Stabilization of residual mercury from gold mining as metacinnabar and cinnabar in ball mills on a pilot scale.

Waste liquid mercury generated as a by-product of the Merrill-Crowe process in gold mining and recovered from mercury-containing waste must be stabilized for secure storage or disposal. This study developed a procedure for mercury stabilization. A ball mill with a 0.5 m3 capacity and a rotational speed of 43 rpm was used to stabilize the residual mercury with sulfur. The treatments were conducted for 30, 60, and 90 min at mercury: sulfur molar ratios of 1.0, 0.8, and 0.67. The ball loading ratio was 7.0 with residual mercury, and the temperature was below 40 °C. The treatment efficiency was evaluated by measuring the concentrations of mercury and other metals using the Toxicity Characteristic Leaching Procedure (TCLP), examining the stabilized residual mercury by X-ray diffraction, and conducting bioassays on Daphnia magna and Lactuca sativa. Principal component analysis (PCA) was performed on the aforementioned variables. The 90-min treatment, with a mercury-to-sulfur molar ratio of 0.67, stabilized mercury mainly as cinnabar compared with the other treatments and presented leachate mercury values below the detection limit <0.003. The leachate from the treatments also showed values of 21.28-38.44 toxic units, classified as very toxic, and generated toxicity, particularly for D. magna, because of the presence of other metals such as Al, Ba, B, Ca, Cu, Cr, Fe, Mn, Ni, and Zn. The variability of the residues in the PCA analysis was explained by the treatment effect and the presence of other metals in the residual mercury. The stabilized residual mercury obtained was classified as non-hazardous and could be stored or disposed of as ordinary waste in a security landfill.

Elastofibromatous changes in giant cell fibroma and amalgam tattoo: Unusual findings in common oral lesions.

Several cases of elastofibromatous lesion affecting the oral mucosa have been reported. Clinically, these lesions may appear as small exophytic lesions or less often as white lesions. Therefore, fibrous hyperplasia and leukoplakia are not uncommonly considered in clinical differential diagnosis. Microscopically, elastic and fibrous connective tissue deposition is seen. Rarely, elastofibromatous changes can be detected when assessing intraoral lesions, including cysts, salivary gland neoplasms, and epithelial dysplasia. Here we report two oral lesions showing elastofibromatous changes, expanding their clinicopathological spectrum. The first case was a 46-year-old man with a history of asymptomatic nodular lesion on the palate 1 year ago, diagnosed as giant cell fibroma with elastofibromatous changes. The second case was a 79-year-old woman who presented a pigmented and mildly symptomatic lesion on the mandibular alveolar mucosa several months ago, diagnosed as amalgam tattoo associated with elastofibromatous changes.

The "Phase Down" of Dental Amalgam Restorations - What are the Criteria for Replacement and Indication?

ABSTRACT Objective: To guide professionals about the criteria for replacing amalgam restorations and inform them about the new guidelines regarding the use/indication of this (amalgam) material after the Minamata Convention - COP-4. Material and Methods: The articles were selected from the databases (PubMed, Scielo, Bireme), and relevant articles on the subject between the years 2003-2021 were selected. Recently, social media have been flooded with dental treatments that aim to perform restorations only with composite resins or other types of esthetic material and completely replace all dental amalgam restorations, irrespective of their time in place, size, and functionality. Results: Although improperly, it has been noted that this information reaches patients, and they are led to believe in the inaccurate data that is passed on, such as, for example, (that amalgam leads to) permanent contamination by mercury, causing systemic problems and the loss of the tooth. Conclusion: The "phase down" of amalgam in research and teaching has previously been observed in several countries worldwide; however, its use is still necessary given particular circumstances, which, theoretically, make it a material with exact indication.

Clinical efficacy of bioactive restorative materials in controlling secondary caries: a systematic review and network meta-analysis.

BACKGROUND: This systematic review and network meta-analysis aimed to compare the clinical efficacy of bioactive and conventional restorative materials in controlling secondary caries (SC) and to provide a classification of these materials according to their effectiveness. METHODS: A search was performed in Pubmed, Web of Science, Embase, BBO, Lilacs, Cochrane Library, Scopus, IBECS and gray literature. Clinical trials were included, with no language or publication date limitations. Paired and network meta-analyses were performed with random-effects models, comparing treatments of interest and classifying them according to effectiveness in the permanent and deciduous dentition and at 1-year or 2/more years of follow-up. The risk of bias and certainty of evidence were evaluated. RESULTS: Sixty-two studies were included in the qualitative syntheses and 39 in the quantitative ones. In permanent teeth, resin composite (RC) (RR = 2.00; 95%CI = 1.10, 3.64) and amalgam (AAG) (RR = 1.79; 95%CI = 1.04, 3.09) showed a higher risk of SC than Glass Ionomer Cement (GIC). In the deciduous teeth, however, a higher risk of SC was observed with RC than with AAG (RR = 2.46; 95%CI = 1.42, 4.27) and in GIC when compared to Resin-Modified Glass Ionomer Cement (RMGIC = 1.79; 95%CI = 1.04, 3.09). Most randomized clinical trials studies showed low or moderate risk of bias. CONCLUSION: There is a difference between bioactive restorative materials for SC control, with GIC being more effective in the permanent teeth and the RMGIC in the deciduous teeth. Bioactive restorative materials can be adjuvants in the control of SC in patients at high risk for caries.

