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Carlos José Soares - One of the best experts on this subject based on the ideXlab platform.
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measuring bond strength between fiber post and root dentin a comparison of different tests
Journal of Adhesive Dentistry, 2010Co-Authors: Carina Strano Castellan, Paulo Vinicius Soares, Carlos José Soares, Paulo Cesar Freitas Santosfilho, Paulo Eduardo Capel CardosoAbstract:PURPOSE: the aim of this study was to evaluate the ability of bond strength tests to accurately measure the bond strength of fiber posts luted into root canals. MATERIALS AND METHODS: the test methods studied were hourglass microtensile (HM), push-out (PS), modified pushout (MP), and pull-out (PL). The evaluated parameters were: bond strength values, reliability (using Weibull analysis), failure mode (using confocal microscopy), and stress distribution (using finite element analysis). Forty human intact single-rooted and endodontically treated teeth were divided into four groups. Each group was assigned one of the test methods. The samples in the HM and PS groups were 1.0 ± 0.1 mm thick; the HM samples were hourglass shaped and the PS samples were disk shaped. For the PL and MP groups, each 1-mm dentin slice was luted with a fiber post piece. Three-dimensional models of each group were made and stress was analyzed based on Von Mises Criteria. RESULTS: PL provided the highest values of bond strength, followed by MP, both of which also had greater amounts of adhesive failures. PS showed the highest frequency of cohesive failures. MP showed a more homogeneous stress distribution and a higher Weibull modulus. CONCLUSION: the specimen design directly influences the biomechanical behavior of bond strength tests.
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Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores.
International endodontic journal, 2010Co-Authors: Luís Henrique Araújo Raposo, Paulo Vinicius Soares, Paulo César Freitas Santos-filho, Gisele Rodrigues Da Silva, Priscilla Barbosa Ferreira Soares, Paulo Cézar Simamoto-júnior, Alfredo Júlio Fernandes-neto, Carlos José SoaresAbstract:Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto AJ, Soares CJ. Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores. International Endodontic Journal. Abstract Aim To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns. Methodology Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 × 105 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0–100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (α = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the Von Mises Criteria. Results No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces. Conclusions The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress–strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.
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influence of different post design and composition on stress distribution in maxillary central incisor finite element analysis
Indian Journal of Dental Research, 2009Co-Authors: Natercia Rezende Da Silva, Carolina Guimaraes Castro, Paulo Cesar Freitas Santosfilho, Gisele Rodrigues Da Silva, Roberto Elias Campos, Paulo V Soares, Carlos José SoaresAbstract:Background: Post design and material has very important effects on dentinal stress distribution since the post placement can create stresses that lead to root fracture. Materials and Methods: In this study we use finite element analysis (FEA) to evaluate stress distribution on endodontically treated maxillary central incisors that have been restored with different prefabricated posts. Six models were generated from the image of anatomical plate: Four metallic posts (ParaPost XH, ParaPost XT, ParaPost XP, and Flexi-Flange) and one fiberglass post (ParaPost Fiber Lux). The sixth model was a control-a sound maxillary central incisor. We used CAD software and exported the models to ANSYS 9.0. All the materials and structures were considered elastic, isotropic, homogeneous, and linear except the fiberglass post which was considered orthotropic. The values for the mechanical properties were obtained by a review of the literature and the model was meshed with 8-node tetrahedral elements. A load of 2N was applied to the lingual surface at an angle of 135°. Results: The stress results were recorded by shear stress and Von Mises Criteria; it was observed that there was no difference for stress distribution among the titanium posts in the radicular portions and into posts. There was higher stress concentration on the coronary portion with the titanium posts than with the glass fiber post. It seems that the metallic posts' external configuration does not influence the stress distribution. Conclusion: Fiber posts show more homogeneous stress distribution than metallic posts. The post material seems to be more relevant for the stress distribution in endodontically treated teeth than the posts' external configuration.
