scholarly journals Effect of Biologically Oriented Preparation Technique on the Stress Concentration of Endodontically Treated Upper Central Incisor Restored with Zirconia Crown: 3D-FEA

Molecules ◽  
2021 ◽  
Vol 26 (20) ◽  
pp. 6113
Author(s):  
Luigi Giovanni Bernardo Sichi ◽  
Fernanda Zapater Pierre ◽  
Laura Viviana Calvache Arcila ◽  
Guilherme Schmitt de Andrade ◽  
João Paulo Mendes Tribst ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Resin Composite ◽  
Maximum Principal Stress ◽  
Structural Testing ◽  
Preparation Technique ◽  
Dental Resin ◽  
Endodontically Treated Teeth ◽  
Element Analysis ◽  
Fixed Base ◽  
Zirconia Crowns

The aim of this study was to evaluate the effect of biologically oriented preparation technique on the stress concentration of endodontically treated upper central incisors restored with zirconia crown (yttria-stabilized zirconia polycrystalline ceramic) through finite element analysis (FEA). Four models of maxillary central incisors containing enamel, dentin, periodontal ligament, cortical and medullary bone were created in CAD. Each model received a polymeric core-build up with nanofilled dental resin composite. The evaluated models were SM—preparation in shoulder 90°; CM—chamfer preparation; BOPT—biologically oriented preparation technique and BOPTB—BOPT preparation 1 mm below the cement-enamel junction. All models received zirconia crowns (5Y-TZP), fiberglass post and 1 mm ferrule. The models were imported into the analysis software with parameters for mechanical structural testing using the maximum principal stress and the tensile strength as the analysis criteria. Then, load of 150 N was applied at the cingulum with 45° slope to the long axis of the tooth, with the fixed base for each model. The type of marginal preparation affected the stresses concentration in endodontically treated teeth and in the zirconia crown margin. Considering the stress magnitude only, BOPT is a viable option for anterior monolithic zirconia crowns; however, with the highest stress magnitude at the restoration margin.

scholarly journals Stress Distribution in Modified Veneer Crowns: 3D Finite Element Analysis

Oral ◽  
2021 ◽  
Vol 1 (3) ◽  
pp. 272-280
Author(s):  
Camila Ferreira Leite Madruga ◽  
Gabriela Freitas Ramos ◽  
Alexandre Luiz Souto Borges ◽  
Guilherme de Siqueira Ferreira Anzaloni Saavedra ◽  
Rodrigo Othávio Souza ◽  
...  
Keyword(s):  
Stress Concentration ◽  
Maximum Principal Stress ◽  
Zirconia Ceramic ◽  
Control Group ◽  
Element Analysis ◽  
New Approach ◽  
Biomechanical Behavior ◽  
Maxillary Molars ◽  
Maxillary Molar ◽  
Group B

(1) Background: to propose a new approach for crown veneers, with the use of an aesthetic porcelain coating, only in part of the zirconia infrastructure, and to analyze its biomechanical behavior to minimize chipping failures. (2) Methods: a maxillary molar was modeled using CAD software, preparing for traditional crowns and veneer crowns with various lengths. Five groups were formed: M—control group (monolithic crown of ultra-translucent zirconia); B—conventional (bilayer crown of ultra-translucent zirconia and ceramic covering); V—veneer (ultra-translucent zirconia crown with reduction only in the buccal and application of covering ceramics); V1—ultra-translucent zirconia crown with buccal reduction and 1 mm occlusal extension for covering ceramic application); V1.5—ultra-translucent zirconia crown with buccal reduction and 1.5 mm occlusal extension for application of covering ceramics. A load of 600 N was performed axially to a fossa bottom to simulate parafunction, and 300 N to the cusp tip to obtain the maximum principal stress results. (3) Results: group B showed a higher stress concentration in the occlusal region of the restorations, while the other groups absorbed the stress and dissipated it throughout the crown, presenting a higher stress concentration in the interface region with the tooth. (4) Conclusion: the highly translucent zirconia ceramic only associated with buccal covering ceramic could add aesthetic gain and rigidity to the system and could be a good option to restore maxillary molars in patients who do not have parafunction.

scholarly journals Elastic stress concentration at radial crossholes in pressurized thick cylinders

2007 ◽  
Vol 42 (6) ◽  
pp. 461-468 ◽  
Author(s):  
T Comlekci ◽  
D Mackenzie ◽  
R Hamilton ◽  
J Wood
Keyword(s):  
Stress Concentration ◽  
Maximum Stress ◽  
Equivalent Stress ◽  
Three Dimensional ◽  
Maximum Principal Stress ◽  
Radius Ratio ◽  
Graphical Form ◽  
Element Analysis ◽  
Parametric Finite Element Analysis ◽  
Von Mises