O ensino do amálgama na formação odontológica ainda é necessário? Percepção de cirurgiões-dentistas / ¿Sigue siendo necesaria la enseñanza de la amalgama en la carrera odontológica? Percepción de los dentistas / Is the teaching of amalgam in dental training still necessary? Perceptions of dentists

A Odontologia tem vivenciado, nos últimos tempos, um declínio acentuado do uso do amálgama, em consequência da evolução dos materiais e técnicas adesivas e das discussões acerca dos riscos de contaminação pelo mercúrio. Assim, buscou-se identificar a percepção dos cirurgiões-dentistas sobre a necessidade da continuidade do ensino do amálgama nos cursos de Odontologia. Trata-se de um estudo transversal, usando um questionário semiestruturado com aspectos relativos às condições sociodemográficas, capacitação para executar os procedimentos, conhecimento acerca do manejo do material e gerenciamento dos resíduos. As respostas objetivas foram analisadas pela estatística descritiva e as subjetivas processadas no software IRaMuTeQ. Dos 257 respondentes, 60,7%afirmam utilizar esse material, 91,8% usam amálgama encapsulado e 95,7% descartam os resíduos em lixo hospitalar. Sobre a permanência do material, 63,4% acreditam ser necessária e 88% concordam que o ensino deva continuar sobretudo considerando o perfil do egresso sugerido pelas Diretrizes Curriculares Nacionais. Dos dados subjetivos emergiram cinco classes/categorias que retratam a percepção dos profissionais sobre relação custo-benefício, acesso ao serviço, condições de trabalho e longevidade das restaurações. Conclui-se que, mesmo com a evolução dos materiais adesivos, o amálgama ainda é necessário, principalmente no serviço público, onde a demanda por restaurações de baixo custo e grande longevidade é alta. Assim, para essa amostra, enquanto não houver um material restaurador livre de mercúrio, barato, de fácil manuseio e durável, o ensino desse conteúdo deve permanecer nos cursos de graduação em Odontologia (AU).

La odontología ha experimentado recientemente una fuerte disminución en el uso de amalgamas como resultado de las discusiones sobre los riesgos de contaminación por mercurio, así como la evolución de los materiales y las técnicas adhesivas. Así, buscamos identificar la percepción de los odontólogos sobre la necesidad de continuar enseñando amalgama en los cursos de odontología. Se trata de un estudio transversal utilizando un cuestionario semiestructurado con aspectos relacionados con las condiciones sociodemográficas, capacitación para realizar los procedimientos, conocimientos sobre manejo de materiales y gestión de residuos. Las respuestas objetivas se analizaron mediante estadística descriptiva y las respuestas subjetivas se procesaron mediante el software IRaMuTeQ. De los 257 encuestados, el 60,7% afirma utilizar este material, el 91,8% utiliza amalgama encapsulada y el 95,7% desecha los residuos en la basura de hospital. En cuanto a la permanencia del material, el 63,4% cree que es necesario y el 88% está de acuerdo en que la enseñanza debe continuar, sobre todo para la graduación de profesionales que van al servicio público. A partir de los datos subjetivos, surgieron cinco clases/categorías que retratan la percepción de los profesionales sobre la rentabilidad, el acceso al servicio, las condiciones de trabajo y la longevidad de las restauraciones. Se concluye que, aún con la evolución de los materiales adhesivos, la amalgama sigue siendo necesaria, especialmente en el servicio público, donde la demanda de restauraciones de bajo costo y gran longevidad es alta. Así, mientras no exista un material restaurador libre de mercurio, económico, fácil de manejar y duradero, la enseñanza de este contenido O ensino do amálgama na formação odontológica ainda é necessário? Percepção de cirurgiões-dentistas debe permanecer en los cursos de graduación en odontología (AU).

Dentistry has recently experienced a sharp decline in the use of amalgam, as a result of the evolution of adhesive materials and techniques and discussions about the risks of mercury contamination. Thus, we sought to identify the perception of dentists about the need to continue teaching amalgam in dentistry courses. This is a cross-sectional study, using a semi-structured questionnaire with aspects related to sociodemographic conditions, training to perform the procedures, knowledge about material management and waste management. The objective responses were analyzed by descriptive statistics and the subjective ones processed in the IRaMuTeQ software. Of the 257 respondents, 60.7% claim to use this material, 91.8% use encapsulated amalgam and 95.7% dispose of waste in hospital waste. Regarding the permanence of the material, 63.4% believe it is necessary and 88% agree that teaching should continue, especially considering the profile of the graduate suggested by the National Curriculum Guidelines. From the subjective data emerged five classes/categories that portray the perception of professionals about cost-benefit ratio, access to service, working conditions and longevity of restorations. It is concluded that, even with the evolution of adhesive materials, amalgam is still necessary, especially in the public service, where the demand for low cost and high longevity restorations is high. Thus, for this sample, as long as there is no mercury-free, inexpensive, easy to handle and durable restorative material, the teaching of this content should remain in undergraduate courses in Dentistry (AU).

