Dental amalgam and mercury in dentistry

Community social responsibility of continued and appropriate use of silver amalgam as dental restorative material in southern India: A cross-sectional study

Background

For more than 150 years, dental amalgam (DA) has been popular as a dental restorative material. Many organizations oppose its use due to perceived toxicity and environmental concerns. Hence, this study aimed to explore the continued use of DA from a South Indian dental practitioners' perspective.

Methods

This cross-sectional study was conducted among fifty-two private and public dental practitioners of Udupi district in Southern India. A self‑administered questionnaire was distributed, that involved assessment of their preferences, continuation of use and concerns of using DA as a restorative material. The percentage contribution of each variable was calculated. Preferences for continuation of use of silver amalgam based upon the age, experience and mercury toxicity as a risk factor were analyzed using Students-t test and Fisher's Exact Test test.

Results

Most dentists were satisfied (87%) with the results of the DA, found minimal failures (96%) and found DA more economical (89%). More than half (54%) of the participants reported that they would not continue the use of DA owing to mercury toxicity and environmental concerns. Dentists with higher age and longer clinical experience preferred continuation of DA.

Conclusions

Despite satisfaction with DA for its minimal failure, longevity and affordability, the authors found that most practitioners did not prefer its continued usage. This highlights their concerns over mercury toxicity and soft tissue lesions and accentuates their community social responsibility. There is also an urgent need to educate dentists on mercury hygiene, mercury waste management and disposal.

Health complaints before and at one and five years after removal of dental amalgam restorations - data from a prospective cohort study in Norway

OBJECTIVE

Health complaints attributed to dental amalgam fillings comprise both intraoral and general health complaints. There are data suggesting that patients with medically unexplained physical symptoms (MUPS) attributed to amalgam fillings show improvement in symptoms after removal of all amalgam fillings. However, data indicating changes of specific health complaints are limited. This study evaluated the changes of health complaints after removal of amalgam restorations in patients with health complaints attributed to dental amalgam fillings.

METHOD

Patients with MUPS attributed to dental amalgam (Amalgam cohort) had all their amalgam fillings removed. The participants indicated an intensity of 11 local and 12 general health complaints on numeric rating scales before the treatment and at follow-up after 1 and 5 years. The comparison groups comprising a group of healthy individuals and a group of patients with MUPS without symptom attribution to dental amalgam did not have their amalgam restorations removed.

RESULTS

In the Amalgam cohort, mean symptom intensity was lower for all 23 health complaints at follow-up at 1 year compared to baseline. Statistically significant changes were observed for specific health complaints with effect sizes between 0.36 and 0.68. At the 5-year follow-up, the intensity of symptoms remained consistently lower compared to before the amalgam removal. In the comparison groups, no significant changes of intensity of symptoms of health complaints were observed.

CONCLUSION

After removal of all amalgam restorations, both local and general health complaints were reduced. Since blinding of the treatment was not possible, specific and non-specific treatment effects cannot be separated.

Mercury Concentration in Saliva and the Impact of Chewing: An Inductively Coupled Plasma Mass Spectrometry Study

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.

Epidemiology of pediatric schistosomiasis in hard-to-reach areas and populations: A scoping review protocol

Background: Schistosomiasis is a neglected tropical disease (NTD) that affects millions of people. Children are the most vulnerable group to developing overt disease. An estimated 779 million people are at risk of schistosomiasis and 50 million preschool-age children (PSAC) need treatment. PSAC are not currently targeted by national chemotherapy campaigns due to a lack of suitable pediatric formulations of praziquantel. The Pediatric Praziquantel Consortium has developed an orally dispersible praziquantel formulation (arpraziquantel) and is facilitating its adoption for schistosomiasis control by endemic countries through the ADOPT program - an implementation research program that paves the way for the large-scale delivery of the child-friendly formulation to treat schistosomiasis in preschool-aged children in endemic countries. A key challenge for comprehensive NTD control including schistosomiasis is reaching all at-risk populations, including those hard to reach. Main access barriers include geographic, social and economic conditions. Objective : This scoping literature review aims to document the epidemiology of schistosomiasis in children under 6 years of age living in hard-to-reach areas and populations. Methods : This review will adopt the five-stage scoping review process of identifying the research question, identifying relevant studies, study selection, charting data and collating, summarizing and reporting results. Electronic databases including Medline, Web of Science, Embase (Ovid), LILACS and African Journals OnLine (AJOL) will be searched for relevant articles. Two independent reviewers will screen identified articles using a two-stage approach of reviewing the title/abstract and then the full text of provisionally retained articles. Relevant literatures will be downloaded into EndNote X9 to maintain and manage citation and facilitate the overall review process. A meta-analysis will be conducted if indicated. Relevance : The results will provide insights into the burden of schistosomiasis among marginalized PSAC, aiming to produce evidence on the need for inclusion of this population when designing the expansion of preventive chemotherapy programs.

