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1.
Braz. dent. j ; 32(3): 44-55, May-June 2021. tab, graf
Article in English | LILACS, BBO | ID: biblio-1345505

ABSTRACT

Abstract In the RLT (Rapid Layer Technology), veneering ceramic and framework are fabricated by computer-aided design/computer-aided manufacturing (CAD/CAM) and then cemented to obtain the restoration. This study aimed to evaluate the effect of the thickness of veneering ceramic manufactured by the RLT technique on the fracture resistance (FR) of bilayer crowns with zirconia frameworks. Twenty zirconia frameworks and twenty feldspathic posterior crowns with two different veneering ceramic occlusal thicknesses (1mm=TF1; 2mm=TF2) were manufactured using CAD/CAM system. The specimens were luted to an epoxy resin abutment with resin cement and mechanically cycled (200N and 4.5×105 Pa, 37°C, 2×106 cycles, 3Hz). The FR test was performed (10kN, 0.5mm/min), and the specimens were analyzed in a stereomicroscope. For the stress analysis (finite element analysis, FEA), a 10kN load was equal to the in vitro test, and the principal stress was evaluated. The FR data were analyzed by Student's t-test and Weibull's analysis. The thickness influenced the FR of bilayer crowns. The FR was higher in the TF2 than in the TF1 group. The TF2 group presented the highest characteristic strength compared to the group TF1. The predominant type of failure was delamination. The FEA showed higher stress concentrations below the loading application point at the veneering cement interface in the 1-mm-thick model. The bilayer crowns manufactured using the approach of 2mm of veneering ceramic promoted higher FR compared to the group with 1mm veneering ceramic. Also, the FEA showed that the veneer ceramic thickness has an effect on stress distribution in zirconia-based bilayer crowns.


Resumo Na RLT (Rapid Layer Technology), a cerâmica de cobertura e infraestrutura são fabricados pelo Computer-Aided Design / Computer-Aided Manufacturing (CAD / CAM) e cimentados para obter a restauração. Este estudo teve como objetivo avaliar o efeito da espessura da cerâmica de cobertura fabricada pela técnica RLT na resistência à fratura (RF) de coroas bilaminadas com infraestrutura de zircônia. Vinte infraestruturas de zircônia e vinte coroas posteriores feldspáticas com duas espessuras oclusais da cerâmica de cobertura (1mm = TF1; 2mm = TF2) foram fabricadas usando o sistema CAD / CAM. Os espécimes foram cimentados em preparos de resina epóxi com cimento resinoso dual e ciclados mecanicamente (200N e 4,5×105 Pa, 37° C, 2×106 ciclos, 3Hz). O teste de RF foi realizado (10kN, 0,5mm / min) e, posteriormente, os espécimes foram analisados em estereomicroscópio. Para a análise de tensão (análise de elementos finitos, FEA), uma carga de 10kN foi aplicada igual ao teste in vitro, e a tensão principal foi avaliada. Os dados de RF foram analisados pelo teste t de Student e análise de Weibull. A espessura mostrou forte influência na RF das coroas bilaminadas. A RF foi maior em TF2 do que no grupo TF1. O grupo TF2 apresentou a maior resistência característica em relação ao grupo TF1. O tipo de falha predominante foi a delaminação. O FEA mostrou maiores concentrações de tensões abaixo do ponto de aplicação da carga, na interface cimento e cerâmica de cobertura no modelo de coroa de 1 mm de espessura. As coroas de bilaminadas confeccionadas com 2 mm de cerâmica de cobertura promoveram maior RF em comparação ao grupo com cerâmica de cobertura de 1 mm. Além disso, a FEA mostrou que a espessura da cerâmica de cobertura tem um efeito na distribuição de tensões em coroas bilaminadas à base de zircônia.


Subject(s)
Humans , Dental Porcelain , Dental Veneers , Technology , Zirconium , Materials Testing , Ceramics , Computer-Aided Design , Dental Restoration Failure , Crowns , Dental Stress Analysis
2.
Braz. dent. j ; 32(2): 53-63, Mar.-Apr. 2021. tab, graf
Article in English | LILACS, BBO | ID: biblio-1339327

ABSTRACT

Abstract The present study was a prospective, controlled, randomized, clinical short-term trial aiming to evaluate the clinical performance of adhesively luted, lithium disilicate and feldspathic glass-ceramics onlays over a period up to 2 years. A total of 11 patients (7 female, 4 male; age range: 18-60 years, mean age: 39 years) were selected for this study. Each patient received a maximum of two restorations per group in a split-mouth-design. LD: Eleven onlays, performed with lithium disilicate-based ceramic (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein), and FP: Eleven onlays, performed with feldspathic ceramic (Vita Mark II, Vita Zanhfabrik, Bad Säckingen). Recalls were performed at 2 weeks (baseline = R1), 1 year (R2) and 2 years (R3) after the cementation by three calibrated blinded independent investigators using mirrors, magnifying eyeglasses, probes and bitewing radiographs. The postoperative sensitivity, secondary caries, marginal integrity, marginal discoloration, color match, surface roughness, tooth integrity, and restoration integrity were evaluated. The Friedman test was used to determine if there was a statistically significant difference in time-to-time comparison of the parameters in the ceramics restorations. A total of 95.4% of the restorations were clinically acceptable at the 2-year recall, without a difference for any evaluation parameter for both ceramic materials. Based on the 2-year data, the CAD-CAM onlays manufactured with feldspathic and lithium-disilicate based ceramics showed similar clinical performance.


Resumo O presente estudo é um estudo clínico prospectivo, controlado, randomizado e de longo curto prazo, com o objetivo de avaliar o desempenho clínico de restauraç ões adesivas cerâmica vítrea reforçada com dissilicato de lítio e cerâmica feldspática por um período de até 2 anos. Um total de 11 pacientes (7 mulheres, 4 homens; faixa etária: 18-60 anos, idade média: 39 anos) foram inseridas para este estudo. Cada paciente recebeu duas restaurações por grupo em um delineamento de boca dividida. LD: Onze onlays, realizados com cerâmica à base de dissilicato de lítio (IPS e.max CAD, Ivoclar Vivadent, Schaan, Liechtenstein); e FP: Onze onlays, realizados com cerâmica feldspática (Vita Mark II, Vita Zanhfabrik, Bad Säckingen). Os retornos foram realizados em 2 semanas (linha de base = R1), 1 ano (R2) e 2 anos (R3) após a cimentação, por três investigadores independentes, cegos e calibrados, usando espelhos, óculos de aumento, sondas e radiografias interproximais. Foram avaliadas a sensibilidade pós-operatória, cárie secundária, integridade marginal, descoloração marginal, correspondência de cores, rugosidade da superfície, integridade dentária e integridade da restauração. O teste de Friedman (95%) foi utilizado para determinar se havia uma diferença estatisticamente significante na comparação periódica dos parâmetros nas restaurações cerâmicas. Um total de 95,4% das restaurações estava clinicamente aceitável no retorno de 2 anos, sem diferença para qualquer parâmetro de avaliação para ambos os materiais cerâmicos. Com base nos dados de 2 anos, as restaurações CAD-CAM fabricados com cerâmica feldspática e à base de dissilicato de lítio apresentaram desempenho clínico semelhante.


