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Worthington HV, Khangura S, Seal K, Mierzwinski-Urban M, Veitz-Keenan A, Sahrmann P, Schmidlin PR, Davis D, Iheozor-Ejiofor Z, Rasines Alcaraz MG. Direct composite resin fillings versus amalgam fillings for permanent posterior teeth. Cochrane Database Syst Rev 2021; 8:CD005620. [PMID: 34387873 PMCID: PMC8407050 DOI: 10.1002/14651858.cd005620.pub3] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
BACKGROUND Traditionally, amalgam has been used for filling cavities in posterior teeth, and it continues to be the restorative material of choice in some low- and middle-income countries due to its effectiveness and relatively low cost. However, there are concerns over the use of amalgam restorations (fillings) with regard to mercury release in the body and the environmental impact of mercury disposal. Dental composite resin materials are an aesthetic alternative to amalgam, and their mechanical properties have developed sufficiently to make them suitable for restoring posterior teeth. Nevertheless, composite resin materials may have potential for toxicity to human health and the environment. The United Nations Environment Programme has established the Minamata Convention on Mercury, which is an international treaty that aims "to protect the [sic] human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds". It entered into force in August 2017, and as of February 2021 had been ratified by 127 governments. Ratification involves committing to the adoption of at least two of nine proposed measures to phase down the use of mercury, including amalgam in dentistry. In light of this, we have updated a review originally published in 2014, expanding the scope of the review by undertaking an additional search for harms outcomes. Our review synthesises the results of studies that evaluate the long-term effectiveness and safety of amalgam versus composite resin restorations, and evaluates the level of certainty we can have in that evidence. OBJECTIVES To examine the effects (i.e. efficacy and safety) of direct composite resin fillings versus amalgam fillings. SEARCH METHODS An information specialist searched five bibliographic databases up to 16 February 2021 and used additional search methods to identify published, unpublished and ongoing studies SELECTION CRITERIA: To assess efficacy, we included randomised controlled trials (RCTs) comparing dental composite resin with amalgam restorations in permanent posterior teeth that assessed restoration failure or survival at follow-up of at least three years. To assess safety, we sought non-randomised studies in addition to RCTs that directly compared composite resin and amalgam restorative materials and measured toxicity, sensitivity, allergy, or injury. DATA COLLECTION AND ANALYSIS We used standard methodological procedures expected by Cochrane. MAIN RESULTS We included a total of eight studies in this updated review, all of which were RCTs. Two studies used a parallel-group design, and six used a split-mouth design. We judged all of the included studies to be at high risk of bias due to lack of blinding and issues related to unit of analysis. We identified one new trial since the previous version of this review (2014), as well as eight additional papers that assessed safety, all of which related to the two parallel-group studies that were already included in the review. For our primary meta-analyses, we combined data from the two parallel-group trials, which involved 1645 composite restorations and 1365 amalgam restorations in 921 children. We found low-certainty evidence that composite resin restorations had almost double the risk of failure compared to amalgam restorations (risk ratio (RR) 1.89, 95% confidence interval (CI) 1.52 to 2.35; P < 0.001), and were at much higher risk of secondary caries (RR 2.14, 95% CI 1.67 to 2.74; P < 0.001). We found low-certainty evidence that composite resin restorations were not more likely to result in restoration fracture (RR 0.87, 95% CI 0.46 to 1.64; P = 0.66). Six trials used a split-mouth design. We considered these studies separately, as their reliability was compromised due to poor reporting, unit of analysis errors, and variability in methods and findings. Subgroup analysis showed that the findings were consistent with the results of the parallel-group studies. Three trials investigated possible harms of dental restorations. Higher urinary mercury levels were reported amongst children with amalgam restorations in two trials, but the levels were lower than what is known to be toxic. Some differences between amalgam and composite resin groups were observed on certain measures of renal, neuropsychological, and psychosocial function, physical development, and postoperative sensitivity; however, no consistent or clinically important harms were found. We considered that the vast number of comparisons made false-positive results likely. There was no evidence of differences between the amalgam and composite resin groups in neurological symptoms, immune function, and urinary porphyrin excretion. The evidence is of very low certainty, with most harms outcomes reported in only one trial. AUTHORS' CONCLUSIONS Low-certainty evidence suggests that composite resin restorations may have almost double the failure rate of amalgam restorations. The risk of restoration fracture does not seem to be higher with composite resin restorations, but there is a much higher risk of developing secondary caries. Very low-certainty evidence suggests that there may be no clinically important differences in the safety profile of amalgam compared with composite resin dental restorations. This review supports the utility of amalgam restorations, and the results may be particularly useful in parts of the world where amalgam is still the material of choice to restore posterior teeth with proximal caries. Of note, however, is that composite resin materials have undergone important improvements in the years since the trials informing the primary analyses for this review were conducted. The global phase-down of dental amalgam via the Minamata Convention on Mercury is an important consideration when deciding between amalgam and composite resin dental materials. The choice of which dental material to use will depend on shared decision-making between dental providers and patients in the clinic setting, and local directives and protocols.