Preparation of fluorescent bimetallic silver/copper nanoparticles and their utility of dual-mode fluorimetric and colorimetric probe for Hg2

A dual-mode colorimetric and fluorimetric probe was successfully established based on silver/copper bimetallic nanoparticles (AgCu-BNPs). The AgCu-BNPs were confirmed as individually bimetallic nanoparticles with a mean size of 7.7 ± 0.2 nm, as characterized by high resolution transmission electron microscopy. Intriguingly, the AgCu-BNPs possess both surface plasmon resonances (SPR) and fluorescence emission. AgCu-BNPs emanate bright blue fluorescence with optical emission centered at 442 nm with high quantum yield of 30.3%, and AgCu-BNPs were attenuated or even quenched by Hg²⁺ via both static and dynamic quenching, coincidently accompanied by a visible color change, which endow AgCu-BNPs a unique utility as dual-mode colorimetric and fluorimetric probes. The detection limits as low as 89 nM and 9 nM were determined by dual-mode of AgCu-BNPs, respectively. The recovery rates in real samples were found to be 97.3-118.8%, and 89.5-112.7% by colorimetric and fluorescent methods separately, demonstrates the good environmental tolerance of the dual-mode probe.

Surface modification of liquid metal as an effective approach for deformable electronics and energy devices

The fields of flexible or stretchable electronics and energy devices, reconfigurable and compliant soft robotics, wearable e-textiles or health-care devices have paid significant attention to the need of deformable conductive electrodes due to its critical role in device performances. Gallium-based liquid metals, such as the eutectic gallium-indium (EGaIn) being an electrically conductive liquid phase at room temperature, have attracted immense interests as a promising candidate for deformable conductor. However, in the case of bulk liquid metal, there are several limitations such as the need of encapsulation, dispersion in a polymer matrix, or accurate patterning. For these reasons, the preparation of liquid metal particles in harnessing the properties in a non-bulk form and surface modification is crucial for the success of incorporating liquid metal into functional devices. Herein, we discuss the current progress in chemical surface modification and interfacial manipulations of liquid metal particles. The physical and chemical properties of the surface modification-assisted liquid metal polymer composite are also reviewed. Lastly, the applications of the surface-modified liquid metal particles such as flexible electrode, soft robotics, energy storage or harvester, thermal conductor, dielectric sensor, and bioelectronics are discussed, and the corresponding perspectives of deformable electronics and energy devices are provided. In particular, we focus on the functionalization method or requirement of liquid metal particles in each application. The challenging issues and outlook on the applications of surface-modified liquid metal particles are also discussed.

Blood and Urine Inorganic and Organic Mercury Levels in the United States from 1999 to 2016

BACKGROUND

Mercury is an environmental hazard. Organic mercury is biologically more toxic than inorganic mercury. Therefore, we studied recent trends in the blood levels of organic and inorganic mercury in the United States.

METHODS

A total of 56,445 participants that had blood mercury and urine mercury measurements in National Health and Nutrition Examination Survey (NHANES) 1999-2016 were included. The organic mercury level was obtained by subtracting the inorganic mercury level from the total mercury level. Results were analyzed using SPSS complex sample module version 25. Pregnant women, children ages <20 years, and different ethnicities were analyzed as subgroups.

RESULTS

Blood organic mercury level increased from (geometric mean [95% confidence interval]) 0.08 [0.07-0.10] to 0.17 [0.16-0.18] µg/L during 1999-2016. It increased significantly (P <0.001) from 0.03 [0.02-0.03] to 0.07 [0.06-0.07] µg/L in children ages <20 and from 0.14 [0.09-0.21] to 0.36 [0.16-0.83] µg/L in pregnant women in this period (P <0.001). In 2013-2016, non-Hispanic Asians had the highest blood organic mercury level among different ethnicities, 0.93 [0.82-1.05] µg/L (P <0.001). Blood inorganic mercury level decreased from 0.31 [0.31-0.31] in 1999-2000 to 0.21 [0.21-0.22] µg/L in 2015-2016 (P <0.001). Urine mercury level decreased from 0.75 [0.71-0.80] in 1999-2000 to 0.16 [0.16-0.17] µg/L in 2015-2016 (P <0.001).