Subject(s)
Humans , Male , Female , Adolescent , Adult , Middle Aged , Young Adult , Inlays , Mouth , Prospective Studies , Dental Porcelain
3.
Int. j. odontostomatol. (Print) ; 14(4): 678-684, dic. 2020. graf
Article in English | LILACS | ID: biblio-1134557

ABSTRACT

ABSTRACT: The present study aims to describe, through a case report, the functioning of bone grafts, where they are obtained including bone banks and the different dental areas in which it is used. A 50-year.old female patient HMR, sought the postgraduate college of dentistry CECAPE for oral rehabilitation. The initial clinical examination revealed the absence of several dental elements in both the maxilla and mandi ble, bone resorption in the entire maxillary extension where there was an absence of elements in the anterior region and the presence of a torus in the palatal region. Initial tomographic examinations of the maxilla and mandible were performed, looking for the best conduct regarding the diagnosis and planning of the case. After the clinical and radiographic examinations was performed, and the diagnosis was reached, it was determined as a treatment for oral rehabilitation of the maxilla, bone grafting and an Implant-supported Removable Partial Prosthesis and for the mandible a Dento-muco-supported Removable Partial Prosthesis. Dental treatments and oral rehabilitation from the use of bone tissues and bone grafting have become commonly used. Procedures that would normally lead to failure started to increase the percentage of successes due to the use of these biomaterials. The use of bone grafts in dentistry has been shown to be a very effective and useful resource, considering its great applicability in bone reconstructions in different areas of dentistry.


RESUMEN: El presente estudio tiene como objetivo describir a través de un informe de caso, el funcionamiento de los injertos óseos, donde se obtienen, incluidos los bancos de huesos y las diferentes áreas dentales en las que se emplea. Una paciente HMR, de 50 años de edad, asistió el centro universitario de posgrado CECAPE para rehabilitación oral. El examen clínico inicial reveló la ausencia de varios dientes tanto en el maxilar como en la mandíbula, la resorción ósea en toda la extensión maxilar donde había ausencia de dientes en la región anterior y la presencia de un torus en la región palatina. Se realizaron exámenes tomográficos iniciales del maxilar y mandíbula, buscando la mejor conducta con respecto al diagnóstico y la planificación del caso. Después de los exámenes clínicos y radiográficos realizados y el diagnóstico listo, se determinó como un tratamiento para la rehabilitación oral del maxilar, el injerto óseo y una prótesis removible implantosoportada y para la mandíbula una prótesis parcial removible dento-muco-soportada. Los tratamientos dentales y la rehabilitación oral a partir del uso de tejidos óseos y el injerto óseo se han utilizado comúnmente. Los procedimientos que normalmente conducirían al fracaso comenzaron a aumentar el porcentaje de éxitos debido al uso de estos biomateriales. Se ha demostrado que el uso de injertos óseos en odontología es un recurso muy eficaz y útil, considerando su gran aplicabilidad en las reconstrucciones óseas en diferentes áreas de la odontología.


Subject(s)
Humans , Female , Middle Aged , Bone Transplantation/methods , Dental Implantation, Endosseous/methods , Bone-Implant Interface/diagnostic imaging , Tomography, X-Ray Computed , Mandible/diagnostic imaging , Mouth Rehabilitation
4.
Rev. bras. odontol ; 77(1): 1-5, jan. 2020. ilus, tab
Article in English | LILACS | ID: biblio-1103246

ABSTRACT

Objetivo: Analisar a influência da resistência de união entre cimento resinoso e cerâmica feldspática utilizando concentrações e tempos de aplicação diferentes de acído fluorídrico (HF). Material e Métodos: Foram confeccionados 18 discos de cerâmica feldspática (Ø10mm - 2mm de espessura) através da técnica incremental, que foram incluídos em resina acrílica e regularizados com lixas de carbeto de silício com granulações de 600, 1200 e 2000 através de uma máquina de polimento com velocidade de 600 rpm para regularização. Logo após foram mergulhadas em água destilada durante 10 minutos em cuba ultrassônica. Todos corpos de prova foram condicionados com HF e silanizados. Foram confeccionados quatro cilindros de cimento sobre cada corpo de prova (n=12), feitos com cimento resinoso Relyx ARC. Logo após, dividiu-se em seis grupos de acordo com o protocolo de tratamento de superfície: G1 (5% - 40s); G2 (5% - 60s); G3 (5% - 80s); G4 (10% - 40s); G5 (10% - 60s) e G6 (10% - 80s). Os corpos de prova foram submetidos ao Teste de Microcisalhamento, com força vertical a uma velocidade de 0,5 mm/min sobre a peça. A resistência de união ao microcisalhamento foi calculada e expressa em Megapascal (MPa). Os dados foram submetidos à análise de variância (ANOVA) dois fatores e para comparações múltiplas foi utilizado o Teste de Tukey, sendo o nível de significância de 5%. Resultados: Quando analisado a concentração do HF, não houve diferenças estatísticas (p>0,05). Na comparação dos tempos de aplicação, G3 (5% - 80s) e G6 (10% - 80s) obtiveram maiores resultados de resistência ao microcisalhamento que os demais grupos. Conclusão: As diferentes concentrações de HF não influenciaram na resistência de união entre cerâmica feldspática e cimento resinoso. Já o aumento do tempo de condicionamento com HF afetou na resistência de união


Objective: analyze the influence of bond strength between resin cement and feldspathic ceramics using different concentrations and application times of hydrofluoric acid (HF). Materials and Methods: 18 feldspathic ceramic discs (Ø10mm - 2mm thickness) were made through the incremental technique, which were included in acrylic resin and regularized with silicon carbide sandpaper with granulations of 600, 1200 and 2000 through a polishing machine with a speed of 600 rpm. Soon after, they were immersed in distilled water for 10 minutes in an ultrasonic bath. All specimens were conditioned with HF and silanized. Four cement cylinders were made on each specimen (n=12), manufactured with Relyx ARC resin cement. After that, it was divided into six groups according to the surface treatment protocol: G1 (5% - 40s); G2 (5% - 60s); G3 (5% - 80s); G4 (10% - 40s); G5 (10% - 60s) e G6 (10% - 80s). The specimens were subjected to the Microshear Test, with vertical force at a speed of 0.5 mm min on the specimen. The microshear bond strength was calculated and expressed in Megapascal (MPa). The data were submitted to two-way analysis of variance (ANOVA) and Tukey's test for multiple comparisons, with a significance level of 5%. Results: when the concentration of HF was analyzed, there were no statistical differences (p>0.05). In the comparison of application times, G3 (5% - 80s) and G6 (10% - 80s) obtained higher results of microshear resistance than the other groups. Conclusion: The different concentrations of HF did not influence the bond strength between feldspathic ceramics and resin cement. However, the increase in the time of HF conditioning affected in the bond strength.