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Affiliation(s)
- Helen V Worthington
- Cochrane Oral Health, Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sara Khangura
- Canadian Agency for Drugs and Technologies in Health (CADTH), Ottawa, Canada
| | - Kelsey Seal
- Canadian Agency for Drugs and Technologies in Health (CADTH), Ottawa, Canada
| | | | - Analia Veitz-Keenan
- Department of Oral Maxillofacial Pathology, Radiology and Medicine, New York University College of Dentistry, New York, USA
| | - Philipp Sahrmann
- Clinic of Conservative and Preventive Dentistry, Center for Dental and Oral Medicine and Maxillo-Facial Surgery, University of Zurich, Zurich, Switzerland
| | - Patrick Roger Schmidlin
- Clinic of Conservative and Preventive Dentistry, Center for Dental and Oral Medicine and Maxillo-Facial Surgery, University of Zurich, Zurich, Switzerland
| | - Dell Davis
- Texas Medical Center Library, Houston Academy of Medicine, Houston, USA
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Yazdanian M, Ghanizadeh G, Rastgoo S, Shokouh SMH. Evaluation of kidney function and oxidative stress biomarkers in prolonged occupational exposure with mercury in dentists. GENE REPORTS 2020. [DOI: 10.1016/j.genrep.2020.100627] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Laimer J, Henn R, Helten T, Sprung S, Zelger B, Zelger B, Steiner R, Schnabl D, Offermanns V, Bruckmoser E, Huck CW. Amalgam tattoo versus melanocytic neoplasm - Differential diagnosis of dark pigmented oral mucosa lesions using infrared spectroscopy. PLoS One 2018; 13:e0207026. [PMID: 30399191 PMCID: PMC6219804 DOI: 10.1371/journal.pone.0207026] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2018] [Accepted: 10/22/2018] [Indexed: 12/14/2022] Open
Abstract
Background Dark pigmented lesions of the oral mucosa can represent a major diagnostic challenge. A biopsy is usually required to determine the nature of such intraoral discolorations. This study investigates the potential use of infrared spectroscopy for differential diagnosis of amalgam tattoos versus benign or malignant melanocytic neoplasms. Materials and methods For this retrospective study, formalin-fixed paraffin-embedded tissue (FFPE) specimens of dark pigmented lesions concerning the oral mucosa or the lip were investigated using mid infrared spectroscopy. The samples were chosen from patients who had undergone a mucosal biopsy at the University Hospital Innsbruck (Austria) between the years 2000 and 2017. Principal component analysis was used for data exploration. Evaluation was based on the superimposition of the recorded spectra and the corresponding histologic slides. Results In total, 22 FFPE specimens were analyzed. Clear differences were found between amalgam and non-amalgam samples. A general weakening of the penetrating infrared radiation allowed for unspecific discrimination between these two classes. An overall accuracy in predicting the correct class of 95.24% was achieved. Conclusion Infrared spectroscopy appears to be a suitable technique to differentiate between amalgam tattoos and melanocytic lesions in FFPE samples. It could potentially be applied in vivo, too, serving as a non-invasive diagnostic tool for intraoral dark pigmented lesions.
