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Fathi A, Hoshyar Y, Ebadian B, Ghorbani M. Comparison of Stress and Strain Distribution Patterns in Canine Implant and Maxillary Bone in Three Occlusal Schemes Using Finite Element Analysis. Eur J Dent 2024; 18:852-859. [PMID: 38331040 PMCID: PMC11290915 DOI: 10.1055/s-0043-1776313] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/10/2024] Open
Abstract
OBJECTIVES This study aimed to compare the pattern of stress and strain distribution in canine implant and maxillary bone in the anterior group function (AGF), posterior group function (PGF), and canine guidance (CG) occlusal schemes by finite element analysis (FEA). MATERIAL AND METHODS In this in vitro experimental study, a dental implant (10 × 4.1 mm) was inserted at the site of the maxillary canine in a model of the maxilla in Mimics software. The implant was scanned three-dimensionally and the data were transferred to SolidWorks software. The von Mises stress, shear stress, deformation, and strain were calculated in the AGF, PGF, and CG occlusal schemes by FEA. STATISTICAL ANALYSIS Data were analyzed by ABAQUS software to calculate the stress transferred to the canine implant and maxillary bone in the three occlusal schemes. RESULTS The maximum and minimum von Mises stress, elastic strain, shear stress, and deformation were noted in the AGF and PGF occlusal schemes, respectively, in all teeth. CONCLUSION The PGF showed minimum von Mises stress, elastic strain, shear stress, and deformation in the canine implant and maxillary bone. Thus, it appears than the PGF is the best occlusal scheme for maxillary canine implant followed by the CG scheme.
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Affiliation(s)
- Amirhossein Fathi
- Department of Prosthodontics, Dental Material Research Center, Dental Research Institute, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Younes Hoshyar
- Dental Students Research Committee, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Behnaz Ebadian
- Dental Implants Research Center, Dental Research Institute, Department of Prosthodontics, School of Dentistry, Isfahan University of Medical Sciences, Isfahan, Iran
| | - Mahsa Ghorbani
- School of Dentistry, Mashhad University of Medical Sciences, Mashhad, Iran
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Tribst JPM, Dal Piva AMDO, Muris J, Kleverlaan CJ, Feilzer AJ. One-piece endodontic crown fixed partial denture: Is it possible? J Prosthet Dent 2024; 131:1118-1125. [PMID: 36801103 DOI: 10.1016/j.prosdent.2023.01.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 01/18/2023] [Accepted: 01/18/2023] [Indexed: 02/18/2023]
Abstract
STATEMENT OF PROBLEM Whether the replacement of a missing tooth with a fixed partial denture supported by an endodontically treated abutment could be improved with 1-piece endodontic crowns is unclear. PURPOSE The purpose of the study was to evaluate the mechanical behavior of a fixed partial denture (FPD) according to the preparation of the abutment teeth (1-piece endodontic crown or complete crown) in terms of stress magnitude in the prosthesis, cement layer, and tooth. MATERIAL AND METHODS A posterior model with 2 abutment teeth (first molar and first premolar) was modeled with a computer-aided design (CAD) software program for conducting a 3-dimensional finite element analysis (FEA). To replace the missing second premolar, the model was replicated in different possible FPDs according to the abutment preparation design (complete crown [Conventional], 2 1-piece endodontic crowns [EC]) or a 1-piece endodontic crown on one of the abutment teeth (first molar [ECM] and first premolar [ECP]) for a total of 4 designs. All FPDs were in lithium disilicate. The solids were imported to an analysis software program (ANSYS 19.2) in the standard for the exchange of product data (STEP) format. The mechanical properties were considered isotropic and the materials to show linear elastic and homogeneous behavior. An axial load (300 N) was applied at the occlusal surface of the pontic. The results were evaluated by colorimetric stress maps of von Mises and maximum principal stress in the prosthesis, maximum principal stress and shear stresses on the cement layer, and maximum principal stress in the abutment teeth. RESULTS The von Mises stresses revealed that all FPD designs behaved similarly and that, considering the maximum principal stress criteria, the pontic was the most stressed region. For the cement layer, the combined designs presented an intermediate behavior, with the ECM more suitable to reducing the stress peak. The conventional preparation allowed less stress concentration in both teeth, and higher stress concentration in the premolar was observed with a 1-piece endodontic crown. The 1-piece endodontic crown decreased the risk of fracture failure. Considering the risk of debonding failure for the prosthesis, the 1-piece endodontic crown preparation was only able to decrease the failure risk when the EC design was used and when only the shear stress was considered. CONCLUSIONS Performing 1-piece endodontic crown preparations to retain a 3-unit lithium disilicate FPD is an alternative to conventional complete crown preparations.
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Affiliation(s)
- João Paulo M Tribst
- Assistant Professor, Department of Oral Regenerative Medicine, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands
| | - Amanda Maria de O Dal Piva
- Assistant Professor, Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands.
| | - Joris Muris
- Assistant Professor, Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Amsterdam, the Netherlands
| | - Cornelis J Kleverlaan
- Professor, Department of Dental Materials Science, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam & Vrije Universiteit, Amsterdam, the Netherlands
| | - Albert J Feilzer
- Professor, Department of Oral Regenerative Medicine, Academic Center for Dentistry Amsterdam (ACTA), University of Amsterdam & Vrije Universiteit, Amsterdam, the Netherlands
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Elraggal A, Abdelraheem IM, Watts DC, Roy S, Dommeti VK, Alshabib A, Althaqafi KA, Afifi RR. Biomechanical reinforcement by CAD-CAM materials affects stress distributions of posterior composite bridges: 3D finite element analysis. Dent Mater 2024; 40:869-877. [PMID: 38609774 DOI: 10.1016/j.dental.2024.04.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2024] [Revised: 03/28/2024] [Accepted: 04/02/2024] [Indexed: 04/14/2024]
Abstract
OBJECTIVES This 3D finite element analysis study aimed to investigate the effect of reinforcing CAD-CAM bars on stress distribution in various components of a posterior composite bridge. METHODS A virtual model mimicking the absence of an upper second premolar was created, featuring class II cavity preparations on the proximal surfaces of the adjacent abutment teeth surrounding the edentulous space. Five distinct finite element analysis (FEA) models were generated, each representing a CAD-CAM reinforcing bar material: 3-YTZP (IPS. emax ZirCAD MO; Zr), lithium disilicate (IPS e.max CAD; EX), nano-hybrid resin composite (Grandio Blocs; GB), Fibre-reinforced composite (Trilor; Tri), and polyetheretherketone (PEEK). A veneering resin composite was employed to simulate the replacement of the missing premolar (pontic). In the FEA, an axial force of 600 N and a transverse load of 20 N were applied at the center of the pontic. Subsequently, maximum von Mises (mvM) and maximum principal stresses (σmax) were computed across various components of the generated models. Additionally, shear stresses at the interface between the CAD-CAM bars and the veneering resin composite were determined. RESULTS CAD-CAM materials with high modulus of elasticity, such as Zr and EX, exhibited the highest mvM stresses and shear stresses while transferring the lowest stress to the veneering resin composite in comparison to other materials. Conversely, PEEK demonstrated the lowest mvM stresses but produced the highest stresses within the veneering resin composite. There was a uniform distribution of mvM stresses in the remaining tooth structure among all groups, except for a noticeable elevation in the molar region of Zr and EX groups. SIGNIFICANCE Reinforcing CAD-CAM bar materials with a high modulus of elasticity, such as Zr and EX, may result in debonding failures at the connector sites of posterior composite bridges. Conversely, GB, PEEK, and Tri have the potential to cause fracture failures at the connectors rather than debonding.