Subject(s)
Acid Etching, Dental , Dentin-Bonding Agents , Resin Cements
5.
Rev. bras. odontol ; 77(1): 1-5, jan. 2020. ilus
Article in English | LILACS | ID: biblio-1104150

ABSTRACT

Objetivo: avaliar as principais caracteristicas das cerâmicas odontológicas, cimentos resinosos, tratamentos de superfície e verificação dos seus devidos modos de falha, frente à literatura e suas respectivas utilizações clínicas. Material e Métodos: foi realizada uma busca bibliográfica nos principais bancos de dados de saúde PUBMED (www.pubmed.gov) e Scholar Google (www.scholar.google.com.br), no qual coletou-se trabalhos que foram publicados de 2002 a 2020. Foram inclusos estudos laboratoriais, relatos de casos, revisões sistemáticas e revisões de literatura, que fossem desenvolvidos em indivíduos vivos. Logo, foram excluídos artigos que não tratavam a respeito das caracteristicas das cerâmicas odontológicas, cimentos resinosos, tratamentos de superfície e verificação dos seus devidos modos de falha, frente à literatura e suas respectivas utilizações clínicas. Resultados: as cerâmicas podem ser classificadas em cerâmicas vítreas, cerâmicas policristalinas e as cerâmicas híbridas. Do mesmo modo que existem diferentes composições das cerâmicas e agentes de união, há também alguns protocolos de tratamento de superfície que se diferem de acordo com a escolha desses materiais. Conclusão: diversos sistemas cerâmicos estão disponíveis no mercado, fazendo com que os profissionais da área protética necessitem de uma constante reciclagem acerca das suas propriedades e indicações, visto que bons resultados não são devidos exclusivamente ao tipo de material utilizado, mas sim, à seleção do melhor material, tipo de preparo em conjunto à habilidade do profissional, cimentos resinosos, tratamentos de superfície e verificação dos seus devidos modos de falha. Nesse contexto, fazem-se necessários maiores estudos com relação às cerâmicas odontológicas e seu devido uso em um cenário clínico


Objective: to evaluate the main characteristics of dental ceramics, resin cements, surface treatments and verification of their failure modes, in relation to the literature and their respective clinical uses. Material and Methods: a bibliographic search was conducted in the main health databases PUBMED (www.pubmed.gov) and Scholar Google (www.scholar.google.com.br), in which studies published from 2002 to 2020 were collected. Laboratory studies, case reports, systematic and literature reviews, which were developed in living individuals, were included. Therefore, articles that did not deal with the main characteristics of dental ceramics, resin cements, surface treatments and verification of their failure modes, in relation to the literature and their respective clinical uses were excluded. Results: ceramics can be classified into glass-matrix ceramics, polycrystalline ceramics and hybrid ceramics. Just as there are different compositions of ceramics and bonding agents, there are also some surface treatment protocols that vary according to the choice of these materials. Conclusion: several ceramic systems are available, making professionals in the prosthetic area need a constant update about their properties and indications, since good results are not due exclusively to the type of material used, but also to the selection of the best material, type of preparation, professional's skill, resin cements, surface treatments and verification of their failure modes. In this context, further studies are needed in relation to dental ceramics and their proper clinical use


Subject(s)
Ceramics/chemistry , Resin Cements , Dental Materials
6.
J. appl. oral sci ; 28: e20200438, 2020. tab, graf
Article in English | LILACS, BBO | ID: biblio-1134779

ABSTRACT

Abstract Glaze application on monolithic zirconia (Y-TZP) can be a practical approach to improve the mechanical properties of this material. Objective Our study evaluated the effect of glazing side and mechanical cycling on the biaxial flexure strength (BFS) of a Y-TZP. Methodology Eighty sintered Y-TZP discs (Ø:12 mm; thickness: 1.2 mm - ISO 6872) were produced and randomly assigned into eight groups (n=10), according to the factors "glazing side" (control - no glazing; GT - glaze on tensile side; GC - glaze on compression side; GTC - glaze on both sides) and "mechanical aging" (non-aged and aged, A - mechanical cycling: 1.2×106, 84 N, 3 Hz, under water at 37°C). Specimens were subjected to BFS test (1 mm/min; 1,000 Kgf load cell) and fractured surfaces were analyzed by stereomicroscopy and SEM. Hsueh's rigorous solutions were used to estimate the stress at failure of glazed specimens. Two-way ANOVA, Tukey's test (5%), and Weibull analysis were performed. Results The "glazing side", "mechanical aging" and the interaction of the factors were significant (p<0.05). Groups GC (1157.9±146.9 MPa), GT (1156.1±195.3 MPa), GTC (986.0±187.4 MPa) and GTC-A (1131.9±128.9 MPa) presented higher BFS than control groups (Tukey, 5%). Hsueh's rigorous solutions showed that the maximum tensile stress was presented in the bottom of zirconia layer, at the zirconia/glaze interface. Weibull characteristic strength (σo) of the GC was higher than all groups (p<0.05), except to GT, GTC-A and GTC, which were similar among them. The fractography showed initiation of failures from zirconia the tensile side regardless of the side of glaze application and fatigue. Conclusion Glazing zirconia applied on both tensile and compression sides improves the flexural strength of Y-TZP, regardless the mechanical aging.


Subject(s)
Zirconium , Dental Porcelain , Flexural Strength , Stress, Mechanical , Surface Properties , Yttrium , Materials Testing , Ceramics
7.
Int. j. odontostomatol. (Print) ; 14(3): 457-463, 2020. tab, graf
Article in English | LILACS | ID: biblio-1114921

ABSTRACT

To evaluate clinically the results of two surgical techniques used for root coverage, the coronally advanced flap in '' L '' isolated (CAF) or associated with subepithelial connective tissue graft (SCTG). The surgical procedures were performed in seventeen individuals, ten individuals in the control group (coronally advanced flap in "L") and seven individuals in the test group (coronally advanced flap in "L" associated with SCTG), who presented Miller class I and II gingival recession. The depth gingival recession (GR) index was evaluated in the following periods: immediate preoperative and 180 postoperative days. The control group had a success rate of 85 +/- 18 % and the test group had a success rate of 95 +/- 4 %. The variable success rates (p=0.36) did not present a statistically significant difference. The isolated CAF or its association with SCTG showed favorable outcomes in the treatments of Miller's class I and II gingival recessions.


El objetivo fue evaluar clínicamente los resultados de dos técnicas quirúrgicas utilizadas para la cobertura radicular, el colgajo coronalmente avanzado en "L" aislado (CAF) o asociado con injerto de tejido conectivo subepitelial (SCTG). Los procedimientos quirúrgicos se realizaron en diecisiete individuos, diez individuos en el grupo de control (colgajo coronario avanzado en "L") y siete individuos en el grupo de prueba (colgajo coronalmente avanzado en "L" asociado con SCTG), que presentaron la clase I de Miller y II recesión gingival. El índice de recesión gingival profunda (RG) se evaluó en los siguientes períodos: preoperatorio inmediato y 180 días postoperatorios. El grupo de control tuvo una tasa de éxito de 85 +/- 18 % y el grupo de prueba tuvo una tasa de éxito de 95 +/- 4 %. Las tasas de éxito variables (p = 0,36) no presentaron una diferencia estadísticamente significativa. La CAF aislada o su asociación con SCTG mostraron resultados favorables en los tratamientos de las recesiones gingivales de clase I y II de Miller.