Results of a parametric finite element analysis investigation of stress concentration at radial crossholes in pressurized cylinders are presented in numerical and graphical form. The analysis shows that the location of maximum stress does not generally occur at the junction between the bores, as is commonly supposed, but at some small distance up the crosshole from the junction. Maximum stress concentration factors (SCFs) are defined on the basis of the maximum principal stress, von Mises equivalent stress, and stress intensity. Three-dimensional plots of the SCF against the cylinder radius ratio b/a and the crosshole-to-main-bore-radius ratio c/a are presented. The SCFs were found to vary across the range of geometries considered with local minima identified within the parameter range in most cases. The results therefore allow designers to select optimum b/a and c/a ratios to minimize stress concentration in real problems.

scholarly journals Resistance Fracture of Minimally Prepared Endocrowns Made By Three Types of Restorative Materials: A 3D Finite Element Analysis

2021 ◽  
Author(s):  
Qingzhen Meng ◽  
Yuejiao Zhang ◽  
Danlu Chi ◽  
Qimei Gong ◽  
Zhongchun Tong
Keyword(s):  
Maximum Principal Stress ◽  
Height Loss ◽  
Pulp Chamber ◽  
Endodontically Treated Teeth ◽  
Element Analysis ◽  
External Edge ◽  
3D Finite Element ◽  
Crown Length ◽  
Cad Cam ◽  
Tooth Tissue

Abstract A thin endocrown restoration was often applied in endodontically treated teeth with vertical bite height loss or inadequate clinical crown length. A model of mandibular molars made by endocrown restoration with 1 mm thickness and 2 mm depth of pulp chamber was constructed and imported into FEA ANSYS v18.0 software. The three CAD/CAM materials, feldspathic (Mark2), lithium disilicate (EMAX) and lava ultimate (LU), were assigned, and the five load indenters were loaded on the full occlusal (FO), occlusal center (OC), central fossa (CF), buccal groove (BG) and mesiobuccal cusp (MC) of restoration in the model. The MinPS and MaxPS of the thin endocrown were significantly higher than those of tooth tissue in five types of loads except for the LU endocrown loaded in the FO group. The smaller the contact surface of the load was, the higher MaxPS and MinPS were. MaxPS and MinPS of the MC were the highest, followed by the BG and CF in the restoration. In the stress distribution of tooth tissue, MaxPS in the LU endocrown accumulated at the external edge of enamel and was significantly higher than MaxPS in Mark2 and EMAX endocrown concentrated on the chamber wall of dentin under OC, CF and BG loads. Within the limitations of this FEA study, the LU endocrown transferred more stress to tooth tissue than Mark2 and EMAX, and the maximum principal stress on endocrown restoration and tooth tissue at the mesiobuccal cusp load was higher than that at the central fossa and buccal groove load.

Numerical Stress Analysis of Internal Ring-Stiffened Tubular T-Joints

1995 ◽  
Vol 117 (2) ◽  
pp. 113-125 ◽  
Author(s):  
D. I. Nwosu ◽  
A. S. J. Swamidas ◽  
K. Munaswamy
Keyword(s):  
Finite Element ◽  
Stress Concentration ◽  
Stress Analysis ◽  
Stress Concentration Factor ◽  
Concentration Factor ◽  
Maximum Principal Stress ◽  
Experimental Investigations ◽  
Internal Ring ◽  
Element Analysis ◽  
T Joints

In order to design a tubular joint to carry a larger load and to possess a longer life, the prime objective of design would be to reduce stress concentration factor at the intersection of the joint; one method to achieve the same is to stiffen the joint with internal ring stiffeners. This paper presents results of the stress analysis for stress distribution, along the intersection of internally ring-stiffened tubular T-joints, under the action of axial and in-plane/out-of-plane (bending) loads, using degenerate shell elements. The stress analyses results are obtained using the general-purpose finite element package called ABAQUS. Post-processing of results has been facilitated by other small programs developed for the purpose. The nominal brace stress and the maximum principal stress values have been used for stress concentration factor computations. The effects of stiffener size, location, number, thickness (τ) and thinness (γ) ratios have been investigated, and the results validated with known analytical and experimental investigations. A comparison of the results obtained from finite element analysis, and experimental results of the Canadian Cooperative Fatigue Studies Program, carried out at Memorial University and University of Waterloo, is also made. The results obtained indicate that stiffening can considerably reduce the stress concentration in joints, and thus increase the load-carrying capacity of tubular T-joints.