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Affiliation(s)
- Johannes Laimer
- University Hospital for Craniomaxillofacial and Oral Surgery, Innsbruck, Austria
| | - Raphael Henn
- Institute of Analytical Chemistry and Radiochemistry, Innsbruck, Austria
| | - Tom Helten
- University Hospital for Craniomaxillofacial and Oral Surgery, Innsbruck, Austria
| | - Susanne Sprung
- Institute of Pathology, Medical University, Innsbruck, Austria
| | - Bettina Zelger
- Institute of Pathology, Medical University, Innsbruck, Austria
| | - Bernhard Zelger
- University Hospital for Dermatology, Venereology and Allergology, Innsbruck, Austria
| | - René Steiner
- University Hospital for Dental Prosthetics and Restorative Dentistry, Innsbruck, Austria
| | - Dagmar Schnabl
- University Hospital for Dental Prosthetics and Restorative Dentistry, Innsbruck, Austria
| | - Vincent Offermanns
- University Hospital for Craniomaxillofacial and Oral Surgery, Innsbruck, Austria
| | | | - Christian W. Huck
- Institute of Analytical Chemistry and Radiochemistry, Innsbruck, Austria
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Zheng LY, Sanders AP, Saland JM, Wright RO, Arora M. Environmental exposures and pediatric kidney function and disease: A systematic review. ENVIRONMENTAL RESEARCH 2017; 158:625-648. [PMID: 28727988 PMCID: PMC5821495 DOI: 10.1016/j.envres.2017.06.029] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 05/29/2017] [Accepted: 06/23/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND Environmental chemical exposures have been implicated in pediatric kidney disease. No appraisal of the available evidence has been conducted on this topic. METHODS We performed a systematic review of the epidemiologic studies that assessed association of environmental exposures with measures of kidney function and disease in pediatric populations. The search period went through July 2016. RESULTS We found 50 studies that met the search criteria and were included in this systematic review. Environmental exposures reviewed herein included lead, cadmium, mercury, arsenic, fluoride, aflatoxin, melamine, environmental tobacco, bisphenol A, dental procedures, phthalates, ferfluorooctanoic acid, triclosan, and thallium/uranium. Most studies assessed environmental chemical exposure via biomarkers but four studies assessed exposure via proximity to emission source. There was mixed evidence of association between metal exposures, and other non-metal environmental exposures and pediatric kidney disease and other kidney disease biomarkers. The evaluation of causality is hampered by the small numbers of studies for each type of environmental exposure, as well as lack of study quality and limited prospective evidence. CONCLUSION There is a need for well-designed epidemiologic studies of environmental chemical exposures and kidney disease outcomes.
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Affiliation(s)
- Laura Y Zheng
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States.
| | - Alison P Sanders
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States.
| | - Jeffrey M Saland
- Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States.
| | - Robert O Wright
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States; Department of Pediatrics, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States.
| | - Manish Arora
- Department of Environmental Medicine and Public Health, Icahn School of Medicine at Mount Sinai, 1 Gustave L. Levy Place, New York, NY 10029, United States.
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Toxic environmental exposures and kidney health in children. Pediatr Nephrol 2016; 31:2043-54. [PMID: 26458883 PMCID: PMC4829489 DOI: 10.1007/s00467-015-3222-3] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2015] [Revised: 09/01/2015] [Accepted: 09/04/2015] [Indexed: 02/06/2023]
Abstract
High-level exposures to a number of agents are known to have direct nephrotoxic effects in children. A growing body of literature supports the hypothesis that chronic, relatively low-level exposure to various nephrotoxicants may also increase the risk for chronic kidney disease (CKD) or accelerate its progression. In this review we highlight several environmental nephrotoxicants and their association with CKD in children and adolescents. We also discuss unique epidemiological challenges in the use of kidney biomarkers in environmental nephrotoxicology.