Subject(s)
Humans , Surgical Flaps , Connective Tissue/transplantation , Gingival Recession/surgery , Tooth Root , Case-Control Studies , Treatment Outcome
8.
Braz. dent. j ; 30(5): 505-510, Sept.-Oct. 2019. tab, graf
Article in English | LILACS | ID: biblio-1039138

ABSTRACT

Abstract The aim of this study was to investigate the three-dimensional wear, volumetric loss and surface roughness after chewing simulation of two glass ceramics. Lithium disilicate (LD, Emax CAD, Ivoclar) and Zirconia reinforced lithium silicate (ZLS, Vita Suprinity, Vita Zhanfabrick) discs (n=20/g) were scanned to obtain stereolithography (STL) files for each sample. All discs were submitted to chewing simulation with sliding configuration (30 N, 300,000 cycles, 6 mm and 1.7 Hz) with steatite as antagonist. The samples were then scanned again and the volume loss and the deepest defect depth was measured using the superimposed file from the baseline using three-dimensional digital parametric inspection software (GOM Inspect, Braunschweig, Germany). Surface roughness (Ra and Rz) was analyzed with a contact profilometer. Data were analyzed by one-way ANOVA and Tukey test (α=0.5%). ANOVA showed significant differences among the groups. Considering the ceramic volume loss, wear depth defect length and Rz roughness, LD (-22.09±5.57%; 0.80±0.06 µm; 3.08±1.02 µm) showed higher mean values than ZLS (-15.67±4.51%; 0.56±0.09 µm; 1.51±0.90 µm). Ra mean values were similar for both materials (p=0.064). All discs exhibited slight surface scratches along with the sliding direction with pitted wear patterns, while large cracks were observed on wear traces. These same areas can be identified in blue, overlapping the STL files before and after chewing simulation in inspection software. The linear reduction generated by sliding contact shows a graph with a similar wear pattern shape. ZLS was more resistant to wear than LD, with less volume loss and shallower surface defects.


Resumo O objetivo deste estudo foi investigar o desgaste tridimensional, perda volumétrica e rugosidade após a simulação de mastigação de dois materiais vitro-cerâmicos. Discos de dissilicato de lítio (LD, Emax CAD, Ivoclar) e silicato de lítio reforçado com zircônia (ZLS, Vita Suprinity, Vita Zhanfabrick) (n=20/g) foram confeccionados e digitalizados para obtenção de arquivos de estereolitografia (STL) de cada amostra. Todos os discos foram submetidos à simulação de mastigação com configuração deslizante (30 N, 300.000 ciclos, 6 mm e 1,7 Hz) com esteatita como antagonista. As amostras foram escaneadas novamente e a perda de volume e o defeito mais profundo foram medidos usando o arquivo sobreposto da linha de base através de um software de inspeção paramétrica digital e tridimensional (GOM Inspect, Braunschweig, Alemanha). A rugosidade superficial (Ra e Rz) foi avaliada através de rugosímetro de contato. Os resultados foram analisados por ANOVA 1-fator e teste Tukey (α=0,5%). ANOVA mostrou diferenças significantes entre os grupos. Considerando a perda de volume cerâmico, comprimento do defeito e rugosidade Rz, LD (-22,09±5,57%; 0,80±0,06 µm; 3,08±1.02 µm) apresentou valores médios superiores a ZLS (-15,67±4,51%; 0,56±0,09 µm; 1.51±0.90 µm). Todos os discos exibiram pequenos arranhões na superfície conforme a direção de deslizamento com padrões de desgaste, enquanto grandes ranhuras foram observadas nos traços de desgaste. Essas mesmas áreas podem ser identificadas em azul, sobrepondo os arquivos STL antes e depois da simulação de mastigação no software de inspeção. A redução linear gerada pelo contato deslizante mostra um gráfico com uma forma de padrão de desgaste semelhante. ZLS foi mais resistente ao desgaste do que LD, com menor perda de volume e menores defeitos superficiais.


Subject(s)
Ceramics , Mastication , Surface Properties , Materials Testing , Dental Porcelain
9.
Int. j. odontostomatol. (Print) ; 13(2): 207-218, jun. 2019. tab, graf
Article in Spanish | LILACS | ID: biblio-1002308

ABSTRACT

RESUMEN: El objetivo de este trabajo consistió en evaluar la resistencia al cizallamiento de brackets ortodónticos cementados a una cerámica odontológica a base de disilicato de litio. Fueron confeccionadas 80 muestras rectangulares de cerámica vítrea a base de disilicato de litio. Las muestras fueron divididas inicialmente en 4 grupos de 20 discos según el tratamiento de superficie: ácido fosfórico 37 % por 30 segundos (HP); ácido hidrofluorhidro 10 % por 60 segundos (HF); óxido de aluminio durante 4 segundos (SB); y aspersión con punta diamantada durante 10 segundos (DW). Cada grupo fue dividido en dos subgrupos para la cementación de brackets Edgwise: metálico y cerámico. Los dos nuevos grupos fueron subdivididos en termociclados o no termociclados. Las muestras termocicladas pasaron por 500 ciclos con variaciones de temperatura entre 5 °C a 55 °C. Los valores numéricos obtenidos en la prueba de cizallamiento se sometieron al análisis estadístico descriptivo (media y desviación estándar), habiéndose realizado la prueba de normalidad Shapiro-Wilk y las pruebas no paramétricas de Kruskal-Wallis y Mann-Whitney. Se verificó que no hubo diferencia estadísticamente significativa en relación al tipo de tratamiento de superficie y la realización o no de termociclado, observándose diferencia estadísticamente significativa sólo en el tipo de bracket, siendo la resistencia de unión en el bracket metálico mayor que en el de cerámica. Así, el tipo de tratamiento de superficie y el envejecimiento por termociclaje no fueron decisivos en la resistencia de unión de brackets ortodónticos a la cerámica de disilicato de litio.


ABSTRACT: To evaluate the shear strength of cemented orthodontic brackets to a dental ceramic based on lithium disilicate. Rectangular samples 80 based glassceramic lithium disilicate were prepared. The samples were initially divided into 4 groups of 20 discs according to surface treatment: 37 % phosphoric acid for 30 seconds (HP); 10 % hydrofluoric acid for 60 seconds (HF); blasting with aluminum oxide for 4 seconds (SB); and diamond-tipped for 10 seconds (DW). Each group was divided into two subgroups for the Edgwise bracket cementation: metallic and ceramic. The two new groups were subdivided into thermocyclers or nonthermocyclics. The thermocycled samples passed 500 cycles with temperature variations between 5 ° C to 55 ° C. The numerical values obtained in the shear test were submitted to descriptive statistical analysis (mean and standard deviation), and the Shapiro-Wilk normality test and nonparametric Kruskal-Wallis and Mann-Whitney tests were performed. It was found that there was no statistically significant difference in the type of surface treatment and conducting or not thermocycling, observing statistically significant difference only on the bracket type, and the bond strength at higher metal bracket than in ceramics. Thus, the type of surface treatment and thermocycling aging were not decisive in the bond strength of orthodontic brackets to the lithium disilicate ceramic.