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Affiliation(s)
- Alaaeldin Elraggal
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK; Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt.
| | - Islam M Abdelraheem
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Sandipan Roy
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Vamsi Krishna Dommeti
- Department of Mechanical Engineering, SRM Institute of Science and Technology, Kattankulathur 603203, Tamil Nadu, India
| | - Abdulrahman Alshabib
- Restorative Dentistry Department, Faculty of Dentistry, King Saud University, Riyadh, Saudi Arabia
| | - Khaled Abid Althaqafi
- Restorative Dentistry Department, Faculty of Dentistry, College of Dental Medicine, University of Umm Al Qura, Makkah, Saudi Arabia
| | - Rania R Afifi
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
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AboElhassan RG, Watts DC, Alamoush RA, Elraggal A. Biomechanical behavior and Weibull survival of CAD-CAM endocrowns with different marginal designs: A 3D finite element analysis. Dent Mater 2024; 40:227-235. [PMID: 37977990 DOI: 10.1016/j.dental.2023.11.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Revised: 11/04/2023] [Accepted: 11/06/2023] [Indexed: 11/19/2023]
Abstract
OBJECTIVES To evaluate and compare the effect of tooth preparation designs and different CADCAM. materials on stress distribution and Weibull survival probability of endocrowns. applied to root canal-treated lower first permanent molar using the 3D finite element. analysis method. METHODS A root canal-treated lower first permanent molar was prepared for endocrowns with a. butt joint or with a ferrule design by placing, circumferentially, a 1-mm wide shoulder. finish line. The prepared molar was scanned for the two designs and modeled on a 3D. Finite element model. Monolithic zirconia (IPS e.max ZirCAD MT, FCZ), lithium. disilicate (IPS e.max CAD, EX), and nano-ceramic resin composite (Lava Ultimate, LU). CAD-CAM materials were used for each preparation to design the virtual endocrown. A. total of six models were built according to the different tooth preparation designs and. endocrown materials. An occlusal load of 600 N and a transverse load of 20 N in. magnitude that simulates the average occlusal load was directed toward the occlusal. surfaces. von Mises and maximum principle values were evaluated Weibull risk-ofrupture. analysis was used to analyze the survival probability of the restorations and. tooth in the different models. RESULTS The highest von Mises were found in the butt joint design for FCZ, EX, and LU (45.3. MPa, 35.2 MPa, and 24.2 MPa, respectively) compared to the ferrule design for the. same materials (42.6 MPa, 31.2 MPa, and 23.6 MPa, respectively). For von Mises. stress distribution in the remaining part of tooth structure (dentin), the highest stresses. were found in LUFerrule which was closely similar to LUButt joint (135.4 MPa and. 134.7 MPa, respectively), followed by EXFerrule and FCZFerrule (132.2 MPa and. 131.7 MPa, respectively), while the lowest stresses were found in EXButt joint and. FCZButt joint (129.0 MPa and 128.4 MPa, respectively). Shear stresses within the. resin cement were the highest in FCZ and EX compared to LU. EX was found to be the. most reliable material with the highest survival probability, while FCZ showed the. lowest survival probability according to the Weibull risk-of-fracture results. SIGNIFICANCE Materials with high elastic modulus transfer more stresses to the endocrown and less. to the remaining tooth structure. Endocrown tooth preparation with ferrule design has. better stress distribution and magnitude compared to the butt joint design.
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Affiliation(s)
- Rewaa G AboElhassan
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt
| | - David C Watts
- Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
| | - Rasha A Alamoush
- Department of Fixed and Removable Prosthodontics, School of Dentistry, the University of Jordan, Amman, Jordan
| | - Alaaeldin Elraggal
- Conservative Dentistry Department, Faculty of Dentistry, Alexandria University, Alexandria, Egypt; Division of Dentistry, School of Medical Sciences, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK.
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Liu C, Eser A, Heintze S, Rothbrust F, Broeckmann C. Computation of the fracture probability and lifetime of all ceramic anterior crowns under cyclic loading - An FEA study. Dent Mater 2023; 39:965-976. [PMID: 37690952 DOI: 10.1016/j.dental.2023.08.173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 08/11/2023] [Accepted: 08/16/2023] [Indexed: 09/12/2023]
Abstract
OBJECTIVES To predict the lifetime and fracture probability of anterior crowns made of a lithium disilicate glass-ceramic (IPS e.max CAD, LD, Ivoclar Vivadent, Liechtenstein) and a zirconia-containing lithium silicate glass-ceramic (Celtra Duo, ZLS, Dentsply Sirona, USA) under cycling loading. METHODS Three-point bending tests were conducted to measure the viscoelastic parameters. These parameters are used to compute the residual stresses of the anterior crown after crystallization. In the next analysis, the cyclic loading on the anterior crown was calculated. Based on this combined stress state (residual stress and stress state due to external cyclic loading), the life cycle and fracture probability of the anterior crown was calculated using the CARES/Life software. Finally, fatigue experiments were carried out to compare and validate the results of the computations. RESULTS Although a sound qualitative comparison of the lifetime of both materials can be done using this methodology, the calculated fracture probability of the anterior crown for both materials was very low in comparison with the fatigue test results using the fatigue parameters determined from the experiments. In order to achieve good correspondence with the experimental results, the SCG exponent n for both materials should be modified by a correlation factor of 0.38. SIGNIFICANCE Using this modified computational strategy, the results of the time-consuming fatigue tests for dental glass-ceramics can be closely predicted. This methodology can be integrated into the development process of new glass-ceramic materials in order to save time and costs.
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Affiliation(s)
- Chao Liu
- IWM, RWTH-Aachen, Augustinerbach 4, D-52062 Aachen, Germany
| | - Atilim Eser
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein.
| | - Siegward Heintze
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | - Frank Rothbrust
- Research & Development, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
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Kihara T, Shigeta Y, Ikawa T, Sasaki K, Shigemoto S, Ogawa T. Designing anterior cantilever resin-bonded fixed dental prostheses based on finite element analysis. J Prosthodont Res 2023; 67:418-423. [PMID: 36372436 DOI: 10.2186/jpr.jpr_d_22_00103] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/01/2023]
Abstract
PURPOSE A resin-bonded bridge (RBB) is a minimally invasive prosthetic treatment option for intact adjacent teeth. However, it is contentious as to whether the mesial or distal adjacent tooth should be used as an abutment. This study aimed to investigate the potential of finite element analysis (FEA) for the selection of abutment teeth and the determination of the optimal design for anterior cantilever RBBs. METHODS Three types of RBBs were designed to simulate loss of the maxillary left lateral incisor. The fixed-fixed RBB (FF-RBB) had one retainer each for the left central incisor and canine. Distal- and mesial-cantilever RBBs (D-CRBB and M-CRBB) had a single retainer on the central incisor and canine, respectively. Three-dimensional models for FEA were generated from computed tomography slices and dental casts. FEA was performed for each RBB to evaluate stresses in the intercuspal, protrusive, and lateral mandibular positions. RESULTS The maximum principal stresses on the bridges in the intercuspal position were 141.9 MPa, 93.6 MPa, and 45.7 MPa, for the FF-RBB, D-CRBB, and M-CRBB, respectively. The stress in the D-CRBB position was greater than in the M-CRBB position in the intercuspal, protrusive, and lateral mandibular positions. CONCLUSIONS Based on the results, M-CRBB on the canine had a higher clinical performance than D-CRBB on the central incisor. FEA was useful for determining the optimal design of RBB for each patient.