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Gul N, Khan S, Khan A, Nawab J, Shamshad I, Yu X. Quantification of Hg excretion and distribution in biological samples of mercury-dental-amalgam users and its correlation with biological variables. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2016; 23:20580-20590. [PMID: 27464660 DOI: 10.1007/s11356-016-7266-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2015] [Accepted: 07/14/2016] [Indexed: 06/06/2023]
Abstract
This is the first study conducted to quantify the excretion and distribution of mercury (Hg) with time (days) in the biological samples collected from Hg dental amalgam users (MDA). The individuals, with Hg-based dental filling were selected, and their biological samples (red blood cells (RBCs), plasma, urine, hair, and nails) were collected on first, third, and 12th day of fillings. The concentrations of Hg observed in the biological samples of MDA were also correlated with the biological variables such as age, weight, restoration, fish consumption, number, and surface area of fillings. The concentrations of Hg in the biological samples of MDA were found 6-8 times higher than the non-amalgam users (control). The concentrations of Hg in the RBCs (4.39 μg/L), plasma (3.02 μg/L), and urine (22.5 μg/L) on first day of filling were found comparatively higher than the concentrations observed on third day (2.15, 1.46, and 12.3 μg/L for RBCs, plasma, urine, respectively) and 12th day (3.05, 2.5, 9.12 μg/L for RBCs, plasma, urine, respectively), while Hg concentrations were found lower in the hair and nails on third day of fillings (1.53 μg/g for hair and 2.35 μg/g for nails) as compared to the 12th day (2.95 μg/g for hair and 3.5 μg/g for nails). The correlations were found significant (p ˂ 0.05) between Hg concentrations in the biological samples of MDA and biological variables (the number of restoration, fish consumption, number, and surface area of fillings), while no significant (p ˃ 0.05) correlations were observed for Hg concentrations in the biological samples with age and weight of MDA. These observations unveil the fact that the use of Hg-based dental filling is the undesirable exposure to Hg which should be replaced by composite (a safer filling material).
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Affiliation(s)
- Nayab Gul
- Department of Environmental Science, University of Peshawar, Peshawar, 25120, Pakistan
| | - Sardar Khan
- Department of Environmental Science, University of Peshawar, Peshawar, 25120, Pakistan.
- Zhejiang Provincial Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, Zhoushan Municipal Center For Disease Control and Prevention, Zhoushan, 316021, China.
| | - Abbas Khan
- Drug Control Administration, Government of Khyber Pakhtunkhwa, Health Department, Peshawar, 25120, Pakistan
| | - Javed Nawab
- Department of Environmental Science, University of Peshawar, Peshawar, 25120, Pakistan
- Department of Environmental and Conservation Sciences, University of Swat, Swat, 19130, Pakistan
| | - Isha Shamshad
- Department of Environmental Science, University of Peshawar, Peshawar, 25120, Pakistan
- Department of Environmental Science, International Islamic University, Islamabad, Pakistan
| | - Xinwei Yu
- Zhejiang Provincial Key Laboratory of Health Risk Factors for Seafood of Zhejiang Province, Zhoushan Municipal Center For Disease Control and Prevention, Zhoushan, 316021, China.
