scholarly journals Biomechanical behavior of indirect composite materials: a 3D-FEA study

2017 ◽  
Vol 20 (3) ◽  
Author(s):  
João Paulo Mendes Tribst ◽  
Amanda Maria de Oliveira Dal Piva ◽  
Alexandre Luis Souto Borges

<p><strong>Objective:</strong> This study aimed to evaluate the influence of the elastic modulus of indirect composite resins (ICR) in the stress distribution of a restored maxillary first premolar. <strong>Material and methods:</strong> A three-dimensional (3D) finite element model of the tooth and the mesial-occlusal-distal (MOD) restoration was created. Three ICR were simulated, by changing the elastic modulus: 10, 15 and 20 GPa. All materials were considered as isotropic, homogeneous and linearly elastic. An occlusal load (200 N) was applied on occlusal surface trough a sphere, and the nodes of the external surface of the root were fixed.  The maximum principal stresses on the tooth and restoration were analyzed. <strong>Results:</strong> According to FE analysis, the lower the ICR elastic modulus, the higher the stress values generated on the remaining tooth. For the restoration, the opposite was observed: the lower the modulus, the lower the stress. <strong>Conclusion:</strong> With the limitations of this study <span style="text-decoration: underline;">it </span>is possible to conclude that the greater the elastic modulus of the restorative material the harder it will be to deflect the cusps, but the easier the fracture of the resin.</p><p><strong>Keywords: </strong>Finite Elements Analysis; Composite Resin; Indirect Restoration; Flexural Strength.</p>

Metals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 573
Author(s):  
María Prados-Privado ◽  
Henri Diederich ◽  
Juan Prados-Frutos

A severely atrophied maxilla presents serious limitations for rehabilitation with osseointegrated implants. This study evaluated the biomechanical and long-term behavior of titanium hybrid-plates in atrophic maxilla rehabilitation with finite elements and probabilistic methodology. A three-dimensional finite element model based on a real clinical case was built to simulate an entirely edentulous maxilla with four plates. Each plate was deformed to become accustomed to the maxilla’s curvature. An axial force of 100 N was applied in the area where the prosthesis was adjusted in each plate. The von Mises stresses were obtained on the plates and principal stresses on maxilla. The difference in stress between the right and left HENGG-1 plates was 3%, while between the two HENGG-2 plates it was 2%, where HENGG means Highly Efficient No Graft Gear. A mean maximum value of 80 MPa in the plates’ region was obtained, which is a lower value than bone resorption stress. A probability cumulative function was computed. Mean fatigue life was 1,819,235 cycles. According to the results of this study, it was possible to conclude that this technique based on titanium hybrid-plates can be considered a viable alternative for atrophic maxilla rehabilitation, although more studies are necessary to corroborate the clinical results.


2019 ◽  
Vol 43 (4) ◽  
pp. 443-453
Author(s):  
Stephen M. Handrigan ◽  
Sam Nakhla

An investigation to determine the effect of porosity concentration and location on elastic modulus is performed. Due to advancements in testing methods, the manufacturing and testing of microbeams to obtain mechanical response is possible through the use of focused ion beam technology. Meanwhile, rigorous analysis is required to enable accurate extraction of the elastic modulus from test data. First, a one-dimensional investigation with beam theory, Euler–Bernoulli and Timoshenko, was performed to estimate the modulus based on load-deflection curve. Second, a three-dimensional finite element (FE) model in Abaqus was developed to identify the effect of porosity concentration. Furthermore, the current work provided an accurate procedure to enable accurate extraction of the elastic modulus from load-deflection data. The use of macromodels such as beam theory and three-dimensional FE model enabled enhanced understanding of the effect of porosity on modulus.


2020 ◽  
Vol 28 (6) ◽  
pp. 603-613 ◽  
Author(s):  
Efe Can Sivrikaya ◽  
Mehmet Sami Guler ◽  
Muhammed Latif Bekci

BACKGROUND: Zirconia has become a popular biomaterial in dental implant systems because of its biocompatible and aesthetic properties. However, this material is more fragile than titanium so its use is limited. OBJECTIVES: The aim of this study was to compare the stresses on morse taper implant systems under parafunctional loading in different abutment materials using three-dimensional finite element analysis (3D FEA). METHODS: Four different variations were modelled. The models were created according to abutment materials (zirconia or titanium) and loading (1000 MPa vertical or oblique on abutments). The placement of the implants (diameter, 5.0 × 15 mm) were mandibular right first molar. RESULTS: In zirconia abutment models, von Mises stress (VMS) values of implants and abutments were decreased. Maximum and minimum principal stresses and VMS values increased in oblique loading. VMS values were highest in the connection level of the conical abutments in all models. CONCLUSIONS: Using conical zirconia abutments decreases von Mises stress values in abutments and implants. However, these values may exceed the pathological limits in bruxism patients. Therefore, microfractures may be related to the level of the abutment.


