Increased mercury emissions from modern dental amalgams.

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.

Neurological disease or intellectual disability among sons of female Swedish dental personnel.

OBJECTIVE: Prenatal exposure to elemental mercury may be a potential hazard for the offspring of female dental personnel working with dental amalgam. The aim of this study was to investigate whether potential in utero exposure to mercury might have affected the development of nervous system of the sons of Swedish female dental personnel leading to an increased risk of neurological disease or intellectual disability. MATERIAL AND METHODS: We used national Swedish registers to investigate risks for diseases potentially related to adverse effects on neurodevelopment. Sons of female dentists (n=1690) and dental nurses (n=10,420) were compared with cohorts consisting of sons of other female healthcare personnel. Due to changes in mercury exposure in dentistry during the study period, analyses were stratified by decade of birth. Hazard ratios (HRs) were calculated using Cox proportional hazard models. RESULTS: We found no elevated risk for neurological disease, epilepsy or intellectual disability among the sons of dental personnel during any of the decades studied. HRs for neurological disease among the dental nurse cohort were even below 1.00 during the 1970s and 1980s. A low number of events resulted in uncertainty regarding results in the dentist cohort. CONCLUSIONS: We did not find any support for the hypothesis that mercury exposure in Swedish dentistry during the 1960s, 1970s or 1980s had any effect on the incidence of neurological disease or intellectual disability among the sons of female dental personnel. Our results imply that current use of dental amalgam should not represent an elevated risk for neurological disease or intellectual disability among the offspring of dental personnel.

Mortality among sons of female dental personnel--a national cohort study.

AIMS: Dental personnel are exposed to mercury when using dental amalgam. This exposure constitutes a potential hazard to offspring of women working in dentistry. The present study examined increased mortality risk in offspring of mothers working in dentistry. METHODS: Mortality was compared between sons of dental personnel and sons of nondental health-care personnel. Hazard ratios were calculated for three decades (1960s-1980s), when the magnitude of mercury exposure in dentistry was likely to have varied. RESULTS: During the 1960s, there was a statistically significant increase in the risk of neonatal mortality for sons of dental nurses when compared with sons of assistant nurses: hazard ratio (HR) 1.82 (95% confidence interval, CI: 1.04-3.22). There was no increased risk in the subsequent decades, but a trend test demonstrated a consistent decrease in the risk over the three decades: HR for trend 0.63 (95% CI: 0.44-0.90). The raised mortality risk was limited to neonatal mortality. The comparison between dentists and physicians had insufficient statistical power. CONCLUSIONS: There is no increased mortality risk among sons of female dentists after the 1960s. Although the results should be interpreted with caution, they suggest a modestly raised risk of neonatal mortality, during the 1960s, when exposure to mercury was thought to be highest.

Early struggles to identify ethical standards in dentistry: Dr. Benjamin Brown and the amalgam war of the 1840s.

Dr. Benjamin Boyer Brown was one of the leading physicians and dentists in St. Louis during the 1830s and 1840s as well as one of its most esteemed citizens for his charitable and educational works. He was also one of the founders of organized dentistry, first editor of the Dental Register of the West, as well as a respected researcher and educator in dentistry, and a member of the American Society of Dental Surgery, a forerunner of the American Dental Association. This society, declared the use of amalgam to be not only unethical but malpractice, and members were forced to sign a pledge not to use it. Although many dentists opposed this decision and ignored the pledge altogether, Dr. Brown was morally unwilling to remain quiet. He vocally opposed the decision of his colleagues to ban amalgam on ethical grounds. In spite of his appeal for reason and his high profile, he was one of the few dentists to be expelled from organized dentistry. He moved to California during the height of the gold rush to begin a new life. Dr. Brown's experience illustrates several issues in dental ethics that remain with us today.

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.

Characterization of dental fillings found in skulls from individuals buried in San Jeronimos Church, New Spain: historical and archaeological evidences.

Repair of teeth during the XIX century was often a very costly and painful procedure. During this period, restoration of teeth was a procedure limited only to those who could afford such care. In this study we analyzed teeth from a skull sample found in San Jeronimo's Church. The characterization of molar fillings was made with techniques such as X-ray fluorescence, X-ray diffraction and electron microscopy. The purpose of this investigation was to establish technical procedures for analysis, and to discuss the results within the context of the socioeconomic status of these individuals and the written descriptions of the dental practice during the XIX century.

The high-copper dental amalgam alloys.

For many years, the amalgamation of silver with mercury to produce a condensable mixture which could be used to restore carious defects in teeth followed a tortuous path of negative results. However, at the turn of the century, amalgam alloys having acceptable characteristics for successful clinical use emerged. From that point on, silver amalgam was widely accepted as the material of choice for low-cost, easily placed, and durable restorations. About 60 years later, a major discovery occurred that resulted in a most significant improvement in the clinical performance of this material. The key to this improvement was an increase in the Cu content of the amalgam alloy which previously had been considered to be inappropriate. This paper describes the history of this discovery, which produced what has come to be known as high-copper dental amalgam alloys.

Mercury toxicity and dental amalgam.

