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The Cochrane Database of Systematic... Aug 2021Traditionally, 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... (Review)
Review
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searched five bibliographic databases up to 16 February 2021 and used additional search methods to identify published, unpublished and ongoing studies SELECTION CRITERIA: To assess efficacy, we included randomised controlled trials (RCTs) comparing dental composite resin with amalgam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.
Topics: Bias; Child; Composite Resins; Dental Amalgam; Dental Caries; Dentition, Permanent; Humans; Randomized Controlled Trials as Topic
PubMed: 34387873
DOI: 10.1002/14651858.CD005620.pub3 -
Oral Health & Preventive Dentistry Mar 2022The Minamata Convention resulted in restrictions in the use of amalgam in daily dental practice. This opens up new discussions about the biocompatibility of amalgam, but... (Review)
Review
The Minamata Convention resulted in restrictions in the use of amalgam in daily dental practice. This opens up new discussions about the biocompatibility of amalgam, but also of composites as alternative materials. In the following review article, these issues will be discussed in more detail to provide dentists with a knowledge base for themselves and for communication with their patients. In addition to mercury in amalgam or monomers in composites, bisphenol A and nanoparticles generated during the grinding, polishing or removal of restorations must also be included in the biocompatibility evaluation. In laboratory tests, these substances cause toxic reactions, and bisphenol A also exhibits estrogen-like effects. However, it must be taken into account that the concentrations used in laboratory tests are much higher than in clinical practice. Thus, both amalgam and composite can be used in the general population. Nevertheless, for scientifically, politically and legally defined risk groups (e.g. dental personnel, allergic persons, pregnant or lactating women, children under 15 years of age, people with certain systemic diseases), indication restrictions and precautionary measures must be observed. The well-known amalgam discussion has taught us the importance of thorough and open risk communication with the patient.
Topics: Benzhydryl Compounds; Biocompatible Materials; Dental Amalgam; Humans; Mercury; Nanoparticles; Phenols; Risk Factors
PubMed: 35308016
DOI: 10.3290/j.ohpd.b2831749 -
International Journal of Environmental... Mar 2019Mercury (Hg) has been identified as one of the most toxic nonradioactive materials known to man. Although mercury is a naturally occurring element, anthropogenic mercury... (Review)
Review
Mercury (Hg) has been identified as one of the most toxic nonradioactive materials known to man. Although mercury is a naturally occurring element, anthropogenic mercury is now a major worldwide concern and is an international priority toxic pollutant. It also comprises one of the primary constituents of dental amalgam fillings. Even though dental mercury amalgams have been used for almost two centuries, its safety has never been tested or proven in the United States by any regulatory agency. There has been an ongoing debate regarding the safety of its use since 1845, and many studies conclude that its use exposes patients to troublesome toxicity. In this review, we present in an objective way the danger of dental amalgam to human health based on current knowledge. This dilemma is addressed in terms of an integrated toxicological approach by focusing on four mayor issues to show how these interrelate to create the whole picture: (1) the irrefutable constant release of mercury vapor from dental amalgams which is responsible for individual chronic exposure, (2) the evidence of organic mercury formation from dental amalgam in the oral cavity, (3) the effect of mercury exposure on gene regulation in human cells which supports the intrinsic genetic susceptibility to toxicant and, finally, (4) the availability of recent epidemiological data supporting the link of dental amalgams to diseases such as Alzheimer's and Parkinson.
Topics: Dental Amalgam; Humans; Mercury; United States
PubMed: 30909378
DOI: 10.3390/ijerph16061036 -
British Dental Journal Nov 2022Phase out of dental amalgam requires investment in prevention measures, research and development of alternative materials, and effective waste management processes. The...
Phase out of dental amalgam requires investment in prevention measures, research and development of alternative materials, and effective waste management processes. The dental profession is supporting the phase-down of dental amalgam but dentists need the full armoury of dental materials and must be trusted to share decision-making with their patients about clinical choices. Unintended consequences of a rapid global phase-out of dental amalgam must be properly understood before it is universally imposed.