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DeRouen TA, Woods JS, Leroux BG, Martin MD. Critique of reanalysis of Casa Pia data on associations of porphyrins and glutathione-S-transferases with dental amalgam exposure. Hum Exp Toxicol 2014; 34:330-2. [PMID: 25005805 DOI: 10.1177/0960327114542885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Affiliation(s)
| | - J S Woods
- University of Washington, Seattle, WA, USA
| | - B G Leroux
- University of Washington, Seattle, WA, USA
| | - M D Martin
- University of Washington, Seattle, WA, USA
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Kim Y, Lee BK. Associations of blood lead, cadmium, and mercury with estimated glomerular filtration rate in the Korean general population: analysis of 2008-2010 Korean National Health and Nutrition Examination Survey data. ENVIRONMENTAL RESEARCH 2012; 118:124-129. [PMID: 22749111 DOI: 10.1016/j.envres.2012.06.003] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/21/2012] [Revised: 05/18/2012] [Accepted: 06/05/2012] [Indexed: 06/01/2023]
Abstract
INTRODUCTION The objective of this study was to evaluate associations between blood lead, cadmium, and mercury levels with estimated glomerular filtration rate in a general population of South Korean adults. METHODS This was a cross-sectional study based on data obtained in the Korean National Health and Nutrition Examination Survey (KNHANES) (2008-2010). The final analytical sample consisted of 5924 participants. Estimated glomerular filtration rate (eGFR) was calculated using the MDRD Study equation as an indicator of glomerular function. RESULTS In multiple linear regression analysis of log2-transformed blood lead as a continuous variable on eGFR, after adjusting for covariates including cadmium and mercury, the difference in eGFR levels associated with doubling of blood lead were -2.624 mL/min per 1.73 m² (95% CI: -3.803 to -1.445). In multiple linear regression analysis using quartiles of blood lead as the independent variable, the difference in eGFR levels comparing participants in the highest versus the lowest quartiles of blood lead was -3.835 mL/min per 1.73 m² (95% CI: -5.730 to -1.939). In a multiple linear regression analysis using blood cadmium and mercury, as continuous or categorical variables, as independent variables, neither metal was a significant predictor of eGFR. Odds ratios (ORs) and 95% CI values for reduced eGFR calculated for log2-transformed blood metals and quartiles of the three metals showed similar trends after adjustment for covariates. DISCUSSION In this large, representative sample of South Korean adults, elevated blood lead level was consistently associated with lower eGFR levels and with the prevalence of reduced eGFR even in blood lead levels below 10 μg/dL. In conclusion, elevated blood lead level was associated with lower eGFR in a Korean general population, supporting the role of lead as a risk factor for chronic kidney disease.
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Affiliation(s)
- Yangho Kim
- Department of Occupational and Environmental Medicine, Ulsan University Hospital, University of Ulsan College of Medicine, Ulsan, South Korea
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Geier DA, Carmody T, Kern JK, King PG, Geier MR. A significant dose-dependent relationship between mercury exposure from dental amalgams and kidney integrity biomarkers: a further assessment of the Casa Pia children's dental amalgam trial. Hum Exp Toxicol 2012; 32:434-40. [PMID: 22893351 DOI: 10.1177/0960327112455671] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Dental amalgams are a commonly used dental restorative material. Amalgams are about 50% mercury (Hg), and Hg is known to significantly accumulate in the kidney. It was hypothesized that because Hg accumulates in the proximal tubules (PTs), glutathione-S-transferases (GST)-α (suggestive of kidney damage at the level of PT) would be expected to be more related to Hg exposure than GST-π (suggestive of kidney damage at the level of the distal tubules). Urinary biomarkers of kidney integrity were examined in children of 8-18 years old, with and without dental amalgam fillings, from a completed clinical trial (parent study). Our study determined whether there was a significant dose-dependent correlation between increasing Hg exposure from dental amalgams and GST-α and GST-π as biomarkers of kidney integrity. Overall, the present study, using a different and more sensitive statistical model than the parent study, revealed a statistically significant dose-dependent correlation between cumulative exposure to Hg from dental amalgams and urinary levels of GST-α, after covariate adjustment; where as, a nonsignificant relationship was observed with urinary levels of GST-π. Furthermore, it was observed that urinary GST-α levels increased by about 10% over the 8-year course of the study among individuals with an average exposure to amalgams among the study subjects from the amalgam group, in comparison with study subjects with no exposure to dental amalgams. The results of our study suggest that dental amalgams contribute to ongoing kidney damage at the level of the PTs in a dose-dependent fashion.