Subject(s)
Humans , Titanium , Orthodontic Brackets , Orthodontic Appliance Design , Esthetics, Dental , Microscopy, Electron, Scanning , Case-Control Studies , Ceramics , Shear Strength
10.
Rev. odontol. UNESP (Online) ; 47(3): 149-154, maio-jun. 2018. tab, ilus
Article in English | LILACS, BBO | ID: biblio-961519

ABSTRACT

Introduction: A new dental implant-abutment design is available with the possibility of improving aesthetic with no compromise of mechanical strength, using perforated CAD/CAM ceramic blocks. Objective: This study evaluated the influence of crown and hybrid abutment ceramic materials combination on the stress distribution of external hexagon implant supported prosthesis. Method: Zirconia, lithium disilicate and hybrid ceramic were evaluated, totaling 9 combinations of crown and mesostructure materials. For finite element analysis, a monolithic crown cemented over a hybrid abutment (mesostructure + titanium base) was modeled and screwed onto an external hexagon implant. Models were then exported in STEP format to analysis software, and the materials were considered isotropic, linear, elastic and homogeneous. An oblique load (30°, 300N) was applied to the central fossa bottom and the system's fixation occurred on the bone's base. Result: For crown structure, flexible materials concentrate less stress than rigid ones. In analyzing the hybrid abutment, it presented higher stress values when it was made with zirconia combined with a hybrid ceramic crown. The stress distribution was similar regarding all combinations for the fixation screw and implant. Conclusion: For external hexagon implant, the higher elastic modulus of the ceramic crowns associated with lower elastic modulus of the hybrid abutment shows a better stress distribution on the set, suggesting a promising mechanical behavior.


Introdução: Um novo design de pilar para implantes dentários está disponível com a possibilidade de melhorar a estética sem comprometer a resistência mecânica, usando blocos cerâmicos perfurados para CAD/CAM. Objetivo: Este estudo avaliou a influência da combinação de diferentes materiais cerâmicos para coroa e para pilar híbrido na distribuição de tensões de prótese sobre implante hexágono externo. Método: Zircônia, dissilicato de lítio e cerâmica híbrida foram avaliados, totalizando 9 combinações de materiais para coroa e mesoestrutura. Para análise de elementos finitos, uma coroa monolítica cimentada sobre um pilar híbrido (mesoestrutura + base de titânio) foi modelada sobre um implante de hexágono externo. Os modelos foram exportados em formato STEP para o software de análise, e os materiais foram considerados isotrópicos, lineares, elásticos e homogêneos. Uma carga oblíqua (30°, 300N) foi aplicada no fundo da fossa central e a fixação do sistema ocorreu na base do osso. Resultado: Para a estrutura da coroa, os materiais flexíveis concentram menos tensão que os rígidos. Ao analisar o pilar híbrido, maiores valores de tensão foram observados quando feito com zircônia combinada com uma coroa de cerâmica híbrida. Em todas as combinações simuladas, a distribuição de tensões foi semelhante para o parafuso de fixação e o implante. Conclusão: Associar um material cerâmico com elevado módulo elástico para a coroa com um material de menor módulo elástico para o pilar híbrido resulta em menor concentração de tensão máxima principal, sugerindo um comportamento mecânico promissor para o sistema hexágono externo.


Subject(s)
Dental Implants , Ceramics , Computer-Aided Design , Finite Element Analysis , Crowns , Esthetics, Dental , Zirconium , Dental Materials
11.
J. oral res. (Impresa) ; 7(1): 30-36, ene. 22, 2018. ilus, tab, graf
Article in English | LILACS | ID: biblio-1119250

ABSTRACT

This study evaluated the shear stress distribution on the adhesive interface and the bond strength between resin cement and two ceramics. For finite element analysis (FEA), a tridimensional model was made using computer-aided design software. This model consisted of a ceramic slice (10x10x2mm) partially embedded on acrylic resin with a resin cement cylinder (Ø=3.4 mm and h=3mm) cemented on the external surface. Results of maximum principal stress and maximum principal shear were obtained to evaluate the stress generated on the ceramic and the cylinder surfaces. In order to reproduce the in vitro test, similar samples to the computational model were manufactured according to ceramic material (Zirconia reinforced lithium silicate - ZLS and high translucency Zirconia - YZHT), (N=48, n=12). Half of the specimens were submitted to shear bond test after 24h using a universal testing machine (0.5 mm/min, 50kgf) until fracture. The other half was stored (a) (180 days, water, 37ºC) prior to the test. Bond strength was calculated in MPa and submitted to analysis of variance. The results showed that ceramic material influenced bond strength mean values (p=0.002), while aging did not: YZHT (19.80±6.44)a, YZHTa (17.95±7.21)a, ZLS (11.88±5.40)b, ZLSa (11.76±3.32)b. FEA results showed tensile and shear stress on ceramic and cylinder surfaces with more intensity on their periphery. Although the stress distribution was similar for both conditions, YZHT showed higher bond strength values; however, both materials seemed to promote durable bond strength.


Subject(s)
Humans , Dental Bonding , Dentin-Bonding Agents/chemistry , Composite Resins/chemistry , Resin Cements , Dental Alloys/chemistry , Dental Porcelain/chemistry , Materials Testing , Adhesiveness , Dental Stress Analysis/methods
12.
Braz. oral res. (Online) ; 32: e53, 2018. tab, graf
Article in English | LILACS | ID: biblio-952144

ABSTRACT

Abstract This in vitro study evaluated the fatigue strength of different ceramic materials indicated for monolithic restorations. Disc-shaped specimens were made according to ISO 6872 from five different ceramic materials: feldspathic ceramic (FC), polymer-infiltrated ceramic network (PIC), lithium disilicate glass-ceramic (LD), zirconia-reinforced lithium silicate glass-ceramic (ZLS), and high translucent tetragonal zirconia polycrystals doped by yttrium (YZ-HT). After obtaining the mean of each material (n = 5) from monotonic load-to-failure tests, specimens (n = 20) were subjected to fatigue tests (staircase method) using a biaxial flexural setup (piston-on-three-balls), to determine the fatigue strength. The parameters used for fatigue tests were: 100,000 cycles at 10 Hz, initial load of ~ 60% of mean load-to-failure, and step size of 5% of the initial load (specific for each ceramic material). Kruskal-Wallis and Bonferroni's test (α = 0.05) were used to analyze the fatigue strength data. Fatigue strength (MPa) of the materials was statistically different among each other as follows: YZ-HT (370.2 ± 38.7) > LD (175.2 ± 7.5) > ZLS (152.1 ± 7.5) > PIC (81.8 ± 3.9) > FC (50.8 ± 1.9). Thus, it can be concluded that, in terms of fatigue, high translucent polycrystalline zirconia is the best choice for monolithic restorations as it bears the highest load before cracking/fracturing.