Amalgam x Composite Resin: supplies and restorative procedures more performed among Oral Health Teams in Brazil

Abstract This study aimed to compare the availability of supplies and amalgam and composite resin restorations among Oral Health Teams (OHT) in Brazilian regions. Secondary data were extracted from Modules I and II of the 1st (2012) and V and VI of the 2nd (2014) and 3rd cycle (2017) of the external evaluation of the National Program for Access and Quality in Primary Care2. The proportions between regions and cycles were compared using the Chi-square test with the z-test adjusted by the Bonferroni method (p<0.05). Among 2012, 2014, and 2017 there was a significant reduction in the proportion of OHT that performed amalgam restorations (87.5%, 89.2%, and 80.2%; p<0.001) and an increase in resin composite (92.5 %, 97.7%, and 99.0%; p<0.001), with the same trend in Brazilian regions (p<0.001). Amalgamator availability decreased among 2012 (99.0%), 2014 (98.4%) and 2017 (85.6%) (p<0.001). Amalgam availability was lower in 2017 (80.1%), compared to 2012 (87.5%) and 2014 (97.5%) (p<0.001). The availability of light curing decreased between 2012 (99.0%), 2014 (98.4%) and 2017 (85.6%) (p<0.001), being less available in the North (95.7%) (p<0.001). The light-curing resin increased between 2012 (94.1%), 2014 (96.6%) and 2017 (97.0%) (p<0.001), with no increase only in the North (p=0.134). While there was a reduction in supplies and amalgam restoration, there was an increase in supplies and resin composite restorations in the period evaluated in all Brazilian regions. However, regional disparities are still evident, with fewer supplies of restorative services in the North region.

Resumo Este estudo objetivou comparar a disponibilidade de fornecimentos e restaurações de amálgama e resina composta entre as Equipas de Saúde Oral (OHT) por regiões brasileiras. Os dados secundários foram extraídos dos módulos I e II do 1º (2012) e V e VI do 2º (2014) e 3º ciclo (2017) da avaliação externa do Programa Nacional de Acesso e Qualidade em Cuidados Primários. As proporções entre regiões e ciclos foram comparadas utilizando o teste Qui-quadrado com o teste z ajustado pelo método de Bonferroni (p<0,05). Entre 2012, 2014, e 2017 houve uma redução significativa na proporção de OHT que realizou restaurações de amálgama (87,5%, 89,2%, e 80,2%; p<0,001) e um aumento na resina composta (92,5%, 97,7%, e 99,0%; p<0,001), com a mesma tendência nas regiões brasileiras (p<0,001). A disponibilidade de amalgamadores diminuiu entre 2012 (99,0%), 2014 (98,4%) e 2017 (85,6%) (p<0,001). A disponibilidade de amálgama foi menor em 2017 (80,1%), em comparação com 2012 (87,5%) e 2014 (97,5%) (p<0,001). A disponibilidade de polimerização por luz diminuiu entre 2012 (99,0%), 2014 (98,4%) e 2017 (85,6%) (p<0,001), estando menos disponível no Norte (95,7%) (p<0,001). A resina fotopolimerizadora aumentou entre 2012 (94,1%), 2014 (96,6%) e 2017 (97,0%) (p<0,001), sem aumento apenas no Norte (p=0,134). Embora tenha havido uma redução nos fornecimentos e restauração de amálgamas, houve um aumento nos fornecimentos e restaurações de resina composta no período avaliado em todas as regiões brasileiras. Contudo, as disparidades regionais são ainda evidentes, com menos oferta de serviços de restauração na região Norte.

Assessment of Bite Forces in Restored Teeth with Different Commonly Used Restorative Materials: A Comparative Study

ABSTRACT Objective: To evaluate and compare bite force (BF) in permanent first molars restored with glass ionomer cement (GIC), composite and amalgam, and normal contralateral permanent first molars. Material and Methods: BF was recorded in decayed permanent first molars, which were filled with GIC (n=30), composite (n=30), and amalgam (n=30), and in healthy contralateral first molars (n=90) with Force Transducer Occlusal Force Meter and compared. Results: BF was significantly higher in normal teeth on the contralateral side compared to teeth restored with GIC and composite. However, in patients with amalgam restoration, though it was less compared to that on the contralateral side, it was not statistically significant (p>0.05). Conclusion: Restoring teeth with various filling materials may improve bite force. In the present study, it was found that the teeth restored with amalgam had higher bite forces in comparison to the other restorative materials used. However, it was not comparable to that observed in the normal tooth (control) on the contralateral side.

Cost-effectiveness of selective caries removal versus stepwise excavation for deep caries lesions

Abstract A multicenter, randomized controlled clinical trial evaluated the effectiveness of two treatments for deep caries lesions in permanent molars - selective caries removal (SCR) to soft dentin with restoration in a single visit, and stepwise excavation (SW) - regarding pulp vitality for a 5-year follow-up period. The present study aimed to determine the cost-effectiveness of these treatments. Treatments were conducted in two Brazilian cities (Brasília and Porto Alegre). At baseline, 299 permanent molars (233 patients) were treated and 229 teeth (174 patients) were evaluated after 5 years. The discounted cash flow method was adopted. The total cost of each treatment was calculated, and the failure cost (endodontic treatment + restoration) was added to the final cost, according to the 5-year failure rates of each therapy (20% for SCR and 44% for SW). A public health service unit composed of three dentists in 4-hour work shifts was used to calculate the monetary value of the treatments, assuming a total of 528 treatments/month. Considering the 229 teeth evaluated after 5 years (115 SCR and 114 SW), SCR provided savings of 43% (amalgam) and 41% (resin composite) per treatment, compared to SW. The SCR technique provides benefits for public finances (direct economy) and for public health services (increase in the number of treatments performed). Considering that maximizing profit and reducing costs are powerful motivating factors for adopting a certain treatment, this study provides data to better support the decision-making process, regarding the management of deep caries lesions in permanent molars.