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Affiliation(s)
- Takuya Kihara
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
| | - Yuko Shigeta
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
| | - Tomoko Ikawa
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
| | - Keita Sasaki
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
| | - Shuji Shigemoto
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
| | - Takumi Ogawa
- Department of Fixed Prosthodontics, School of Dental Medicine, Tsurumi University, Japan
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Kosewski P, De Angelis F, Sorrentino E, Mielczarek A, Buonvivere M, D’Arcangelo C. Effect of the Abutment Rigidity on the Wear Resistance of a Lithium Disilicate Glass Ceramic: An In Vitro Study. J Funct Biomater 2023; 14:395. [PMID: 37623640 PMCID: PMC10455685 DOI: 10.3390/jfb14080395] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Revised: 07/20/2023] [Accepted: 07/21/2023] [Indexed: 08/26/2023] Open
Abstract
Lithium disilicate (LDS) glass ceramics are among the most common biomaterials in conservative dentistry and prosthodontics, and their wear behavior is of paramount clinical interest. An innovative in vitro model is presented, which employs CAD/CAM technology to simulate the periodontal ligament and alveolar bone. The model aims to evaluate the effect of the abutment rigidity on the wear resistance of the LDS glass ceramic. Two experimental groups (LDS restorations supported by dental implants, named LDS-on-Implant, or by hybrid ceramic tooth replicas with artificial periodontal ligament, named LDS-on-Tooth-Replica) and a control group (LDS-Cylinders) were compared. Fifteen samples (n = 15) were fabricated for each group and subjected to testing, with LDS antagonistic cusps opposing them over 120,000 cycles using a dual axis chewing simulator. Wear resistance was analyzed by measuring the vertical wear depth (mm) and the volume loss (mm3) on each LDS sample, as well as the linear antagonist wear (mm) on LDS cusps. Mean values were calculated for LDS-Cylinders (0.186 mm, 0.322 mm3, 0.220 mm, respectively), LDS-on-Implant (0.128 mm, 0.166 mm3, 0.199 mm, respectively), and LDS-on-Tooth-Replica (0.098 mm, 0.107 mm3, 0.172 mm, respectively) and compared using one-way-ANOVA and Tukey's tests. The level of significance was set at 0.05 in all tests. Wear facets were inspected under a scanning electron microscope. Data analysis revealed that abutment rigidity was able to significantly affect the wear pattern of LDS, which seems to be more intense on rigid implant-abutment supports compared to resilient teeth replicas with artificial periodontal ligament.
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Affiliation(s)
| | - Francesco De Angelis
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, School of Dentistry, “G. D’Annunzio” University of Chieti, 66100 Chieti, Italy; (M.B.); (C.D.)
| | - Edoardo Sorrentino
- Department of Innovative Technologies in Medicine & Dentistry, “G. D’Annunzio” University of Chieti, 66100 Chieti, Italy;
| | - Agnieszka Mielczarek
- Department of Conservative Dentistry, Medical University of Warsaw, 02091 Warsaw, Poland;
| | - Matteo Buonvivere
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, School of Dentistry, “G. D’Annunzio” University of Chieti, 66100 Chieti, Italy; (M.B.); (C.D.)
| | - Camillo D’Arcangelo
- Unit of Restorative Dentistry and Endodontics, Department of Medical, Oral and Biotechnological Science, School of Dentistry, “G. D’Annunzio” University of Chieti, 66100 Chieti, Italy; (M.B.); (C.D.)
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Zhai Z, Qian C, Jiao T, Sun J. In vitro fracture and fatigue resistance of monolithic zirconia crowns fabricated by stereolithography. J Prosthet Dent 2023:S0022-3913(23)00127-0. [PMID: 36966099 DOI: 10.1016/j.prosdent.2023.02.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 02/22/2023] [Accepted: 02/22/2023] [Indexed: 03/27/2023]
Abstract
STATEMENT OF PROBLEM Stereolithography has been used to print zirconia ceramic crowns with acceptable dimensional accuracy and fracture force. However, studies that compared the fatigue resistance of zirconia crowns fabricated by stereolithography are lacking. PURPOSE The purpose of this in vitro study was to compare the fracture and fatigue resistance of monolithic zirconia crowns printed by stereolithography apparatus (SLA) and digital light processing (DLP) with those of zirconia crowns milled by computer numerical control (CNC). MATERIAL AND METHODS A total of 120 crowns were fabricated (n=40/material) and underwent 0, 104, 105, or 106 dynamic loading cycles of 30 to 300 N in artificial saliva, followed by a static fracture loading test (n=10). After fracture, 1 crown from each group was selected for fractography analysis by scanning electron microscopy (SEM). Data were statistically analyzed through 2-way ANOVA and post hoc analysis for multiple comparisons (α=.05). RESULTS The 2-way ANOVA results showed that the mean ±standard deviation force at fracture was the highest for CNC (before fatigue loading: 5154 ±568 N, 104: 5735 ±1231 N, 105: 5523 ±797 N, and 106: 6007 ±1258 N), followed by DLP (before fatigue loading: 3381 ±612 N, 104: 4046 ±1146 N, 105: 2929 ±559 N, and 106: 3223 ±739 N), and the lowest for SLA (before fatigue loading: 2956 ±598 N, 104: 2757 ±421 N, 105: 3326 ±391 N, and 106: 3103 ±246 N) (P<.01). The fracture force of the crowns was not significantly affected by the number of fatigue cycles (P>.05). Fractography analysis showed that the number of arrest lines increased for crowns of all 3 materials. SEM images also showed the steps of SLA and DLP from their layer-by-layer printing and small cracks between layers of SLA after 106 loading cycles. CONCLUSIONS The fracture force of monolithic zirconia crowns milled by CNC was significantly higher than that of zirconia crowns printed by stereolithography. Zirconia crowns printed by SLA and DLP could withstand typical clinical conditions, and their fracture and fatigue resistance exceeded the clinically estimated average occlusal forces.
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Affiliation(s)
- Zidi Zhai
- Graduate student, Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; and Shanghai Research Institute of Stomatology, Shanghai, PR China
| | - Chao Qian
- Senior Lecturer, Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; and Shanghai Research Institute of Stomatology, Shanghai, PR China
| | - Ting Jiao
- Professor, Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; and Shanghai Research Institute of Stomatology, Shanghai, PR China
| | - Jian Sun
- Professor, Department of Prosthodontics, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; and Shanghai Research Institute of Stomatology, Shanghai, PR China.
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A brief review on fatigue test of ceramic and some related matters in Dentistry. J Mech Behav Biomed Mater 2023; 138:105607. [PMID: 36549251 DOI: 10.1016/j.jmbbm.2022.105607] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
The characteristics of dental ceramics have been extensively studied over the years to provide highly qualified materials for use in prosthetic restorations. The ability to adhere to dental substrates, outstanding aesthetics (translucency, color, and substrate masking ability) and improved mechanical properties provide these materials with optical features and high strength to withstand masticatory stimuli. Different classifications are adopted, and it is generally considered that glass-ceramics have better optical characteristics due to the high glass content, and polycrystalline ceramics have superior strength favored by their densified and organized crystals, hampering crack growth. This knowledge was largely built-up during years of scientific research through different testing methodologies, but mainly employing static loads. It is important to not only take into account the intensity of loads that these materials will be exposed to, but also the effect of the intermittence of cyclic load application leading to mechanical fatigue and the influence of factors related to the crack origin and their propagation under this condition. Furthermore, the bonding surface of ceramic restorations requires surface treatments that improve the bond strength to luting agents; however, these treatments require caution because of their potential to produce defects and affect the structural behavior. Moreover, ceramic restorations often require internal adjustments for proper seating or external adjustments for fitting the occlusal contact with the antagonist. In this sense, finishing/polishing protocols may alter the defect population, as luting agents may also interact by filling in the superficial defects on the restoration intaglio surface. Thus, the balance among all these factors will define the performance of a restorative setup, as well as the posterior exposure to the humid environment and the masticatory stimuli (cyclical loading), which may favor developing slow and subcritical growth of cracks in ceramic materials and the degradation of the bond interface. Therefore, it is essential that the concepts which explain the fatigue mechanism are understood, as well as the crack propagation and failure patterns of restorative ceramic materials.
