Is amalgam removal in patients with medically unexplained physical symptoms cost-effective? A prospective cohort and decision modelling study in Norway.

There are many patients in general practice with health complaints that cannot be medically explained. Some of these patients attribute their health complaints to dental amalgam restorations. This study examined the cost-effectiveness of the removal of amalgam restorations in patients with medically unexplained physical symptoms (MUPS) attributed to amalgam fillings compared to usual care, based on a prospective cohort study in Norway. Costs were determined using a micro-costing approach at the individual level. Health outcomes were documented at baseline and approximately two years later for both the intervention and the usual care using EQ-5D-5L. Quality adjusted life year (QALY) was used as a main outcome measure. A decision analytical model was developed to estimate the incremental cost-effectiveness of the intervention. Both probabilistic and one-way sensitivity analyses were conducted to assess the impact of uncertainty in costs and effectiveness. In patients who attribute health complaints to dental amalgam restorations and fulfil the inclusion and exclusion criteria, amalgam removal is associated with modest increase in costs at societal level as well as improved health outcomes. In the base-case analysis, the mean incremental cost per patient in the amalgam group was NOK 19 416 compared to the MUPS group, while mean incremental QALY was 0.119 with a time horizon of two years. Thus, the incremental costs per QALY of the intervention was NOK 162 680, which is usually considered cost effective in Norway. The estimated incremental cost per QALY decreased with increasing time horizon, and amalgam removal was found to be cost saving over both 5 and 10 years. This study provides insight into the costs and health outcomes associated with the removal of amalgam restorations in patients who attribute health complaints to dental amalgam fillings, which are appropriate instruments to inform health care priorities.

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 .

Exposure to mercury from dental amalgam: actual contribution for risk assessment.

OBJECTIVE: Mercury dental amalgam restorations are an important source of chronic exposure to mercury in the whole population and special attention should be paid not only to occupational exposure to mercury during the preparation and administration of amalgam. The authors' report is an up-to-date contribution to the health risk assessment of mercury use in dentistry, namely occupational exposure to mercury in dentists working with dental amalgam and exposure to mercury in persons treated with amalgam dental restorations. METHODS: Determination of total mercury in samples of biological material (urine, hair) was performed during 2017 and 2018 in 50 persons by the AAS method using the mercury vapour generation technique at 254.6 nm. RESULTS: Current dental exposures based on the most recent findings do not exceed acceptable risk levels and are below the biological limit of mercury in urine valid for occupationally exposed persons (100 µg.g-1 of creatinine), namely median value was 1.48 (min. < limit of detection (LOD), max. 17.14) µg.g-1 of creatinine (40 persons), total mercury content in hair of dental personnel expressed as median value was 0.340 (min. 0.060, max.1.628) µg.g-1. In controls (10 persons) was total mercury content in urine expressed as median value 0.36 (min. < LOD, max. 2.74) µg.g-1 of creatinine, in hair was median value 0.224 (min. 0.059, max. 0.453) µg.g-1. CONCLUSIONS: Authors support opinion that amalgam fillings in the oral cavity are a permanent source of mercury for the body itself.

Replacing amalgam with a high-viscosity glass-ionomer in restoring primary teeth: A cost-effectiveness study in Brasilia, Brazil.

OBJECTIVES: When planning primary oral health care services the cost implications of adopting new intervention practices are important, especially in resource-strapped countries. Although on a trajectory to be phased-out, amalgam remains the standard of care in many countries. METHODS: Adopting a government perspective, this study compared the costs of performing amalgam and ART/high-viscosity glass-ionomer cement (HVGIC) restorations and the consequences of failed restorations over 3 years in suburban Brasilia, Brazil. Cost data were collected prospectively; cost estimates were developed for the study sample and a projection of 1000 single- and 1000 multiple-surface restorations per group. Probabilistic sensitivity analysis was conducted in TreeAge Pro. RESULTS: Results were mixed. For single-surface restorations, ART/HVGIC will cost US$51 per failure prevented, while for multiple-surface restorations, ART/HVGIC was cost-effective with a savings of US$11 compared to amalgam. Probabilistic sensitivity analysis (Monte Carlo simulation) predicted amalgam would be cost-effective 49.2% of the time compared to HVGIC at 50.6% of the time at a willingness to pay threshold of US$237 per failure prevented. Personnel accounted for more than half the cost burden for both methods; instruments and supplies accounted for about one third. The per restoration cost to replace amalgam with HVGIC ranges from US$1 to a savings of US$0.84. CONCLUSION: Replacing amalgam with a high-viscosity glass-ionomer as part of the ART method comes at a minimal increase in cost for governments. Increasing the number of restorations seems to diminish the cost burden. CLINICAL SIGNIFICANCE: ART/HVGIC could be considered a viable alternative to amalgam in primary teeth.