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Affiliation(s)
- D A Geier
- Institute of Chronic Illnesses, Inc., Silver Spring, USA
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Al-Saleh I, Al-Sedairi AA, Elkhatib R. Effect of mercury (Hg) dental amalgam fillings on renal and oxidative stress biomarkers in children. THE SCIENCE OF THE TOTAL ENVIRONMENT 2012; 431:188-96. [PMID: 22683759 DOI: 10.1016/j.scitotenv.2012.05.036] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/10/2011] [Revised: 05/10/2012] [Accepted: 05/10/2012] [Indexed: 05/24/2023]
Abstract
We examined the effect of mercury (Hg) associated with dental amalgam fillings on biomarkers of renal and oxidative stress in children between the ages of 5-15.5 years. Urine samples were analyzed for N-acetyl-β-D-glucosaminidase (NAG), α(1)-microglobulin (α(1)-MG), β(2)-microglobulin (β(2)-MG), retinol binding protein (RBP), albumin (ALB), 8-hydroxy-2-deoxyguanosine (8-OHdG) and malondialdehyde (MDA). The level of urinary Hg (UHg-C) was calculated as μg/g creatinine. Multiple regression analyses revealed that the excretion of urinary NAG was significantly associated with the presence of dental amalgam fillings (β=0.149, P=0.03) and the levels of UHg-C (β=0.531, P=0), with an interaction between the two (P=0). The increase in urinary NAG in relation to UHg-C levels had a dose-effect pattern. The lowest observed effect was seen at UHg-C levels above 1.452 μg/g creatinine, which is lower than previously reported. In contrast, α(1)-MG was negatively associated with the presence of dental amalgam fillings (β=-0.270, P=0), but positively with UHg-C levels (β=0.393, P=0). There were 7 children without, and one child with, dental amalgam fillings with urinary α(1)-MG levels above the reference limit of >7 mg/g creatinine. Even though α(1)-MG seems to be a reliable biomarker for early changes in renal functions, it might exert its effect only at a higher level of exposure. An inverse relationship was also observed between urinary 8-OHdG levels and the presence of dental amalgam fillings. This might suggest that the dental amalgam does not increase DNA damage but reduces the capacity to repair DNA, leading to lower urinary excretion of 8-OHdG. On the other hand, we found that Hg affected the excretion of urinary 8-OHdG in a dose-related pattern that was mostly associated with long-term exposure to low Hg levels. Urinary NAG levels were positively associated with urinary MDA levels (β=0.516, P=0) but not with 8-OHdG (β=0.134, P=0.078) after adjustment for potential confounders. Both UHg-C and the presence of dental amalgam fillings remained predictors of the NAG model. Our data provide evidence that low exposure to Hg from dental amalgam fillings exerts an effect on kidney tubular functions in children. Oxidative stress may have played a role in this mechanism. The results of this study would also suggest that urinary NAG is the most sensitive of all the investigated renal biomarkers. These results should be confirmed with further investigation.
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Affiliation(s)
- Iman Al-Saleh
- Biological & Medical Research Department, King Faisal Specialist Hospital & Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia.