Materiais restauradores em odontopediatria: preferência de pais e crianças e análise bibliométrica-altimétrica / Restorative materials in pediatric dentistry: children's and adults' preference and bibliometric-altmetric analysis

Atualmente, diversos materiais restauradores encontram-se disponíveis para aplicabilidade em Odontopediatria. Os avanços dos materiais restauradores conduzem à necessidade de novos estudos nessa temática. O presente estudo apresenta duas propostas de investigação: 1) Estudo transversal com objetivo de avaliar a preferência de pais/responsáveis e crianças quanto ao emprego do compômero colorido (Twinky Star®, Voco, Alemanha); 2) Estudo bibliométrico altimétrico com objetivo de analisar 50 artigos mais citados referente aos materiais restauradores utilizados em Odontopediatria e o alcance dessa informação científica nas mídias on-line. O estudo transversal envolveu 260 pares de pais/responsáveis e crianças de 5 a 11 anos de idade de dois serviços de saúde da região metropolitana de Belo Horizonte-MG. Exame quanto à cárie dentária foi realizado por examinadora calibrada para o critério da Organização Mundial da Saúde. Um manequim odontológico contendo restaurações com compômeros coloridos e materiais convencionais (resina composta, ionômero de vidro e amálgama) foi apresentado aos participantes do estudo e realizou-se inquérito sobre a preferência dos materiais dentários. O Questionário de Estilo e Dimensões dos Pais (PSDQ) e o Eysenck Personality Questionnaire Junior (EPQ-J) foram aplicados, este último apenas para pais/responsáveis de crianças de 5 e 6 anos de idade. Análises descritivas, bivariadas e regressão multivariada de Poisson foram realizadas. A maioria dos pais/responsáveis (74,2%) preferiu materiais convencionais. A idade da criança (p=0,006), a renda familiar (p= 0,001) e o nível de escolaridade (p< 0,001) associaram se a essa escolha. A análise multivariada demonstrou que crianças menores de 7 anos apresentaram 1,20 vezes maior probabilidade de escolher compômeros coloridos do que seus pares mais velhos (p< 0,001), assim como pais/responsáveis com menos de 11 anos de escolaridade e cujos filhos eram menores de 7 anos apresentaram 2,17 e 1,74 maior probabilidade para escolher compômeros coloridos, respectivamente. Concluiu-se que responsáveis com maior escolaridade apresentaram maior resistência às restaurações coloridas e crianças menores de 7 anos aceitaram melhor este material. O estudo bibliométrico-altimétrico adotou estratégia de busca em três bases (Web of Science, Scopus e Google Scholar), independente da data de publicação. Após seleção dos artigos por um grupo de cinco pesquisadores, em março de 2023, foram incluídos estudos que avaliassem qualquer material restaurador empregado em dentes decíduos e analisados dados referentes ao título, número de citações, país/continente, autoria, periódico, instituição, desenho do estudo, tipo de material restaurador, e escore altimétrico. Os artigos, publicados entre 1991 a 2002, apresentaram variação de citações de 19 a 113. Os autores com maior número de citações foram Qvist V e Teglers PT. O estudo experimental foi o principal delineamento de estudo observado e o cimento de ionomero de vidro foi o material mais reportado. A Europa foi o continente, e o Brasil, o país com maior número de citações. O escore altimétrico esteve presente em 23 artigos, com ênfase para dois artigos (43/6º e 73/7º). Concluiu-se que o cimento de ionômero de vidro foi o material mais estudado. Ficou evidente o distanciamento entre a posição dos trabalhos nas análises bibliométrica e altimétrica, apontando necessidade de disseminação da informação além dos círculos acadêmicos.

Currently, an arsenal of restorative materials is available for applicability in pediatric dentistry. The advances in restorative materials conducted to need for further studies in this thematic. The present study presents two investigation proposals: 1) Cross-sectional study aiming to evaluate the preference of parents and children regarding the use of colored compomer (Twinky Star®, Voco, Germany); 2) Bibliometric-altmetric study aiming to analyze the 50-most cited papers regarding to restorative materials used in pediatric dentistry and the dissemination of scientific information in online media. The cross-sectional study included 260 pairs of caregivers/children aged 5 to 11, in two public health services, in the metropolitan region of Belo Horizonte-MG. Examination for dental caries was performed by an examiner calibrated to the criteria of the World Health Organization. A dental mannequin containing colored compomers restorations and conventional materials (composite resin, glass ionomer cement and dental amalgam) was presented to the population and a survey was conducted about the preference of dental materials. Parents' Style and Dimensions Questionnaire (PSDQ) and Eysenck Personality Questionnaire Junior (EPQ-J) were applied, the last one only for parents/caregivers of children aged 5 to 6. Descriptive, bivariate and Poisson regression analyzes were performed. Most adults (74.2%) preferred conventional materials. Family income (p= 0.001) and education level (p< 0.001) were associated with its choice. Age up to 7 (p< 0.001) associated with children's choice for colored restorations (72.3%). Children younger than 7 had 1.20 higher probability to choose colored compomers than their older pairs, while adults with children younger than 7 and less than 11 years of schooling had 1.74 and 2.17 higher probability to choose colored compomers, respectively. It was concluded that caregivers with higher educational level showed greater resistance to use of colored restorations and children younger than 7 had better acceptance of colored material. The bibliometrics-altmetrics study adopted a search strategy in three databases (Web of Science, Scopus and Google Scholar), independent of the year of publication. After selection of papers by a panel of five researchers, in March 2023, any restorative material used in deciduous teeth was included and data about the title, number of citations, country/continent, authorship, journal, design of the study, type of restorative material, university and altmetrics score were analyzed. The papers, published between 1991 and 2002, ranged from 19 to 113 citations. The authors with the highest number of citations were Qvist V and Teglers PT. The experimental study was the main study design observed. Analyzing the continent and country with the highest number of citations, Europe highlighted and Brazil was predominant. The altmetric score was present in 23 papers, emphasizing two articles (43/6th and 73/7th). It was concluded that glass ionomer cement was the most studied material. A gap between the position of the papers correlating the bibliometrics and altmetrics analyzes was evident, demonstrating the need to disseminate the information beyond academic circles.