There is adequate evidence that dental amalgam restorations, during and after placement, results in the release of Hg into the patient's body. Whether the Hg released from amalgam is due to placement procedures, surface abrasion, or later corrosion breakdown, there is evidence that a low level Hg release continues for years. It is generally agreed that if amalgam was introduced today as a restorative material, they would never pass F.D.A. approval. With new and more accurate techniques of measuring Hg levels, especially in tissue and blood, additional studies are necessary to relate blood-Hg levels with dental amalgam restorations. Studies must relate existing restorations as well as the placement of new restorations to body-Hg levels. It is possible that we have accepted a potentially dangerous material as being safe.

Dental mercury--a public health hazard.

The aim of this review is to point out the health hazards of the uncontrolled global use of implanted mercury-leaking dental amalgam fillings. In spite of the pandemic use of amalgam, most dentists and doctors are still ignorant about the levels of mercury exposure and its health implications. This review discusses the following chronically neglected aspects in clinical practice: The use of materials science in calculating the mercury exposure levels, which may exceed the TLVs by an order of magnitude; Microbial dissolution and methylation of mercury from amalgam by oral and intestinal bacteria; Diagnostic problems and effects of chronic mercury exposure with emphasis on intestinal, cardiovascular, mental and neurologic symptoms and disorders; Diagnostic value of faeces--instead of urine examination--as the main indicator of Hg exposure; Lack of control groups unexposed to Hg (amalgam free) for epidemiologic investigations of health problems; Contribution of dental mercury to environmental pollution. In conclusion, a lack of interdisciplinary research and of a critical approach to established clinical routine appears to be the reason for the failure of the dental profession to protect the patient from Hg exposure when saving the tooth.

Amalgam at the new millennium.

Dental amalgam has served as an excellent and versatile restorative material for many years, despite periods of controversy. The authors review its history, summarize the evidence in regard to its performance and offer predictions for the future of this material. For the present, amalgam should remain the material of choice for economical direct restoration of posterior teeth. When esthetic concerns are paramount, tooth-colored materials, placed meticulously, can provide an acceptable alternative.

A grave matter--dental findings of people buried in the 19th and 20th centuries.

The exhumed remains of 181 people, buried during the period 1848-1984 were examined. Because of the carelessness of exhumations, only 125 yielded sufficient information to compare the condition of skulls and jaws with the period in the grave, while 63 yielded information about the teeth. No correlation could be shown between the condition of the skulls and jaws and the period interred, but it was found that the better preserved remains belonged to younger people. Dental findings included the presence of healthy and decayed teeth, gold foil restorations, gold and porcelain inlays, amalgam and silicate fillings, and vulcanite and acrylic dentures. Amalgam restorations were present in people buried from 1875 (114 years ago) and vulcanite dentures from 1882 (107 years ago). The characteristics of the earliest amalgam restorations showed that they could have been placed before 1850. Findings of this study indicate that: (a) one cannot on the appearance of exhumed remains estimate the burial period, (b) dental features were well preserved and can be used for dental identification if antimortem data are available, (c) advanced dentistry could have been practised in South Africa during the last century, and (d) recovery of human skeletal remains from old cemeteries should be undertaken with care to preserve as much information as possible. A plea is made for closer co-operation between developers of old graveyard sites and scientists in order to preserve as much information as possible.

A history of dental amalgam.

OBJECTIVES: Silver amalgam alloy has been used as a dental restorative material since the beginnings of restorative dentistry. It rose as an easily manipulated and low cost material in comparison to other restorative techniques of the time, but it had poor dimensional stability and clinical behavior. Successive research led to the standardization of both its composition and some aspects of its mechanical properties, which have contributed to its widespread acceptance. Nevertheless, the risk of environmental toxicity generated by mercury and its poor esthetics have given rise to the search for alternative and more promising materials. This article endeavors to give a brief historical description of the main events which have led to development of modern silver amalgam alloys. SIGNIFICANCE: It is concluded that extensive knowledge of the use of silver amalgam alloy has made it the most widely used restorative material for the posterior oral cavity. However, in recent years its preponderance has been brought into question even though some innovative ideas have been suggested which could help improve this material in the future.

Amalgama y mercurio. Visión y evolución en la odontología restauradora actual / Amalgam and mercury. Vision and evolution in current restorative dentistry

La amalgama dental ha sido un material restaurador muy confiable, de gran utilidad en la odontología y que, aún con su gran aceptación y amplio uso en la profesión dental, ha presentado siempre muy limitado reconocimiento profesional, por su poca o nula capacidad estética o de color de diente y por las «guerras¼ que ha tenido que librar a través de sus muchos años de vida. El mercurio es un componente importante en la mezcla de la amalgama dental, y su presencia ha sido uno de los factores preponderantes que han causado el detrimento injusto del uso de este material restaurador, que ha demostrado un comportamiento clínico excelente en sus casi 200 años de vida (AU)

Dental amalgam has been a very trustable restorative material, highly utilized in dentistry and although with high acceptance and ample use in the dental profession, it has always had to deal with limited professional acknowledgement due to little or poor esthetic and lack of tooth color and because of the many «wars¼ it has to fight in the many years of life. Mercury is a very important component of the mix in the dental amalgam and its presence has been one of the key factors that has caused the unjustified detriment of the use of this restorative material that has shown an excellent clinical behavior in the almost 200 years of life (AU)