Influência da dentina bovina e do dispositivo de microtração na resistência de união de sistemas adesivos

Pós-graduação em Odontologia Restauradora - ICT

Biomechanical influence of crown-to-implant ratio on stress distribution over internal hexagon short implant: 3-D finite element analysis with statistical test

The study of short implants is relevant to the biomechanics of dental implants, and research on crown increase has implications for the daily clinic. The aim of this study was to analyze the biomechanical interactions of a singular implant-supported prosthesis of different crown heights under vertical and oblique force, using the 3-D finite element method. Six 3-D models were designed with Invesalius 3.0, Rhinoceros 3D 4.0, and Solidworks 2010 software. Each model was constructed with a mandibular segment of bone block, including an implant supporting a screwed metal-ceramic crown. The crown height was set at 10, 12.5, and 15 mm. The applied force was 200 N (axial) and 100 N (oblique). We performed an ANOVA statistical test and Tukey tests; p < 0.05 was considered statistically significant. The increase of crown height did not influence the stress distribution on screw prosthetic (p > 0.05) under axial load. However, crown heights of 12.5 and 15 mm caused statistically significant damage to the stress distribution of screws and to the cortical bone (p <0.001) under oblique load. High crown to implant (C/I) ratio harmed microstrain distribution on bone tissue under axial and oblique loads (p < 0.001). Crown increase was a possible deleterious factor to the screws and to the different regions of bone tissue. (C) 2014 Elsevier Ltd. All rights reserved.

Stress distribution in delayed replanted teeth splinted with different orthodontic wires: a three-dimensional finite element analysis

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

Effect of long-term storage on nanomechanical and morphological properties of dentin-adhesive interfaces

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

Occurrence of periodontal pathogens in ethnic groups from a native Brazilian reservation

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

First identification of interspecies hybridization in the freshwater stingrays Potamotrygon motoro and P-falkneri (Myliobatiformes, Potamotrygonidae)

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

Finite element analysis of the influence of geometry and design of zirconia crowns on stress distribution

Purpose: To evaluate the influence of the geometry and design of prosthetic crown preparations on stress distribution in compression tests, using finite element analysis (FEA). Materials and Methods: Six combinations of 3D drawings of all-ceramic crowns (yttria-stabilized zirconia framework and porcelain veneer) were evaluated: F, flat preparation and simplified crown; FC, flat preparation and crown with contact point; FCM, flat preparation and modified crown; A, anatomical preparation and simplified anatomical crown framework; AC, anatomical preparation and crown with contact point; and ACM, anatomical preparation and modified crown. Bonded contact types at all interfaces with the mesh were assigned, and the material properties used were according to the literature. A 200 N vertical load was applied at the center of each model. The maximum principal stresses were quantitatively and qualitatively analyzed. Results: The highest values of tensile stress were observed at the interface between the ceramics in the region under the load application for the simplified models (F and A). Reductions in stress values were observed for the model with the anatomical preparation and modified infrastructure (ACM). The stress distribution in the flat models was similar to that of their respective anatomical models. Conclusions: The modified design of the zirconia coping reduces the stress concentration at the interface with the veneer ceramic, and the simplified preparation can exert a stress distribution similar to that of the anatomical preparation at and near the load point, when load is applied to the center of the crown.

Stress distribution around osseointegrated implants with different internal-cone connections: photoelastic and finite element analysis

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

N=1 SUSY backgrounds with an AdS factor from non-Abelian T duality

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Finite-difference calculation of donor energy levels in a spherical quantum dot subject to a magnetic field

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A coupling technique for non-matching finite element meshes

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

Computer graphics applied to anatomy: a study of two bio-cad modeling methods on finite element analysis of human edentulous hemi-mandible

Modeling is a step to perform a finite element analysis. Different methods of model construction are reported in literature, as the Bio-CAD modeling. The purpose of this study was to perform a model evaluation and application using two methods of Bio-CAD modeling from human edentulous hemi-mandible on the finite element analysis. From CT scans of dried human skull was reconstructed a stereolithographic model. Two methods of modeling were performed: STL conversion approach (Model 1) associated to STL simplification and reverse engineering approach (Model 2). For finite element analysis was used the action of lateral pterygoid muscle as loading condition to assess total displacement (D), equivalent von-Mises stress (VM) and maximum principal stress (MP). Two models presented differences on the geometry regarding surface number (1834 (model 1); 282 (model 2)). Were observed differences in finite element mesh regarding element number (30428 nodes/16683 elements (model 1); 15801 nodes/8410 elements (model 2). D, VM and MP stress areas presented similar distribution in two models. The values were different regarding maximum and minimum values of D (ranging 0-0.511 mm (model 1) and 0-0.544 mm (model 2), VM stress (6.36E-04-11.4 MPa (model 1) and 2.15E-04-14.7 MPa (model 2) and MP stress (-1.43-9.14 MPa (model 1) and -1.2-11.6 MPa (model 2). From two methods of Bio-CAD modeling, the reverse engineering presented better anatomical representation compared to the STL conversion approach. The models presented differences in the finite element mesh, total displacement and stress distribution.

Effect of crown-to-implant ratio on peri-implant stress: a finite element analysis

The aim of this study was to evaluate stress distribution in the fixation screws and bone tissue around implants in single-implant supported prostheses with crowns of different heights (10,12.5, 15 mm crown-to-implant ratio 1:1, 1.25:1, 1.5:1, respectively). It was designed using three 3-Dmodels. Each model was developed with a mandibular segment of bone block including an internal hexagon implant supporting a screw-retained, single metalceramic crown. The crown height was set at 10, 12.5, and 15 mm with crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. The applied forces were 200 N (axial) and 100 N (oblique). The increase of crown height showed differences with the oblique load in some situations. By von Mises'criterion, a high stress area was concentrated at the implant/fixation screw and abutment/implant interfaces at crown-to-implant ratio of 1:1, 1.25:1, 1.5:1, respectively. Using the maxiinum principal criteria, the buccal regions showed higher traction stress intensity, whereas the distal regions showed the largest compressive stress in all models. The increase of C/I ratio must be carefully evaluated by the dentist since the increase of this C/I ratio is proportional to the increase of average stress for both screw fixation (C/I 1:1 to 1:1.25 ratio = 30.1% and C/I 1:1 to 1 :1.5 ratio = 46.3%) and bone tissue (C/I 1:1 to 1:1.25 ratio = 30% and C/I 1:1 to 1:1.5 ratio = 51.5%). (C) 2014 Elsevier B.V. All rights reserved.

Differential habitat use by demographic groups of the redfinger rubble crab Eriphia gonagra (Fabricius, 1781)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Metacommunity versus Biogeography: a case study of two groups of neotropical vegetation-dwelling arthropods

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