Topics: Dental Amalgam; Dental Restoration, Permanent; Mercury
PubMed: 36434231
DOI: 10.1038/s41415-022-5217-3 -
Journal of Health & Pollution Jun 2019Mercury in dental amalgam is a hidden source of global mercury pollution, resulting from the illegal diversion of dental mercury into the artisanal and small-scale gold... (Review)
Review
BACKGROUND
Mercury in dental amalgam is a hidden source of global mercury pollution, resulting from the illegal diversion of dental mercury into the artisanal and small-scale gold mining sector, to crematoria emissions from the deceased and sewage sludge that is sold to farmers. These significant mercury sources result in air, water, and food contamination that consequently have a negative impact on human health.
OBJECTIVES
The aim of the present study was to investigate and report on all of the various pathways mercury in dental amalgam can enter the environment.
METHODS
The present study searched the electronic data bases of PubMed and Google Scholar. Peer reviewed journals and references of studies included for full-text review were examined for potentially relevant studies. Articles published between 2000 to 2018 were searched and specifically screened for articles that referenced "Dental Amalgam," and the following key words in various combinations: "Minamata Convention on Mercury Treaty," "Sewage Sludge," "Cremation," and "Artisanal and Small-Scale Gold Mining." Data were included on the most populous countries of China, India, the United States, Brazil, and the European Union collectively. We also included data on cremation statistics and current global trends, looking at populations where cremation is a common practice, such as Japan and India.
DISCUSSION
Dental amalgam represents a significant, but understudied area of global mercury pollution that includes cremation, sewage sludge, burial, and small-scale gold mining.
CONCLUSIONS
Mercury used in products and processes, including dental amalgams, is a global pollutant. Even after the last mercury dental amalgam is placed, its toxic legacy will continue for decades, because of its pervasive bioaccumulation in the environment. Government regulatory agencies should make it mandatory to utilize available technologies, not only in developing countries, but also in developed countries, to reduce mercury contamination.
COMPETING INTERESTS
The authors declare no competing financial interests.
PubMed: 31259088
DOI: 10.5696/2156-9614-9.22.190612 -
British Dental Journal May 2022With the phasing down of dental amalgam use in response to the Minamata Convention, it is likely that resin-based composite restoratives will be the dental material of... (Review)
Review
With the phasing down of dental amalgam use in response to the Minamata Convention, it is likely that resin-based composite restoratives will be the dental material of choice for the direct restoration of compromised dentition in the UK, at least for the foreseeable future. The current materials have a finite lifespan, with failures predominately due to either secondary caries or fracture. Consequently, there is considerable in vitro research reported each year with the intention of producing improved materials. This review describes the recent research in materials designed to have low polymerisation shrinkage and increased mechanical properties. Also described is research into materials that are either antimicrobial or are designed to release ions into the surrounding oral environment, with the aim of stimulating remineralisation of the surrounding dental tissues. It is hoped that by describing this recent research, clinicians will be able to gain some understanding of the current research that will potentially lead to new products that they can use to improve patient treatment in the future.
Topics: Composite Resins; Dental Amalgam; Dental Caries; Dental Materials; Dental Restoration, Permanent; Humans
PubMed: 35562465
DOI: 10.1038/s41415-022-4240-8 -
Human & Experimental Toxicology 2022For more than 150 years, dental amalgam fillings (50% metallic mercury (Hg) by weight) have been used in American dentistry. The US Food and Drug Administration (FDA)...
OBJECTIVE
For more than 150 years, dental amalgam fillings (50% metallic mercury (Hg) by weight) have been used in American dentistry. The US Food and Drug Administration (FDA) acknowledged that amalgams release Hg vapor that may be harmful to certain patients. This study examined the impact of Hg vapor exposure from amalgams in American adults.
METHODS
Amalgam-Hg vapor exposure among 158,274,824 weighted-adult Americans was examined in the 2015-2018 National Health and Nutrition Examination Survey (NHANES). Beta (β)-coefficients were calculated for the correlation between the number of amalgam surfaces and daily micrograms (μg) of urinary Hg and daily μg of Hg vapor exposure from amalgams per kilogram (Kg) bodyweight.