Mercury pollution in Peru: geographic distribution, health hazards, and sustainable removal technologies.

Peru is one of the great gold producers worldwide. However, a significant portion of the gold produced in Peru derives from artisanal small-scale gold mining (ASGM) in the Andes and Amazon. In ASGM, gold amalgamation with mercury (Hg) is a critical procedure to refine gold through the formation of Au-Hg alloys. Due to the rudimentary and improvised techniques conducted by small-scale and informal miners, Hg contamination has become of great concern and is strictly associated with ASGM. Multiple studies have evidenced notably high concentrations of Hg in consumable fish species, rivers, sediments, and air in locations where ASGM is one of the main sources of income to local communities and is carried out aggressively. In the present review, we have conducted a systematic search for national and international literature reporting the concentration and distribution of Hg pollution across environmental compartments, biota, and human samples in Peru. The results and data retrieved from the articles were quantitatively and qualitatively analyzed, and the distribution of Hg across environmental compartments was visualized through a geographic information system. Additionally, we reviewed the use of adsorption techniques as alternatives to treat Hg0 vapor from the gold shop and smelter flues, one of the main sources of hazardous levels of Hg exposure.

Longevity of Resin Composite and Amalgam Posterior Restorations: A Systematic Review.

OBJECTIVES: The objective of this systematic review was to compare the longevity of direct amalgam and composite resin restorations, in posterior teeth, through clinical, prospective or retrospective studies, with at least 5 years of follow-up. MATERIALS AND METHODS: Studies published in the last 15 years (from 2006 to 2021) were collected using the PubMed and Medline databases. RESULTS: The search strategy associated with the established inclusion and exclusion criteria resulted in a total of 17 articles. Factors related to failures in the performance of restorations were analyzed together with the clinical performance results of each material over the years of study, according to the methodology of each article. CONCLUSIONS: Regardless of the restorative material, the successful results over more than 5 years are due much more to the correct application of the technique, the operator's skill/knowledge and factors related to the patient, such as the type of tooth, number of faces involved in the restoration and oral hygiene.

Evaluation of Microleakage at the Junction Between Combined Amalgam/Composite Resin Restorations Using Different Bonding Systems in Class II Cavities

Abstract Objective: To evaluate the microleakage at the junction between amalgam-composite resin restorations using different bonding systems. Material and Methods: In this in-vitro study, standard class II cavities were prepared on 40 human maxillary premolars. The axial and gingival floor depths of the cavities were 2 mm and 1 mm below (cementoenamel junction), respectively. The samples were divided into 4 groups (n = 10). In all groups, a layer of 1-mm thick amalgam was used as a coating for the initial part of the gingival floor. In group 1, no bonding system was used for amalgam restoration. In group 2, G-Premio Bond was applied. G-Premio bond + alloy primer and single bond + alloy primer were used in group 3 and group 4, respectively. The rest of the cavities in all groups were then repaired using FiltekZ250 composite. The samples were thermocycled at 500 rpm and immersed in 1% methylene blue solution for 24 hours to allow dye penetration. Once cut, the samples were placed under a stereomicroscope (40X) to determine the microleakage rate. Data analysis was carried out using post-hoc and Chi-square tests (p<0.05). Results: The highest and lowest microleakage rate was related to groups 1 and 3, respectively. There was a significant difference between groups (1,2) and (1,3), and (1,4), and groups (2,3) (p<0.05). Conclusion: The use of alloy primer and bonding could reduce the microleakage between the two restorations (AU).

Glass ionomer heated or not to identify bone defect created in rat calvaria / Ionômero de vidro aquecido ou não para identificação de defeitos ósseos criados em calvárias de ratos

Introduction: Some experimental models have been used to evaluate the use of biomaterials in bone regeneration. Among them are the critical size defects (CSD) created in rat calvaria. An experimental model has been described in the literature, in which "L" markings are performed on the margins of the bone defects in order to assist in the precise identification of these defects during laboratory processing and analysis of the results. In the proposed model, the "L" markings are filled with amalgam. Objective: The purpose of the present study was to evaluate the amalgam replacement of an experimental bony defect model in rat calvaria by heated or unheated glass ionomer. Material and method: 24 rats were used. A 5 mm CSD was created at each animal calvaria. Two "L" shaped markings were made 2 mm from the margins of the bone defect, filled with amalgam (Group AM), heated glass ionomer cement (Group GIh) or not (Group GI). The animals were euthanized 15 days postoperatively. The areas of the surgical defect and the L-shaped marking were histomorphometrically analyzed and the data were analyzed statistically (p <0.05). Result: There were no significant clinical, histological or methodological differences among the experimental groups. Conclusion: It can be concluded that GI can replace AM in the proposed experimental model and GI heating did not promote additional benefits.