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Madruga CFL, Dal Piva AMDO, Pereira GKR, Caneppele TMF, Valandro LF, Bottino MA. Sintering mode of a translucent Y-TZP: Effects on its biaxial flexure fatigue strength, surface morphology and translucency. J ESTHET RESTOR DENT 2022; 34:1197-1205. [PMID: 35560703 PMCID: PMC9790507 DOI: 10.1111/jerd.12923] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 04/08/2022] [Accepted: 04/25/2022] [Indexed: 12/30/2022]
Abstract
OBJECTIVE This investigation evaluated the effect of two sintering modes of a translucent zirconia (Y-TZP) on its surface roughness, topography, phase-transformation (t → m), translucency and biaxial flexure fatigue strength. MATERIALS AND METHODS To do so, 50 Y-TZP discs (Ø = 15 mm; thickness = 1.2 mm; IPS e.max ZirCAD LT) were prepared and divided into two groups: Standard mode (SM) and Fast mode (FM). Staircase fatigue testing was performed (piston-on-three balls set-up, ISO 6872:2015), as well as surface roughness, profilometry, scanning electron microscopy (SEM-FEG), energy dispersive X-ray spectroscopy (EDX), phase transformation (t → m) using X-ray diffraction analysis (XRD), translucency parameter analysis (TP and TP00 ) and fractography. RESULTS The results showed no statistical significant differences for roughness parameters (p > 0.05, SM: Ra = 0.13 ± 0.02, Rz = 1.21 ± 0.26 and RSm = 24.91 ± 2.19; FM: Ra = 0.14 ± 0.03, Rz = 1.32 ± 0.25 and RSm = 24.68 ± 2.16) or flexural fatigue strength (SM: 512 (464-560) MPa; FM: 542 (472-611) MPa) between the groups. In addition, similarity in surface morphological features (SEM and profilometry), composition and phases (EDX and XRD) was observed between the firing protocols. Fractography showed that the failure origin occurred on the tensile side. Sintering mode did not affect the TP (F = 0.001, p = 0.97) and TP00 (F = 0.12, p = 0.72). CONCLUSIONS Therefore, the fast-sintering mode is suggested as a viable alternative to the standard mode since it does not influence the evaluated surface morphology, microstructure, fatigue strength and translucency of a translucent monolithic zirconia. CLINICAL SIGNIFICANCE The fast sintering mode is a viable alternative for zirconia without compromising its topography, microstructure, mechanical performance or translucency.
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Affiliation(s)
- Camila Ferreira Leite Madruga
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
| | - Amanda Maria de Oliveira Dal Piva
- Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA)Universiteit van Amsterdam and Vrije UniversiteitAmsterdamNoord‐HollandThe Netherlands
| | - Gabriel Kalil Rocha Pereira
- Post‐Graduate Program in Oral Science (Prosthodontics Units), Faculty of DentistryFederal University of Santa Maria (UFSM)Santa MariaRio Grande do Sul StateBrazil
| | - Taciana Marco Ferraz Caneppele
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
| | - Luiz Felipe Valandro
- Post‐Graduate Program in Oral Science (Prosthodontics Units), Faculty of DentistryFederal University of Santa Maria (UFSM)Santa MariaRio Grande do Sul StateBrazil
| | - Marco Antonio Bottino
- Post‐Graduate Program in Applied Sciences to Oral Health (Restorative Dentistry)São Paulo State University (Unesp), Institute of Science and TechnologySão José dos CamposSão Paulo StateBrazil
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Bataineh K, Al Janaideh M, Abu-Naba'a LA. Fatigue Resistance of 3-Unit CAD-CAM Ceramic Fixed Partial Dentures: An FEA Study. J Prosthodont 2022; 31:806-814. [PMID: 35118758 DOI: 10.1111/jopr.13487] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2021] [Accepted: 01/25/2022] [Indexed: 01/04/2023] Open
Abstract
PURPOSE To estimate the fatigue life of 3-unit molar fixed partial dentures (FPDs) made from two different monolithic ceramic systems, zirconia cercon (ZC) and lithium disilicate (LD). The effect of the connector size on the fatigue resistance of the monolithic FPD was also investigated. METHODS Two models for the FPDs were built, a 3-unit all-ceramic and a porcelain-fused-to-metal. The porcelain-fused-to-metal FPD model was used as the control. Actual 3-unit FPDs (replacing the second lower premolar) were constructed using a computer aided design and computer-aided manufacturing (CAD-CAM) system. Finite element analysis (FEA) was executed. A hemispherical indenter was used to simulate occlusal load. The occlusal load phase of the chewing cycle was applied at the premolar pontic. RESULTS The failure location for the monolithic FPD was always located at the distal connector. Connector size played a key role in determining the long-term survival of the prosthesis. The fatigue resistance was predicted to be 670 N for the ZC with a connector size 4 × 3 mm, while it was only 226 N for LD. As for porcelain-fused-to-metal (PFM), FEA predicts that fatigue resistance can reach up to 770 N. Under the cyclic load of 670 N, the fatigue life for the zirconia FPD with connector size 4 × 3 mm was 2.23 × 106 cycles while it survived only 3.1 × 105 cycles when the connector was reduced to 3.5 × 2.5 mm. The angle of the oblique load has a significant effect on the stress distribution. CONCLUSION 3-unit monolithic FPDs made of ZC have superior fatigue performance compared to those made of LD. The fatigue life of the zirconia FPD was about three times longer than that made of LD with a connector size of 4 mm × 3 mm. The survival rates of ZC FPDs are comparable to porcelain-fused-to-metal. A significant reduction in fatigue strength is predicted for reduced connector size. Therefore, it is necessary to establish general guidelines for the minimum connector size.
