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A dureza é uma propriedade bastante utilizada para comparar tanto os materiais restauradores como os tecidos biológicos. É definida pela resistência do material à deformação plástica e mensurada pela relação da força aplicada e a área de endentação. Para esse estudo foram utilizados dois materiais: amálgama e resina composta e dois tecidos dentais: dentina e esmalte bovinos. No total foram confeccionados 20 espécimes, divididos em 4 grupos: A (Amálgama), R (Resina Composta), D (Dentina) e E (Esmalte) de acordo com cada superfície. Para os grupos A e R foram confeccionadas cavidades que foram restauradas com os respectivos materiais, no grupo E teve a superfície apenas planificada e o grupo D teve desgaste até a exposição de dentina. Para os testes foram utilizados os endentadores Vickers e Knoop; as cargas de 25, 50 e 100gf em cinco tempos de endentação 5, 15, 30, 45, e 60s. Os valores dos testes foram submetidos à análise estatística pelo teste Kruskall-Wallis e Student-Newman-Keuls (p<0,05). Os resultados permitiram concluir que para o amálgama deve se utilizar no mínimo uma carga de 50gf em um tempo mínimo de 30s tanto para a Vickers como para a Knoop. Na resina composta uma carga de 50gf e tempo de 45s para a Knoop e na dureza Vickers não apresentou diferenças. Na dentina a carga ideal é de pelo menos 50gf em qualquer dos tempos na dureza Vickers e Knoop. E o esmalte uma carga de 100gf para qualquer tempo na dureza Knoop. / The hardness is a mechanical property utilized to compare restorative materials such as biological tissue and can be defined as the resistance of material for a permanent impression and a number related to the applied force and the surface area. As each material has its own mechanical characteristic, for this study utilized two materials: amalgam and composite resin and two dental tissues: bovine dentin and enamel. In total were 20 specimes, divided among 4 groups: A, R, D, E equivalent for each superficial. The groups A and R received cavities preparation that were restored into with the respective materials, the group D had the superficial wore until exposure of the dentin and the group E was so planning. For the microhardness testing were utilized Vickers and Knoop indenter; loads of 25, 50 and 100gf in 5 time of application 5, 15, 30, 45 e 60 seconds. The values were submitted for statistical analysis by Kruskall-Wallis and Student-Newman-Keus tests (p<0.05). Due to the results, it is concluded that the amalgam presented a minimum load adequated of 50gf and a time of application of 30 seconds as the Vickers as Knoop. In the composite resin the minimum load was 50gf and time was 45s for Knoop, the Vickers didnt have statistical diference. In dentin the minimum load was 50gf for all studies times for two tests. And the enamel presented the minimum load adequated was 100gf for all the times in the Knoop microhardness, the Vickers test didnt have statistical diference.

Orientador: Maria Salete Machado Cândido / Banca: Osmir Batista de Oliveira Júnior / Banca: Denise Pedrini / Resumo: O objetivo deste trabalho foi avaliar através de Análise Metalográfica em Microscopia Eletrônica de Varredura, a ocorrência de possíveis alterações na microestrutura do amálgama, e analisar, através de fotomicrografias, a presença de fendas na interface dente/restauração, quando este é associado a três diferentes materiais adesivos intermediários, sendo eles: Panávia F, Vidrion F e Scotchbond Multi-Uso Plus (SBMP). Para este estudo, foram utilizados 20 terceiros molares recentemente extraídos, os quais receberam preparos Classe I, assim restaurados: GRUPO I (controle): restaurações com amálgama sem a presença de agente intermediário, GRUPO II: restaurações com amálgama associadas ao Panávia F; GRUPO III: restaurações com amálgama associadas ao Vidrion F; e, GRUPO IV: restaurações com amálgama associadas ao SBMP. Após confecção das restaurações, de acordo com as instruções dos fabricantes, os corpos-de-prova permaneceram em água destilada a 370C +/- por 24h e foram submetidos a termociclagem (8oC a 550C). Em seguida, os corpos-de-prova foram seccionados longitudinalmente no sentido mésio-distal e submetidos à análise Metalográfica em Microscopia Eletrônica de Varredura e à análise da interface adesiva através da mensuração da fenda em três regiões distintas: (IA1) interface esmalte/restauração; (IA2) interface ângulo/restauração; (IA3) interface parede pulpar/restauração. Os resultados foram submetidos à análise descritiva e estatística, pela análise de variância, com p=0,05, cujos resultados nos permitiram concluir que: a) Nenhum dos materiais intermediários testados determinou alterações na microestrutura do amálgama; b) Houve aumento significativo na presença de porosidades no interior do amálgama nos Grupos II e III; c) A associação do amálgama aos materiais intermediários não