Dental devices: classification of dental amalgam, reclassification of dental mercury, designation of special controls for dental amalgam, mercury, and amalgam alloy; technical amendment. Final rule; technical amendment.

The Food and Drug Administration (FDA) published a final rule in the Federal Register of August 4, 2009 (74 FR 38686) which classified dental amalgam as a class II device, reclassified dental mercury from class I to class II, and designated special controls for dental amalgam, mercury, and amalgam alloy. The effective date of the rule was November 2, 2009. The final rule was published with an inadvertent error in the codified section. This document corrects that error. This action is being taken to ensure the accuracy of the agency's regulations.

Dental devices: classification of dental amalgam, reclassification of dental mercury, designation of special controls for dental amalgam, mercury, and amalgam alloy. Final rule.

The Food and Drug Administration (FDA) is issuing a final rule classifying dental amalgam into class II, reclassifying dental mercury from class I to class II, and designating a special control to support the class II classifications of these two devices, as well as the current class II classification of amalgam alloy. The three devices are now classified in a single regulation. The special control for the devices is a guidance document entitled, "Class II Special Controls Guidance Document: Dental Amalgam, Mercury, and Amalgam Alloy." This action is being taken to establish sufficient regulatory controls to provide reasonable assurance of the safety and effectiveness of these devices. Elsewhere in this issue of the Federal Register, FDA is announcing the availability of the guidance document that will serve as the special control for the devices.

The food and drug administration agrees to classify mercury fillings.

In the United States Court of Appeals of the District of Columbia Circuit, the Appellants Mom's Against Mercury, Connecticut Coalition for Environmental Justice, Oregonians for Life, California Citizens for Health Freedom, Kevin J. Biggers, Karen Johnson, Linda Brocato, R. Andrew Landerman, and Antia Vazquez Tibaul filed a petition for review of Regulatory Inaction by the Food and Drug Administration (FDA). On Monday June 2, 2008, the lawsuit was settled with the FDA after it agreed to classify mercury fillings. During its negotiation session with the Appellants, the FDA indicated that it would change its website on mercury fillings. The FDA no longer claims that no science exists about the safety of mercury amalgam or that other countries have acted for environmental reasons only. On its website, the FDA now states the following: "Dental amalgams contain mercury, which may have neurotoxic effects on the nervous systems of developing children and fetus." The FDA also states that "Pregnant women and persons who may have a health condition that makes them more sensitive to mercury exposure, including individuals with existing high levels of mercury bioburden, should not avoid seeking dental care, but should discuss options with their health practitioner." The FDA decision to classify mercury fillings is a reflection of the legislations enacted in Europe and Canada that highlight the neurotoxic effects of mercury fillings.

Cellular responses to dental amalgam in vitro.

Cytotoxicity of fine cut amalgam was persistent until 24 hours after trituration in vitro, whereas cytotoxicity of spherical amalgam diminished more quickly. Increasing mercury content in spherical amalgam increased cytotoxicity. Possible reactions for the diminution of cytotoxicity of amalgams with time are discussed.

New direct restorative materials. FDI Commission Project.

People worldwide have become increasingly aware of the potential adverse effects on the environment, of pollution control and of toxic effects of food, drugs and biomaterials. Amalgam and its potential toxic side effects (still scientifically unproven) continue to be discussed with increasing controversy by the media in some countries. Consequently, new direct restorative materials are now being explored by dentists, materials scientists and patients who are searching for the so-called 'amalgam substitute' or 'amalgam alternative'. From a critical point of view some of the new direct restorative materials are good with respect to aesthetics, but all material characteristics must be considered, such as mechanical properties, biological effects, and longterm clinical behaviour.

Works in progress: a comparison of dental school experiences between passing and failing NERB candidates, 2001.

The purpose of this report is to compare outcomes on the North East Regional Board of Dental Examiners (NERB) clinical examination to selected measures of academic performance in one U.S. dental school. The data came from results of the spring 2001 NERB examination at that school. Five measures of academic performance--number of Class II amalgam restorations completed, number of Class III/IV composite restorations completed, fixed prosthodontic units performed, fourth-year class rank, and GPA-were compared between those who passed and those who failed NERB's restorative exercise (RESTOR) and provisional fixed partial denture exercise (SIM). Analyses could not confirm a positive relationship between the school performance measures and the NERB outcome of passing RESTOR on the first attempt. On the other hand, those who passed SIM on the first attempt had, on the average, performed more amalgams, composites, and fixed prosthodontic units as students than those who failed; they also had, on average, better class rank and higher GPA. Therefore, only performance on SIM related to performance in school. However, both RESTOR and SIM had a similar number of failures from the top as well as the bottom portions of the class. These preliminary data from one dental school class raise questions about the validity of the NERB clinical examination for licensure decisions.