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Affiliation(s)
- Khaled Bataineh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Mohammad Al Janaideh
- Department of Mechanical Engineering, Jordan University of Science and Technology, Irbid, Jordan
| | - Layla A Abu-Naba'a
- Department of Prosthodontics, Jordan University of Science and Technology, Irbid, Jordan
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12
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Luft RL, da Rosa LS, Machado PS, Valandro LF, Sarkis-Onofre R, Pereira GKR, Bacchi A. Influence of connector cross-sectional geometry on the load-bearing capacity under fatigue of implant-supported zirconia fixed partial prosthesis. J Prosthet Dent 2022; 128:1335.e1-1335.e8. [DOI: 10.1016/j.prosdent.2022.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 10/13/2022] [Accepted: 10/13/2022] [Indexed: 11/19/2022]
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13
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Lu WJ, Srimaneepong V, Chen CS, Huang CH, Lin HC, Liu CF, Huang HH. Influence of Aging on the Fracture Characteristics of Polyetheretherketone Dental Crowns: A Preliminary Study. Polymers (Basel) 2022; 14:polym14194123. [PMID: 36236071 PMCID: PMC9572468 DOI: 10.3390/polym14194123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 09/17/2022] [Accepted: 09/28/2022] [Indexed: 11/09/2022] Open
Abstract
Although polyetheretherketone (PEEK) is becoming more widely used in dentistry applications, little is known about how aging will affect this material. Therefore, this study aimed to investigate the influence of an aging treatment on fracture characteristics of PEEK dental crowns. Additionally, the impact of the addition of titanium dioxide (TiO2) into PEEK was examined. Two types of commercial PEEK discs were used in this study, including TiO2-free and 20% TiO2-containing PEEK. The PEEK dental crowns were fabricated and aging-treated at 134 °C and 0.2 MPa for 5 h in accordance with the ISO 13356 specification before being cemented on artificial tooth abutments. The fracture loads of all crown samples were measured under compression tests. Results demonstrated that adding TiO2 enhanced the fracture load of PEEK crowns compared to TiO2-free PEEK crowns before the aging treatment. However, the aging treatment decreased the fracture load of TiO2-containing PEEK crowns while increasing the fracture load of TiO2-free PEEK crowns. The fracture morphology of TiO2-containing PEEK crowns revealed finer feather shapes than that of the TiO2-free PEEK crowns. We concluded that adding TiO2 increased the fracture load of PEEK crowns without aging treatment. Still, the aging treatment influenced the fracture load and microscopic fracture morphology of PEEK crowns, depending on the addition of TiO2.
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Affiliation(s)
- Wen-Ju Lu
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Viritpon Srimaneepong
- Department of Prosthodontics, Faculty of Dentistry, Chulalongkorn University, Bangkok 10330, Thailand
| | - Chiang-Sang Chen
- Department of Orthopedic Surgery, Far Eastern Memorial Hospital, New Taipei City 220, Taiwan
- Department of Materials and Textiles, Asia Eastern University of Science and Technology, New Taipei City 220, Taiwan
| | - Chang-Hung Huang
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Department of Medical Research, MacKay Memorial Hospital, Taipei 251, Taiwan
| | - Hui-Ching Lin
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Department of Stomatology, Taipei City Hospital, Zhongxing Branch, Taipei 103, Taiwan
- General Education Center, University of Taipei, Taipei 106, Taiwan
| | - Chia-Fei Liu
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
| | - Her-Hsiung Huang
- Department of Dentistry, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Institute of Oral Biology, National Yang Ming Chiao Tung University, Taipei 112, Taiwan
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 404, Taiwan
- Department of Bioinformatics and Medical Engineering, Asia University, Taichung 413, Taiwan
- Department of Education and Research, Taipei City Hospital, Taipei 103, Taiwan
- Department of Stomatology, Taipei Veterans General Hospital, Taipei 112, Taiwan
- Correspondence:
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Ellakany P, Fouda SM, Mahrous AA, AlGhamdi MA, Aly NM. Influence of CAD/CAM Milling and 3D-Printing Fabrication Methods on the Mechanical Properties of 3-Unit Interim Fixed Dental Prosthesis after Thermo-Mechanical Aging Process. Polymers (Basel) 2022; 14:polym14194103. [PMID: 36236050 PMCID: PMC9572976 DOI: 10.3390/polym14194103] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 09/16/2022] [Accepted: 09/18/2022] [Indexed: 11/20/2022] Open
Abstract
This study assessed the influence of CAD/CAM milling and 3D-printing fabrication methods on mechanical properties of 3-unit interim fixed dental prosthesis (IFDPs) after thermo-mechanical aging. Forty 3-unit IFDPs were fabricated on a mandibular right second premolar and second molar of a typodont cast. Samples were fabricated from the following materials; auto-polymerized polymethyl methacrylate (conventional resin), CAD/CAM PMMA (milled resin) and two different CAD/CAM 3D-printed composite resins; digital light processing Asiga (DLP AS) and stereolithography NextDent (SLA ND). Mechanical properties were compared between the studied materials using Kruskal−Wallis test, followed by multiple pairwise comparisons using Bonferroni adjusted significance. There was a significant difference in flexural strength and microhardness between the studied materials (p < 0.001), with the highest mean ± SD reported in the milled IFDPs (174.42 ± 3.39, 27.13 ± 0.52), and the lowest in the conventional IFDPs (98.02 ± 6.1, 15.77 ± 0.32). Flexural strengths differed significantly between the conventional IFDPs and all materials except DLP AS. The highest elastic modulus was recorded in the milled group, and the lowest in the SLA ND group (p = 0.02). In conclusion, superior flexural strength, elastic modulus, and hardness were reported for milled IFDPs. SLA ND printed IFDPs showed comparable mechanical properties to milled ones except for the elastic modulus.
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Affiliation(s)
- Passent Ellakany
- Department of Substitutive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam 32210, Saudi Arabia
- Correspondence: ; Tel.: +966-547812107
| | - Shaimaa M. Fouda
- Department of Substitutive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam 32210, Saudi Arabia
| | - Amr A. Mahrous
- Department of Substitutive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam 32210, Saudi Arabia
| | - Maram A. AlGhamdi
- Department of Substitutive Dental Sciences, College of Dentistry, Imam Abdulrahman Bin Faisal University, Dammam 32210, Saudi Arabia
| | - Nourhan M. Aly
- Department of Pediatric Dentistry and Dental Public Health, Faculty of Dentistry, Alexandria University, Alexandria 21527, Egypt
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15
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Fracture Load and Fracture Patterns of Monolithic Three-Unit Anterior Fixed Dental Prostheses after In Vitro Artificial Aging-A Comparison between Color-Gradient and Strength-Gradient Multilayer Zirconia Materials with Varying Yttria Content. J Clin Med 2022; 11:jcm11174982. [PMID: 36078912 PMCID: PMC9457031 DOI: 10.3390/jcm11174982] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2022] [Revised: 08/18/2022] [Accepted: 08/19/2022] [Indexed: 12/02/2022] Open
Abstract
(1) Background: Due to advantages such as avoidance of chipping, pulp-friendly tooth preparation and cost reduction, zirconia is increasingly being used monolithically without veneering. Nevertheless, to enable good aesthetics, various multilayer systems have been developed. The aim of this study was to investigate the impact of different zirconia multilayer strategies and yttria levels on fracture load, fracture pattern, stress distribution and surface roughness. (2) Methods: Monolithic three-unit anterior FDPs were made from three different color-gradient zirconia multilayer materials with different yttria levels corresponding to varying strength and degrees of translucency grades (Katana HTML, STML, UTML, Kuraray) and one strength-gradient zirconia multilayer material (Katana YML, Kuraray) and artificially aged in a chewing simulator (1.2 × 106 load cycles, 50 N, 2 × 3000 thermocycles, 5−55 °C). Analyses of fracture load, fracture pattern, fracture surfaces, stress distribution and roughness were performed after the fracture load test. Shapiro−Wilk, Kruskal−Wallis, Mann−Whitney U-tests and one-way ANOVA were used (p < 0.05). (3) Results: Fracture loads of the high strength color-gradient material HTML and the strength-gradient material YML were comparable after 5 years of aging (p = 0.645). Increasing yttria levels resulted in a decrease in fracture resistance of 42−57% (p < 0.05). Surface roughness of different zirconia generations is comparable after polishing and aging. (4) Conclusions: Color-gradient multilayer zirconia materials and new strength-gradient zirconia materials with similar yttria levels in the basal layers show comparable mechanical properties and are suitable for anterior FDPs.