CONCLUSION

Blood organic mercury increased over the period 1999-2016 in the US population, including children and pregnant women, whereas there was a steady decline in both blood inorganic mercury and urine mercury levels.

Mercury in Dental Amalgam, Online Retail, and the Minamata Convention on Mercury

The Minamata Convention on Mercury (ref. 1) is a global treaty to protect human and environmental health from adverse effects of the toxic element mercury and its compounds. During the Third Conference of Parties (COP-3) in November 2019, elimination of the use of dental amalgam in oral health care was discussed. Dental amalgam is one of the most commonly used restorative materials in oral health care due to its strength and longevity (ref. 2). However, the use of mercury in an amalgam adds to global environmental mercury pollution and can contribute to adverse health effects on humans and other organisms. The outcomes of the COP-3 meeting included a call for information on the availability at a national scale, the economic and technical feasibility of alternatives, and the associated risks or benefits. In this feature, we discuss the risks and benefits of dental amalgam, the global tracking of availability and procurement, and the implications and realities for global phase out. We suggest a better accounting of mercury use in dental amalgam is needed with sales being made only to registered practitioners via a Know Your Customer approach.

What German dentists choose for their teeth: A Web-based survey of molar restorations and their longevity

STATEMENT OF PROBLEM

Which restorative material is best suited for treating the posterior molar region is unclear. As dentists presumably choose the most appropriate restoration, German dentists were asked how their own molars were treated.

PURPOSE

The purpose of this survey study was to examine molar restorations and their durability in German dentists.

MATERIAL AND METHODS

In the official journal of the Federal Dental Association, German dentists were asked to participate in an online survey that gathered demographic data and information on the type and durability of their molar restorations. To reduce selection bias, the data were weighted for region, sex, and age of the dentist.

RESULTS

The data set consisted of 1719 molars from 288 dentists. Restorations included gold inlays (25%), composite resin (24.3%), amalgam (11.8%), ceramic inlays (5.4%), glass ionomer cement or compomer (0.8%), gold crowns (21.8%), ceramic crowns (6.6%), and metal-ceramic crowns (4.3%). Notable differences were identified based on the sex, age, and region of the dentist. Women selected increased esthetic options, as did young dentists. Restorations made of gold, amalgam, and base metal had the highest longevity, at more than 20 years CONCLUSIONS: Among German dentists, restorations with metallic materials dominated in molars, with gold accounting for the largest share. In recent years, the proportion of tooth-colored restorations has increased, and in particular, young dentists use composite resin and ceramics.

Rethinking the Dental Amalgam Dilemma: An Integrated Toxicological Approach

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.

Nanoparticles used in dentistry: A review

Nanotechnology is widely used in our day to day life including its use in medicine. Using nanotechnology, it is easy to analyze and manipulate atoms, chemical bonds and molecules present between various compounds. Nanotechnology is used in the dental field as nano dentistry. While choosing the nanoparticle for the use in the field of nano dentistry its chemical, physical, along with the biological aspect of nanostructures are taken into account. Often various atoms or molecules are added to form the functional structure. Nanostructures are used in innovations or diagnosis of dentistry. Some nanoparticles are used for oral disease preventive drugs, prostheses and for teeth implantation. Nanomaterials further deliver oral fluid or drugs, preventing and curing some oral disease (oral cancer) and maintain oral health care up to a high extent. This review summarises the use of various widely used nanoparticle in the field of dentistry.

Mercury exposure in the work place and human health: dental amalgam use in dentistry at dental teaching institutions and private dental clinics in selected cities of Pakistan