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two dimensional fea of dowels of different compositions and external surface configurations
Journal of Prosthodontics, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Cesar Freitas Santos Filho, Paulo Vinicius Soares, Denildo De Magalhaes, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
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Two‐Dimensional FEA of Dowels of Different Compositions and External Surface Configurations
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Vinicius Soares, Denildo De Magalhaes, Paulo Santos Filho, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
Paulo Vinicius Soares - One of the best experts on this subject based on the ideXlab platform.
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Restorative material and loading type influence on the biomechanical behavior of wedge shaped cervical lesions
Clinical Oral Investigations, 2016Co-Authors: Fabricia Araujo Pereira, Livia Favaro Zeola, Rodrigo Dantas Pereira, G. Milito, Bruno Rodrigues Reis, Paulo Vinicius SoaresAbstract:Objectives To evaluate the influence of restorative materials used on the rehabilitation of MOD cavities and loading type, on biomechanical behavior of wedge-shaped (WS) lesions in endodontically treated maxillary premolars. The investigation was conducted by 3D finite element analysis (FEA) and strain gauge test. Materials and methods Six models were generated, with MOD cavities and endodontic treatment: A (MOD amalgam restoration), R (MOD composite restoration), AL (A + cervical lesion (L)), RL, ALR (A + cervical lesion restored with composite (LR)), and RLR. Each model underwent two compressive loading (100N): axial and oblique—45° angle to the long axis on the buccal cusp. The models were analyzed by Von Mises Criteria. For strain gauge test, 14 standardized maxillary premolars were treated according to the groups described for FEA. Two strain gauges were bonded on each sample submitted to compressive loading in a mechanical testing machine. Results A presented higher stress concentration and strain values than R. Oblique loading promoted highest stress concentration and strain rates for all groups. ALR and RLR presented similar stress–strain distribution pattern when compared to A and R. Conclusion The interaction between MOD cavity restored with amalgam and oblique loading propitiated the highest stress concentration and strain values on cervical region and WS lesion. Clinical relevance The MOD cavity restored with composite resin is a better option than amalgam to improve the biomechanical behavior of wedge-shaped lesion, avoiding dental failure. In addition, the occlusal interferences must be removed, allowing homogeneous contact distribution and preventing WS lesion progression.
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measuring bond strength between fiber post and root dentin a comparison of different tests
Journal of Adhesive Dentistry, 2010Co-Authors: Carina Strano Castellan, Paulo Vinicius Soares, Carlos José Soares, Paulo Cesar Freitas Santosfilho, Paulo Eduardo Capel CardosoAbstract:PURPOSE: the aim of this study was to evaluate the ability of bond strength tests to accurately measure the bond strength of fiber posts luted into root canals. MATERIALS AND METHODS: the test methods studied were hourglass microtensile (HM), push-out (PS), modified pushout (MP), and pull-out (PL). The evaluated parameters were: bond strength values, reliability (using Weibull analysis), failure mode (using confocal microscopy), and stress distribution (using finite element analysis). Forty human intact single-rooted and endodontically treated teeth were divided into four groups. Each group was assigned one of the test methods. The samples in the HM and PS groups were 1.0 ± 0.1 mm thick; the HM samples were hourglass shaped and the PS samples were disk shaped. For the PL and MP groups, each 1-mm dentin slice was luted with a fiber post piece. Three-dimensional models of each group were made and stress was analyzed based on Von Mises Criteria. RESULTS: PL provided the highest values of bond strength, followed by MP, both of which also had greater amounts of adhesive failures. PS showed the highest frequency of cohesive failures. MP showed a more homogeneous stress distribution and a higher Weibull modulus. CONCLUSION: the specimen design directly influences the biomechanical behavior of bond strength tests.
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Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores.