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Hinz S, Bensel T, Bömicke W, Henningsen A, Rudolph J, Boeckler AF. Impact of the Veneering Technique and Framework Material on the Failure Loads of All-Ceramic Computer-Aided Design/Computer-Aided Manufacturing Fixed Partial Dentures. MATERIALS 2022; 15:ma15030756. [PMID: 35160701 PMCID: PMC8836578 DOI: 10.3390/ma15030756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 01/08/2022] [Accepted: 01/15/2022] [Indexed: 02/04/2023]
Abstract
Objectives: Zirconia (Y-TZP) ceramics are considered as posterior fixed partial denture (FPD) materials; however, their applications are limited due to chipping. The use of monolithic lithium disilicate (LiDi) glass ceramics in posterior FPDs can be advantageous. This in vitro study aims to compare the loads until failure of posterior Y-TZP-FPDs and LiDi-FPDs before and after aging.
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Affiliation(s)
- Sebastian Hinz
- Department of Prosthodontics, Martin-Luther-University Halle-Wittenberg, Magdeburgerstraße 16, 06112 Halle, Germany; (J.R.); (A.F.B.)
- Correspondence: (S.H.); (T.B.)
| | - Tobias Bensel
- Department of Prosthodontics, Martin-Luther-University Halle-Wittenberg, Magdeburgerstraße 16, 06112 Halle, Germany; (J.R.); (A.F.B.)
- Correspondence: (S.H.); (T.B.)
| | - Wolfgang Bömicke
- Department of Prosthetic Dentistry, University Hospital Heidelberg, University of Heidelberg, Im Neuenheimer Feld 400, 69120 Heidelberg, Germany;
| | - Anders Henningsen
- Department of Oral and Maxillofacial Surgery, University Hospital Hamburg-Eppendorf, 20246 Hamburg, Germany;
| | - Judith Rudolph
- Department of Prosthodontics, Martin-Luther-University Halle-Wittenberg, Magdeburgerstraße 16, 06112 Halle, Germany; (J.R.); (A.F.B.)
| | - Arne F. Boeckler
- Department of Prosthodontics, Martin-Luther-University Halle-Wittenberg, Magdeburgerstraße 16, 06112 Halle, Germany; (J.R.); (A.F.B.)
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UCHIKURA K, MURAKAMI N, YAMAZAKI T, LYU H, NAGATA K, ONA M, IWASAKI N, TAKAHASHI H, WAKABAYASHI N. Fracture resistance of CAD/CAM restorative materials in mismatched removable partial denture rests: An <i>in vitro</i> experimental and finite element analysis. Dent Mater J 2022; 41:466-472. [DOI: 10.4012/dmj.2021-224] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Affiliation(s)
- Keiichiro UCHIKURA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Natsuko MURAKAMI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toshiki YAMAZAKI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Huaxin LYU
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Kohji NAGATA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masahiro ONA
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Naohiko IWASAKI
- Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hidekazu TAKAHASHI
- Oral Health Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki WAKABAYASHI
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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18
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Lyu H, Murakami N, Yamazaki T, Wada J, Utsumi M, Wakabayashi N. Evaluation of PEEK and zirconia occlusal rest designs for removable partial dentures based on finite element analysis. J Prosthodont Res 2022; 67:196-205. [PMID: 35644568 DOI: 10.2186/jpr.jpr_d_22_00011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Purpose We aimed to assess removable partial denture occlusal rests composed of polyether-ether-ketone (PEEK) and zirconia, using finite element analysis.Methods Three-dimensional PEEK and zirconia rest models, including the occlusal rest (1.5 mm thickness at the basal portion, 3.0 mm width) and minor connector (1.5 mm thickness, 6.0 mm height), and rest seat models with mechanical properties of enamel were constructed. The radius of transitional curvature between the rest and minor connector was 0.1-0.5 mm. The rest and rest seat model interfaces were set as frictional contacts (μ = 0.1), and the base of the rest seat model was restrained in all the directions. A 100 N downward load was applied perpendicular to the bottom surface of the minor connector. The maximum value of the first principal stress (Max-S1) was compared to the flexural and fatigue strengths of each material. Occlusal rests with 1.0-2.0 mm thickness, 2.0-3.5 mm width, and 0.5 mm radius of transitional curvature were analyzed.Results Max-S1 was observed at the transitional part and decreased with increasing radius of the transitional curvature, rest width, and thickness. PEEK rests with at least 1.5 mm thicknesses and 3.0 mm widths showed lower Max-S1 than the flexural strength. Max-S1 of all PEEK rests exceeded the PEEK fatigue strength, whereas Max-S1 of the zirconia rests was lower than the zirconia fatigue strength.Conclusions Zirconia occlusal rests with conventional metal rest designs have sufficient fatigue strength. PEEK occlusal rests have insufficient fatigue strength and may not withstand repeated mastication.
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Affiliation(s)
- Huaxin Lyu
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Natsuko Murakami
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Toshiki Yamazaki
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Junichiro Wada
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Miona Utsumi
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
| | - Noriyuki Wakabayashi
- Advanced Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University, Tokyo, Japan
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Hoorizad M, Valizadeh S, Heshmat H, Tabatabaei SF, Shakeri T. Influence of resin cement on color stability of ceramic veneers: in vitro study. Biomater Investig Dent 2021; 8:11-17. [PMID: 33554126 PMCID: PMC7850403 DOI: 10.1080/26415275.2020.1855077] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
Statement of the problem Long-term success of ceramic veneers depends on the color stability of resin cement used for their cementation. Color change of cement may be seen through the ceramic and compromise esthetics. Purpose This study aimed to compare the color change of two resin cements and their visibility through the ceramic veneers after accelerated artificial aging. Materials and methods In this in vitro study, color change (ΔE) was measured in the following groups (n = 10) before and after accelerated artificial aging: group 1, IPS e.max press high translucent ceramic discs; groups 2, Variolink NLC resin cement discs; group 3, Choice 2 resin cement discs; groups 4, Variolink NLC discs bonded to e.max ceramic discs; group 5, Choice 2 disc bonded to e.max ceramic discs. Color change was measured using a spectrophotometer according to International Commission on Illumination Lab (CIELab). Data were analyzed using one-way ANOVA and Tukey’s post-hoc test. Results Group 2 showed the highest (ΔE = 10.4 ± 0.9) and group 1 the lowest (ΔE = 0.9 ± 0.4) color change. The color change of Variolink was significantly greater than Choice 2 either alone (p < .001) or through the ceramic discs (p < .004). The color change of both cements was lower through the ceramic veneer and this reduction was statistically significant (p < .001). Conclusion Noticeable color change may be expected in areas of cement exposure for both cements studied. Also, in case of using Variolink cement, the color change may be seen through the ceramic veneers.