scholarly journals How Can Stress Be Controlled in Endodontically Treated Teeth? A 3D Finite Element Analysis

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
İhsan Yıkılgan ◽  
Oya Bala
Keyword(s):  
Finite Element ◽  
Elastic Moduli ◽  
Resin Composite ◽  
Three Dimensional ◽  
Endodontically Treated Teeth ◽  
Element Analysis ◽  
Dental Tissues ◽  
Dimensional Finite Element ◽  
Stress Formation ◽  
Three Dimensional Finite Element

The aim of this study was to analyze the stresses that develop by oblique and vertical forces in endodontically treated maxillary second premolars that were restored with resin composite. Additionally, in our study the effects of the different restorative approaches and use of different base materials on stress formation were analyzed using three-dimensional finite element stress analysis. For restoration, the models representing both cusp capping, palatinal cusp capping, standard MOD restoration, and use of woven fiber in occlusal part were prepared. In all models, oblique forces caused more stress than did vertical forces. Materials with low elastic moduli cause high amounts of stress, whereas materials with elastic moduli similar to that of dental tissues cause low amounts of stress. Additional approaches such as cusp capping, functional cusp capping, and woven fiber use do not affect stress formation on the tooth after endodontic treatment.

scholarly journals Resistance fracture of minimally prepared endocrowns made by three types of restorative materials: a 3D finite element analysis

2021 ◽  
Vol 32 (11) ◽  
Author(s):  
Qingzhen Meng ◽  
Yuejiao Zhang ◽  
Danlu Chi ◽  
Qimei Gong ◽  
Zhongchun Tong
Keyword(s):  
Maximum Principal Stress ◽  
Height Loss ◽  
Pulp Chamber ◽  
Endodontically Treated Teeth ◽  
Element Analysis ◽  
External Edge ◽  
3D Finite Element ◽  
Crown Length ◽  
Cad Cam ◽  
Tooth Tissue

AbstractA thin endocrown restoration was often applied in endodontically treated teeth with vertical bite height loss or inadequate clinical crown length. A model of mandibular molars made by endocrown restoration with 1 mm thickness and 2 mm depth of pulp chamber was constructed and imported into FEA ANSYS v18.0 software. The three CAD/CAM materials, feldspathic (Mark2), lithium disilicate (EMAX), and lava ultimate (LU), were assigned, and the five load indenters were loaded on the full occlusal (FO), occlusal center (OC), central fossa (CF), buccal groove (BG), and mesiobuccal cusp (MC) of restoration in the model. The MinPS and MaxPS of the thin endocrown were significantly higher than those of tooth tissue in five types of loads except for the LU endocrown loaded in the FO group. The smaller the contact surface of the load was, the higher MaxPS and MinPS were. MaxPS and MinPS of the MC were the highest, followed by the BG and CF in the restoration. In the stress distribution of tooth tissue, MaxPS in the LU endocrown accumulated at the external edge of enamel and was significantly higher than MaxPS in Mark2 and EMAX endocrown concentrated on the chamber wall of dentin under OC, CF and BG loads. Within the limitations of this FEA study, the LU endocrown transferred more stress to tooth tissue than Mark2 and EMAX, and the maximum principal stress on endocrown restoration and tooth tissue at the mesiobuccal cusp load was higher than that at the central fossa and buccal groove load.

scholarly journals Effect of Restorative Material on Mechanical Response of Provisional Endocrowns: A 3D—FEA Study

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 649
Author(s):  
João Paulo Mendes Tribst ◽  
Alexandre Luiz Souto Borges ◽  
Laís Regiane Silva-Concílio ◽  
Marco Antonio Bottino ◽  
Mutlu Özcan
Keyword(s):  
Stress Distribution ◽  
Mechanical Response ◽  
Resin Composite ◽  
Maximum Shear Stress ◽  
Acrylic Resin ◽  
Maximum Principal Stress ◽  
Dental Tissue ◽  
Element Analysis ◽  
Cement Layer ◽  
Restorative Materials