International endodontic journal, 2010Co-Authors: Luís Henrique Araújo Raposo, Paulo Vinicius Soares, Paulo César Freitas Santos-filho, Gisele Rodrigues Da Silva, Priscilla Barbosa Ferreira Soares, Paulo Cézar Simamoto-júnior, Alfredo Júlio Fernandes-neto, Carlos José SoaresAbstract:Raposo LHA, Silva GR, Santos-Filho PCF, Soares PV, Soares PBF, Simamoto-Junior PC, Fernandes-Neto AJ, Soares CJ. Effect of anti-rotation devices on biomechanical behaviour of teeth restored with cast post-and-cores. International Endodontic Journal. Abstract Aim To test the hypothesis that the presence of an anti-rotation device (ARD) and its location can influence the biomechanical behaviour of root filled teeth restored with cast post-and-cores and metallic crowns. Methodology Fifth two bovine incisor roots were selected and divided into four groups (n = 13): Nd- without ARD; Bd- buccal ARD; Ld- lingual ARD; BLd- buccal and lingual ARD. The specimens were restored with cast post-and-cores and metallic crowns. After a fatigue process (3 × 105 50 N), three strain gauges were attached on the buccal, lingual and proximal surfaces and the samples of each group (n = 3) were submitted to a 0–100 N load. Fracture resistance was assessed in a mechanical testing machine (n = 10). Strain values and fracture resistance data were analysed by one-way anova and Tukey Honestly Significant Difference (HSD) test (α = 0.05). The failure mode was then evaluated under an optical stereomicroscope. Bidimensional models of each group were generated for finite element analysis (FEA) and analysed using the Von Mises Criteria. Results No significant difference in fracture resistance values and fracture modes occurred between the four groups. The BLd group had higher stress concentrations in the buccal dentine and higher strain values on the proximal surfaces. Conclusions The anti-rotation devices did not influence significantly the fracture resistance and fracture mode. However, the stress–strain values were increased when the anti-rotation device was prepared on the buccal and lingual faces concomitantly.
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two dimensional fea of dowels of different compositions and external surface configurations
Journal of Prosthodontics, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Cesar Freitas Santos Filho, Paulo Vinicius Soares, Denildo De Magalhaes, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
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Two‐Dimensional FEA of Dowels of Different Compositions and External Surface Configurations
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Vinicius Soares, Denildo De Magalhaes, Paulo Santos Filho, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
Gurcan Eskitascioglu - One of the best experts on this subject based on the ideXlab platform.
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Effect of Different Treatment Options on Biomechanics of Immature Teeth: A Finite Element Stress Analysis Study.
Journal of endodontics, 2017Co-Authors: Sema Belli, Oğuz Eraslan, Gurcan EskitasciogluAbstract:Abstract Introduction Immature teeth (IT) can be managed by using several treatment options, depending on the vitality of the tooth. The aim of this finite element stress analysis study was to evaluate the effect of different treatment procedures on the stresses in three-dimensional IT models. Methods Three-dimensional finite element stress analysis premolar tooth model was created as control (model 1), modified to simulate IT. Eleven models were created to simulate IT filled with (model 2) calcium hydroxide (CH), (model 3) mineral trioxide aggregate (MTA), (model 4) Biodentine (B), (models 5 and 6) MTA plug and B plug without root-filling, (models 7 and 8) MTA plug and B plug with root-filling with composite restoration, and amputation by using (model 9) CH, (model 10) MTA, and (model 11) B. Materials and structures were assumed to be homogenous and isotropic. A 300 N load was applied to the models from the functional cusps and central fossa with a 135° angle. Cosmosworks structural analysis program was used. The results were presented considering the Von Mises Criteria, and the scale range was limited to 0–10 + MPa. Results CH use in comparison with temporary filling increased the stresses within the root. MTA filling showed less stresses when compared with B filling. MTA and B plug increased the stresses at apical and root; however, when the roots were filled using gutta-percha and the crowns were restored with composite resin, the stresses at the coronal side of the roots were reduced. The stresses were distributed more favorably in the models simulating CH, MTA, or B amputation. Amputation by using MTA and B showed similar stresses with natural tooth model. Conclusions CH is not a favorable dressing material for IT when compared with MTA and B. MTA or B plug increases the stresses at apical, whereas root-filling reduces the stresses within the root. Amputation by using CH, MTA, and B in combination with composite resin restoration may save both the coronal and root structure of IT.