Introdução: Alguns modelos experimentais têm sido usados para avaliar o uso de biomateriais na regeneração óssea. Entre eles estão os defeitos de tamanho crítico (DTC) criados em calvárias de ratos. Um modelo experimental foi descrito na literatura onde marcações em L são realizadas nas margens do defeito ósseo para auxiliar na identificação precisa desses defeitos durante o processamento laboratorial e análise dos resultados. No modelo experimental proposto, as marcações em "L" são preenchidas com amálgama. Objetivo: Avaliar a substituição do amálgama por ionômero de vidro aquecido ou não em um modelo experimental para identificação de defeito ósseo criado em calvária de ratos. Material e método: Foram utilizados 24 ratos. Um DTC de 5 mm de diâmetro foi criado na calvária de cada animal. Duas marcações em "L" foram realizadas a 2 mm das margens do defeito ósseo, preenchidas com amálgama (Grupo AM), ionômero de vidro aquecido (Grupo CIVaq) ou não (Grupo CIV). Os animais foram eutanasiados aos 15 dias pós-operatórios. A área do defeito cirúrgico e das marcações em "L" foram histomorfometricamente avaliadas e os dados estatisticamente analisados (p<0,05). Resultado: Não houve diferença estatisticamente significativa entre os grupos experimentais para as análises metodológicas, clínicas ou histomorfométrica realizadas. Conclusão: Dentro dos limites deste estudo, pode-se concluir que CIV pode substituir o AM no modelo experimental proposto e o aquecimento do CIV não promoveu benefícios adicionais.

Recomendaciones sobre la reparación de restauraciones de amalgama / Recommendations about the repair of dental amalgam restorations

Introducción: La reparación de restauraciones de amalgama, los materiales, las caras de los dientes de preferencia para realizarlas y su controversia con la contraparte de realizar reemplazos, es algo que amerita atención por los investigadores para lograr definiciones y protocolos precisos. Objetivo: Sistematizar sobre las recomendaciones de la literatura con respecto a la reparación de restauraciones de amalgama. Métodos: Se realizó una revisión cualitativa. Se plantearon criterios de inclusión y exclusión para la selección de los artículos. La búsqueda se realizó en Scopus y Pubmed. De las investigaciones resultantes de la búsqueda fueron decantados los artículos que no coincidían con el problema de investigación en cuestión, luego los que no cumplían los criterios de inclusión y exclusión. Se realizó una evaluación de la calidad y validez de los artículos seleccionados para ser incluidos en esta investigación y, finalmente, se le dio lectura a los textos completos y resúmenes para extraer los datos necesarios para completar la base de datos de la investigación. Quedaron un total de 27 artículos que fueron tamizados en una base de datos Excel, la que luego se exportó al software SPSS para su procesamiento estadístico. Resultados: El 44,4 por ciento y 55,6 por ciento de los artículos recomiendan reparar las restauraciones con amalgama y resina compuesta, respectivamente. Casi la mitad de los artículos (48,1 por ciento) no precisaron una cara del diente susceptible o no para realizar reparaciones. El 44,4 por ciento concluyen con que es un tratamiento recomendable. Conclusiones: Es recomendable realizar reparaciones de restauraciones de amalgama con amalgama dental y con resina compuesta. No está claramente definido cuál cara del diente es susceptible o no a recibir reparaciones y es un tratamiento que puede formar parte del arsenal terapéutico de los odontólogos(AU)

Introduction: The repair of amalgam restorations, the materials used, the tooth sides preferred to perform them, and the controversy with the replacement option, are all topics deserving the attention of researchers with a view to achieving accurate definitions and protocols. Objective: Systematize the recommendations available in the literature about the repair of amalgam restorations. Methods: A qualitative review was carried out. Inclusion and exclusion criteria were established for the selection of papers. The search was conducted in Scopus and Pubmed. Papers not related to the research problem at hand were the first to be discarded. Then those not meeting the inclusion and exclusion criteria. An evaluation was performed of the quality and validity of the remaining papers, and finally their full texts and abstracts were read to retrieve the data required to complete the database of the study. The 27 papers thus obtained were sifted in an Excel database, which was then exported to the SPSS software for statistical processing. Results: 44.4 percent and 55.6 percent of the papers recommend to repair restorations with amalgam and composite resin, respectively. Almost half (48.1 percent) do not state any preference for a specific tooth side to perform the repair. 44.4 percent recommend the treatment. Conclusions: It is advisable to perform repairs of amalgam restorations with dental amalgam and with composite resin. It is not clearly defined which tooth side is preferred to undergo the repair. This treatment may be part of the therapeutic arsenal of dentists(AU)

Tatuaje de amalgama: Pigmentación exógena más común de la cavidad oral / Amalgam tattoo: Most common exogenous pigmentation of the oral cavity

Resumen El propósito de este estudio es analizar las características clínicas de la pigmentación de amalgama en la cavidad oral, comúnmente, denominada también tatuaje de amalgama, el objetivo es aumentar el conocimiento de esta entidad patológica y diferenciarla de otras lesiones de mayor importancia clínica.