2019 ◽  
pp. 0000-0000 ◽  
Author(s):  
Karina Albino Lencioni ◽  
Pedro Yoshito Noritomi ◽  
Ana Paula Macedo ◽  
Ricardo Faria Ribeiro ◽  
Rossana Pereira Almeida

This study analyzed the biomechanical behavior of rigid and non-rigid tooth-implant supported fixed partial dentures. Different implants were used in order to observe the load distribution over teeth, implants, and adjacent bone using three-dimensional finite element analysis. A simulation of tooth loss of the first and second right molars was created with an implant placed in the second right molar and a prepared tooth with simulated periodontal ligament (PDL) in the second right premolar. Configurations of two types of implants and their respective abutments, i.e., external hexagon (EX) and Morse taper (MT), were transformed into a 3D format. Metal-ceramic fixed partial dentures were constructed with rigid and non-rigid connections. Mesh generation and data processing were performed on the 3D FEA results. Static loading of 50 N (premolar) and 100 N (implant) were applied. When an EX implant was used, with a rigid or non-rigid connection, there was intrusion of the tooth in the distal direction with flexion of the periodontal ligament. Tooth intrusion did not occur when the MT implant was used independent of a rigid or non-rigid connection. The rigid or non-rigid connection resulted in a higher incidence of compressive forces at the cortical bone and stress in the abutment/pontic area, regardless of whether EX or MT implants were used. MT implants have a superior biomechanical performance in tooth-implant supported fixed partial dentures. This prevents the intrusion of the tooth independent of the connection. Both types of implants that were studied caused a greater tendency of compressive forces at the crestal area.


2017 ◽  
Vol 20 (4) ◽  
pp. 115 ◽  
Author(s):  
Victória Luswarghi Souza Costa ◽  
João Paulo Mendes Tribst ◽  
Alexandre Luiz Souto Borges

<p><strong>Objective:</strong> The aim of this study was to observe the influence of different occlusal contacts in a superior pre-molar structure using Finite Element Analysis. <strong>Material and Methods:</strong> A three-dimensional model of a superior pre-molar was designed to simulate three occlusion situations, namely central occlusion and two types of lateral occlusion contacts. The model presents enamel, dentin, a periodontal ligament and a fixation cylinder separately. All materials were considered isotropic, linear and homogeneous, and the contacts of each structure were perfectly bonded. On analysis software, a load was applied to an occlusal surface at 40° to the long axis on lateral contacts, and directed to the long axis on central occlusion contact. <strong>Results:</strong> The results were obtained in stress maps and the maximum values were then plotted in table for quantitative comparison, with the enamel concentrating more stress than dentin and the occlusal contact presenting the worst biomechanical behavior. <strong>Conclusion: </strong>Within the limitations of this study, it is possible conclude that: eccentric contacts have higher potential to develop abfraction lesions on the cervical region of teeth, thus increasing the magnitude of tensile and shear stresses.</p><p><strong>Keywords</strong></p><p>Finite Elements Analysis, Abfraction; Stress distribution; Occlusion, Premolar.</p>


2020 ◽  
Vol 23 (3) ◽  
Author(s):  
Ana Luiza Barbosa Jurema ◽  
Marcela Moreira Penteado ◽  
João Paulo Mendes Tribst ◽  
Taciana Marco Ferraz Caneppele ◽  
Alexandre Luiz Souto Borges

Objective: This study aimed to evaluate the biomechanical behaviour of endodontically treated teeth with direct veneer that received or not intra-radicular glass fiber post by finite elements analysis. Material and methods: Six models were designed, varying the presence or absence of glass fiber post and the thickness of direct veneer (0.5, 0.7 and 1 mm). Tridimensional models of maxillary central incisors were obtained with CAD software, Rhinoceros 4.0, and transferred to CAE software, ANSYS 17.2, which a 100N load was applied in a 45° on the lingual surface to simulate functional movements. Geometry contacts were bonded, and the structures were isotropic, linear, elastics, and homogeneous. After coherence and convergence analysis of mashes, the chosen fail criterion was the maximum principal stresses. Results: For cement, glass fiber post, the stress distribution was similar independently of glass fiber post presence or veneer thickness. Models with glass fiber post had better stress distribution and lower values of maximum stress for inner dentin and veneers. Veneers with 0.5 and 1 mm had higher stress concentration areas. Conclusions: It can be concluded that glass fiber post is favorable for restored teeth with direct veneers, and very thin or very thick preparations can damage the biomechanical behavior of restorations.KeywordsDental veneers; Finite element analysis; Nonvital tooth; Post and core technique.


