RESUMO

The aim of this study is to evaluate the machinability of four CAD/CAM materials (n = 13) assessed by brittleness index, Vickers hardness, and fracture toughness and interaction among such mechanical properties. The materials selected in this in vitro study are Feldspathic ceramic [FC], Lithium-disilicate glass ceramic [LD], leucite-reinforced glass ceramic [LR], and nanofilled resin material [RN]. Slices were made from the blocks following original dimensions 14 × 12 × 3 mm (L × W × H), using a precision slow-speed saw device and then surfaces were regularized through a polishing device. Brittleness index and fracture toughness were calculated by the use of specific equations for each one of the properties. The Vickers hardness was calculated automated software in the microhardness device. One-way Anova and Pearson's correlation were applied to data evaluation. LD obtained the highest values for brittleness index and was not significantly different from FC. LR presented statistically significant difference compared with RN, which had the lowest mean. Vickers hardness showed LD with the highest average, and no statistical difference was found between FC and LR. RN presented the lowest average. Fracture toughness showed FC and LR not statistically different from each other, likewise LD and RN. The brittleness index, considered also as the machinability of a material, showed within this study as positively dependent on Vickers hardness, which leads to conclusion that hardness of ceramics is related to its milling capacity. In addition, fracture toughness of pre-sintered ceramics is compared to polymer-based materials.

Assuntos

RESUMO

Abstract: The aim of this study is to evaluate the machinability of four CAD/CAM materials (n = 13) assessed by brittleness index, Vickers hardness, and fracture toughness and interaction among such mechanical properties. The materials selected in this in vitro study are Feldspathic ceramic [FC], Lithium-disilicate glass ceramic [LD], leucite-reinforced glass ceramic [LR], and nanofilled resin material [RN]. Slices were made from the blocks following original dimensions 14 × 12 × 3 mm (L × W × H), using a precision slow-speed saw device and then surfaces were regularized through a polishing device. Brittleness index and fracture toughness were calculated by the use of specific equations for each one of the properties. The Vickers hardness was calculated automated software in the microhardness device. One-way Anova and Pearson's correlation were applied to data evaluation. LD obtained the highest values for brittleness index and was not significantly different from FC. LR presented statistically significant difference compared with RN, which had the lowest mean. Vickers hardness showed LD with the highest average, and no statistical difference was found between FC and LR. RN presented the lowest average. Fracture toughness showed FC and LR not statistically different from each other, likewise LD and RN. The brittleness index, considered also as the machinability of a material, showed within this study as positively dependent on Vickers hardness, which leads to conclusion that hardness of ceramics is related to its milling capacity. In addition, fracture toughness of pre-sintered ceramics is compared to polymer-based materials.

Assuntos

RESUMO

AIM: The aim of this study was to evaluate the inner surface of two ceramic systems: IPS Empress II (Ivoclar Vivadent, Germany) and In-Ceram Alumina (Vita Zahnfabrick, Germany) submitted to surface treatments, especially by Nd:YAG laser. MATERIALS AND METHODS: Fifty samples were prepared in pellet form for each ceramic system according to manufacturers' specifications. The samples were stored at room temperature and then be subjected to surface treatment: without treatment (T0) (control), hydrofluoric acid-etched (T1), hydrofluoric acid-etched associated with the airborne particle-abraded (T2); CoJet system (T3), Nd:YAG laser (T4). The data were performed the statistical analysis by ANOVA and Tukey's test (p < 0.001). RESULTS: The group control (T0) of the ceramics, the analysis showed the lowest roughness values; for the System Alumina In-Ceram, treatment with hydrofluoric acid (T1), associated with hydrofluoric acid and airborne particle-abraded (T2) and Nd:YAG laser (T4), had no statistically significant difference, whereas for the IPS Empress System II treatment with hydrofluoric acid (T1) and hydrofluoric acid associated with airborne particle-abraded (T2), had no statistically significant difference between the system and also CoJet (T3) and hydrofluoric acid associated with the airborne particle-abraded (T2). Photomicrographs of scanning electron microscopy showed different characteristics to the treatments for each ceramic system. CONCLUSION: The IPS Empress II had the appearance of favoring the retention when treated with hydrofluoric acid, as well as its association with the airborne particle-abraded. Uncertainty in Alumina, treatment with hydrofluoric acid associated with the airborne particle-abraded and CoJet system and provided a surface with irregularities. With respect to the laser further studies should be performed for parameters that are ideal for your application. CLINICAL RELEVANCE: The ceramic restorations are attractive due of their excellent esthetics and the ability to stay for long periods. However, the retention of ceramic requires further study.