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Affiliation(s)
- Maryam Hoorizad
- Department of Operative Dentistry, Islamic Azad University, Tehran, Iran
| | - Sara Valizadeh
- Department of Operative Dentistry, School of dentistry, Tehran University of Medical Sciences, Tehran, Iran.,Laser Research Center of Dentistry, Dental Research Center, Dentistry Research Institute, Tehran University of Medical Sciences, Tehran, Iran
| | - Haleh Heshmat
- Membership of Dental material research center, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
| | - Seyedeh Farnaz Tabatabaei
- Membership of Dental material research center, Tehran Medical Sciences, Islamic Azad University, Tehran, Iran
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Liu C, Eser A, Albrecht T, Stournari V, Felder M, Heintze S, Broeckmann C. Strength characterization and lifetime prediction of dental ceramic materials. Dent Mater 2021; 37:94-105. [DOI: 10.1016/j.dental.2020.10.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2020] [Revised: 07/20/2020] [Accepted: 10/16/2020] [Indexed: 10/23/2022]
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Nawafleh N, Bibars AR, Elshiyab S, Janzeer Y. In vitro Simulation of Periodontal Ligament in Fatigue Testing of Dental Crowns. Eur J Dent 2020; 14:380-385. [PMID: 32645731 PMCID: PMC7440937 DOI: 10.1055/s-0040-1713953] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
OBJECTIVE Fatigue testing of restorative material has been appreciated as an appropriate method to evaluate dental restorations. This study aims to investigate the influence of periodontal ligament (PDL) simulation on fatigue and fracture tests results of zirconia crowns. MATERIALS AND METHODS A standard tooth preparation for all ceramic zirconia crown was made on a typodont mandibular molar. The prepared master die was duplicated using epoxy resin to produce 40 replicas. PDL simulation was made by surrounding the root of 20 dies with a 0.3-mm thick silicon layer. The other 20 specimens had no PDL simulation. Zirconia crowns were fabricated using computer-aided design/computer-aided manufacturing technology and cemented to the epoxy resin dies. Ten crowns from each group were subject to chewing simulation with simultaneous thermocycling (5-55°C). All specimens were then loaded until failure in universal testing machine. STATISTICAL ANALYSIS Statistical analysis was conducted using SPSS software. Shapiro-Wilk test confirmed the normal distribution of data. Descriptive statistic was performed and differences between the groups were analyzed using paired samples t-test. RESULTS All fatigued crowns survived chewing simulation; no failure was observed after finishing simulation. The highest mean fracture load recorded was 3,987 ± 400 N for the no fatigue/no periodontal simulation group. Comparing the mean fracture load of the two groups with periodontal simulation and the two groups with no periodontal simulation showed no statistically significant difference (p > 0.5). CONCLUSION Considering the testing set-up applied in this study, simulating PDL using resilient materials does not affect the in vitro survival and fracture resistance of zirconia crowns.
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Affiliation(s)
- Noor Nawafleh
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Abdel Raheem Bibars
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Shareen Elshiyab
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
| | - Yasmeen Janzeer
- Department of Applied Dental Sciences, Faculty of Applied Medical Sciences, Jordan University of Science and Technology, Irbid, Jordan
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Kermanshah H, Motevasselian F, Kakhaki SA, Özcan M. Effect of ceramic material type on the fracture load of inlay-retained and full-coverage fixed dental prostheses. Biomater Investig Dent 2020; 7:62-70. [PMID: 32342046 PMCID: PMC7170296 DOI: 10.1080/26415275.2020.1744443] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2019] [Accepted: 03/03/2020] [Indexed: 10/28/2022] Open
Abstract
Objective: Ceramic inlay-retained fixed partial denture (IRFPD) is a conservative prosthetic option but the mechanical durability of new high strength zirconia reinforced glass ceramic FPDs is not investigated. The purpose of this study was to compare fracture load of 3-unit ceramic FPDs. Materials and methods: Extracted premolars and molars (N = 64) were used to create three test groups (IRFPDs) and one control group (full coverage FPD) (n = 8). The teeth were embedded in PMMA resin with a mesiodistal distance of 6 mm. Premolars had a distal and molars had a mesial inlay preparation (width: 3 mm; height: 4 mm) in the test groups. IRFPDs were made from a zirconia reinforced lithium silicate (VS) or a monolithic zirconia. Zirconia IRFPDs received 2 types of surface treatments: sandblasting (Zr-IRFPD) or internal coating with feldspathic porcelain (ZrC-IRFPD). Control group was made from monolithic zirconia with the same connector size and zirconia surfaces were sandblasted (Zr-FPD). All restorations were cemented using a resin luting cement. After 5000 thermo-cycles, fracture load values (N) were determined with a universal testing machine at a crosshead speed of 0.75 mm/min. Data were analyzed using 1-way ANOVA and Tukey`s post hoc test (p ˂ .05). Result: Fracture load (mean ± SD) of Zr-FPDs, Zr-IRFPDs and ZrC-IRFPDs were 672 ± 183, 672 ± 123 and 638 ± 59, respectively, being not statistically different (p > .05). VS-IRFPD exhibited statically lower values (391 ± 136). The predominant mode of failure was fracture at the connector area in all groups. Conclusion: The fracture load of 3-unit IRFPD was significantly affected by types of ceramics but the retainer design and surface treatment in Zr groups did not show a significant effect.
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Affiliation(s)
- Hamid Kermanshah
- Restorative Dentistry department, Tehran University of Medical Sciences School of Dentistry, Tehran, Iran
| | - Fariba Motevasselian
- Restorative Dentistry department, Tehran University of Medical Sciences School of Dentistry, Tehran, Iran
| | - Saeedeh Alavi Kakhaki
- Restorative Dentistry department, Tehran University of Medical Sciences School of Dentistry, Tehran, Iran
| | - Mutlu Özcan
- Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, University of Zurich, Zurich, Switzerland
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Huang X, Zou L, Yao R, Wu S, Li Y. Effect of preparation design on the fracture behavior of ceramic occlusal veneers in maxillary premolars. J Dent 2020; 97:103346. [PMID: 32325176 DOI: 10.1016/j.jdent.2020.103346] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2019] [Revised: 03/27/2020] [Accepted: 04/15/2020] [Indexed: 11/19/2022] Open
Abstract
OBJECTIVES The fracture strengths of four types of occlusal veneers and a traditional full crown ceramic restoration and the influence of preparation design on the stress of restorations were examined. METHODS Forty intact maxillary premolars randomly divided into five groups were prepared based on the demands of type O (occlusal surface coverage), OF (occlusal and lingual surface coverage), POF (occlusal, lingual, and mesial surface coverage), and POFP (occlusal, lingual, mesial, and distal surface coverage) veneers and full crown, and then restored by glass ceramic. Specimens were subjected to fracture resistance tests after cyclic loading. The fracture strengths and modes were analyzed statistically. The level of significance was set at α = 0.05. One maxillary premolar was prepared for type O, OF, POF, POFP veneer and full crown, and then scanned to establish finite element models. The mean fracture load was applied vertically to calculate the maximum principal stress on the ceramic. RESULTS Type O veneer showed higher fracture strength than type POF and POFP veneers (P < 0.05). Both type O and OF veneers exhibited higher fracture strength than full crown (P < 0.05). No significant difference in failure mode was observed. The maximum principal stress for type O, OF, POF, POFP veneers, and full crown increased progressively and concentrated at the bonding surface directly beneath the loading area. CONCLUSIONS Four types of occlusal veneer showed fracture strengths that considerably exceeded normal biting forces. They represent conservative alternatives to full crowns and present a viable treatment for severely worn teeth. CLINICAL SIGNIFICANCE The occlusal veneers with different preparation designs, including type O, OF, POF and POFP veneers, show higher fracture resistances than traditional full coverage crowns that considerably exceed the normal biting forces. Therefore, these represent conservative alternatives to crown restorations and present a viable treatment for restoring severely worn teeth.
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Affiliation(s)
- Xiaoqiong Huang
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Leiyan Zou
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Run Yao
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China
| | - Shuyi Wu
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
| | - Yan Li
- Hospital of Stomatology, Guanghua School of Stomatology, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, People's Republic of China.