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Effect of post-restoration on stresses in premolars with endodontic–periodontal lesion: an FEA study
Journal of Adhesion Science and Technology, 2016Co-Authors: Sema Belli, Oğuz Eraslan, Sema S. Hakki, M. Eskitascioglu, Gurcan EskitasciogluAbstract:AbstractAim: This finite elemental stress analysis (FEA) study was aimed to test the effect of fiber and metal posts on stress distribution in premolar teeth with endodontic–periodontal (EP) lesion. Methodology: Three FEA models representing different EP lesions (primary endodontic disease (PED), PED with periodontal involvement and true-combined) were created. Tooth-model without EP lesion was used as control. The root-canals were assumed as root-filled, restored using glass-fiber or metal posts, resin composite build-up, and ceramic crown. A 300 N load was applied from the palatal surface of the crown with a 135° angle. The SolidWorks/Cosmosworks structural analysis program was used for FEA analysis. Results were presented by considering Von Mises Criteria. Results: Maximum stress values for PED, PED with periodontal-involvement and true-combined lesions were 2.26, 1.25, 0.74 MPa for glass-fiber post; 2.08, 1.51, 1.18 MPa for metal post, respectively. If there is PED, fiber-post gave an advantage to the...
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Effect of Root Filling on Stress Distribution in Premolars with Endodontic-Periodontal Lesion: A Finite Elemental Analysis Study.
Journal of endodontics, 2015Co-Authors: Sema Belli, Oğuz Eraslan, Gurcan EskitasciogluAbstract:Abstract Introduction Endodontic-periodontal (EP) lesions require both endodontic and periodontal therapies. Impermeable sealing of the root canal system after cleaning and shaping is essential for a successful endodontic treatment. However, complete healing of the hard and soft tissue lesions takes time, and diseased bone, periodontal ligament, and tooth fibrous joints are reported to have an increased failure risk for a given load. Considering that EP lesions may affect the biomechanics of teeth, this finite elemental analysis study aimed to test the effect of root fillings on stress distribution in premolars with EP lesions. Methods Three finite elemental analysis models representing 3 different types of EP lesions (primary endodontic disease [PED], PED with secondary periodontic involvement, and true combined) were created. The root canals were assumed as nonfilled or filled with gutta-percha, gutta-percha/apical mineral trioxide aggregate (MTA) plug, and MTA-based sealer. Materials used were assumed to be homogenous and isotropic. A 300-N load was applied from the buccal cusp of the crown with a 135° angle. The Cosmoworks structural-analysis program (SolidWorks Corp, Waltham, MA) was used for analysis. Results were presented considering Von Mises Criteria. Results Stresses at the root apex increased with an increase in lesion dimensions. Root filling did not affect stress distribution in the PED model. An MTA plug or MTA-based sealer created more stress areas within the root compared with the others in the models representing PED with periodontic involvement and true combined lesions. Conclusions Stresses at the apical end of the root increase with increases in lesion dimensions. MTA-based sealers or an MTA plug creates more stresses when there is periodontic involvement or a true combined lesion.
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Effects of NaOCl, EDTA and MTAD when applied to dentine on stress distribution in post-restored roots with flared canals.
