Dentists' restorative decision‐making and implications for an ‘amalgamless’ profession. Part 1: a review

The Minamata Convention has agreed to a worldwide reduction and ultimate elimination in the production and use of mercury containing products. This will have implications for the practice of dentistry. Australian organizations' pronouncements on the issue are limited and research examining the Australian context dated. The restoration of teeth with direct materials has changed significantly since the 1980s. Up to this time amalgam was the material of choice for direct posterior restorations. Its properties and guidelines for placement were, and remain, well established. Resin composite has replaced amalgam as the material of choice in many clinical situations. Despite inherent clinical disadvantages compared to amalgam, there continues to be a shift toward greater use of resin composite. There is consensus worldwide that the restoration of posterior teeth using resin composite now exceeds that of amalgam. The reasons for this are reviewed in this article along with current evidence and commentary relating to direct restorative and evidence‐based decision‐making, minimally invasive approaches, and approaches to education. The implications for these in an ‘amalgamless’ profession are identified.     

Community dental officers' use and knowledge of restorative techniques for primary molars: an audit of two Trusts in Wales

Objective. A baseline audit of current levels of knowledge about, and use of, restorative techniques in children’s primary molars. Design. A survey of community dental officers. Setting. Two large Trusts in Wales. Sample. Eighteen dental officers (five from Trust A and 13 from Trust B) from a total of 23 (six from Trust A and 17 from Trust B). Outcome measures. Dental officers’ use of restorative materials in primary molars. Dental officers’ participation in postgraduate training for restorative techniques. Dental officers’ consideration of the research literature on ‘best practice’ in restorative techniques. Results. Dental officers in these two Trusts were not using stainless steel crowns (SSCs) for restoring primary molars. All 18 dental officers reported using glass ionomer cement (GIC) and amalgam as restorative materials, whilst six reported using GIC exclusively. Only 11 dentists mentioned using stainless steel crowns and this was in conjunction with carrying out a pulpotomy. Fewer dentists had been taught to use GIC than either SSCs or amalgam for restoring primary teeth during undergraduate training. A hands‐on, user‐friendly, postgraduate training course is considered the most effective way of teaching dentists about restorative techniques. The research evidence on SSCs did not appear to influence these dental officers in their use of restorative materials. Conclusions. This study offers important baseline data about the acceptability of differing restorative techniques and about the type of intervention that could bring about change in pattern of use by community dental officers in two large Trusts in Wales. If a postgraduate course in the use of stainless steel crowns is to meet dental officers’ needs, it should address their concerns about the use of crowns.     

A comparative life cycle assessment of dental restorative materials

ObjectivesDifferent types of direct-placement dental materials are used for the restoration of structure, function and aesthetics of teeth. The aim of this research investigation is to determine, through a comparative cradle-to-gate life cycle assessment, the environmental impacts of three direct-placement dental restorative materials (DRMs) and their associated packaging.MethodsThree direct-placement dental materials; dental amalgam, resin-based composite (RBC) and glass polyalkenoate cements (GIC) are assessed using primary data from a manufacturer (SDI Limited, Australia). The functional unit consisted of ‘one dental restoration’ of each restorative system under investigation: 1.14 g of dental amalgam; 0.25 g of RBC (plus the adhesive = 0.10 g); and 0.54 g of GIC. The system boundary per restoration included the raw materials and their associated packaging materials for each DRM together with the processing steps for both the materials and packaging. The environmental impacts were assessed using an Egalitarian approach under the ReCiPe method using Umberto software and the Ecoinvent database. Nine different impact categories were used to compare the environmental performance of these materials.ResultsDental amalgam had the highest impact across most of the categories, but RBC had the highest Global Warming Potential. The highest sources of the environmental impacts for each restorative material were: Amalgam, derived from material use; RBC, derived from energy use in processing material and packaging material; GIC, derived from material and energy use for packaging.SignificanceLess intensive energy sources or more sustainable packaging materials can potentially reduce the impacts associated with RBC and GIC thus making them suitable alternatives to dental amalgam.     