Subject(s)
Stress, Mechanical , Ceramics/chemistry , Computer-Aided Design , Dental Restoration Failure , Reference Values , Surface Properties , Tensile Strength , Zirconium/chemistry , Materials Testing , Microscopy, Electron, Scanning , Reproducibility of Results , Pliability , Dental Porcelain/chemistry , Dental Stress Analysis
13.
Braz. dent. sci ; 21(3): 296-301, 2018. tab, ilus
Article in English | LILACS, BBO | ID: biblio-911397

ABSTRACT

Objective: The aim of this study was to evaluate the internal and marginal adaptation of inlays fabricated from different types of impressions (conventional and digital) and different ceramics (feldspathic and lithium disilicate). Material and Methods: Forty premolars were prepared for all-ceramic inlay restoration and assigned to 4 groups (n=10), according to the impression method (conventional with addition silicone and digital impression) and ceramic type (lithium disilicate and feldspathic ceramic blocks). For each type of impression, 10 inlays were milled from lithium disilicate blocks and the other 10 from feldspathic ceramic blocks in a CAD-CAM facility. The internal adaptation was analyzed by the replica technique. The marginal fit was analyzed under a stereo microscope by directly measuring the gap formed between the inlay and the tooth in the proximal and occlusal regions. Results: The marginal or internal adaptations were not affected by type of impression (conventional = digital impression), irrespective of the ceramic type. Only the internal adaptation was affected by the material type, i.e., feldspathic ceramic had lower values than lithium dissilicate ceramic, when considering the digital impression. Conclusion: The conventional and digital impressions promoted similar marginal and internal adaptation for feldspathic and disilicate ceramic inlays. For the digital impression the feldspathic inlays showed better internal adaptation than lithium dissilicate inlays. (AU)


Objetivo: O objetivo deste estudo foi avaliar a adaptação interna e marginal de inlays confeccionadas a partir de diferentes tipos de moldagens (convencional e digital) e diferentes materiais cerâmicos (feldspática e dissilicato de lítio). Materiais e Métodos: Quarenta pré-molares foram preparados para inlay totalmente cerâmica e distribuídos em 4 grupos (n = 10) segundo o método de moldagem (convencional com silicone de adição e moldagem digital) e tipo cerâmica (dissilicato de lítio e blocos de cerâmica feldspática). Para cada tipo de moldagem, 10 inlays foram confeccionadas a partir de pastilhas de dissilicato de lítio e as outras 10 de blocos de cerâmica feldspática, por meio do sistema CAD-CAM. A adaptação interna foi analisada pela técnica da réplica. O ajuste marginal foi analisado com estéreo microscópio medindo diretamente o espaço entre a inlay e o dente nas regiões proximal e oclusal. Resultados: As adaptações marginais e internas não foram afetadas pelo tipo de moldagem (convencional = impressão digital), independentemente do tipo de cerâmica. Somente a adaptação interna foi afetada pelo material, sendo que a cerâmica feldspática apresentou menores valores que a cerâmica de dissilicato, considerando a moldagem digital. Conclusão: As moldagens convencional e digital promoveram adaptação marginal e interna semelhante de inlays de cerâmica feldspática e dissilicato testadas. Para moldagem digital, a cerâmica feldspática mostrou melhor adaptação interna do que a dissilicato de lítio (AU)


Subject(s)
Dental Impression Technique , Dental Marginal Adaptation , Inlays , Metal Ceramic Alloys
14.
Braz. j. oral sci ; 17: e18222, 2018. ilus
Article in English | LILACS, BBO | ID: biblio-970620

ABSTRACT

Aim: The goal of this study was to clarify the stress distribution in a full arch prosthesis according to the implant number and height in order to guide the clinical choice during planning. Methods: A computational analysis was performed to analyze the stress distribution in implants and bone tissue according to implant number (3, 4 or 5) and height (5, 8, 11 mm). A model of a jaw with polyurethane properties to simulate bone tissue was created through the Rhinoceros software (version 5.0 SR8, McNeel North America, Seattle, WA, USA). The titanium bar was fixed to the implant through a retention screw. The final geometry was exported in STEP format to ANSYS (ANSYS 15.0, ANSYS Inc., Houston, USA) and all materials were considered homogeneous, isotropic and linearly elastic. To assess distribution of stress forces, an axial load (200 N) was applied on the cantilever. Results in Von-Mises stress and strain criteria's were obtained for implants and bone, respectively. Qualitative and quantitative evaluations were performed. Results: The implant number and height influenced the prosthesis biomechanics, with more von-Mises stress and bone strain concentration for combination of 3 implants with 5 mm. Conclusion: It was concluded that higer length and more quantity of implant supporting a full arch prosthesis promoted less stress concentration during the simulated load. Decreasing the number of implants in rehabilitation is more harmful than decreasing their length for the stress and strain distribution


Subject(s)
Prosthodontics , Tensile Strength , Finite Element Analysis , Bone-Implant Interface
15.
Rev. bras. ciênc. saúde ; 22(1): 7-14, 2018. tab, ilus
Article in Portuguese | LILACS | ID: biblio-882669

ABSTRACT

Objetivo: Avaliar o efeito da concentração e do tempo de condicionamento com ácido fluorídrico na rugosidade e morfologia superficial de uma zircônia glazeada. Materiais e Métodos: Blocos de cerâmica à base de zircônia (5×5×3 mm) (Vita YZ-2000-Cubes, Vita- Zahnfabrik, Alemanha) foram confeccionados e divididos em 6 grupos, de acordo com os fatores "concentração do ácido fluorídrico (HF)" (5% e 10%) e "tempo de condicionamento" (20 s, 60 s e 90 s) (n=2): HF10/20 = HF 10% + 20 s; HF10/60 = HF 10% + 60 s; HF10/90 = HF 10% + 90 s; HF5/20 = HF 5% + 20 s; HF5/60 = HF 5% + 60 s; HF5/ 90 = HF 5% + 90 s. O glaze (Vita Akzent, Vita-Zahnfabrik, Alemanha) foi aplicado com o auxílio de um pincel e sinterizado de acordo com as recomendações do fabricante. Após os diferentes protocolos de condicionamento, foram aferidas cinco medições de rugosidade (Ra) para cada espécime em Perfilômetro Digital (Wyko®, Modelo NT- 1100, Veeco, EUA). Os dados (µm) obtidos foram analisados estatisticamente com análise de variância (ANOVA 2-fatores) e Teste de Tukey (95%). Resultados: O fator "concentração do ácido fluorídrico" (p=0,149) não foi significante estatísticamente. No entanto, o fator "tempo de condicionamento" (p=0,009) foi significante. A interação entre os fatores também apresentou significância estatística (p=0,00). As médias de rugosidade (±desvio-padrão) obtidas foram (µm): GHF10/20=1,94(±0,72)A, GHF5/90=1,92(±0,19)A, GHF5/ 20=1,38(±0.48)AB, GHF5/60=1,18(±0,63)B, GHF10/60=1,17(±0,30)B, GHF10/90=0,82(±0,27)B (Tukey). Conclusão: Conclui-se que o ácido fluorídrico (10%) em maior concentração, associado a um menor tempo de condicionamento (20 s), promoveu maior rugosidade superficial da zircônia glazeada. (AU)


