Probably billions of people throughout the world have mercury amalgam fillings in their teeth. Although use of amalgam fillings has been decreasing, particularly in developing countries, it has been estimated that, between 1993 and 2008, about 900 million dental amalgam fillings were inserted in the United States– an average of about 60 million a year.
It is well accepted that the presence of cytokines belonging to the Th1/Th17/Th22 axis of immuno-inflammatory response in the joint environment, such as IL-1β, IL-17 and IL-22, respectively, are associated with pathogenesis of several synovial joint degenerative disorders. During temporomandibular joint osteoarthritis (TMJ-OA), IL-1β and IL-17 have been implicated in the inflammation and resorption of sub-chondral bone; however, the role of Th22 response in the TMJ-OA pathophysiology has not been established. This study aimed to compare the expression of Th1/Th17/Th22-type cytokines, chemokines and chemokine receptors in synovial fluid samples obtained from TMJ-OA or disk displacement with reduction (DDWR) patients. In addition, it aimed to associate these levels with joint pain, imagenological signs of bone degeneration, RANKL production, osteoclastogenesis and osteoclast-induced bone resorption. Higher levels of IL-1β, IL-17 and IL-22 were expressed in TMJ-OA compared with DDWR subjects, and these increased levels significantly correlated with RANKL expression, joint pain and articular bone degeneration. Higher levels of CCR5, CCR6 and CCR7, as well as their respective ligands CCL5 and CCL20, responsible for recruitment of IL-1β, IL-17 and IL-22-producing cells, were over-expressed in TMJ-OA compared with DDWR subjects. Osteoclastogenesis and osteoclast-induced bone resorption were significantly greater in presence of synovial fluid from TMJ-OA compared with DDWR subjects. These data demonstrate that cytokines, CCLs and CCRs associated with the Th1/Th17/Th22 axis of immuno-inflammatory response are involved in TMJ-OA pathogenesis. These findings suggest that IL-22 is involved in the RANKL expression in TMJ-OA, which in turn induces differentiation of osteoclasts and subsequent resorption of sub-chondral bone.
The Minamata Convention on Mercury, with its objective to protect human health and the environment from the dangers of mercury (Hg), entered into force in 2017. The Convention outlines a life-cycle approach to the production, use, emissions, releases, handling, and disposal of Hg. As it moves into the implementation phase, scientific work and information are critically needed to support decision-making and management. This paper synthesizes existing knowledge and examines three areas in which researchers across the natural sciences, engineering, and social sciences can mobilize and disseminate knowledge in support of Hg abatement and the realization of the Convention’s objective: (1) uses, emissions, and releases; (2) support, awareness raising, and education; and (3) impacts and effectiveness. The paper ends with a discussion of the future of Hg science and policy.
Introduction
This study’s purpose is to determine whether nonconsumption of tap water is associated with lower prevalence of elevated blood lead levels and higher prevalence of dental caries in children and adolescents.
Methods
Cross-sectional data from the National Health and Nutrition Examination Survey 2005–2014 recorded drinking water source (n=15,604) and blood lead levels (n=12,373) for participants aged 2–19 years, and dental caries experience for the 2011–2014 subset (n=5,677). The threshold for elevated blood lead level was ≥3 μg/dL. A binary outcome indicated presence or absence of dental caries experience. Multivariable generalized linear models estimated adjusted prevalence ratios with 95% confidence limits.
Results
In analysis conducted in 2017, 15% of children and adolescents did not drink tap water, 3% had elevated blood lead levels ≥3 μg/dL, and 50% had dental caries experience. Children and adolescents who did not drink water were less likely than tap water drinkers to have an elevated blood lead level (adjusted prevalence ratios=0.62, 95% confidence limits=0.42, 0.90). Nonconsumers of tap water were more likely to have dental caries (adjusted prevalence ratios=1.13, 95% confidence limits=1.03, 1.23). Results persisted after adjustment for other covariates and using a higher threshold for elevated blood lead level.
Conclusions
In this nationally representative U.S. survey, children and adolescents who did not drink tap water had lower prevalence of elevated blood lead levels and higher prevalence of dental caries than those who drank tap water.