Dental associations with blood mercury in pregnant women.

OBJECTIVES: There is curiosity concerning the source of mercury that is absorbed into the mother's blood and which may affect the developing fetus. This study therefore sets out to determine the extent to which dental amalgam (DA) may contribute to total blood mercury (TBHg) levels of pregnant women in the UK. METHODS: Whole blood samples and information on diet and socio-demographic factors were collected from pregnant women (n = 4484) enrolled in the Avon Longitudinal Study of Parents and Children (ALSPAC). The whole blood samples were assayed for total mercury levels using inductively coupled plasma dynamic reaction cell mass spectrometry (ICP-DRC-MS), and the women were retrospectively asked about features of their dental care during the pregnancy. Linear regression was used to estimate the relative contributions of DA to TBHg levels (log-transformed) based on R(2) values, compared to the results from dietary and socio-demographic variables. RESULTS: The contribution to the variance of the mothers' TBHg levels by dental variables was 6.47%, a figure comparable to the 8.75% shown for seafood consumption in this population. Dietary and dental variables explained 20.16% of the variance, with socio-demographic variables contributing only a further 3.40%. The number of amalgams in the mouth at the start of pregnancy accounted for most of the variance in dental variables. CONCLUSIONS: Dental amalgam contributes a comparable amount of variance in TBHg to seafood consumption in this population. However, because the measures of DA exposure were imprecise, these findings are likely to be an underestimate. There is no evidence to date in the literature that fetal exposures to mercury from maternal DAs have adverse effects on the developing child, but long-term studies are warranted.

Managing the phase-down of amalgam: part II. Implications for practising arrangements and lessons from Norway.

The announcement of the Minamata Convention has triggered the lead into a phase-down in the use of dental amalgam. This paper considers aspects of this development in the context of the experience of banning the use of dental amalgam in Norway. It is suggested that strong top-down leadership and joined-up working by all relevant stakeholders, including patients, may be one of the most important keys to an effective, seamless transition to the provision of preventatively orientated, patient-centred, minimally interventive operative dentistry, based on state-of-the-art selection and application of tooth-coloured restorative materials. The benefits of such a transition are considered to be an important goal for dentistry in the UK.

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.

Reliance on social security benefits by Swedish patients with ill-health attributed to dental fillings: a register-based cohort study.

BACKGROUND: Some people attribute their ill health to dental filling materials, experiencing a variety of symptoms. Yet, it is not known if they continue to financially support themselves by work or become reliant on different types of social security benefits. The aim of this study was to analyse reliance on different forms of social security benefits by patients who attribute their poor health to dental filling materials. METHODS: A longitudinal cohort study with a 13-year follow up. The subjects included were 505 patients attributing their ill health to dental restorative materials, who applied for subsidised filling replacement. They were compared to a cohort of matched controls representing the general population (three controls per patient). Annual individual data on disability pension, sick leave, unemployment benefits, and socio-demographic factors was obtained from Statistics Sweden. Generalized estimating equations were used to test for differences between cohorts in number of days on different types of social security benefits. RESULTS: The cohort of dental filling patients had a significantly higher number of days on sick leave and disability pension than the general population. The test of an overall interaction effect between time and cohort showed a significant difference between the two cohorts regarding both sick leave and disability pension. In the replacement cohort, the highest number of sick-leave days was recorded in the year they applied for subsidised replacement of fillings. While sick leave decreased following the year of application, the number of days on disability pension increased and peaked at the end of follow-up. CONCLUSIONS: Ill health related to dental materials is likely to be associated with dependence on social security benefits. Dental filling replacement does not seem to improve workforce participation.

Exposure to dental amalgam restorations in pregnant women.