International endodontic journal, 2014Co-Authors: Sema Belli, Oğuz Eraslan, M. Eskitascioglu, Gurcan EskitasciogluAbstract:Aim To evaluate the effect of NaOCl, EDTA and MTAD on the stress distribution and levels in roots with flared canals and three different aesthetic post systems using finite element stress analysis (FEA). Methodology Three-dimensional (3D) FEA models simulating a maxillary incisor with excessive structural loss and flared root canals were created. The dentine of the first models of each post group was assumed as homogenous, whereas the others were deemed as having their elastic modulus affected up to 100 μm deep as a result of irrigation protocol (5.25 NaOCl, 17% EDTA and MTAD for 2 h). A sound incisor tooth model was used as the control. Restorations were created according to the post system used (pre-fabricated fibre post (PFP)), polyethylene fibre (Ribbond) post and core build-up (RBP), and one-piece milled zirconia post and core (ZP). Ceramic crowns were added to the models. A 300-N static load was applied at the centre of the palatal surface of the models to calculate the stress distributions. The SolidWorks/Cosmosworks structural analysis programmes were used for FEA analysis. Results were presented by considering Von Mises Criteria. Results The analysis of the Von Mises stresses revealed that RBP created less stress in the remaining root dentine when compared to PFP and ZP. ZP maintained the stresses inside its body and reduced stress on the palatal surface of the root; however, it forwarded more stress towards the apical area. NaOCl-, EDTA- and MTAD-treated dentine increased the stresses within the root structure regardless of the effect of the post system used (11–15.4 MPa for PFP, 9.5–13.02 MPa for RBP and 14.2 MPa for ZP). Amongst the irrigation solutions used, EDTA and MTAD increased the stresses more than NaOCl in all models. All the irrigation solutions showed the same stress levels and distributions in the ZP model. Conclusion NaOCl-, EDTA- and MTAD- treated dentine and a rigid post with high elastic modulus may increase fracture risk in roots with flared canals by increasing the stresses within root dentine. Therefore, solutions that alter the elastic modulus of dentine less (such as NaOCl) or an individually shaped post–core system constructed with a material that has an elastic modulus close to dentine (polyethylene fibre) should be used in weak roots.
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Monoblocks in root canals: a finite elemental stress analysis study.
International endodontic journal, 2011Co-Authors: Sema Belli, Oğuz Eraslan, Gurcan Eskitascioglu, Vistasp M. KarbhariAbstract:Belli S, Eraslan O, Eskitascioglu G, Karbhari V. Monoblocks in root canals: a finite elemental stress analysis study. International Endodontic Journal, 44, 817–826, 2011. Abstract Aim To investigate using finite element stress analysis (FEA) primary, secondary and tertiary monoblocks created either by adhesive resin sealers or by different adhesive posts and to evaluate the effect of interfaces on stress distribution in incisor models. Methodology Seven maxillary incisor FEA models representing different monoblocks using several materials were created as follows: (a) primary monoblock with Mineral Trioxide Aggregate; (b) secondary monoblock with sealer (MetaSEAL) and Resilon; (c) tertiary monoblock with EndoREZ; (d) primary monoblock with polyethylene fibre post-core (Ribbond); (e) secondary monoblock with glass-fibre post and resin cement; (f) tertiary monoblock with bondable glass-fibre post; (g) tertiary monoblock with silane-coated ceramic post. A 300 N load was applied from the palatal surface of the crown with a 135° angle to the tooth long axis. Materials used in the study were assumed to be homogenous and isotropic except the glass-fibre post; the results are expressed in terms of Von Mises Criteria. Results Maximum stresses were concentrated on force application areas (18–22.1 MPa). The stresses within the models increased with the number of interfaces both for the monoblocks created by the sealers (1.67–8.33 MPa) and for the monoblocks created by post-core systems (1.67–11.7 MPa). Conclusions Stresses within roots increased with an increase in the number of the adhesive interfaces. Creation of a primary monoblock within the root canal either by an endodontic sealer or with an adhesive post-core system can reduce the stresses that occur inside the tooth structure.
Luis Roberto Marcondes Martins - One of the best experts on this subject based on the ideXlab platform.