Abstract The purpose of this study is to analyze the clinical characteristics of amalgam pigmentation in the oral cavity, commonly known as amalgam tattoo, in order to increase the knowledge of this pathological entity and to differentiate it from other important lesions.

The protective role of selenium against dental amalgam-induced intracellular oxidative toxicity through the TRPV1 channel in DBTRG glioblastoma cells

Abstract Objective The exposure to mercury (Hg) from dental amalgams is a suspected causative factor in neurological diseases. This study investigated the toxic effects of two different amalgam compositions related to Hg and the protective effects of selenium against the toxic effects of Hg through the TRPV1 channel in the human DBTRG glioblastoma cell line. Methodology Six groups of the cells were organized. Analyses of cell viability, apoptosis, caspase 3 and caspase 9 activities, mitochondrial membrane depolarization, reactive oxygen species (ROS) production, and Western Blotting for protein expression levels were performed. Results Cell viability values were lower in amalgam with high copper (HCu) and low copper (LCu) groups independently of time but were increased by selenium and capsazepine (p<0.001 and p<0.05). Conversely, apoptosis rates, caspase 3 and caspase 9 expression, ROS formation, mitochondrial membrane depolarization, and protein expression levels were higher in the HCu and LCu groups but were decreased by selenium (p<0.001 and p<0.05). Conclusions Selenium combined with an amalgam of either HCu or LCu decreases the toxic effects created by Hg in human DBTRG glioblastoma cells.

Amalgam allergy and Burning Mouth Syndrom: treatment and 25 years recall / Alergia ao amálgama e Síndrome da ardência bucal: tratamento e 25 anos de proservação

Background: Burning mouth syndrome (BMS) is a non-neuropathic chronic orofacial pain condition, characterized by the presence of burning/warm sensation without specific mucosal lesions. Objective: The aim of the present clinical case report is to describe the positive outcome of dental treatment of a patient with BMS and followed up for 25 years. Data Treatment: This report describes the case of a 50-year-old black woman sought treatment for burning, and persistent swelling of tong (24h/day) occurring over years. Clinical evaluation of the oral environment revealed the tongue with cracking, darkened points areas, surrounded by whitish areas. Twelve teeth presented extensive amalgam restorations. Patch testing revealed a very strong hypersensitivity to Amalgam. All amalgam restorations were substituted by composite resin restorations. Results and Conclusion: Burning sensation disappeared completely after these restorations had been changed. After 25-year follow-up period, it was observed that burning sensation has never been felt anymore. Clinical Significance: Burning mouth syndrome is a chronic orofacial pain, usually without specific mucosal lesions. The etiology is complex and multifactorial and the treatment should be made specifically for each pacient. (AU)

Introdução: A síndrome de ardência bucal (SAB) é uma condição de dor orofacial crônica não neuropática, caracterizada pela presença de sensação de queimação/calor sem lesões específicas da mucosa. Objetivo: Oobjetivo do presente relato de caso clínico é descrever a evolução positiva do tratamento odontológico de uma paciente com SAB e o retorno após 25 anos. Tratamento dos Dados: Este relato descreve o caso de uma mulher negra de 50 anos que buscou tratamento por queimadura e edema persistente da língua (24h/dia) ocorrendo ao longo dos anos. A avaliação clínica da cavidade bucal revelou a língua com áreas fissuradas e áreas com pontos escurecidos circundadas por áreas esbranquiçadas. Doze dentes apresentavam restaurações extensas de amálgama de prata. O teste de contato revelou hipersensibilidade muito forte ao amálgama de prata. Todas as restaurações de amálgama de prata foram substituidas por restaurações de resina composta. Resultados e Conclusão: A sensação de queimação desapareceu completamente após a substituição das restaurações. Após um periodo de 25 anos, observou-se que a sensação de queimação nunca foi mais relatada. Significado Clínico: a síndrome da ardência bucal é uma dor orofacial crônica, geralmente sem lesões específicas da mucosa. A etiologia é complexa e multifatorial e o tratamento deve ser feito especificamente para cada paciente.(AU)

Evaluation of Effectiveness of Self-Adhesive Composites for Amalgam Repair with or Without Alloy Primer, in Terms of Shear Bond Strength / Evaluación de la efectividad de los compuestos autoadhesivos para la reparación de amalgamas con o sin imprimación de aleación, en términos de resistencia al cizallamiento