Objective: The aim of this study was to evaluate the effect of different etching protocols on the surface roughness of a glazed zirconia. Material and Methods: Zirconia ceramic-blocks (5 × 5 × 3 mm) (Vita YZ-2000-Cubes, Vita-Zahnfabrik, Germany) were prepared and divided into 6 groups according to the variables "concentration of hydrofluoric acid (HF)" (5 % and 10 %) and " etching time " (20 s, 60 s and 90 s) (n = 2), as follows: HF10/20 = HF 10% + 20 s; HF10/60 = HF 10% + 60 s; HF10/90 = HF 10% + 90 s; HF5/20 = HF 5% + 20 s; HF5/60 = HF 5% + 60 s; HF5/90 = HF 5% + 90 s. The glaze (Vita Akzent, Vita- Zahnfabrik, Germany) was applied with a brush and sintered according to the manufacturer's recommendations. After different etching protocols, five roughness (Ra) measurements were taken for each specimen in a digital profilometer (Wyko ®, Model NT-1100, Veeco, USA). The data were statistically analyzed using analysis of variance (ANOVA 2­way) and Tukey's test (95%). Results: The variable "concentration of hydrofluoric acid" (p=0.149) was not statistically significant, while the variable "etching time" (p=0.009) was significant. The interaction between variables was statistically significant (p = 0.00). The roughness averages (± standard deviation) obtained were (µm): GHF10/20=1.94(±0.72)A, GHF5/90=1.92(±0.19)A, GHF5/ 20=1.38(±0.48)AB, GHF5/60=1.18(±0.63)B, GHF10/60=1.17(±0.30)B, GHF10/90=0.82(±0.27)B (Tukey). Conclusion: It can be concluded that hydrofluoric acid (10%) at a higher concentration associated with a lower etching time (20 s) promoted higher superficial roughness on glazed zirconia. (AU)


Subject(s)
Ceramics , Zirconium , Vitrification
16.
Braz. oral res. (Online) ; 32: e28, 2018. tab, graf
Article in English | LILACS | ID: biblio-889483

ABSTRACT

Abstract: The effects of several ceramic surface treatments on bond strength of a polymer-infiltrated ceramic network and resin composite as repair material were evaluated. CAD-CAM blocks of a polymer-infiltrated ceramic network (Vita Enamic) were sliced and subjected to aging process, followed by embedding in acrylic resin. The bonding/repair area was treated as follows (n = 30): C- without treatment; UA- universal adhesive application; FM- 10% hydrofluoric acid and silane application; OM-airborne-particle abrasion with aluminum oxide and silane application; RP- tribochemical silica coating; and CA- surface grinding and application of universal adhesive. Composite resin cylinders were made on the treated surface. Specimens from each group were assigned randomly to two subgroups (n = 15) considering storage condition: Baseline (shear tests after 48 hours) or Storage (tests after 6 months under distilled water). The treated surfaces were analyzed by goniometry, roughness, and SEM. Two-way ANOVA and 1-way ANOVA were applied to analyze the bond data and roughness / contact angle data, respectively, followed by Tukey's test (α = 5%). Surface treatments and storage conditions affected bond strengths (p < 0.01). Surface grinding (CA) followed by universal adhesive promoted the highest value of bond strength (14.5 ± 4.8 MPa for baseline, 8.5 ± 3.4 MPa for storage) and the roughest ceramic surface. Grinding with silicon carbide paper (simulating diamond bur) followed by the application of a universal adhesive system is the best option for repairing fractures of the polymer-infiltrated ceramic network.


Subject(s)
Ceramics/chemistry , Composite Resins/chemistry , Dental Bonding/methods , Polymers/chemistry , Analysis of Variance , Computer-Aided Design , Dental Restoration Failure , Materials Testing , Microscopy, Electron, Scanning , Reference Values , Reproducibility of Results , Shear Strength/drug effects , Surface Properties/drug effects , Time Factors
17.
J. appl. oral sci ; 25(5): 566-574, Sept.-Oct. 2017. tab, graf
Article in English | LILACS, BBO | ID: biblio-893657

ABSTRACT

Abstract Objective: This study evaluated the influence of porcelain (VM9, VITA Zahnfabrik, Germany) thickness on the flexural strength and crack propagation in bilayered zirconia systems (YZ, VITA Zahnfabrik, Germany). Material and Methods: Thirty zirconia bars (20.0x4.0x1.0 mm) and six zirconia blocks (12.0x7.5x1.2 mm) were prepared and veneered with porcelain with different thickness: 1 mm, 2 mm, or 3 mm. The bars of each experimental group (n=10) were subjected to four-point flexural strength testing. In each ceramic block, a Vickers indentation was created under a load of 10 kgf for 10 seconds, for the propagation of cracks. Results: The results of flexural strength were evaluated by One-way ANOVA and Tukey's test, with a significance level of 5%. The factor "thickness of the porcelain" was statistically significant (p=0.001) and the l-mm group presented the highest values of flexural strength. The cracks were predominant among the bending specimens with 1 and 2 mm of porcelain, and catastrophic failures were found in 50% of 3-mm-thick porcelain. After the indentation of blocks, the most severe defects were observed in blocks with 3-mm-thick porcelain. Conclusion: The smallest (1 mm) thickness of porcelain on the zirconia infrastructure presented higher values of flexural strength. Better resistance to defect propagation was observed near the porcelain/ zirconia interface for all groups. Higher flexural strength was found for a thinner porcelain layer in a bilayered zirconia system. The damage caused by a Vickers indentation near and far the interface with the zirconia shows that the stress profiles are different.


Subject(s)
Zirconium/chemistry , Ceramics/chemistry , Dental Porcelain/chemistry , Reference Values , Surface Properties , Tensile Strength , Time Factors , Materials Testing , Reproducibility of Results , Analysis of Variance , Pliability , Microscopy, Confocal , Dental Restoration Failure , Dental Stress Analysis , Hardness Tests , Hot Temperature
18.
Braz. dent. sci ; 20(2): 85-92, 2017. ilus, tab, graf
Article in English | LILACS, BBO | ID: biblio-846427

ABSTRACT

Objective: To evaluate the effect of different irrigation solutions prior to post cementation on the resin bonding to bovine root dentine. Material and Methods: 60 bovine roots (16 mm) were prepared to 12 mm with specific drill of a double-tapered fiber post system, included in PMMA, and divided into 6 groups, considering the irrigation solutions (IS) prior to cementation: Gr1- saline solution (control), Gr2- NaOCl 0.5 %, Gr3- NaOCl 1 %, Gr4- NaOCl 2.5 %, Gr5- NaOCl 5 %, Gr6- Chlorexidine 2 % (solution). The root canals were irrigated with IS 20 ml during 10 min. Then they were rinsed with 20 ml of distilled water and dried with paper points. One fiber post was molded with polyvinylsiloxane and 60 posts made of resin cement (PRC) were obtained moments before the cementation. The root canal dentin was etched with H2PO3 37 %/15 s + washing/drying, a multi-bottle etch&rinse adhesive system was applied and the PRC were resin luted with dual resin cement (DuolinkTM, Bisco). Each specimen was cut into 4 slices of ±1.8mm in thickness and submitted to push-out test (1 mm/min). Results: ANOVA showed that bond strength was significantly affected by IS (P < 0.0001). The highest bond strengths (MPa) were those for the groups 4 (3.51 ± 1.52) and 5 (3.0 ± 1.16). The groups 1 (0.70 ± 0.30), 2 (0.80 ± 0.24), 3 (1.26 ± 0.57) and 6 (0.90 ± 0.41) were statistically similar to each other. Conclusion: The resin bonding to the root dentine was higher when higher concentrations of hypochlorite solutions were used. (AU)