foi... (Resumo completo, clicar acesso eletrônico abaixo). / Abstract: The aim of the present study was evaluate utilizing Metalographic Analysis in Scanning Electronic Microscopy the occurrence of possible alterations in amalgam microstructure and evaluate, by means of photomicrographies, the presence of gaps in tooth/restoration interface, when associated to three different intermediate adhesive materials, that was: Panavia F, Vidrion F and Scotchbond Multi Purpose Plus (SBMP). For this study, twenty recently extracted third molars were used, and a Class I cavity was made in each tooth and filled in the following form: Group I (control): amalgam restorations without intermediate agent, Group II: amalgam restoration associated with Panavia F, Group III: amalgam restorations associated with Vidrion F, Group IV: amalgam restorations associated with SBMP. After the fillins was made accordingly with the manufacturer's instruction, the test bodies stood in distilled water at 37º C +/- for 24 hours, then being submitted to thermocycling (8º C to 55ºC). Then the test bodies was longitudinally cutted in the medial-distal way, and submitted to the Metalographic Analysis in Scanning Electronic Microscopy and to the adhesive interface analysis through the gap mensuration in three distinct regions: (IA1) tooth/restoration interface; (IA2) angle/restoration interface; (IA3) pulpar wall/restoration interface. The results were submitted to the descriptive and statistical analysis, by the analysis of variance (ANOVA) (p=0,05), which results allowed the following conclusions: a) none of the tested intermediate materials determined amalgam microstructure alterations; b) there was significant increase in porosities in the interior of amalgam of the groups II and III; c) The association of amalgam with intermediate materials was not capable to avoid the gap formation in the tooth/restoration interface... (Complete abstract, click electronic address below). / Mestre

A dureza é uma propriedade bastante utilizada para comparar tanto os materiais restauradores como os tecidos biológicos. É definida pela resistência do material à deformação plástica e mensurada pela relação da força aplicada e a área de endentação. Para esse estudo foram utilizados dois materiais: amálgama e resina composta e dois tecidos dentais: dentina e esmalte bovinos. No total foram confeccionados 20 espécimes, divididos em 4 grupos: A (Amálgama), R (Resina Composta), D (Dentina) e E (Esmalte) de acordo com cada superfície. Para os grupos A e R foram confeccionadas cavidades que foram restauradas com os respectivos materiais, no grupo E teve a superfície apenas planificada e o grupo D teve desgaste até a exposição de dentina. Para os testes foram utilizados os endentadores Vickers e Knoop; as cargas de 25, 50 e 100gf em cinco tempos de endentação 5, 15, 30, 45, e 60s. Os valores dos testes foram submetidos à análise estatística pelo teste Kruskall-Wallis e Student-Newman-Keuls (p<0,05). Os resultados permitiram concluir que para o amálgama deve se utilizar no mínimo uma carga de 50gf em um tempo mínimo de 30s tanto para a Vickers como para a Knoop. Na resina composta uma carga de 50gf e tempo de 45s para a Knoop e na dureza Vickers não apresentou diferenças. Na dentina a carga ideal é de pelo menos 50gf em qualquer dos tempos na dureza Vickers e Knoop. E o esmalte uma carga de 100gf para qualquer tempo na dureza Knoop. / The hardness is a mechanical property utilized to compare restorative materials such as biological tissue and can be defined as the resistance of material for a permanent impression and a number related to the applied force and the surface area. As each material has its own mechanical characteristic, for this study utilized two materials: amalgam and composite resin and two dental tissues: bovine dentin and enamel. In total were 20 specimes, divided among 4 groups: A, R, D, E equivalent for each superficial. The groups A and R received cavities preparation that were restored into with the respective materials, the group D had the superficial wore until exposure of the dentin and the group E was so planning. For the microhardness testing were utilized Vickers and Knoop indenter; loads of 25, 50 and 100gf in 5 time of application 5, 15, 30, 45 e 60 seconds. The values were submitted for statistical analysis by Kruskall-Wallis and Student-Newman-Keus tests (p<0.05). Due to the results, it is concluded that the amalgam presented a minimum load adequated of 50gf and a time of application of 30 seconds as the Vickers as Knoop. In the composite resin the minimum load was 50gf and time was 45s for Knoop, the Vickers didnt have statistical diference. In dentin the minimum load was 50gf for all studies times for two tests. And the enamel presented the minimum load adequated was 100gf for all the times in the Knoop microhardness, the Vickers test didnt have statistical diference.