During the past two decades, mercury has come under increasing scrutiny with regard to its safety both in the general population and in occupationally exposed groups. It's a growing issue of global concern because of its adverse environmental and health impacts. Very few investigations on mercury amalgam use in the dentistry sector have been carried out in South Asia and there is little data reported on mercury contamination of indoor/outdoor air at dental sites. According to an earlier SDPI study, reported in 2013, alarmingly high mercury levels were observed in air (indoor as well as outdoor) at 11 of the 34 visited dental sites (17 dental teaching institutions, 7 general hospitals & 10 dental clinics) in five main cities of Pakistan. 88% of the sites indicated indoor mercury levels in air above the USA EPA reference level of 300 ng/m3. According to our study, carried out at 38 dental teaching institutions in 12 main cities (in Khyber Pakhtunkhwa, Punjab and Sindh provinces) of Pakistan, respondents were of the opinion that the currently offered BDS curriculum does not effectively guide outgoing dental professionals and does not provide them adequate knowledge and training about mercury/mercury amalgam and other mercury related human health and mercury waste issues. 90% of respondents supported the review and revision of the present dental curriculum offered at dental teaching institutions in the country, at the earliest. A study has also been conducted to assess the status of mercury amalgam use in private dental clinics in Gilgit, Hunza, Peshawar, Rawalpindi and Islamabad. More than 90 private dental clinics were visited and dental professionals/private clinics in-charge were interviewed during June-July, 2015. The focus areas of the study were Hg amalgam toxicity, its waste management practices and safety measures practiced among the dental practitioners. In the light of the findings described and discussed in this brief report, to safeguard public health and for the protection of environment, it is strongly recommended that since mercury amalgam use cannot be banned immediately in the country, its use may be regularized and allowed subject to use of "Amalgam Separators," "Capsulated Mercury" and "Mechanized Mixing," use of mercury amalgam be banned for children (below 12 years age) and pregnant women. The curriculum currently being taught at medical and dental colleges in the country be reviewed and revised, to ensure adequate training towards minimizing mercury exposure.

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.

The Minamata Convention on Mercury: attempting to address the global controversy of dental amalgam use and mercury waste disposal

In October 2013, a new international binding treaty instrument called the Minamata Convention on Mercury opened for signature in Minamata City, Japan, the site of arguably the worst public health and environmental disaster involving mercury contamination. The treaty aims to curb the significant health and environmental impacts of mercury pollution and includes provisions addressing the mining, export and import, storage, and waste management of products containing mercury. Importantly, a provision heavily negotiated in the treaty addresses the use of dental fillings using mercury amalgam, an issue that has been subject to decades of global controversy. Though use of dental amalgam is widespread and has benefits, concerns have been raised regarding the potential for human health risk and environmental damage from emissions and improper waste management. While the Minamata Convention attempts to address these issues by calling for a voluntary phase-down of dental amalgam use and commitment to other measures, it falls short by failing to require binding and measurable targets to achieve these goals. In response, the international community should begin exploring ways to strengthen the implementation of the dental amalgam treaty provisions by establishing binding phase-down targets and milestones as well as exploring financing mechanisms to support treaty measures. Through strengthening of the Convention, stakeholders can ensure equitable access to global oral health treatment while also promoting responsible environmental stewardship.

Human brain mercury levels related to exposure to amalgam fillings

The safety of dental amalgam as the primary material in dental restoration treatments has been debated since its introduction. It is widely accepted that amalgam restorations continuously release elemental mercury (Hg) vapor, which is inhaled and absorbed by the body and distributed to tissues, including the brain. The aim of the present study was to investigate whether the presence of amalgam fillings is correlated with brain Hg level. The Hg levels in the parietal lobes of the brains of 32 cadavers were analyzed with an atomic absorption spectrometer with the mercury hydride system. A total of 32 brain samples were tested; of these, 10 were from cadavers with amalgam fillings, while 22 of them were amalgam free. Hg was detected in 60.0% (6 of 10) of the samples in the amalgam group and in 36.3% (8 of 22) in the amalgam-free group. The average Hg level of the amalgam group was 0.97 ± 0.83 µg/g (minimum: 0.3 µg/g and maximum: 2.34 µg/g), and in the amalgam-free group, it was 1.06 ± 0.57 µg/g (minimum: 0.17 µg/g and maximum: 1.76 µg/g). The results of the present study showed no correlation between the presence of amalgam fillings and brain Hg level.

Human exposure and health effects of inorganic and elemental mercury

Mercury is a toxic and non-essential metal in the human body. Mercury is ubiquitously distributed in the environment, present in natural products, and exists extensively in items encountered in daily life. There are three forms of mercury, i.e., elemental (or metallic) mercury, inorganic mercury compounds, and organic mercury compounds. This review examines the toxicity of elemental mercury and inorganic mercury compounds. Inorganic mercury compounds are water soluble with a bioavailability of 7% to 15% after ingestion; they are also irritants and cause gastrointestinal symptoms. Upon entering the body, inorganic mercury compounds are accumulated mainly in the kidneys and produce kidney damage. In contrast, human exposure to elemental mercury is mainly by inhalation, followed by rapid absorption and distribution in all major organs. Elemental mercury from ingestion is poorly absorbed with a bioavailability of less than 0.01%. The primary target organs of elemental mercury are the brain and kidney. Elemental mercury is lipid soluble and can cross the blood-brain barrier, while inorganic mercury compounds are not lipid soluble, rendering them unable to cross the blood-brain barrier. Elemental mercury may also enter the brain from the nasal cavity through the olfactory pathway. The blood mercury is a useful biomarker after short-term and high-level exposure, whereas the urine mercury is the ideal biomarker for long-term exposure to both elemental and inorganic mercury, and also as a good indicator of body burden. This review discusses the common sources of mercury exposure, skin lightening products containing mercury and mercury release from dental amalgam filling, two issues that happen in daily life, bear significant public health importance, and yet undergo extensive debate on their safety.

