Influence of convergence angle of tooth preparation on the fracture resistance of Y-TZP-based all-ceramic restorations

Objective: To investigate the influence of the convergence angle of tooth preparation on the fracture load of Y-TZP-based ceramic (YZ-Vita YZ) substructure (SB) veneered with a feldspathic porcelain (VM9-Vita VM9). Methods: Finite element stress analysis (FEA) was performed to examine the stress distribution of the system. Eighty YZ SB were fabricated using a CAD-CAM system and divided into four groups (n = 20), according to the total occlusal convergence (TOC) angle: G6-6° TOC; G12-12° TOC; G20-20° TOC; and G20MOD-20° TOC with modified SB. All SB were veneered with VM9, cemented in a fiber reinforced epoxy resin die, and loaded to failure. Half of the specimens from each group (n = 10) were cyclic fatigued (106 cycles) before testing. Failure analysis was performed to determine the fracture origin. Data were statistically analyzed using Anova and Tukey's tests (α = 0.05). Results: The greatest mean load to fracture value was found for the G20MOD, which was predicted by the FEA. Cyclic fatigue did not significantly affect the load of fracture. Catastrophic failure originating from the internal occlusal surface of the SB was the predominant failure mode, except for G20MOD. Significance: The YZ-VM9 restorations resisted greater compression load than the usual physiological occlusal load, regardless of the TOC angle of preparations. Yet, the G20MOD design produced the best performance among the experimental conditions evaluated. © 2013 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

Regular and switching platform: Bone stress analysis with varying implant diameter

The aim of this study was to evaluate stress distribution of the peri-implant bone by simulating the biomechanical influence of implants with different diameters of regular or platform switched connections by means of 3-dimensional finite element analysis. Five mathematical models of an implant-supported central incisor were created by varying the diameter (5.5 and 4.5 mm, internal hexagon) and abutment platform (regular and platform switched). For the cortical bone, the highest stress values (rmax and rvm) were observed in situation R1, followed by situations S1, R2, S3, and S2. For the trabecular bone, the highest stress values (rmax) were observed in situation S3, followed by situations R1, S1, R2, and S2. The influence of platform switching was more evident for cortical bone than for trabecular bone and was mainly seen in large platform diameter reduction.

Surface agents' influence on the flexural strength of bilaminated ceramics

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Stress analysis in bone tissue around single implants with different diameters and veneering materials: A 3-D finite element study

The aimof this study was to evaluate the stress distribution on bone tissue with a single prosthesis supported by implants of large and conventional diameter and presenting different veneering materials using the 3-D finite elementmethod. Sixteenmodels were fabricated to reproduce a bone block with implants, using two diameters (3.75 × 10 mmand 5.00 × 10 mm), four different veneering materials (composite resin, acrylic resin, porcelain, and NiCr crown), and two loads (axial (200 N) and oblique (100 N)). For data analysis, the maximum principal stress and vonMises criterion were used. For the axial load, the cortical bone in allmodels did not exhibit significant differences, and the trabecular bone presented higher tensile stresswith reduced implant diameter. For the oblique load, the cortical bone presented a significant increase in tensile stress on the same side as the loading for smaller implant diameters. The trabecular bone showed a similar but more discreet trend. There was no difference in bone tissue with different veneering materials. The veneering material did not influence the stress distribution in the supporting tissues of single implant-supported prostheses. The large-diameter implants improved the transference of occlusal loads to bone tissue and decreased stress mainly under oblique loads.Oblique loading was more detrimental to distribution stresses than axial loading. © 2013 Elsevier B.V. All rights reserved.

Desgaste abrasivo e dureza de seis resinas compostas expostas a diferentes tempos de fotopolimerização com aparelhos de LED e lâmpada incandescente

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Uma contribuição para o estudo do efeito causado pela névoa salina em isoladores cerâmicos de chaves fusíveis

Pós-graduação em Ciência e Tecnologia de Materiais - FC

Avaliação in vitro da translucidez de dois sistemas cerâmicos metal-free: In-Ceram x Empress 2

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação in vitro da microinfiltração marginal em restaurações indiretas inlay de porcelana. Efeito de diferentes agentes cimentantes

Pós-graduação em Ciências Odontológicas - FOAR

Estudo da interface titânio/porcelana, com três porcelanas de ultra baixa fusão, empregando-se microscopia eletrônica de varredura e dilatometria

Pós-graduação em Ciências Odontológicas - FOAR

Argilas da formação Corumbataí como base para obtenção de grés porcelanato por via seca

Pós-graduação em Geologia Regional - IGCE

Avaliação da influência de diferentes materiais oclusais na confecção de próteses fixas implantossuportadas unitárias com diferentes diâmetros dos implantes osseointegrados: estudo pelo método dos elementos finitos tridimensionais

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estudo experimental da remoção, por jato de ar comprimido, de detritos na superfície de corte de rebolo diamantado durante a retificação da alumina refrigerada pela técnica MQL

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito de tratamentos de superfície sobre a adesão de reparo com resina composta em restarações cerâmicas á base de zircônia Y-TPZ envelhecida hidrotermicamente

Pós-graduação em Reabilitação Oral - FOAR

Avaliação pelo método dos elementos finitos de cargas axiais aplicadas sobre implantes e componentes protéticos com diversas inclinações

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Avaliação da resistência ao cisalhamento de sistemas para reparo em metalocerâmicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)