Abstract Purpose: The purpose of the present research was to evaluate the effectiveness of self-adhesive composites in amalgam repair as time-saving alternatives to universal bonding-universal composite materials, with or without the usage of Alloy Primer in terms of shear bond strength. Materials and Methods: Forty- two disc-shaped amalgam samples were prepared by condensing into 6×2 mm holes in acrylic resin blocks, sandblasted with 50 μm Al2O3 and randomly divided into 6 groups according to repair material [Constic (Group C), Fusio Liquid Dentin (Group FLD), Universal bonding+Universal composite (Group Control), Alloy Primer+Constic (Group APC), Alloy Primer+Fusio Liquid Dentin (Group APFLD), Alloy Primer+Universal bonding+Universal composite (Group APControl)]. After shear bond strength test, the fracture modes were determined under a digital microscope. Statistical analysis was performed using one-way analysis of variance and Tukey's post hoc test. Results: The highest shear bond strength values were obtained for Fusio Liquid Dentin, among the three repair materials when Alloy Primer was not applied (p<0.05). Usage of Alloy Primer increased shear bond strength values of the investigated repair materials to amalgam, except Fusio Liquid Dentin. Conclusion: Within the limitations of the present research, it can be concluded that; the investigated self-adhesive composite materials could be time-saving alternatives to the Universal bonding+Universal composite for the purpose of amalgam repair, in terms of shear bond strength. The clinicians could prefer Fusio Liquid Dentin self-adhesive composite material without Alloy Primer application for the purpose of amalgam repair in non-cooperative patients.

Resumen Propósito: El propósito de la presente investigación fue evaluar la efectividad de las resinas compuestas autoadhesivas en la reparación de amalgamas como alternativas que ahorran tiempo con respecto a las resinas compuestas universales de adhesión universal, con o sin el uso de Alloy Primer en términos de resistencia al cizallamiento. Materiales y métodos: Se prepararon 42 muestras de amalgama en forma de disco condensándolas en orificios de 6×2 mm en bloques de resina acrílica, arenadas con 50 μm de Al2O3 y divididas al azar en 6 grupos según el material de reparación [Constic (Grupo C), Fusio Liquid Dentin (Grupo FLD), Adhesivo universal+Resina universal (Grupo Control), Imprimación de aleación+Constic (Grupo APC), Imprimación de aleación+Fusio Liquid Dentin (Grupo APFLD), Imprimación de aleación+Adhesivo universal+Resina universal (Grupo APControl)]. Después de la prueba de resistencia al cizallamiento, los modos de fractura se determinaron bajo un microscopio digital. El análisis estadístico se realizó mediante análisis de varianza unidireccional y la prueba post hoc de Tukey. Resultados: Se obtuvieron los valores de resistencia al cizallamiento más altos para Fusio Liquid Dentin, entre los tres materiales de reparación cuando no se aplicó Alloy Primer (p<0.05). El uso de Alloy Primer aumentó los valores de resistencia al cizallamiento de los materiales de reparación investigados para la amalgama, excepto Fusio Liquid Dentin. Conclusión: Dentro de las limitaciones de la presente investigación, se puede concluir que; los materiales compuestos autoadhesivos investigados podrían ser alternativas que ahorran tiempo con respecto al adhesivo universal+resina universal con el fin de reparar las amalgamas, en términos de resistencia a la cizalladura. Los clínicos podrían preferir el material compuesto autoadhesivo Fusio Liquid Dentin sin la aplicación Alloy Primer con el fin de reparar amalgamas en pacientes poco cooperadores.

Restorations after selective caries removal: 5-Year randomized trial.

OBJECTIVE: To compare the survival of restorations placed in deep caries lesions after selective caries removal to soft dentin (SCRSD) over a 5-year period. A secondary aim was to investigate whether the material (amalgam or resin composite) affected the survival of restorations. METHODS: This study used data derived from a multicenter randomized controlled clinical trial (Clinical trials registration NCT00887952). Inclusion criteria were: patients with permanent molars presenting occlusal or proximal deep caries lesions (≥1/2 of the dentin thickness on radiographic examination), positive response to a cold test, absence of spontaneous pain, negative sensitivity to percussion, and absence of periapical lesions. The teeth were randomized into SCRSD and restoration in a single visit or stepwise excavation (SW). Each of these groups was divided according to the filling material: amalgam (AM) or resin composite (RC). Survival analyses were performed to estimate therapy success rates over 5 years (adjusted Weibull regression model). RESULTS: 172 restorations were evaluated, 95 from SCRSD group and 77 from SW group, being 61 AMG and 111 RC. The 5-year survival analysis showed similar success rates for SW (76 %) and SCRSD (79 %) as well as for AM and RC (p > 0.05). CONCLUSION: This study showed that, after a 5-year follow-up period, the presence of decayed tissue beneath restorations in deep caries lesions did not seem to affect restoration survival. Amalgam and resin composite restorations had similar survival rates, irrespective of the caries removal technique used - SCRSD or SW. CLINICAL SIGNIFICANCE: Selective caries removal to soft dentin can be used in the management of deep caries to avoid pulp exposure and preserve tooth structure without affecting restoration longevity.

Pesticides determination in foods and natural waters using solid amalgam-based electrodes: Challenges and trends.

The intensive use of pesticides in agricultural practices has promoted the appearance of environmental and public health problems. So, there has been a sharp increase in the development of simple, fast, sensitive, selective, and low-cost methods to analyse pesticides. Among them, electroanalytical methods have been frequently employed; however, the performance of these methods is strongly influenced by the working electrode material and so an adequate choice is critical to success of the analysis. Solid amalgam-based electrodes have been widely used; this review critically discusses the evolution of the preparation and use of these electrodes and their application in analysis of pesticides from different chemical classes, indicating challenges and trends in pesticide electroanalysis. The relationship between pesticides' chemical structures and electrochemical behaviour on a mercury-based electrode is explored in order to indicate the use of electroanalysis in pesticide determination.