Objetivo: Determinar la asociación entre la percepción acerca de la amalgama con la práctica del uso de barreras de bioseguridad al eliminar dicho material por parte de los odontólogos de Lima - Perú.   Materiales y métodos: La muestra estuvo conformada por 196 odontólogos generales y/o especialistas del Colegio Odontológico del Perú y de un centro universitario de salud.  La percepción acerca de la amalgama y el uso de barreras de bioseguridad fueron evaluadas mediante una encuesta que constaba de 12 preguntas, para la cual se comprobó su confiabilidad obteniendo un valor de Cronbach de 0.94. Además, se utilizó la prueba de Chi cuadrado y prueba exacta de Fisher para asociar estas variables. El nivel de significancia se estableció como p< 0.05.   Resultados: Con respecto a la percepción de la amalgama, el 41.84% de odontólogos la consideraban segura; mientras que el 58.16% insegura. Sin embargo, se encontraron diferencias estadísticamente significativas solo en la asociación del cambio de filtro del aire acondicionado con la variable de percepción de seguridad sobre la amalgama (p=0.038).    Conclusiones: No se encontró asociación entre la percepción de la amalgama y el uso de barreras de bioseguridad durante su eliminación. Además, sólo el 1.02% de encuestados realizaban seguimientos periódicos de mercurio. Por ello, se enfatiza la necesidad de implementación de cursos académicos acerca de la toxicidad de la amalgama y métodos de barreras de bioseguridad durante su manipulación. / Objective: To determine the association between amalgam perception and the use of biosafety barriers when removing such material by odontologists from Lima-Peru. Materials and methods: The sample was composed of 196 general dentists and/or specialists from the Dental College of Peru and from a University Health Center. Amalgam perception and the use of biosafety barriers were tested through a survey which consisted of 12 questions, and whose reliability was assessed using Cronbach’s alpha giving a value of 0.94. In addition, the Chi-square and Fisher´s exact tests were used to associate these variables. The significance level was set as p< 0.05. Results: Regarding amalgam perception, a total of 41.84 percent of dentists declared it to be safe; while 58.16 percent of them declared it to be unsafe. However, statistically significant differences were found only in the association of air- conditioning filter change and the amalgam safety perception variable (p=0.038). Conclusions: No association was found between amalgam perception and the use of biosafety barriers when removing it. Furthermore, only 1.02 percent of the respondents were carrying out regular monitoring of mercury. Consequently, emphasis is placed on the need of implementing academic courses about amalgam toxicity and biosafety barrier methods during its manipulation. / Tesis

The electrochemic's behaviour of the bile acids (cholic, glycocholic, deoxycholic, ursodeoxycholic and lithocholic acid) was studied on the meniscus-modified silver solid amalgam electrode (m-AgSAE) by differential pulse voltammery. Bile acids provide in the solution of the Britton - Robinson buffer and methanol (9:1) in the pH range 3.0 to 12.0 a cathodal signal in the high negative potentials: cholic acid, deoxycholic acid, ursodeoxycholic acid and lithocholic acid about −1400 mV and glycocholic acid, which alone is the conjugate with glycine, about −1500 mV. Cholic acid, glycocholic acid, deoxycholic acid and ursodeoxycholic acid provide the highest peaks to pH 5.0, approximately in their pKa values. Lithocholic acid provides peaks from pH 7.0. It was demonstrated by the cyclic voltammetry that the electrochemical behavior is influenced by the adsorption of the bile acids to the electrode; presumed reaction at the working electrode - a reduction of a proton of a carboxylic group, is controlled by the diffusion and the process is quasireversible. Utilization of the electrochemical reduction of bile acids for the voltammetric determination does not seem very suitable. It has been proven that the presence of the methanol deteriorates the measuring results for glycocholic acid. In the presence of...