Assuntos

RESUMO

PURPOSE: The purpose of this study was to evaluate the effect of self-adhesive and self-etching resin cements on the bond strength of nonmetallic posts in different root regions. MATERIALS AND METHODS: Sixty single-rooted human teeth were decoronated, endodontically treated, post-space prepared, and divided into six groups. Glass-fiber (GF) posts (Exacto, Angelus) and fiber-reinforced composite (FRC) posts (EverStick, StickTeck) were cemented with self-adhesive resin cement (Breeze) (SA) (Pentral Clinical) and self-etching resin cement (Panavia-F) (SE) (Kuraray). Six 1-mm-thick rods were obtained from the cervical (C), middle (M), and apical (A) regions of the roots. The specimens were then subjected to microtensile testing in a special machine (BISCO; Schaumburg, IL, USA) at a crosshead speed of 0.5 mm/min. Microtensile bond strength data were analyzed with two-way ANOVA and Tukey's tests. RESULTS: Means (and SD) of the MPa were: GF/SA/C: 14.32 (2.84), GF/SA/M: 10.69 (2.72), GF/SA/A: 6.77 (2.17), GF/SE/C: 11.56 (4.13), GF/SE/M: 6.49 (2.54), GF/SE/A: 3.60 (1.29), FRC/SA/C: 16.89 (2.66), FRC/SA/M: 13.18 (2.19), FRC/SA/A: 8.45 (1.77), FRC/SE/C: 13.69 (3.26), FRC/SE/M: 9.58 (2.23), FRC/SE/A: 5.62 (2.12). The difference among the regions was statistically significant for all groups (p < 0.05). The self-adhesive resin cement showed better results than the self-etching resin cement when compared to each post (p < 0.05). No statistically significant differences in bond strengths of the resin cements when comparable to each post (p > 0.05). CONCLUSION: The bond strength values were significantly affected by the resin cement and the highest values were found for self-adhesive resin cement.

Assuntos

RESUMO

Atualmente, a resina composta é o material de eleição para restaurações corretas nos cientes posteriores. A Odontologia Restauradora visa, a cada d s melhorar esse material e facilitar a prática restauradora. 0 presente artig c descreve a técnica da matriz oclusal confeccionada para agilizar e preservar 3 oclusal de um primeiro molar inferior acometido por lesão de cárie. Associada a essa técnica foi utilizada uma nova resina composta à base de silorano, podendo ser colocada em incrementos maiores, pois esse material possui baixa contração e tensão de polimerização. Pôde-se concluir que o uso de matriz oclusal associada com uma resina composta de baixa contração pode simplificar o trabalho clínico e resultar em uma excelente restauração com reprodução dos detalhes anatômicos.

Assuntos

RESUMO

Nanotecnologia, ciência do minúsculo, gera produtos capazes de manipular átomos e moléculas com aplicação no processo de esterilização de instrumentais odontológicos. Objetivo: Avaliar a ação autolimpante e esterilizante do processo de fotocatálise heterogênea desencadeado pela ação da luz UV e branca sobre o recobrimento de instrumentos odontológicos com nanopartículas de TiO2 e Ag. Material e método: Foram realizados testes bacteriológicos em espátulas odontológicas revestidas com nanopartículas de TiO2 e Ag (uma ou três camadas) e contaminadas com 10 mcrl dos microrganismos Enterococcus faecalis e Pseudomonas aeruginosa. Após contaminação, as espátulasforam expostas à luz UV e branca por 120 minutos, transferidas para tubos contendo meio BHI e incubadas a 35-37 °C. Foram feitas leituras em intervalos de 24, 48, 72 e 96 horas para verificação do crescimento das bactérias e testes de controle e recuperação. Resultado: A Pseudomonas aeruginosa foi inativada após exposição de 120 minutos à luz UV, indicando a ocorrência do processo de fotocatálise heterogênea no recobrimento de nanopartículas de TiO2 e Ag das espátulas. A Pseudomonas aeruginosa não foi inativada pela exposição à luz branca e o Enterococcus faecalis não foi inativado pela exposição à luz UV e à branca nas espátulas de cimento odontológico recobertas com nanopartículas de TiO2 e Ag, nas leituras de até 96 horas, ocorrendo o crescimento bacteriano. Conclusão: Não houve influência do revestimento das espátulas com uma ou três camadas de nanopartículas de TiO2 e Agnos resultados. A fotocatálise heterogênea da Pseudomonas aeruginosa foi confirmada pela exposição à luz UV da espátula com revestimento de TiO2 e Ag, mas não pela luz branca. A fotocatálise heterogênea do Enterococcus fecalis não foi confirmada tanto pela exposição do TiO2 e Ag à luz UV como à branca.