OBJECTIVES: The Norwegian Mother and Child Cohort Study (MoBa) started in 1999 to identify environmental factors that could be involved in mechanisms leading to disease. Questions have been raised about potential risks to the fetus from prenatal exposure to mercury from amalgam fillings in pregnant women. The aim of the present study was to identify factors potentially associated with amalgam fillings in pregnant women participating in the Norwegian Mother and Child Cohort Study (MoBa). An additional aim was to obtain information about dental treatment in the cohort. METHODS: Total of 67,355 pregnancies from the MoBa study were included in the present study. Information regarding age, education, smoking habits, alcohol consumption, weight, and height for the women was obtained from a questionnaire that was filled in at the 17th week of pregnancy. In another questionnaire, which was sent to all participants in the 30th week of pregnancy, the women reported types of dental treatment during pregnancy, total number of teeth, and number of teeth with amalgam fillings. The self-assessed number of teeth and number of teeth with amalgam fillings were validated in an external sample of 97 women of childbearing age. RESULTS: Odds ratio for having more than 12 teeth with amalgam fillings increased considerably with age. Other significant risk factors for having high exposure to amalgam were low education, high body mass index (BMI), and smoking during pregnancy. Women with the lowest levels of education had a twofold increased odds ratio of having more than 12 teeth filled with amalgam compared with women who had more than 4 years of university studies. According to the results from the validation of self-assessed number of teeth with amalgam fillings, the information obtained was reliable. CONCLUSION: Age, education, smoking habits, and BMI were associated with amalgam exposure.

Mercury exposure assessment in Iranian women's hair of a port town with respect to fish consumption and amalgam fillings.

In this study we aimed to estimate the level of mercury in women's hair and its association with fish consumption and amalgam fillings in an Iranian southern port town (named Mahshahr). A total number of 195 hair samples were collected randomly from women aged 25-45 years free from occupational exposures to mercury. Additional information about these women's age, weight, height, number of pregnancies, level of education, number of amalgam fillings and fish consumption were also gathered. The determination of Hg level in hair samples was carried out by the LECO, AMA 254, Advanced Mercury Analyzer, according to ASTM standard No. D-6722. The average mercury level in these women's hair was 2.95+/-2.33microg/g (ranged from 0.07 to 24.46microg/g). In the next stage, the study participants were divided into four groups with respect to their fish consumption and number of amalgam fillings; A) <3 amalgam fillings, <3 times fish consumption per month, B) <3 amalgam fillings, >7 times fish consumption per month, C) >6 amalgam fillings, <3 times fish consumption per month, and D) >6 amalgam fillings, >7 times fish consumption per month. Statistical analysis showed that the Hg level was significantly different in these four groups (P<0.001). Mercury levels in this sample exceeded the USEPA-recommended 1microg/g in 76.4% of the studied population. Finally, the multiple linear regression results revealed that frequency of fish consumption and amalgam restorations are the most important routes of Hg exposure. However, the main determinant of Hg exposure was the intake of Hg through fish consumption.

Assessment of blood mercury levels in practicing Turkish clinicians, dental students, and dental nurses.

OBJECTIVES: Potential sources of exposure of the dental health team and their patients to mercury vapor in the dental clinic include accidental spillage of elemental mercury, use of mechanical amalgamators, and dry cutting of old amalgam restorations using high-speed instrumentation. The purpose of this study was to evaluate the extent of mercury exposure in Turkish dental staff by cold-vapor atomic absorption spectrometry. METHOD AND MATERIALS: A total of 211 clinicians, dental students, and dental nurses answered a questionnaire concerning sex, age, occupation, number of amalgam restorations performed per week, number of amalgam restorations removed per week, methods of trituration, number of amalgam restorations present in their own mouths, frequency of fish consumption, smoking, vitamin intake, and bruxism. For each subject, a 5-mL sample of whole blood was drawn and frozen until the time of analysis. Blood mercury levels were measured by means of cold-vapor atomic absorption spectrometry. Blood mercury levels were also analyzed in a control group of 58 non-dental-staff blood donors. RESULTS: Normal blood mercury values are considered to be in the range of 0 to 5 ng Hg/mL. Of the dental staff evaluated, 51.7% had a blood concentration of mercury less than 5 ng Hg/mL, and 33.6% had a blood concentration above 5 ng Hg/mL. The difference between the test and control groups was statistically significant (P < .01). CONCLUSION: Mercury is being absorbed as a result of dental practice but that although there is, in general, a low level of mercury contamination in the dental operatory because of amalgam work, sufficient care is being taken to prevent higher levels of contamination with an increased use of mercury.

Treatment of health complaints attributed to amalgam.

The aim of the present study was to compare the reduction of subjective complaints by 3 treatment strategies in 90 "amalgam patients" whose complaints could not be explained by a medical or psychological disorder. The individuals were randomly assigned either to removal of dental amalgam only (removal group), or removal in combination with a "biological detoxification" therapy with high doses of vitamins and trace elements (removal-plus group), or participation in a health promotion program without removal of dental amalgam (no-removal group). Between baseline and month 12, the sum score of main complaints decreased by 3.5 (SD=2.2) points on average in the removal group as well as in the removal-plus group, and by 2.5 (SD=2.4) points in the no-removal group (p=0.152). Both removal groups showed a significant decrease in steady-state levels of inorganic mercury compared with the no-removal group. Thus, all 3 interventions were associated with clinically relevant improvements.