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Robati Anaraki M, Torab A, Mounesi Rad T. Comparison of stress in implant-supported monolithic zirconia fixed partial dentures between canine guidance and group function occlusal patterns: A finite element analysis. J Dent Res Dent Clin Dent Prospects 2019; 13:90-97. [PMID: 31592107 PMCID: PMC6773921 DOI: 10.15171/joddd.2019.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2019] [Accepted: 07/30/2019] [Indexed: 12/18/2022] Open
Abstract
Background. Monolithic zirconia is an emerging material for crowns and bridges. The possibility of full digital design has made it an attractive alternative material for implant-supported prostheses. A proper design is vital in the success of such a prosthesis like any other. This study, in the shortage of scientific evidence, has tried to assess the stress distribution of occlusal forces inside the implant-prosthesis system of a 3-unit bridge made of monolithic zirconia. Methods. A 3-unit monolithic zirconia bridge supported by two implant fixtures placed on the teeth #13 and #15 was digitalized. It was converted to a mesh of 59000 nodes and 34000 elements. Five types of occlusal forces (one as vertical centric, two at 15º and 30º simulating canine pattern of lateral movement, and two at 15º and 30º simulating group function pattern) were applied. The stress distribution among all the components of the implant-bridge system was assessed using Ansys Workbench 14 software and finite element analysis. Results. The maximum stress was between 286 and 546 MPa, which were found in either the fixture‒abutment screw area or in the upper part of the pontic connector between the canine and first premolar. The maximum pressure increased with an increase in the angle of occlusal force. Significantly higher stress was recorded in the group function occlusal pattern. Conclusion. Monolithic zirconia can be promising in designing bridges in the canine‒premolar area. However, proper design is necessary with more attention to the connectors and types of occlusal forces.
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Affiliation(s)
- Mahmood Robati Anaraki
- Dental and Periodontal Research Center, Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Ali Torab
- Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
| | - Taymaz Mounesi Rad
- Department of Prosthodontics, Faculty of Dentistry, Tabriz University of Medical Science, Tabriz, Iran
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Dal Piva AMO, Tribst JPM, Saavedra GSFA, Souza ROA, de Melo RM, Borges ALS, Özcan M. Short communication: Influence of retainer configuration and loading direction on the stress distribution of lithium disilicate resin-bonded fixed dental prostheses: 3D finite element analysis. J Mech Behav Biomed Mater 2019; 100:103389. [PMID: 31398693 DOI: 10.1016/j.jmbbm.2019.103389] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2019] [Revised: 08/01/2019] [Accepted: 08/04/2019] [Indexed: 11/19/2022]
Abstract
The present study elucidates the mechanical performance of different designs of resin-bonded fixed dental prostheses made of lithium disilicate simulating masticatory loads of anterior or canine guidance. A three-dimensional model of maxilla was constructed containing central incisor and canine teeth, with edentulous space of the lateral incisor. Three designs of prosthesis were created: retained in central incisor (1-I), retained in canine (1-C) and fixed in both teeth (2-IC). The computational analysis was performed for load in canine and central incisor separately (100N, 45°). The tensile and shear stresses were calculated for the resin-bonded fixed dental prosthesis, bonding surface of each retainer and cement layer using 3D finite element analysis. The 20 highest stress values were analyzed using two-way ANOVA and post-hoc Tukey test, all with α = 5%. The computational analysis showed that 2-retainer resin-bonded fixed dental prosthesis presented the worst prognosis regardless of the mandibular movement. ANOVA showed that Mandibular movement*Retainer interaction influenced on the tensile and shear stresses values (p < 0.01). Higher stresses were observed in the connector region for all groups (13-82.2 MPa; 11-70.2 MPa). In order to reduce the stress concentration in the resin-bonded fixed dental prosthesis and the retainer made of lithium disilicate, the occlusion may serve as the selection criteria of the unitary abutment for better sustainability.
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Affiliation(s)
- Amanda M O Dal Piva
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Brazil; Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, the Netherlands.
| | - João P M Tribst
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Brazil; Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081 LA, Amsterdam, Noord-Holland, the Netherlands.
| | - Guilherme S F A Saavedra
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José dos Campos/SP, Brazil.
| | - Rodrigo O A Souza
- Department of Restorative Dentistry, Division of Prosthodontics, Federal University of Rio Grande do Norte (UFRN), Natal, Brazil.
| | - Renata M de Melo
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José dos Campos/SP, Brazil.
| | - Alexandre L S Borges
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José dos Campos/SP, Brazil.
| | - Mutlu Özcan
- University of Zürich, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Rämistrasse 71, 8006, Zurich, Switzerland.
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Tribst JPM, Dal Piva AMO, de Melo RM, Borges ALS, Bottino MA, Özcan M. Short communication: Influence of restorative material and cement on the stress distribution of posterior resin-bonded fixed dental prostheses: 3D finite element analysis. J Mech Behav Biomed Mater 2019; 96:279-284. [PMID: 31077955 DOI: 10.1016/j.jmbbm.2019.05.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2019] [Revised: 05/01/2019] [Accepted: 05/03/2019] [Indexed: 11/24/2022]
Abstract
The goal of this study was to compare the mechanical response of resin-bonded fixed dental prosthesis (RBFDP) made in zirconia, metal, lithium disilicate and composite resin cemented using resin cements with different elastic modulus. For the finite element analysis, a three-dimensional model of partial right maxilla was used to create a model with edentulous space in the second premolar and the cavity's preparation on the first pre-molar and first molar to receive a RBFDP. The model was imported to the analysis software in which they were divided into mesh composed by nodes (371,101) and tetrahedral elements (213,673). Each material was considered isotropic, elastic and homogeneous. No-separation contacts were considered between restoration/resin cement and resin cement/tooth. For all other structures the contacts were considered ideal. The model fixation occurred at the base of the bone and an axial load of 300 N was applied on the pontic occlusal surface. To simulate polymerization shrinkage effects on the cement, the thermal expansion approach was used. The displacement and maximum principal stress (in MPa) were selected as failure criteria. The prosthesis made in composite resin showed higher displacement, while in zirconia showed higher stress concentration. Tensile stress between restoration/cement, cement and cement/cavity was directly proportional to the restorative material's elastic modulus. The more rigid cement increases the tensile zones in the cement layer but decreases the stress between prosthesis and cement. The molar cavity showed higher stress concentration between restoration/cement than the preparation in the pre-molar tooth. The use of composite resin for the manufacturing of RBFDP increases the displacement of the set during the loading. However, it reduces the amount of stress concentration at the adhesive interface in comparison with the other materials.
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Affiliation(s)
- João Paulo M Tribst
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Brazil; Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081, LA Amsterdam, Noord-Holland, the Netherlands.
| | - Amanda M O Dal Piva
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Brazil; Department of Dental Materials Science, Academic Centre for Dentistry Amsterdam (ACTA), Universiteit van Amsterdam and Vrije Universiteit, Gustav Mahlerlaan #3004, 1081, LA Amsterdam, Noord-Holland, the Netherlands.
| | - Renata M de Melo
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José Dos Campos/SP, Brazil.
| | - Alexandre L S Borges
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José Dos Campos/SP, Brazil.
| | - Marco Antonio Bottino
- Post-Graduate Program in Restorative Dentistry (Prosthodontic), Department of Dental Materials and Prosthodontics, São Paulo State University (Unesp/SJC), Engenheiro Francisco José Longo Avenue, 777, 12245-000, São José Dos Campos/SP, Brazil.
| | - Mutlu Özcan
- University of Zürich, Dental Materials Unit, Center for Dental and Oral Medicine, Clinic for Fixed and Removable Prosthodontics and Dental Materials Science, Rämistrasse 71, 8006, Zurich, Switzerland.
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