Objetivo: Avaliar o efeito de diferentes soluções de irrigação antes da cimentação do pino na resistência de união da resina à dentina radicular bovina. Material e Métodos: Foram preparadas 60 raízes bovinas (16 mm) a 12 mm com broca específica de um sistema de pino de fibra com dupla conicidade, incluídas no PMMA, e divididas em 6 grupos, considerando as soluções irrigadoras (IS) antes da cimentação: Gr1-Solução salina (controle), Gr2-NaOCl 0,5 %, Gr3-NaOCl 1 %, Gr4-NaOCl 2,5 %, Gr5-NaOCl 5 %, Gr6-Clorexidina 2 % (solução). Os canais radiculares foram irrigados com 20 ml de IS durante 10 min. Depois, foram lavados com 20 ml de água destilada e secos com pontas de papel. Um pino de fibra foi moldado com polivinilsiloxano e 60 pinos de cimento resinoso (PRC) foram obtidos momentos antes da cimentação. A dentina radicular foi condicionada com H2PO3 37 %/15 s + lavagem/ secagem, aplicou-se o sistema de adesivo e o PRC foi cimentado com cimento resinoso dual (DuolinkTM, Bisco). Cada amostra foi cortada em 4 fatias de ± 1,8 mm de espessura e submetida a teste push-out (1 mm/ min). Resultados: ANOVA mostrou que a força de união foi significativamente afetada pelo IS (P< 0,0001). As maiores resistências de união (MPa) foram para os grupos 4 (3,51 ± 1,52) e 5 (3,0 ± 1,16). Os grupos 1 (0,70 ± 0,30), 2 (0,80 ± 0,24), 3 (1,26 ± 0,57) e 6 (0,90 ± 0,41) foram estatisticamente semelhantes entre si. Conclusão: A resistência de união da resina à dentina radicular foi maior quando foram utilizadas concentrações maiores de soluções de hipoclorito. (AU)


Subject(s)
Animals , Cattle , Dentin , Resin Cements
19.
Braz. oral res. (Online) ; 31: e82, 2017. tab, graf
Article in English | LILACS | ID: biblio-952081

ABSTRACT

Abstract Monolithic restorations of Y-TZP have been recommended as a restorative alternative on prosthetic dentistry as it allows a substantial reduction of ceramic thickness, which means a greater preservation of tooth structure. However, the influence of grinding and aging when using a thinner layer of the material is unclear. This investigation aimed to evaluate and compare the effects of ceramic thickness (0.5 mm and 1.0 mm), grinding and aging (low-temperature degradation) on the mechanical behavior and surface characteristics of a full-contour Y-TZP ceramic. Y-TZP disc-shaped specimens (15 mm diameter) were manufactured with both thicknesses and randomly assigned into 4 groups considering the factors 'grinding with diamond bur' and 'aging in autoclave'. Surface topography (roughness, 3D profilometry and SEM), phase transformation, flexural strength and structural reliability (Weibull) analyses were executed. Grinding affected the surface topography, while aging did not promote any effect. An increase in m-phase content was observed after grinding and aging, although different susceptibilities were observed. Regardless of zirconia's thickness, no deleterious effect of grinding or aging on the mechanical properties was observed. Thus, in our testing assembly, reducing the thickness of the Y-TZP ceramic did not alter its response to grinding and low temperature degradation and did not impair its mechanical performance.


Subject(s)
Yttrium/chemistry , Zirconium/chemistry , Microscopy, Electron, Scanning , Ceramics/chemistry , Surface Properties , Tensile Strength , Time Factors , X-Ray Diffraction , Materials Testing , Random Allocation , Reproducibility of Results , Analysis of Variance , Cold Temperature , Statistics, Nonparametric , Pliability
20.
Braz. dent. j ; 27(6): 693-699, Nov.-Dec. 2016. tab, graf
Article in English | LILACS | ID: biblio-828065

ABSTRACT

Abstract Polyetheretherketone (PEEK) is a material suitable for frameworks of fixed dental prostheses. The effect of different surface treatments on the bond strength of PEEK bonded to human dentin was evaluated. One hundred PEEK cylinders (3 mm×3 mm) were divided into five groups according to surface treatment: silica coating, sandblasting with 45 μm Al2O3 particles, etching with 98% sulfuric acid for 5, 30 and for 60 s. These cylinders were luted with resin cement onto 50 human molars. First, each tooth was embedded in epoxy resin and the buccal dentin surface was exposed. Then, two delimited dentin areas (Æ:3 mm) per tooth were etched with 35% phosphoric acid and bonded with a two-step self-priming adhesive system. After the luting procedure the specimens were stored in water (24 h/37 °C). Shear bond strength (SBS) was tested using a universal testing machine (crosshead speed 0.5 mm/min; load cell 50 kgf) and failure types were assessed. Stress data (MPa) were analyzed using the Kruskal-Wallis test. Comparison of the proportions of different failure types was performed using the Bonferroni method (p<0.05). Kruskal-Wallis demonstrated that differences among groups were not significant (p=0.187). Mean SBS were as follows: silica coating, 2.12±1.12 MPa; sandblasting, 2.37±0.86 MPa; sulfuric acid 5 s, 2.28±1.75 MPa; sulfuric acid 30 s, 1.80±0.85 MPa; sulfuric acid 60 s, 1.67±0.94 MPa. Adhesive and mixed failures were predominant in all groups. Both physical and chemical surface treatments produced adhesion between PEEK, resin cement and dentin.


Resumo O poli-éter-éter-cetona (PEEK) é um material indicado para as estruturas de próteses parciais fixas. O efeito de diferentes tratamentos de superfície na resistência de união entre PEEK e dentina humana foi avaliado. Cem cilindros de PEEK (3 mm×3 mm) foram divididos em cinco grupos de acordo com tratamento de superfície: silicatização, jateamento com partículas de Al2O3 45 µm, condicionamento com ácido sulfúrico 98% por 5, 30 e 60 s. Esses cilindros foram cimentados com cimento resinoso em cinquenta molares humanos. Primeiro, cada dente foi incluído em resina epóxica e a superfície dentinária vestibular foi exposta. Depois, duas áreas (Æ:3 mm) em dentina/por dente foram delimitadas, condicionadas com ácido fosfórico a 35% e receberam aplicação de um sistema adesivo de dois passos. Após o procedimento de cimentação, as amostras foram armazenadas em água (24 h/37 °C). A resistência da união ao cisalhamento (SBS) foi testada em uma máquina universal de ensaios (velocidade 0,5 mm/min; célula de carga 50 kgf), e foram avaliados os tipos de falha. Os dados de tensão (MPa) foram analisados pelo teste de Kruskal-Wallis. A comparação das percentagens de diferentes tipos de falha foi realizada utilizando o método de Bonferroni (p<0,05). O teste de Kruskal-Wallis demonstrou que as diferenças entre os grupos não foram significantes (p=0,187). As médias de SBS foram: silicatização, 2,12±1,12 MPa; jateamento, 2,37±0,86 MPa; ácido sulfúrico por 5 s, de 2,28±1,75 MPa; ácido sulfúrico por 30 s, 1,80±0,85 MPa, ácido sulfúrico por 60 s, 1,67±0,94 MPa. Falhas adesivas e mistas foram predominantes em todos os grupos. Ambos tratamentos de superfície, físicos e químicos, promoveram adesão entre PEEK, cimento resinoso e dentina.


Subject(s)
Humans , Acid Etching, Dental/methods , Dental Bonding , Ketones , Polyethylene Glycols , Dental Cements , Dental Stress Analysis , Materials Testing , Microscopy, Electron, Scanning
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