[Amalgam risk assessment with coverage of references up to 2005]. / Amalgam: Eine Risikobewertung unter Berücksichtigung der neuen Literatur bis 2005.

Amalgam, which has been in use in dentistry for 150 years, consists of 50 % elemental mercury and a mixture of silver, tin, copper and zinc. Minute amounts of mercury vapour are released continuously from amalgam. Amalgam contributes substantially to human mercury load. Mercury accumulates in some organs, particularly in the brain, where it can bind to protein more tightly than other heavy metals (e. g. lead, cadmium). Therefore, the elimination half time is assumed to be up to 1 - 18 years in the brain and bones. Mercury is assumed to be one of the most toxic non-radioactive elements. There are pointers to show that mercury vapour is more neurotoxic than methyl-mercury in fish. Review of recent literature suggests that mercury from dental amalgam may lead to nephrotoxicity, neurobehavioural changes, autoimmunity, oxidative stress, autism, skin and mucosa alterations or non-specific symptoms and complaints. The development of Alzheimer's disease or multiple sclerosis has also been linked to low-dose mercury exposure. There may be individual genetical or acquired susceptibilities for negative effects from dental amalgam. Mercury levels in the blood, urine or other biomarkers do not reflect the mercury load in critical organs. Some studies regarding dental amalgam reveal substantial methodical flaws. Removal of dental amalgam leads to permanent improvement of various chronic complaints in a relevant number of patients in various trials. Summing up, available data suggests that dental amalgam is an unsuitable material for medical, occupational and ecological reasons.

[10 years of observation by public health offices in Baden-Württemberg--assessment of human biomonitoring for mercury due to dental amalgam fillings and other sources]. / 10 Jahre Beobachtungsgesundheitsämter in Baden-Württemberg--Beurteilung der Human-Biomonitoring-Untersuchungen bezüglich der Quecksilber-Belastung durch Amalgamfüllungen und andere Quellen.

Since 1992, in Baden-Württemberg, ten-year old children have been surveyed in the project "Sentinel Health Departments" to study their exposure to environmental pollutants and possible health effects. In the four study areas 1200 children have been investigated every year initially, since 1996 every second year. The data for mercury in body fluids are reported here. The decrease in the body burden of mercury as a result of the declining usage of dental amalgam fillings, was been verified. In 1992/93, of all the children who had been surveyed, the 95 percentile for the body burden of mercury was 3.1 microg/l and in 2000/01 1.35 microg/l. Also to be discussed is the reason why mercury-based cosmetic ointments seriously exceed the HBM-II-intervention-value. Because of using these ointments, concentrations of mercury in urine up to 1400 microg/l were found. A study within the project "Sentinel Health Departments" compared the concentrations of mercury in the urine of adults with those in blood and salvia. The results support the opinion that mercury in urine is appropriate for estimating the mercury uptake from dental amalgam fillings. It can be assumed that these results reflect the situation in the entire Federal Republic of Germany. The ten years' experience confirms that the concept of the "Sentinel Health Departments" is excellently suited to obtain data relevant for environmental health of children. Environmental health protection and the essential gathering of data for future health observation in Baden-Württemberg.

Nordic dentists' knowledge and attitudes on dental amalgam from health and environmental perspectives.

The aim of this study was to identify differences and similarities between the Nordic countries in dentists' use of dental amalgam as a restorative material, and also their knowledge and attitudes about amalgam from health, environmental, ethical, economic and social points of view. Procedures for handling amalgam waste were also studied. A random sample of 250 dentists was drawn from the national registers of authorized dentists in each country in late autumn 1997. At the beginning of 1998, a questionnaire was sent to all the dentists in the study group. The response rate was 77.6% in Denmark, 73.2% in Finland, 78.8% in Norway, and 84.0% in Sweden. In Finland and Sweden the use of dental amalgam had almost ceased, particularly for younger patients, while in Norway and especially in Denmark it was still widely used. Dentists' knowledge of the environmental effects of amalgam was confused, but most dentists had installed amalgam separators in their dental units by 1998. The majority of dentists in each country wanted to keep dental amalgam as a restorative material even in the future, and they did not want to ban the import of mercury to their home countries. Most dentists considered amalgam to be a health risk for at least some patients, and a great majority (from 76% in Sweden to 94% in Norway) considered composite as a possible odontological risk to patients. Since a majority of the dentists considered both amalgam and composites possibly harmful to patients, efforts to develop better alternatives to amalgam should continue.