1994 ◽  
Vol 07 (01) ◽  
pp. 35-39 ◽  
Author(s):  
T. K. Cheung ◽  
K. N. Thompson

SummaryFracture of the proximal sesamoid bones is a common injury of racing horses, usually resulting from over-dorsiflexion of the metacarpophalangeal joint. The purpose of this study was to develop a computer-aided method utilizing stereo-radiography, computed tomography, and finite element method to determine three-dimensional stress distribution in the proximal sesamoid bones during metacarpophalangeal joint dorsiflexion. The stress pattern was characterized by a compressive component on the articular part of the bone and a tensile component on the non-articular part of the bone. Maximum principal stresses were 2.5, 9.1 and 15.5 MPa and minimum principal stresses were -1.9, -9. 2 and -14. 9 MPa for metacarpophalangeal joint angles of 140°, 125° and 110°, respectively. The distal portion of the articular part of the bone experienced the largest compressive stress. In this study changes in the orientation and magnitude of the ligament force vectors did not significantly change stress patterns of the proximal sesamoid bone.This study was designed to determine stress patterns of the proximal sesamoid bones in horses. Stress patterns were determined by finite element method analysis. Compressive stresses were present on the articular side, and tensile stresses were present on the nonarticular side of the bones. The magnitude of load applied to the bone did not appreciably change the pattern of stresses.


2019 ◽  
Vol 45 (5) ◽  
pp. 363-370
Author(s):  
Gokce Soganci Unsal ◽  
Guzin Neda Hasanoglu Erbasar ◽  
Filiz Aykent ◽  
Ozgun Yusuf Ozyilmaz ◽  
Mahmut Sertac Ozdogan

The biomechanical behavior of the edentulous mandible with bone irregularities that has been rehabilitated with implant-supported overdentures has become an important factor for treatment planning. Restorative options, including dental implants with various attachments, affect the stress distribution. The purpose of this study was to evaluate the stress distribution of cortical bone around the implant neck and implant structures in overdentures with two different attachment types at the edentulous mandible and with different bone heights using three-dimensional finite element analysis. Five three-dimensional models of an edentulous mandible were designed and implemented. Ten models were constructed with ball and locator attachments. Static bilateral and unilateral vertical and oblique occlusal loads with magnitudes of 100 N were applied to the overdentures. The principal stresses were higher in the presence of oblique loads compared to vertical loads in all the analyzed models. Maximum principal stresses were observed around the mesial side of the contralateral implant, and the minimum principal stresses were noted around the distal side of ipsilateral implant during unilateral vertical loading. These patterns were reversed during oblique loadings. The ball attachment models yielded lower von Mises stress values than the locator models at all the loading conditions, while the stress distributions were similar in the models with the same and different bone levels. Correspondingly, bone corrections due to irregularities may not be necessary in terms of biomechanics. The results of this study may provide clinicians a better understanding for the mandibular overdenture design in the cases at which different bone heights exist.


2018 ◽  
Author(s):  
Saman Naghieh ◽  
Mohammad Reza Karamooz-Ravari ◽  
Md Sarker ◽  
Eva Karki ◽  
Xiongbiao Chen

Tissue scaffolds fabricated by three-dimensional (3D) bioprinting are attracting considerableattention for tissue engineering applications. Because the mechanical properties of hydrogelscaffolds should match the damaged tissue, changing various parameters during 3D bioprintinghas been studied to manipulate the mechanical behavior of the resulting scaffolds. Crosslinkingscaffolds using a cation solution (such as CaCl2) is also important for regulating the mechanicalproperties, but has not been well documented in the literature. Here, the effect of variedcrosslinking agent volume and crosslinking time on the mechanical behavior of 3D bioplottedalginate scaffolds was evaulated using both experimental and numerical methods. Compressiontests were used to measure the elastic modulus of each scaffold, then a finite element model wasdeveloped and a power model used to predict scaffold mechanical behavior. Results showed thatcrosslinking time and volume of crosslinker both play a decisive role in modulating the mechanicalproperties of 3D bioplotted scaffolds. Because mechanical properties of scaffolds can affect cellresponse, the findings of this study can be implemented to modulate the elastic modulus ofscaffolds according to the intended application.


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