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

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.

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

The impact of dental amalgam on the development of Parkinson's disease (PD) is still uncertain, although a positive association between dental amalgam and PD has been found in a few case-control studies. The patients with amalgam fillings restored between 2000 and 2008 were identified by using the National Health Insurance Research Database (NHIRD) in Taiwan. The same number of patients who had no new amalgam filling restored was matched by sex, age, and treatment date. Both cohorts were followed up from the treatment date until the date of diagnosis of PD, death, or the end of the year 2008. The individuals who received amalgam fillings had a significantly higher risk of PD afterward (adjusted hazard ratio [HR]=1.583, 95% confidence interval [CI]=1.122-2.234, p=0.0089) than those who did not. In the individuals who received amalgam fillings, being diagnosed with diabetes or hyperlipidemia demonstrated a significantly lower HR of PD occurrence than in the patients without diabetes or hyperlipidemia (HR=0.449, 95% CI=0.254-0.794, p=0.0059; HR=0.445, 95% CI=0.260-0.763, p=0.0032) after adjusting for comorbidities and Charlson-Deyo Comorbidity Index (CCI) scores. Meanwhile, hypertension increased the hazard risk of PD (HR=1.645, 95% CI=1.098-2.464, p=0.0159). The patients exposed to dental amalgam fillings were 1.583 times more likely to have PD afterward compared to their non-exposed counterparts after adjusting for comorbidities and CCI scores.

Oral health is a neglected area of global health, although oral disease is one of the most common public health issues worldwide. Despite advances in modern dentistry, untreated dental caries in permanent teeth was reported as the most prevalent of the 328 conditions assessed in 2016 Global Burden of Disease Study. The restorative model for managing dental caries was developed in the 1900s, alongside dental amalgam as one of the restorative materials commonly used to treat dental caries. Together they still provide the backbone of oral health services in most countries today. A shift away from the restorative model and the widespread use of dental amalgam was perhaps unimaginable even a decade ago, despite the World Health Organization (WHO) calling for oral health to be incorporated into policies for the integrated prevention and treatment of chronic noncommunicable and communicable diseases, and into maternal and child health policies. The Minamata Convention on Mercury (2013) is an international legally binding treaty that aims to protect the human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. The convention addresses mercury-added products, including dental amalgam, which is made of approximately 50% of elemental mercury by weight, and proposes nine measures to phase down the use of dental amalgam. These measures show the interconnected and interdependent nature of phasing down dental amalgam, and reinforce the need for a multipronged approach as called for by WHO. The implementation of the convention and its provision for dental amalgam can catalyse the shift away from the restorative model of care and the use of mechanically retained filling materials, such as dental amalgam, towards preventive and minimal intervention dentistry that predominantly uses adhesive dental materials. Implementation will also provide an opportunity to strengthen oral health promotion and oral disease prevention within an integrated, people-centred model of health services.

A set of high-copper amalgam alloys have been prepared based on the change in the ratio of copper to silver using elemental components of high purity 99.9%. The amalgamation processes were done by mixing alloy powders with mercury at a fixed ratio. Structural properties were studied using X-ray diffraction and Optical Microscopy. Also, microhardness, and compressive strength were used to study some other important mechanical properties. The prepared amalgams were compared with well-known commercial amalgams; ANA 2000 and Standalloy F. The results of X-ray diffraction showed several prime phases in alloys and amalgams whose proportions and distribution depended on the copper content in the alloy. The results of mechanical test measurements showed a linear increase in the mechanical properties with increasing copper content in the amalgams. The results were similar to the measured values of the commercial amalgam.