Amalgam: Its history and perils

The current amalgam issue is not new. In the 1840s, there was even an "amalgam war" between the dentists who advocated the use of gold as a restorative material and those who used silver amalgam as a filling material. There were complaints of the ill effects of mercury in the amalgam as a health problem. The split on this issue threatened to divide dentistry into two camps: those who used amalgam and those who condemned it. The first national dental society in the United States, the American Society of Dental Surgeons, had to disband because of the controversy. There was even a "New Departure" movement in the 1880s to eliminate gold as a restorative material in badly broken down teeth, which could be more readily salvaged by the use of material that did not require the force of condensation needed to pack a gold foil, then considered the ultimate restorative material. However, amalgam has proven to be an excellent restorative material with few side effects--amalgam saves teeth.     

Dental amalgam and human health

The use of dental amalgam as a restorative material has long been a contentious issue because of its elemental mercury component. While microleakage of mercury from amalgam has been conclusively confirmed over the past 30 years intensive research has failed to identify deleterious health outcomes. Mercury, as with other metals entering the body tissues, appears to be tolerated at low levels. Nevertheless, a contrary opinion is held by some professional and lay groups who advocate a zero tolerance for inhaled or ingested elemental mercury. They identify dental amalgam as an aetiological factor for neurological conditions such as chronic fatigue syndrome, multiple sclerosis and Alzheimer's disease resulting from chronic mercury poisoning. Epidemiological and clinical evidence of widespread chronic mercury toxicity associated with a body burden of amalgam has consistently failed to be established even in populations with a high prevalence of dental amalgam restorations. On current evidence, international consensus heavily supports the statement that amalgam does not constitute a health risk to patients. However, exposure to volatile free mercury in dental clinics should be controlled to eliminate occupational risk. This paper provides a general review of the current situation and issues. It offers a consensus viewpoint for practitioners and lay people in reaching an informed decision on dental amalgam restorations.     

Controversy of silver amalgam as a restorative material

Silver amalgam contains mercury leading to concerns about the potential toxic effects of amalgam on the health of dental patients. The debate over the toxicity of silver amalgam restorations has divided the dental profession for over a century. The use of amalgam restorations for anterior teeth have been declining worldwide due to patient’s safety concerns and preference for tooth colored restorations. Nevertheless, amalgam has served the dental profession for decades and benefited hundreds of millions of patients because of its longevity as a dental restorative material. Amalgam is still the World’s most widely used restorative material for posterior teeth.     

Dental amalgam: regulating its use and disposal

Although dental amalgam has been a restorative material for more than 150 years, government regulation of its use and disposal came much later with the creation of new federal laws and agencies. None of the federal laws regulating dental amalgam today were written specifically to regulate amalgam. Instead, these new laws and agencies were created to address broad public safety concerns, where little or no regulation existed before, in the areas of medical devices and drugs and environmental pollution. It is the interpretation and implementation of environmental laws that recently have had the greatest impact on dental practices.     

The post-amalgam era: a selection of materials and their longevity in the primary and young permanent dentitions

Summary. Objectives. During the last decade there has been a rapid change in the selection of dental restorative materials as the use of amalgam has decreased. The aim of this study was to obtain information on children's restorative dental care in Finland and to analyse the longevity of failed restorations. Design. A random sample of public dental health care centres was drawn from the registers and the dentists working there were asked to record information for each restoration they placed during a three‐day period. The survey data comprised a total of 2186 restorations in patients younger than 17 years. Results. Of the children in need of restorative treatment, only a few had previous amalgam restorations. Primary caries was the main reason for restorative treatment in both primary and permanent dentitions (80% and 83%, respectively). In primary teeth, the most common restorative material was resin‐modified glass ionomer cement (57·4%), whereas in permanent teeth, composite resin dominated (58·7%). Amalgam was not used at all in the primary dentition and in only 0·6% of permanent teeth. Eighteen per cent of treatments in primary and 12% in permanent teeth were replacements of previous fillings. The mean age of failed glass ionomer restorations was 2·8 years (n = 101) in the primary dentition, and 3·5 years (n = 54) in the permanent dentition. Conclusions. Until better restorative materials are developed, more attention should be paid to the prevention of dental caries as well as to the proper handling of alternative materials.     

Amalgam--resurrection and redemption. Part 2: The medical mythology of anti-amalgam.