Voltammetric methods for the determination of diazepam (DZ) and nordiazepam (NDZ) were developed. Techniques differential pulse voltammetry (DPV) and DC voltammetry for determination of both substances at meniscus modified silver solid amalgam electrode (m-AgSAE) were used. Effect of pHa in media of mixture of Britton-Robinson buffer and methanol (9:1) and 0,1 mol.l-1 NaOH was studied. Stability of the signal with repeated measurements in 0,1 mol.l-1 and methanol (9:1) was monitored. Optimal pHa 13,2 of 0,1 mol.l-1 NaOH was used for determination of DZ by DPV and DCV techniques. Optimal pHa 10,2 in media of mixture of Britton-Robinson buffer and methanol (9:1) was used for determination of NDZ by DPV and DCV techniques. Under these conditions were measured linear dependences in the calibration. Concentration range of DZ was measured with DCV in range of 1.10-4 - 6.10-6 mol.l-1 and DPV with DCV technique in range of 1.10-4 - 2.10-6 mol.l-1. Concentration range of NDZ was measured with DCV technique in range of 1.10-4 - 4.10-6 mol.l-1 and DPV technique in range of 1.10-4 - 2.10-6 mol.l-1. The limit of detection was calculated for DZ 6,6 .10-6 mol.l-1 with DCV and 1.10-6 mol.l-1 with DPV. The limit of detection was calculated for NDZ 5,5.10-6 mol.l-1 with DCV and 1,7.10-6 mol.l-1 with DPV. Developed method...

Voltammetric methods for the determination of diazepam (DZ) and nordiazepam (NDZ) were developed. Techniques differential pulse voltammetry (DPV) and DC voltammetry were used for determination of DZ and NDZ at meniscus modified silver solid amalgam electrode (m-AgSAE). The effect of pHa on the intensity of signal was observed in the mixture of Britton-Robinson buffer and methanol (9:1), and in the mixture of 0.1 mol.l−1 NaOH and methanol (9:1). The stability of the signal during repeated measurements in the mixture of 0.1 mol.l−1 NaOH and methanol (9:1), and in the mixture of BR buffer and methanol (9:1) was monitored. Optimal pHa 13.2 of medium of 0.1 mol.l−1 NaOH and methanol (9:1) was used for determination of DZ with DPV and DCV techniques. Optimal pHa 10.1 of medium of BR buffer and methanol (9:1) was used for determination of NDZ with DPV and DCV techniques. Under these conditions linear dependencies calibration were measured. Concentration range of DZ was measured with DCV in range of 10x10−5 - 6x10−6 mol.l−1 and with DPV technique in range of 10x10−5 - 2x10−6 mol.l−1 . Concentration range of NDZ was measured with DCV technique in range of 10x10−5 - 4x10−6 mol.l−1 and with DPV technique in range of 10x10−5 - 2x10−6 mol.l−1 . The limit of detection for DZ was calculated 6.6x10−6 mol.l−1 with DCV and...

O objetivo do presente estudo foi diferenciar reações liquenóides de contato (RLC) de lesões de líquen plano oral (LPO) em pacientes do nosso ambulatório. De um total de 45 pacientes (36 mulheres e 9 homens; média idade = 48,7 anos) com lesões sugestivas de LPO, 18 apresentavam características clínicas compatíveis com RLC, ou seja, lesões próximas ou em contato direto com restaurações em amálgama. Estes pacientes foram classificados em classe I (discreta relação da lesão com amálgama), classe II (moderada relação) e classe III (intensa relação). Todos os pacientes com RLC foram encaminhados para realização de teste epicutâneo padrão (alérgenos \"standard\", Grupo Brasileiro de Dermatites de Contato) e específico (materiais odontológicos, Trolab, Hermal, Alemanha). A substituição do amálgama foi indicada para pacientes classe II e III; em pacientes classe I o tratamento foi indicado somente quando apresentavam teste epicutâneo positivo. Dois pacientes foram excluídos deste estudo por não comparecimento às consultas e 1 por não apresentar resultado anátomo-patológico compatível com LPO. Em pacientes classe I (3 casos), apenas um caso apresentou teste epicutâneo positivo, sendo que a substituição da restauração não resultou em melhora clínica da lesão. Em pacientes classe II (9 casos), teste epicutâneo positivo em 8 casos, a substituição resultou em melhora parcial em 7 casos e total em 2 caso. Em pacientes classe III (3 casos), teste epicutâneo positivo em 2 casos, a substituição resultou em melhora total de todos os casos. Existe um número representativo de pacientes com RLC em nosso meio, sendo que estas lesões podem apresentar associação discreta, moderada ou intensa com o amálgama. Pacientes com associação discreta (classe I) não têm benefício após substituição do material restaurador, enquanto pacientes classe II e III beneficiam-se após substituição do amálgama, obtendo resolução parcial ou total das lesões. A caracterização clínica de lesões LPO associada ao amálgama seguida da substituição do material restaurador tem valor superior aos testes epicutâneos em termos de diagnóstico de RLC. / The purpose of this study was to characterize oral lichenoid reactions (OLR) in our clinic. In a group of 45 patients (36 female and 9 male; mean age = 48.7) with oral lichen planus (OLP), 18 were identified as having OLR because these patients had their OLR lesions related to amalgam fillings. These OLR lesions were clinically graded according to their proximity with the amalgam fillings: class I (weak association with amalgam fillings), class II (moderate association), and class III (strong association). All patients were skin patch