RESULTS
About 91 million (57.8%) adults had ≥1 amalgam surface and about 67 million (42.2%) had no amalgams. A β-coefficient = 0.041 significantly correlated the number of amalgam surfaces to daily amounts of urinary Hg. Differences were observed for gender and racial groups. Daily Hg vapor doses from amalgams were in excess of the most restrictive California's Environmental Protection Agency (EPA) safety limit for about 86 million (54.3%) adults and in excess of the least restrictive US EPA safety limit among about 16 million (10.4%) adults. The mean allowable number of amalgam surfaces ranged from 1.28 for adult females under the California's EPA safety limit to 16.23 for adult males under the US EPA safety limit.
CONCLUSION
Given that American adults are receiving significant, ongoing exposure to Hg vapor from amalgams, careful evaluation of the need to reduce use of amalgams should be considered.
Topics: Adult; Dental Amalgam; Female; Gases; Humans; Male; Mercury; Nutrition Surveys
PubMed: 35786065
DOI: 10.1177/09603271221106341 -
British Dental Journal Jan 2017Discusses how dental and medical scares have resulted in a "culture of fear" which has damaged patients and dentists. Forty years of pessimism have created a demoralised...
Discusses how dental and medical scares have resulted in a "culture of fear" which has damaged patients and dentists. Forty years of pessimism have created a demoralised and risk-averse society. The reality of a steadily improving world demands a new attitude of rational optimism and a healthy scepticism about new scares.
Topics: Acquired Immunodeficiency Syndrome; Attitude of Health Personnel; Attitude to Health; Child; Creutzfeldt-Jakob Syndrome; Dental Amalgam; Dental Care for Children; Dentist-Patient Relations; Dentists; Fear; Female; Fluorides, Topical; Health Behavior; Health Knowledge, Attitudes, Practice; Humans; Immunity; Male; Radiography, Dental; Risk Factors
PubMed: 28084346
DOI: 10.1038/sj.bdj.2017.23 -
Swiss Dental Journal 2017Allergen-triggered lichenoid oral mucosa lesions may occur both in oral lichen planus (OLP) and oral lichenoid lesions (OLL). Clinically, OLP and OLL are difficult to...
Allergen-triggered lichenoid oral mucosa lesions may occur both in oral lichen planus (OLP) and oral lichenoid lesions (OLL). Clinically, OLP and OLL are difficult to distinguish from each other. An OLP should be checked by histological examination. Therefore all patients with OLP should be included into a close control interval due to the the potential malignant transformation, whereas in the literature a higher risk of malignancy is attributed to OLL in comparison with OLP. Based on a clinical case, it is demonstrated that an interdisciplinary approach in allergy and mucous diagnosis is necessary to verify the correaltion between a contact allergy to amalgam and the lichenoid mucosal lesions. The subsequent treatment exemplifies the steps of dental therapies with multiple contact allergies to dental materials.
Topics: Biopsy; Dental Amalgam; Dental Restoration, Permanent; Female; Humans; Lichenoid Eruptions; Middle Aged; Mouth Mucosa; Patch Tests; Stomatitis
PubMed: 28134970
DOI: No ID Found -
Frontiers in Oral Health 2023This paper set out to investigate the relationship between teaching and clinical practice of direct posterior restoration placement at tertiary dental institutions in...
INTRODUCTION
This paper set out to investigate the relationship between teaching and clinical practice of direct posterior restoration placement at tertiary dental institutions in South Africa.
METHODS
A cross-sectional study using a mixed methods approach was conducted, and all the South African dental schools were invited to participate. The quantitative phase of the study analyzed the Conservative Dentistry department's records of direct restorations at a single dental school. The number of amalgam and tooth-colored restorations placed by students in the fourth and fifth year of the program from 2004 to 2019 were compared. During the qualitative phase, semi-structured interviews were held with staff from the four dental schools involved with the teaching of direct posterior restorations.
RESULTS
The predominant direct posterior restoration placed in student clinics over a 15-year period at a South African dental school was tooth colored (75%). Teaching times do not correspond to a decrease in the placement of dental amalgam restorations for both one-surface and two-surface posterior restorations and a concomitant increase in the tooth-colored restorations.
DISCUSSION
Academic staff involved in teaching identified that South Africa's ratification of the Minamata Convention has consequences for dental education and training. However, all schools reported that dental amalgam would continue to be taught in the absence of an appropriate alternative.
PubMed: 37539092
DOI: 10.3389/froh.2023.1118361