Dental clinics--a burden to environment?

To estimate environmental burden of mercury from dental clinics, a survey was conducted in 1993 at dental clinics in northern part of Sweden. Factors regarding amalgam separators, maintenance and disposal of collected sludge, age of clinics, cleaning of waste pipes, and sorting and handling of amalgam contaminated products were investigated. The result showed that many were not familiar with maintenance of the amalgam separator. A majority, 68%, were working in clinics older than 10 years, but only 9% reported that waste pipes had been cleaned or changed. Classification of amalgam contaminated products as high-risk and low-risk waste differed a lot, as well as handling of waste products. The result shows that there is need for more information and attention to all individuals working in Dental Care on how to reduce environmental burden of mercury from dental clinics.

Effects of designs of Class 2 preparations on resistance of teeth to fracture.

This study was designed to evaluate the effect of isthmus width on the strength of the remaining tooth structure in maxillary first premolars restored with class 2 silver amalgam restorations. One hundred ten sound maxillary first premolars freshly extracted as a part of orthodontic treatment were collected. The teeth were then divided into 10 groups of 11 teeth each. Ideal class 2 mesio-occlusal, disto-occlusal and mesio-occlusodistal cavities with different isthmus widths i.e. one half the intercuspal distance, one third the intercuspal distance and one fourth the intercuspal distance and one fourth the intercuspal distance were prepared. Compressive forces were applied using a Universal Testing Machine and load to the point of fracture was determined. Intact teeth produced the best tooth fracture resistance i.e. 105.4 MPa, followed by preparations with isthmus width of one fourth, one third and one half intercuspal distance in the order.

Amalgama dental: ¿obturación funcional o simple relleno cavitario? / Dental amalgam: functional obturation or simple cavity filling?

Siendo la amalgama el material restaurador más utilizado en odontología, aún cien años después, sus resultados clínicos en general dejan mucho que desear, más por un manejo inadecuado del material que por el material mismo. Se presenta aquí una clasificación del material con la idea de conocer más sobre su desarrollo. Es indudable que con el desarrollo tecnológico, las preparaciones cavitarias para restauraciones con amalgama hayan sufrido grandes modificaciones si se comparan con las utilizadas a principios de siglo, existiendo una nueva propuesta de diseño cavitario. Al final se hacen algunas observaciones sobre tres grandes factores que inciden en el desarrollo de una buena restauración: fractura marginal, falta de armonía y función oclusal y excesos interproximales, con lo que se busca que el operador mejore la forma de trabajo con dicho material y se aumente el éxito para lograr con la amalgama dental

Efeito de sistemas adesivos na resistência à fratura de pré-molares superiores humanos restaurados com amálgama / Effect of bonded amalgam on the fracture resistance of human premolars

Comparou-se, in vitro, a resistência à fratura de pré-molares superiores humanos com preparos cavitários MOD extensos em cinco diferentes situaçöes: preparos näo restaurados, restaurados com amálgama ou restaurados pela técnica que associa o amálgama aos adesivos All Bond 2, Amalgambond Plus e Scotchbond Multi Uso Plus. As amostras restauradas permaneceram armazenadas em água destilada por 24 horas em uma estufa a 37ºC, para entäo serem submetidas ao carregamento axial de compressäo na máquina de ensaios universal Kratos. Os valores de resistência obtidos foram submetidos a Análise de Variância a um critério e ao teste estatístico Student-Newman-Keuls. Os resultados permitiram concluir que resistência à fratura de pré-molares superiores humanos com restauraçöes MOD de amálgama forradas com os sistemas adesivos Amalgambond Plus (79,5Kgf), Scotchbond Multi Uso Plus (85,4Kgf) e All Bond 2 (86,1Kgf) näo é estatisticamente superior àqueles restaurados com amálgama associado ao verniz cavitário (80,5Kgf) e que os dentes näo restaurados (61,8Kgf) apresentaram resistência significantemente inferior aos demais grupos restaurados

Ligas para amálgama contendo zinco: quando devemos usá-las? / Dental amalgam alloy containing zinc: when should we use them?

O presente estudo teve por objetivo avaliar, por revisäo da literatura, o efeito da inclusäo do zinco nas ligas de amálgama dentário. Para isso, foram analisadas a microestrutura, as propriedades físicas, a corrosäo, a deterioraçäo, fraturas marginais e a citoxicidade do amálgama