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two dimensional fea of dowels of different compositions and external surface configurations
Journal of Prosthodontics, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Cesar Freitas Santos Filho, Paulo Vinicius Soares, Denildo De Magalhaes, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
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Two‐Dimensional FEA of Dowels of Different Compositions and External Surface Configurations
Journal of prosthodontics : official journal of the American College of Prosthodontists, 2009Co-Authors: Carlos José Soares, Carolina Guimaraes Castro, Paulo Vinicius Soares, Denildo De Magalhaes, Paulo Santos Filho, Luis Roberto Marcondes MartinsAbstract:Purpose: The degree of stress generated in the endodontically treated and restored tooth can be influenced by the composition and configuration of the dowels used for the restoration. Using two-dimensional (2D) finite element analysis (FEA), this study tested the hypothesis that the characterization of the stress distribution can be influenced by which evaluation method is employed: protrusion loading and 4-point flexural strength test or varying the type of material (carbon and glass fiber) or the external configuration of the dowel (smooth and serrated). Materials and Methods: For simulation of the protrusion load test, models were generated with Mechanical-AutoCAD V6 software from an image of an anatomical plate, one maxillary central incisor, and two dowels and exported to Ansys 9.0. The bone region model was fixed, and a tangential load of 1 N with a 135° inclination to the tooth longitudinal axis was applied at the level of the palatal surface of the crown. In the simulation of a 4-point flexural strength test, a 1 N perpendicular load was applied in two points to the dowel. The dental materials and structures were considered elastic, isotropic, homogeneous, and linear, with the exception of the dowel, which was assumed to exhibit orthotropic behavior. Mechanical properties were defined based on a review of the literature, and the model was meshed with an eight node tetrahedral element. Results: The stress results from both tests were analyzed according to Von Mises Criteria and principal stresses (Sx). Data from the 4-point flexural strength test simulation showed that, for the serrated dowels, a higher stress concentration was found; however, no difference in the occlusal load for material or dowel configuration was found. Conclusions: These results suggest that although the external configuration of the dowel influences direct loading, when the dowel is integrated to the tooth and setting material, the influence on biomechanical behavior disappears.
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influence of restorative technique on the biomechanical behavior of endodontically treated maxillary premolars part ii strain measurement and stress distribution
Journal of Prosthetic Dentistry, 2008Co-Authors: Paulo Vinicius Soares, Luis Roberto Marcondes Martins, Paulo Cesar Freitas Santosfilho, Henner Alberto Gomide, Cleudmar Amaral De Araujo, Carlos José SoaresAbstract:Statement of problem. Unresolved controversy exists concerning the preferred cavity design and restorative technique used to restore endodontically treated maxillary premolars to minimize strain and improve stress distribution under occlusal load. Purpose. The purpose of this study was to analyze the influence of cavity design and restorative material on strain measurement and stress distribution in maxillary premolars under occlusal loading conditions, and correlate these influences with the failure modes analyzed in Part I. Material and methods. For the strain gauge test, 21 additional specimens were prepared as described in Part 1 of this study (n=3). Two strain gauges were fixed on the buccal (B) and palatal (P) cusps of each specimen with cyanoacrylate adhesive. The specimens were submitted to continuous axial compression loading at a speed of 0.5 mm/min, using a 6-mm sphere, to a maximum limit of 150 N in a universal testing machine. Total strain values were obtained by combining the B and P cusp strain values. These values were submitted to 2-way ANOVA and the Dunnet test (α=.05). For finite element analyses, 7 numerical 2-D models were generated: MODd, direct mesio-occlusal-distal preparation; MODi, indirect mesio-occlusal-distal preparation; AM, MODd restored with amalgam; CR, MODd restored with composite resin; LPR, MODi restored with laboratory-processed composite resin; and LGC, MODi restored with leucite-reinforced glass ceramic; each corresponding to 1 of the experimental groups tested in Part I of this study. The models were analyzed with finite element software, using the Von Mises Criteria for stress distribution analysis. Results. With the strain gauge test, MODd, MODi, and AM groups showed significantly higher strain values than the CR, LPR, and LGC. Finite element analyses revealed that tooth structure removal and the type of restorative material altered the stress distribution pattern. The MODd, MODi, AM, and LPR models showed higher stress concentration within the tooth structure. Conclusions. The specimens with adhesive restorations were shown to behave in a manner similar to the biomechanical behavior of healthy teeth, while the behavior of those restored with amalgam restorations was more like that observed for teeth with nonrestored cavity preparations. These results directly correlate with the fracture mode results obtained in Part I of this study. (J Prosthet Dent 2008;99:114-122)
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Stress distributions in elastic‐plastic rotating disks with elliptical thickness profiles using Tresca and Von Mises Criteria
ZAMM, 2005Co-Authors: Ahmet N EraslanAbstract:Analytical and numerical solutions for the elastic-plastic stress distribution in rotating variable thickness solid and annular disks are obtained under plane stress assumption. The thickness of the disk is assumed to vary radially in elliptic form which represents a wide range of continuously variable nonlinear cross-sectional profiles. Tresca's yield criterion and its associated flow rule are used to obtain analytical solutions for a linear hardening material. A computational model is developed to obtain solutions using the Von Mises yield criterion, deformation theory of plasticity and a Swift-type hardening law. Both linear and nonlinear hardening materials are considered in solutions obtained by using Von Mises criterion. The stresses, displacement and plastic strains are calculated for solid and annular disks rotating at different speeds and the results are presented in graphical forms.