Mercury-containing amalgam restorative material has come under attack for its alleged harmful effects on systemic health. A literature search revealed that amalgam restorations release small quantities of mercury but apparently not enough to cause systemic health problems. Mercury from dental amalgam restorations cannot be linked to kidney damage, Alzheimer's disease, multiple sclerosis, other central nervous system diseases, "amalgam disease," mental disorders, damage to the immune system, increases in antibiotic resistance, or harmful reproductive effects. Dentists occupationally exposed to mercury have not been shown to suffer harmful reproductive or other systemic health effects, provided proper mercury hygiene is used. There are legitimate health concerns about alternative restorative materials, including resin composite. According to the latest scientific information available, dental amalgam remains a safe and effective restorative material.     

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.     

Assessing short and long‐term educational impact of visits to hospice via a combination of qualitative methods

While qualitative methods have gained considerable recognition in medical education research, employing multiple qualitative data sources in assessing long‐term educational impact is rare. Utilising in‐depth data analysis method to six cross‐sectional cohorts (2004–2009) of students’ reflection papers (n = 213), this article demonstrates how students experienced subtle but important shifts in their attitudes (including personal, professional and spiritual domains) after making field visits to a hospice centre as part of the Special Needs Dentistry module. For retrospective assessment of learning retention, a pilot focus group was conducted with three junior faculty members who participated in the field visits to a hospice during their own undergraduate training. A subsequent focus group was conducted with graduates of the 2008 (n = 8) cohort using a refined discussion guide arising from the analysis of pilot group results. Graduates were unanimous in stating that the visits had sown ‘seeds’ in their minds and hearts, seeds which started to grow after they completed dental school and began to practice. This is demonstrative of the long‐term positive educational impact of the pedagogical design that entailed a special site visit coupled with post‐visit debrief and written reflection.     

牙科银汞合金安全性问题的现状

由于牙科银汞合金性能优良，使用方便，以及费用低廉，在近150多年来已成为最常用的补牙材料。然而长期以来，对于银汞合金的安全性问题一直有所争议。本文将重点分析和讲座近年来发表的有关银汞合金安全性的主要文献。现有的科学资料表明，使用操作不当是银汞合金对牙科专业人员健康的主要危险因素；应用新技术现已可测出银汞合金修复体在口腔内释放的微量汞。但至今尚未有任何证据能确定这些来自银汞合金修复体的微量汞会对人体健康造成伤害。因此，银汞合金仍可被认为是安全和有效的补牙材料，除非今后有新的不同的研究结果，目前似无必要停止使用牙科银汞合金。     

The relationship of metals to the general health of the patient, the dentist and office staff

Recently a few dental practitioners have asserted that some of the metallic dental restorative materials can be toxic to patients. In particular, nickel from base-metal casting alloys and mercury from silver amalgam have been implicated. Nickel is a strong allergen and a weak carcinogen. However, current evidence does not support the view that the making and use of base-metal cast restorations causes an increased incidence of either of these problems in dental personnel or in patients. Mercury rarely causes allergy but the possibility of such an event must be remembered. Mercury has a strong potential for causing chronic toxicity. Dental personnel must use caution in the handling of free mercury in the process of making amalgam restorations. There is evidence that mercury can be released from dental amalgam restorations, but only in very small quantities. Except for the claims of those practitioners who decry the use of dental amalgam, there is no evidence to support the view that there is a toxic hazard to patients who have amalgam restorations.     

A multi‐country comparison of reasons for dental non‐attendance

The purpose of this study was to describe differences across countries with respect to the reasons for dental non‐attendance by Europeans currently 50 yr of age and older. The analyses were based on retrospective life‐history data from the Survey of Health, Ageing, and Retirement in Europe and included information on various reasons why respondents from 13 European countries had never had regular dental visits in their lifetime. A series of logistic regression models was estimated to identify reasons for dental non‐attendance across different welfare‐state regimes. The highest proportion of respondents without any regular dental attendance throughout their lifetime was found for the Southern welfare‐state regime, followed by the Eastern, the Bismarckian, and the Scandinavian welfare‐state regimes. Factors such as patients’ perception that regular dental treatment is ‘not necessary’ or ‘not usual’ appear to be the predominant reason for non‐attendance in all welfare‐state regimes. The health system‐level factor ‘no place to receive this type of care close to home’ and the perception of regular dental treatment as ‘not necessary’ were more often referred to within the Southern, Eastern, and Bismarckian welfare‐state regimes than in Scandinavia. This could be relevant information for health‐care decision makers in order to prioritize interventions towards increasing rates of regular dental attendance.     

