakly with prevention measures linked to risk of mercury poisoning. Awareness campaigns were launched as well as actions for the improvement of work conditions: efficient aspiration of offices containing fixed sources of mercury, adequate storage of mercury and waste, and compliance to occupational hygiene rules.

[Is there a link between the mercury release of amalgam fillings and the results of psychological questionnaires?]. / Gibt es Zusammenhänge zwischen der Quecksilberbelastung durch Amalgamfüllungen und Ergebnissen testpsychoIogischer Fragebogen-Untersuchungen?

Amalgam as a dental filling material shows excellent material property. It is fast, easy and economical to implement. Evidence for the release of mercury (Hg) from amalgam fillings was given in a number of studies. Mercury release from amalgam dental fillings is often claimed to be a possible cause of unspecific chronic symptoms such as chronic fatigue, headache and migraine. The present study explored relationships between the mercury release from amalgam fillings and the results of psychological questionnaires. The urine of 126 men and women in the age range of 16 to 76 years was examined. 45 participants did not present any amalgam restorations. The mercury released into the urine was measured by using cold-vapour AAS. The results of the study show that chronic mercury exposure, in the low concentration range, is not linked with chronic subjective symptoms.