Nanotechnology, the science of minuscule, has developed products which are able t o manipulate atoms and molecules that could be applied in the sterilization process of dental instruments. Objetives: The objective of the present study was to evaluate the self-cleaning action of TiO2 and Ag nanoparticles coating on dental instruments by the photocataliys process under UV and visible light irradiation. Material and method: Microbiologic tests were done using dental cement spatulas coated with TiO2 and Ag nanoparticles (one or three layers), and contaminated with 10 mcrl of Pseudomonas aeruginosa and Enterococcus faecalis, respectively. After contamination, they were exposed to ultraviolet light and visible light for 120 minutes. Next, they were transferred to and stored in test tubeswith BHI (Brain Heart Infusion) and incubated in 35 to 37 °C. Checking times for bacterial growth and for control and retrieval tests were done at: 24, 48, 72 and 96 hours. Result: The Pseudomonas aeruginosa was inactive after120 minutes of ultraviolet light irradiation, thus confirming the heterogeneous photocatalytic activity of TiO2 and Ag. The Pseudomonas aeruginosa was not inactivated under visible light irradiation and the Enterococcus faecalis was not inactivated under UV and visible light irradiation of the dental cement spatulas coated with TiO2 and Agnanoparticles in the readings to 96 hours, showing bacterial growth. Conclusion: There were no influence of one or three layers of TiO2 and Ag nanoparticles coating of the spatulas in the results. The heterogeneous photocatalysis activity of TiO2 and Ag under UV light irradiation was confirmed for Pseudomonas aeruginosa but not under visible light. Enterococcus faecalis did not confirmed the photocatalytics activity of TiO2 and Ag under UV light irradiation and visible lights irradiation.

Assuntos

RESUMO

Introdução: Com o sucesso alcançado com a utilização das resinascompostas em dentes anteriores, prontamente se iniciou o seu empregona região posterior. Contudo a aplicação indiscriminada dessesmateriais em cavidades das mais variadas amplitudes rapidamentedenunciou sua falta de resistência ao desgaste oclusal e proximal.Objetivo: Analisar a rugosidade superficial de resinas compostas emfunção da técnica de acabamento e polimento. Material e métodos:Foram confeccionados oito grupos experimentais (n = 15), divididosde acordo com a técnica de acabamento ou polimento: G1 ? resinacomposta Z250TM sem acabamento ou polimento superficial; G2? Z250TM com acabamento e polimento superficial; G3 ? resina P60TMsem acabamento nem polimento superficial; G4 ? resina P60TM comacabamento e polimento superficial; G5 ? resina Prodigy CondensableTM sem acabamento ou polimento superficial; G6 ? resina ProdigyCondensableTM com acabamento e polimento superficial; G7 ? resinaSurefillTM sem acabamento nem polimento superficial; G8 ? resinaSurefillTM com acabamento e polimento superficial. Empregaram-setrês resinas compostas compactáveis e uma micro-híbrida (grupocontrole). A rugosidade superficial foi avaliada por meio de um aparelhode rugosímetro em três pontos em cada amostra. Submeteram-seos resultados a análise de variância e ao teste de Tukey (p < 0,05).Resultados: A resina composta Prodigy CondensableTM apresentoumenor rugosidade superficial, enquanto a SurefillTM mostrou maiorrugosidade superficial. Na comparação entre as resinas não houvediferença estatística significante apenas entre a P60TM e a SurefillTM(p ? 0,05). Conclusão: A rugosidade superficial foi menor em todos ostipos de resina composta com a matriz de poliéster em comparação àssuperfícies obtidas após o procedimento de acabamento e polimento.