Understanding the mercury reduction issue: the impact of mercury on the environment and human health

Mercury has been used in both medicine and dentistry for centuries. Recent media attention regarding the increased levels of mercury in dietary fish, high levels of mercury in air emissions, and conjecture that certain diseases may be caused by mercury exposure has increased public awareness of the potential adverse health effects of high doses of mercury. Dentistry has been criticized for its continued use of mercury in dental amalgam for both public health and environmental reasons. To address these concerns, dental professionals should understand the impact of the various levels and types of mercury on the environment and human health. Mercury is unique in its ability to form amalgams with other metals. Dental amalgam--consisting of silver, copper, tin, and mercury--has been used as a safe, stable, and cost-effective restorative material for more than 150 years. As a result of this use, the dental profession has been confronted by the public on two separate health issues concerning the mercury content in amalgam. The first issue is whether the mercury amalgamated with the various metals to create dental restorations poses a health issue for patients. The second is whether the scraps associated with amalgam placement and the removal of amalgam restorations poses environmental hazards which may eventually have an impact on human health. Despite the lack of scientific evidence for such hazards, there is growing pressure for the dental profession to address these health issues. In this article, the toxicology of mercury will be reviewed and the impact of amalgam on health and the environment will be examined.     

Non‐stick properties of thin‐film coatings on dental‐restorative instruments

The non‐stick properties of thin‐film coatings on dental‐restorative instruments were investigated by static contact‐angle measurement using dental filler resin as well as by scanning electron microscopy of the amount of sticking dental restorative material. Furthermore, using a customized dipping measurement set‐up, non‐stick properties were evaluated by measuring force‐by‐time when the instrument was pulled out of restorative material. Minor improvements in non‐stick properties were obtained with commercial diamond‐like carbon and commercial polytetrafluoroethylene‐based coatings. Major improvements were obtained with an in‐house fabricated superhydrophobic coating prepared by a multistep process consisting of surface microstructuring by etching in hydrogen fluoride (HF): hydrogen peroxide (H₂O₂) (1:1; vol/vol), atomic layer deposition of a 7 nm coating of aluminium oxide and titanium oxide, and a self‐assembled monolayer of fluorinated organosilicon. Superhydrophobic coatings provide a possible future solution to prevent unwanted adnerence of composite restorative material to dental instruments.     

Dental materials for posterior restorations

Abstract Assessment of the quality of dental restorations by the Ryge system is described. Generally, the quality of dental restorations is shown to be dependent on the technique sensitivity of the restorative material as well as the skill and experience of the dentist. Concerning biocompatibility, adverse reactions related to amalgam restorations are unlikely or scarce, due to small amounts of released mercury. Resin based restorative materials contain a large number of organic compounds and, as such, the toxic and allergenic potentials are unknown. Gold and ceramics turn out to be the most biotolerable dental materials. Based on studies on longevity, data indicate that the median age of amalgam restorations is 10-12 years, of gold castings 13-14 years and more, and of composite restorations 4 years. Data on longevity of ceramic restorations are sparse. Secondary caries appears to be the most frequent cause for replacement of the different restorations, followed by marginal degradation. Secondary caries account for more failures among the resin based restorations than among amalgam. Reviewing the literature, it appears that amalgam is the best and most economic dental material for routine posterior restorations with reasonable durability. Gold is recommended for complex restorations. Resin based composites may be limited to small restorations where cosmetics is the main aspect, as wear and recurrent caries are main problems. Ceramic restorations comprise aesthetic restorations with excellent bio-compatibility, however, data on longevity and marginal adaptation are not encouraging.     

Using packable composites for direct posterior placement

BACKGROUND: Although dentists have been using resin-based composites successfully to restore posterior teeth in Class II situations for several years, creating a functional, anatomical proximal contact remains a clinical challenge for many clinicians. OVERVIEW: This article presents a step by-step technique for creating a predictable proximal contact using a packable resin-based composite as the restorative material. Using a technique that is similar to that for amalgam will enable the dentist to make a successful transition to using composite as an alternative to amalgam in some posterior teeth. PRACTICE IMPLICATIONS: More patients today are well-informed about dental care and are seeking tooth-colored restorative alternatives. Excellent materials and proven techniques are making the transition from traditional metallic restorations easier and more predictable. With this article, the authors aim to help dentists gain confidence in their technique and enable them to provide this service for their patients.