Mercury (Hg) burden in children: the impact of dental amalgam

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.

Maternal fish consumption, mercury levels, and risk of preterm delivery

BACKGROUND

Pregnant women receive mixed messages about fish consumption in pregnancy because unsaturated fatty acids and protein in fish are thought to be beneficial, but contaminants such as methylmercury may pose a hazard.

METHODS

In the Pregnancy Outcomes and Community Health (POUCH) study, women were enrolled in the 15th to 27th week of pregnancy from 52 prenatal clinics in five Michigan communities. At enrollment, information was gathered on amount and category of fish consumed during the current pregnancy, and a hair sample was obtained. A segment of hair closest to the scalp, approximating exposure during pregnancy, was assessed for total mercury levels (70-90% methylmercury) in 1,024 POUCH cohort women.

RESULTS

Mercury levels ranged from 0.01 to 2.50 pg/g (mean = 0.29 microg/g; median = 0.23 microg/g). Total fish consumption and consumption of canned fish, bought fish, and sport-caught fish were positively associated with mercury levels in hair. The greatest fish source for mercury exposure appeared to be canned fish. Compared with women delivering at term, women who delivered before 35 weeks' gestation were more likely to have hair mercury levels at or above the 90th percentile (> or = 0.55 microg/g), even after adjusting for maternal characteristics and fish consumption (adjusted odds ratio = 3.0; 95% confidence interval, 1.3-6.7).

CONCLUSION

This is the first large, community-based study to examine risk of very preterm birth in relation to mercury levels among women with low to moderate exposure. Additional studies are needed to see whether these findings will be replicated in other settings.

Visual impairment on dentists related to occupational mercury exposure

A detailed assessment of visual function was obtained in subjects with low-level occupational mercury exposure by measuring hue saturation thresholds and contrast sensitivity functions for luminance and chromatic modulation. General practice dentists (n=15) were compared to age-matched healthy controls (n=13). Color discrimination estimated by the area of Mac Adam ellipses was impaired, showing diffuse discrimination loss. There was also reduction of contrast sensitivity for luminance and chromatic (red-green and blue-yellow) modulation, in all tested spatial frequencies. Low concentrations of urinary mercury (1.97±1.61μg/g creatinine) were found in the dentists group. Color discrimination as well as contrast sensitivity function, assessed psychophysically, constitutes a sensitive indicator of subtle neurotoxic effect of elemental mercury exposure.

Restorative service patterns in Australia: amalgam, composite resin and glass ionomer restorations

AIM

To examine the provision of amalgam, composite resin and glass ionomer restorations, and to assess whether these main restorative services varied by patient, visit and oral health characteristics.

DESIGN

A cross-sectional survey incorporating a log of service items provided on a typical day.

SETTING

Australian private general practice.

METHODS

Data on services and patients were collected by a mailed survey from a random sample of dentists from each State/Territory in Australia in 1998-99 with a response rate of 71%.

MAIN OUTCOME MEASURES

Rates per visit of amalgam, composite resin and glass ionomer restorations among dentate adults who had received a restoration.

RESULTS

Analysis showed older patients had lower amalgam rates but higher glass ionomer rates, composite resin rates were lower at emergency visits, capital city patients had higher amalgam rates but lower composite resin rates, patients with decayed teeth had higher amalgam and composite resin rates, and use of restorative materials varied by clinical problem.

CONCLUSIONS

Despite widespread use of alternative materials, amalgam rates remained high in circumstances such as replacement restorations and restorations involving more than one surface. Other restorative materials also had specific applications. Both amalgam and composite resins were provided at higher rates to patients with active caries but composite resins were also used at higher rates for aesthetic problems. Glass ionomer restorations were used at higher rates for initial and one-surface restorations, and for conditions such as root caries and dentinal sensitivity.

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.