Introduction: The success achieved by the use of composite resins inanterior teeth precipitately leads their use in posterior teeth. However,the indiscriminate application of these materials in cavities with severaldiverse sizes rapidly pointed out their lack of resistance to oclusaland proximal wear. Objective: To evaluate the surface roughnessof composite resin in relation to finishing and polishing technique.Material and methods: Eight experimental groups (n = 15) were dividedaccording to finishing and polishing technique: G1 ? Z250TM compositeresin without surface finishing and polishing; G2 ? Z250TM compositeresin plus surface finishing and polishing; G3 ? P60TM composite resinwithout surface finishing and polishing; G4 ? P60TM composite resinplus surface finishing and polishing; G5 ? Prodigy CondensableTMcomposite resin without surface finishing and polishing; G6 ? ProdigyCondensableTM composite resin plus surface finishing and polishing;G7 ? SurefillTM composite resin without surface finishing and polishing;G8 ? SurefillTM composite resin plus surface finishing and polishing.Three packable and one microhybrid (control group) composite resinwas used. The surface roughness was measured using a profilometerat three points in each sample. The results were evaluated by ANOVAand Tukey test (p < 0.05). Results: Prodigy CondensableTM compositeresin showed the lowest surface roughness, while SurefillTM showed thehighest surface roughness. Comparing the resins used, only betweenP60TM and SurefillTM there were no statistically significant differences(p ? 0.05). Conclusion: Surface roughness was lower in all types ofresin composites surfaces in contact with Mylar matrix strip than inareas submitted to finishing and polishing procedure.

RESUMO

Introdução A procura por tratamentos estéticos tem aumentadograças à conscientização da sociedade sobre a importância da saúdee da estética dental. Nos dias de hoje, tem havido um substancialdesenvolvimento dos sistemas cerâmicos, tornando-os confiáveise com resultados previsíveis. As cerâmicas dentárias, além dequimicamente estáveis, apresentam propriedades ópticas excelentesquando comparadas às estruturas dentárias, o que lhes garante umposto especial no rol dos materiais restauradores estéticos. Objetivo,relato de caso e conclusão: Descrever um caso clínico com sucessoenvolvendo a estética de dentes anteriores, restaurados com coroaspuras de cerâmica (IPS e.max® Ivoclar Vivadent).

Introduction: Society?s change of parameters for health and aestheticshas resulted in an increased demand for dental treatments. Nowadays,ceramics systems have shown a substantial development, becoming more reliable and predictable. Dental ceramics, besides being chemicallystable, present excellent optical properties when compared to dentalstructures, thus assuring a special position in the list of aestheticrestorative materials. Objective, case report and conclusion: Thisarticle describes a successful clinical procedure involving the anteriorteeth aesthetics, which were restored with all-ceramic crowns (IPSe.max® Ivoclar Vivadent).

RESUMO

A esterilização e a biossegurança em Odontologia assim como em Ortodontia tem recebido inúmeras sugestões como também modificações, com o intuito de minimizar as chances de contaminação entre pacientes e profissionais. Vários são os trabalhos que classificam os procedimentos odontológicos como: críticos, semicríticos e acríticos, a fim de estabelecer protocolos de desinfecção, esterilização e biossegurança. Assim atenção especial ao paciente, preocupação com o profissional e pessoal auxiliar, bem como cuidado nos ambiente clínico e laboratorial tem sido ressaltados na busca de procedimentos de controle total de esterilização de instrumentais abordando vários métodos para enfim estabelecer um protocolo rígido no ambiente de trabalho.

Assuntos

RESUMO

Com base em uma revisão de literatura, pode-se verificar que existe grande quantidade de metodologias propostas para se verificar a translucidez e opacidade de materiais restauradores estéticos, diretos e indiretos. Estes métodos proporcionam medidas qualitativas (inspeção visual, fotografias) e medidas quantitativas (espectrofotometria de luz visível, por transmissão direta ou total; aparelho de eletroforese de Juan; cálculo do raio de contraste, por espectrofotometria ou goniofotometria), cabendo ao pesquisador análise crítica das vantagens e desvantagens de cada metodologia antes da opção em utilizá-la.

With base in a literature review, it can be verified that a great amount of methodologies exists proposals to verify the translucency and opacity of the aesthetic restorative materials, indirect and directs, which provides to qualitative measure (visual inspection, photographs) and quantitative measure (espectrofotometria of visible light, for direct or total transmission; eletroforese of Juan; calculation of the contrast ray, for espectrofotometria or goniofotometria), having therefore to the researcher a critical analysis of the advantages and disadvantages of each methodology before the option using it.

Assuntos