tested for both standard allergens (Standard - Brazilian Group of Contact Dermatitis, Brazil) and specific allergens (Dental material - TROLAB, Hermal, Germany). Amalgam restoration was replaced in all class II and III patients and in class I only when patients were positive skin patch test. Two patients were excluded from the study because they missed follow ups and one because histopathological analysis does not show OLP features. From 3 cases class I only 1 had positive skin patch test, but did not have improvement of the oral lesions after amalgam replacement. Class II patients (9 cases) positive skin patch test in 8 cases, resulted in substantial improvement in 7 cases and complete resolution in 2 case after amalgam replacement. Class III patients (3 cases) positive patch test in 2 cases, result in complete improvement in all cases after amalgam replacement. We can conclude that there are a representative number of patients with ORL in our clinic showing either a weak, moderate or strong association with amalgam fillings. Patients with a weak association (class I) did not have benefit after amalgam replacement, while patients with a moderate and strong association (class II and III) had benefit after amalgam replacement with substantial improvement or complete resolution of the lesions. Clinical characterization of the association between OLP lesions and amalgam filling, followed by its replacement, outperformed skin patch testing for diagnosing ORL lesions.

The partial removal of carious dentine was studied by means of a literature review and a multicenter randomized controlled clinical trial. The clinical trial compared the effectiveness of an alternative treatment for deep caries lesions and the stepwise excavation in Public Health Services in Brazil. The treatment consists of partial removal of carious dentine followed by restoration in one session. A cost-effectiveness analysis the two treatments was performed. The clinical performance of amalgam and resin restorations placed in deep caries lesions with or without decayed tissue beneath them was also evaluated. Inclusion criteria: patients with ≥ nine years old, permanent molars with deep caries lesions and absence of periapical alterations, pulp sensitivity; absence of spontaneous pain; negative percussion test. The subjects were assigned to: test-group - partial removal of carious dentine (PDR) and restoration, and control-group - stepwise excavation (SW). SW consists of partial removal of carious tissue, indirect pulp capping with calcium hydroxide cement; temporary filling; cavity re-opening after 60 days, removal of the remaining soft carious tissue and filling. Clinical and radiological exams were performed annually. The outcomes were: (1) pulp sensitivity to cold test and absence of periapical alterations, assuming those parameters as indicators of pulp vitality; and (2) success of the restoration. To determine the cost-effectiveness of the treatments, the discounted cash flow method was adopted. The data were submitted to Kaplan-Meier, Log-rank test and logistic regression analysis, P<0.05. There were performed 299 treatments, 146 SW and 153 tests. There were no differences between the groups regarding baseline characteristics - age, gender and family income. The number of teeth evaluated after one and two years were 180 and 122. After one year of treatment performance, the therapy success rates were 97.9% and 74.1% of success in test and control groups respectively (P<0.000). After 2 years of follow-up, therapy survival rates of PDR and SW were 93.7% and 73.3% respectively (P=0.000). A total of 29 therapeutic failures were observed: PDR group - pulpitis (n=3), osteitis (n=1), hyperemia (n=2); SW group - pulpitis (n=15), necrosis (n=6), extraction (n=1) and restoration fracture (n=1). None of the variables studied showed a significant causal influence on the success rate, besides the type of treatment. After two year of follow-up, 181 restorations had been evaluated, 86 from the SW group and 95 from the PDR group; 65.8% were from the resin composite group and 34.2% were amalgam restorations. The survival analysis of the treatment associated with the filling material showed no difference in the rate of success (P=0.564). Regarding the treatment, both groups presented a similar rate of success: SW=95.3% and PDR=94.7% (P=0.928). Resin composite restorations presented 96.8% of success and amalgam restorations presented 94.1% of success (P=0.446). The reason for failure was fracture of filling material. The PDR provides an economy of R$ 143.37 (67.78%) per treatment compare to SW and 2.39% in the overall economy in the annual cost of the public health center. Partial caries removal could be performed as definitive treatment and the procedure of re-opening the cavity to remove the residual infected dentine is not necessary. The maintenance of carious dentine does not interfere in the maintenance of pulp vitality. The presence of decayed tissue in deep caries lesions does not seem to interfere with the survival of the restorations. Performing the partial removal of carious dentine in one session generates benefits for the public finances (direct economy), for the public health services (increase in number of treatments performed) and for the patients (comfort and time).