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.
AUTHORS’ CONCLUSIONS:
There is insufficient evidence to determine the caries-inhibiting effect of slow-release fluoride glass beads. The body of evidence available is of very low quality and there is a potential overestimation of benefit to the average child. The applicability of the findings to the wider population is unclear; the study had included children from a deprived area that had low levels of fluoride in drinking water, and were considered at high risk of caries. In addition, the evidence was only obtained from children who still had the bead attached at 2 years (48% of all available children); children who had lost their slow-release fluoride devices earlier might not have benefited as much from the devices.
Dental implant is being considered successful if the patient is pleased with both of its functional and esthetic outcome. As implant complications (such as peri-implantitis, inappropriate implant position, wrong angulation, and implant location too close to anatomical structures) have been frequently encountered in dental practice, therefore, thorough knowledge to manage such complications is the key prerequisite to prevent the failure of implant. The present case report discussed the etiology, diagnosis of early peri-implantitis, and periodontal abscess with their successful management through periodontal regeneration and diode laser-assisted therapy.
The rising prevalence of autism spectrum disorder (ASD) in recent decades might reflect an increased burden from the synergistic action of new ecotoxicological factors such as aluminum (Al3+), heavy metals, pesticides, fertilizers, endocrine disruptors, and others. ASD pathogenesis is still poorly understood. Although epidemiological studies have identified fluoride (F) as a developmental neurotoxin, F is not included among the ASDrisk factors. Millions of people drink fluoridated tap water for the prevention of tooth decay. Currently, about 500 million people live in endemic areas with high concentrations of F in groundwater and in the biosphere. Endemic fluorosis is a progressive degenerative disease. Comparing the fluorosis pathological symptoms with ASD pathological symptoms supports the view that F might play a role in ASD etiology. Mitochondrial dysfunctions, oxidative stress and inflammation, decreased melatonin levels, and decrease of IQ have been observed in both ASD and endemic fluorosis. It has been estimated that, in the United States of America, the total costs of ASD per year will reach 461 billion USD by the year 2025. This significant burden, which has widespread effects from the personal level to the state economy, can be probably lowered by focusing more on ASD prevention, including the elimination of F.
We review recent progress in our understanding of the global cycling of mercury (Hg), including best estimates of Hg concentrations and pool sizes in major environmental compartments and exchange processes within and between these reservoirs. Recent advances include the availability of new global datasets covering areas of the world where environmental Hg data were previously lacking; integration of these data into global and regional models is continually improving estimates of global Hg cycling. New analytical techniques, such as Hg stable isotope characterization, provide novel constraints of sources and transformation processes. The major global Hg reservoirs that are, and continue to be, affected by anthropogenic activities include the atmosphere (4.4-5.3 Gt), terrestrial environments (particularly soils: 250-1000 Gg), and aquatic ecosystems (e.g., oceans: 270-450 Gg). Declines in anthropogenic Hg emissions between 1990 and 2010 have led to declines in atmospheric Hg0 concentrations and HgII wet deposition in Europe and the US (- 1.5 to – 2.2% per year). Smaller atmospheric Hg0 declines (- 0.2% per year) have been reported in high northern latitudes, but not in the southern hemisphere, while increasing atmospheric Hg loads are still reported in East Asia. New observations and updated models now suggest high concentrations of oxidized HgII in the tropical and subtropical free troposphere where deep convection can scavenge these HgII reservoirs. As a result, up to 50% of total global wet HgII deposition has been predicted to occur to tropical oceans.
Scientific research on Hg transport and fate in the environment and risk to human and wildlife health is growing at a time when international and national policy approaches are needed and being formulated (Evers et al. 2016; Sunderland et al. 2016). The time is optimal for translating the science of Hg pollution and providing guidance to policymakers so that decisions made under the Minamata Convention and national and local efforts to control and mitigate Hg releases and limit exposure can be based on the most rigorous and current scientific research. These four synthesis papers represent collective findings of the international Hg science and policy communities. They will provide a basis in the coming years for developing policy to minimize environmental effects and exposures of Hg.