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stress distributions in elastic plastic rotating disks with elliptical thickness profiles using tresca and Von Mises Criteria
Zamm-zeitschrift Fur Angewandte Mathematik Und Mechanik, 2005Co-Authors: Ahmet N EraslanAbstract:Analytical and numerical solutions for the elastic-plastic stress distribution in rotating variable thickness solid and annular disks are obtained under plane stress assumption. The thickness of the disk is assumed to vary radially in elliptic form which represents a wide range of continuously variable nonlinear cross-sectional profiles. Tresca's yield criterion and its associated flow rule are used to obtain analytical solutions for a linear hardening material. A computational model is developed to obtain solutions using the Von Mises yield criterion, deformation theory of plasticity and a Swift-type hardening law. Both linear and nonlinear hardening materials are considered in solutions obtained by using Von Mises criterion. The stresses, displacement and plastic strains are calculated for solid and annular disks rotating at different speeds and the results are presented in graphical forms.
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on the elastic plastic deformation of a rotating disk subjected to a radial temperature gradient
Mechanics Based Design of Structures and Machines, 2003Co-Authors: Ahmet N Eraslan, Tolga AkisAbstract:Abstract Elastic–plastic stress distribution in a nonisothermal rotating annular disk is analyzed by the use of Tresca and Von Mises Criteria. An energy equation that accounts for the convective heat transfer with a variable heat transfer coefficient is modeled. For a given angular velocity, the steady temperature distribution in the disk is obtained by the analytical solution of the energy equation. Tresca yield criterion and its associated flow rule are used to obtain the analytical stress distributions for a linearly hardening material. A computational model is developed to analyze elastic–plastic deformations of the disk using Von Mises yield criterion and its flow rule. This model incorporates Swift's hardening law to simulate linear as well as nonlinear hardening material behavior. It is shown that the stress distribution in the disk is affected significantly by the presence of the temperature gradient.
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INELASTIC DEFORMATIONS OF ROTATING VARIABLE THICKNESS SOLID DISKS BY TRESCA AND Von Mises Criteria
International Journal of Computational Engineering Science, 2002Co-Authors: Ahmet N EraslanAbstract:Inelastic stresses and displacements in rotating solid disks of exponentially varying thickness have been investigated using Tresca's and Von Mises' yield Criteria. In both Criteria, linear strain hardening material behavior is assumed. A previously obtained analytical solution is adopted in the analysis when Tresca criterion is used. An efficient numerical solution procedure has been designed to obtain the solution of Von Mises. Plastic limit angular velocities have been calculated for different values of the geometric parameters. In all the cases investigated the difference between Tresca and Von Mises, in finding plastic limit angular velocities was less than 3%. The inelastic stresses, displacement and strains have been calculated for disks of different profiles and the results presented in graphical forms.