Background: Urinary mercury concentrations are widely used as a measure of mercury exposure from dental amalgam fillings. No studies have evaluated the relationship of these measures in a longitudinal context in children. Objective: We evaluated urinary mercury in children 8-18 years of age in relation to number of amalgam surfaces and time since placement over a 7-year course of amalgam treatment. Methods: Five hundred seven children, 8-10 years of age at baseline, participated in a clinical trial to evaluate the neurobehavioral effects of dental amalgam in children. Subjects were randomized to either dental amalgam or resin composite treatments. Urinary mercury and creatinine concentrations were measured at baseline and annually on all participants. Results: Treatment groups were comparable in baseline urinary mercury concentration (~ 1.5 µg/L). Mean urinary mercury concentrations in the amalgam group increased to a peak of ~ 3.2 µg/L at year 2 and then declined to baseline levels by year 7 of follow-up. There was a strong, positive association between urinary mercury and both number of amalgam surfaces and time since placement. Girls had significantly higher mean urinary mercury concentrations than boys throughout the course of amalgam treatment. There were no differences by race in urinary mercury concentration associated with amalgam exposure. Conclusions: Urinary mercury concentrations are highly correlated with both number of amalgam fillings and time since placement in children. Girls excrete significantly higher concentrations of mercury in the urine than boys with comparable treatment, suggesting possible sex-related differences in mercury handling and susceptibility to mercury toxicity.

Background and Objectives: Prolonged contact between oral mucosa and dental amalgam restorations may influence local epithelial homeostasis, but the remodeling profile of clinically non-dysplastic mucosa exposed to long-standing amalgam remains insufficiently characterized. This study aimed to evaluate histopathological changes and CK19, Ki67, and p53 expression in the oral mucosa adjacent to long-term amalgam restorations. Materials and Methods: A retrospective observational analysis was performed on 108 oral mucosal specimens, including 78 samples in direct contact with amalgam restorations and 30 non-exposed controls. Exposed cases were grouped according to contact duration: 5–10 years, 11–20 years, and ≥21 years. Histopathological parameters and immunohistochemical expression of CK19, Ki67, and p53 were semi-quantitatively assessed, and an exploratory Integrated Epithelial Remodeling Score was calculated. Results: Longer amalgam exposure was significantly associated with increased inflammatory infiltrate, basal hyperplasia, acanthosis, fibrosis, suprabasal CK19 redistribution, and higher Ki67 labeling indices. The Integrated Epithelial Remodeling Score differed significantly among exposure groups, with higher values in intermediate- and long-duration exposure categories. p53 expression showed statistically detectable but heterogeneous variation. No epithelial dysplasia was observed. Conclusions: Long-term contact with dental amalgam restorations was associated with a coordinated, non-dysplastic remodeling phenotype of the oral mucosa. Given the age imbalance across exposure duration groups, these findings should be interpreted as exposure-associated patterns rather than evidence of a direct causal effect. Because no comparison group exposed to other restorative materials was included, material-specificity for dental amalgam cannot be inferred. In architecturally preserved mucosa, suprabasal CK19 expression may reflect adaptive epithelial plasticity rather than preneoplastic transformation.

Dental amalgam remains a reliable posterior restorative material in many settings despite global mercury phase-down policies. This study evaluates CaF₂-modified high-copper dental amalgam within a controlled composition window (0.5–3.0 wt%) using an integrated microstructure–property–release approach, while maintaining specimen integrity. Phase constitution and microstructural features were characterized by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive spectroscopy (SEM-EDS), and Fourier-transform infrared spectroscopy (FTIR), and correlated with American Dental Association (ADA)-standard physicomechanical metrics (dimensional change, compressive strength, hardness, and creep) and with Hg and F⁻ release under the present in-vitro conditions. One-way analysis of variance (ANOVA) with Holm correction was used for physicomechanical endpoints (α = 0.05). XRD confirmed retention of the characteristic set-amalgam phases (γ1–Ag₂Hg₃ and η–Cu₆Sn₅) and showed CaF₂ reflections, with no additional reaction-derived crystalline phases detected within the instrument’s detection limits. Compressive strength and hardness increased with CaF₂ content, while dimensional change and creep decreased, yielding the best overall load-bearing response at 3 wt% CaF₂. Mercury release was lowest at 0.5 wt% CaF₂ (0.0326 ppb; ~99.2% lower than the master alloy, M) under the present protocol. At 3 wt% CaF₂, Hg release approached the SG43 reference. Fluoride release varied with composition. Overall, CaF₂ enables tailoring a practical balance between mechanical performance and Hg/F⁻ release, depending on the targeted clinical priority.