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Al-Saleh I, Al-Sedairi AA. Mercury (Hg) burden in children: the impact of dental amalgam. THE SCIENCE OF THE TOTAL ENVIRONMENT 2011; 409:3003-3015. [PMID: 21601239 DOI: 10.1016/j.scitotenv.2011.04.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/28/2010] [Revised: 04/23/2011] [Accepted: 04/26/2011] [Indexed: 05/30/2023]
Abstract
The risks and benefits of using mercury (Hg) in dental amalgam have long been debated. This study was designed to estimate Hg body burden and its association with dental amalgam fillings in 182 children (ages: 5-15 years) living in Taif City. Hg was measured in urine (UHg), hair (HHg) and toenails (NHg) by the Atomic Absorption Spectrophotometer with Vapor Generator Accessory system. Urinary Hg levels were calculated as both micrograms per gram creatinine (μg/g creatinine) and micrograms per liter (μg/L). We found that children with amalgam fillings (N=106) had significantly higher UHg-C levels than children without (N=76), with means of 3.763 μg/g creatinine versus 3.457 μg/g creatinine, respectively (P=0.019). The results were similar for UHg (P=0.01). A similar pattern was also seen for HHg, with means of 0.614 μg/g (N=97) for children with amalgam versus 0.242 μg/g (N=74) for those without amalgam fillings (P=0). Although the mean NHg was higher in children without amalgam (0.222 μg/g, N=61) versus those with (0.163 μg/g, N=101), the relationship was not significant (P=0.069). After adjusting for many confounders, the multiple logistic regression model revealed that the levels of UHg-C and HHg were 2.047 and 5.396 times higher, respectively, in children with dental amalgam compared to those without (P<0.01). In contrast, a significant inverse relationship was seen between NHg levels and dental amalgam fillings (P=0.003). Despite the controversy surrounding the health impact of dental amalgam, this study showed some evidence that amalgam-associated Hg exposure might be related with symptoms of oral health, such as aphthous ulcer, white patches, and a burning-mouth sensation. Further studies are needed to reproduce these findings. The present study showed that significant numbers of children with or without amalgam had Hg levels exceeding the acceptable reference limits. The detrimental neurobehavioral and/or nephrotoxic effects of such an increased Hg on children should be a cause of concern, and further investigation is warranted. Our results are alarming and indicate an urgent need for biomonitoring and assessment of exposure. Changes in dental practices involving amalgam, especially for children, are highly recommended in order to avoid unnecessary exposure to Hg.
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Affiliation(s)
- Iman Al-Saleh
- Biological & Medical Research Department, King Faisal Specialist Hospital & Research Centre, PO Box: 3354, Riyadh 11211, Saudi Arabia.
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Mackert JR. Randomized controlled trial demonstrates that exposure to mercury from dental amalgam does not adversely affect neurological development in children. J Evid Based Dent Pract 2010; 10:25-9. [PMID: 20230961 DOI: 10.1016/j.jebdp.2009.11.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
SUBJECTS The study subjects were 507 children (228 females and 279 males) from the Casa Pia school system in Lisbon, Portugal; the same cohort of children used in a previous study. The children were 8 to 12 years old at the time of enrollment in the study, which began in January of 1997. To be included in the study, a child must have had at baseline at least one carious lesion in a permanent tooth, no previous exposure to amalgam treatments, urinary mercury level less than 10 mg/L, blood lead level less than 15 mg/dL, IQ greater than or equal to 67 as obtained with the Comprehensive Test of Nonverbal Intelligence, and no interfering health condition. KEY EXPOSURE/STUDY FACTOR Study subjects were randomly assigned to receive dental treatment with either amalgam or resin-based composite for posterior restorations (and composite for all anterior restorations). By the end of year 1, the participants had a mean of 8.3 surfaces restored with amalgam, and the mean number of surfaces restored varied between 7.7 and 10.7 during the 7 years of follow-up. MAIN OUTCOME MEASURE The primary outcome measures for the study were the presence of neurological hard signs (NHSs), such as tremor, and the presence and severity of neurological soft signs (NSSs), such as synkinesias. NHSs were scored as present or absent. Tremor was reported separately from other NHSs because of its relationship to mercury toxicity. Observation of NSSs did not begin until follow-up year 2, so there were no baseline data for NSSs. NSSs were evaluated using the examination described by Peters et al, and each item was scored from 0 (absent) to 3 (maximum deviation). MAIN RESULTS Over the 7-year duration of the study, there were slight differences in the percentages of subjects exhibiting any NHSs (including tremor, which was reported separately) between the 2 treatment groups, but the directions of the differences were not consistent from year to year, and the differences were not statistically significant in any year. No statistically significant difference in NSSs--either percentage of subjects exhibiting NSSs or NSS severity scores--was observed between the 2 groups in any year. CONCLUSIONS The results of this study demonstrate that exposure to mercury from dental amalgam does not adversely affect neurological development in children.
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Affiliation(s)
- J Rodway Mackert
- Medical College of Georgia, School of Dentistry, Room AD-3273, Department of Oral Rehabilitation, Augusta, GA 30912-1260, USA.
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