The goal of this study was to evaluate the stress distribution in an endocrown restoration according to different provisional restorative materials. An endodontically treated maxillary molar model was selected for conducting the finite element analysis (FEA), with a determined amount of dental remnant of 1.5 mm. The model was imported to the analysis software (ANSYS 19.2, ANSYS Inc., Houston, TX, USA) in STEP format. All contacts were considered perfectly bonded. The mechanical properties of each structure were considered isotropic, linear, elastic, and homogeneous. Three different provisional restorative materials were simulated (acrylic resin, bis-acrylic resin, and resin composite). An axial load (300 N) was applied at the occlusal surface in the center of the restoration. Results were determined by colorimetric stress maps of maximum principal stress, maximum shear stress, and total deformation. The different materials influenced the stress distribution for all structures; the higher the material’s elastic modulus, the lower the stress magnitude on the cement layer. In the present study, all provisional restorative materials showed similar stress patterns in the endocrown and on the cement layer however, with different magnitude. Based on this study limitation, the use of resin composite to manufacture provisional endocrowns is suggested as a promising material to reduce the stresses in the cement layer and in the dental tissue surfaces.

Fatigue Failure Analysis Using the Theory of Critical Distance

2011 ◽  
Vol 462-463 ◽  
pp. 663-667 ◽  
Author(s):  
Ruslizam Daud ◽  
Ahmad Kamal Ariffin ◽  
Shahrum Abdullah ◽  
Al Emran Ismail
Keyword(s):  
Stress Concentration ◽  
Fatigue Failure ◽  
Notch Root ◽  
High Stress ◽  
Critical Distance ◽  
Future Research ◽  
Element Analysis ◽  
Linear Elastic ◽  
The Finite Element Analysis ◽  
Elastic Fracture

This paper explores the initial potential of theory of critical distance (TCD) which offers essential fatigue failure prediction in engineering components. The intention is to find the most appropriate TCD approach for a case of multiple stress concentration features in future research. The TCD is based on critical distance from notch root and represents the extension of linear elastic fracture mechanics (LEFM) principles. The approach is allowing possibilities for fatigue limit prediction based on localized stress concentration, which are characterized by high stress gradients. Using the finite element analysis (FEA) results and some data from literature, TCD applications is illustrated by a case study on engineering components in different geometrical notch radius. Further applications of TCD to various kinds of engineering problems are discussed.

scholarly journals Folding photopolymerized origami sheets by post-curing

2021 ◽  
Vol 3 (1) ◽  
Author(s):  
Xiaodong He ◽  
Christopher-Denny Matte ◽  
Tsz-Ho Kwok
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Stress Distribution ◽  
Maximum Principal Stress ◽  
Second Step ◽  
Post Processing ◽  
Element Analysis ◽  
Digital Light Processing ◽  
Processing Step ◽  
Lower Maximum

AbstractThe paper presents a novel manufacturing approach to fabricate origami based on 3D printing utilizing digital light processing. Specifically, we propose to leave part of the model uncured during the printing step, and then cure it in the post-processing step to set the shape in a folded configuration. While the cured regions in the first step try to regain their unfolded shape, the regions cured in the second step attempt to keep their folded shape. As a result, the final shape is obtained when both regions’ stresses reach equilibrium. Finite element analysis is performed in ANSYS to obtain the stress distribution on common hinge designs, demonstrating that the square-hinge has a lower maximum principal stress than elliptical and triangle hinges. Based on the square-hinge and rectangular cavity, two variables—the hinge width and the cavity height—are selected as principal variables to construct an empirical model with the final folding angle. In the end, experimental verification shows that the developed method is valid and reliable to realize the proposed deformation and 3D development of 2D hinges.

Effect of washing procedures on trace-element content of hair.

1977 ◽  
Vol 23 (9) ◽  
pp. 1771-1772 ◽  
Author(s):  
G S Assarian ◽  
D Oberleas
Keyword(s):  
Trace Element ◽  
Trace Element Analysis ◽  
Trace Element Content ◽  
Magnesium Content ◽  
Preparation Technique ◽  
Element Analysis ◽  
Significant Difference ◽  
Trace Element Status ◽  
Mg Content ◽  
Source Of Information

Abstract A pooled sample of hair was divided and portions prepared for analysis by three washing procedures, to evaluate the effect of washing procedure on the subsequent trace-element (Zn, Cu, Mg) content. The methods selected were a detergent wash, a hexane-ethanol wash, and an acetone-ether-detergent wash. For all elements, there was a significant difference among the results after these wash procedures. Magnesium content of hair was most affected by washing, containing less than half of the magnesium of the unwashed hair. The detergent wash removed the most zinc and magnesium; the acetone-ether-detergent wash removed the most copper. Our results indicate that the trace-element analysis of hair is sensitive to the preparation technique and therefore is an unreliable source of information about trace-element status.

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