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Thadathil Varghese J, Islam F, Farrar P, Prentice L, Prusty BG. Multi-response optimisation analysis of material properties in dental restorative composites under the influence of thermal and thermomechanical stimuli - A 3D finite element study. J Mech Behav Biomed Mater 2024; 150:106363. [PMID: 38169207 DOI: 10.1016/j.jmbbm.2023.106363] [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: 10/12/2023] [Revised: 12/24/2023] [Accepted: 12/27/2023] [Indexed: 01/05/2024]
Abstract
OBJECTIVES Restored teeth undergo more damage than intact teeth. Therefore, the scientific investigation of their mechanical and physical behaviour under varying oral conditions is vital. The current study is to numerically investigate the stresses on a class-II mesio-occluso-distal (MOD) restored molar due to thermal and thermomechanical stimuli with varying input properties such as coefficient of thermal expansion and elastic properties. This is performed to optimise the dental restoration material, thereby reducing the stresses and failure of the restoration. METHODS An upper molar was scanned using μ-CT for segmenting and modelling the enamel and dentine. A class-II MOD cavity was then prepared on the model, after which non-manifold meshing was generated. The coefficient of thermal expansion (CTE) and elastic modulus (E) properties of the restoration were varied from 20 × 10-6 °C-1 to 55 × 10-6 °C-1 and 5 GPa-20 GPa, respectively. After the material properties and boundary conditions were set for the finite element (FE) analysis, the thermal and thermomechanical loading analyses were performed to demonstrate the influence of input parameters on the stress. The maximum values of principal stresses on the restoration-enamel junction and the restoration were evaluated. The results were statistically processed using analysis of variance, response surface methodology (RSM) and optimisation analysis to estimate the most optimum inputs for minimising principal stresses. RESULTS The study reveals that the location of principal stress occurs at the restoration-enamel junction (REJ) and the restoration changes based on the composite material value of E and CTE due to thermal and thermomechanical stimuli. The REJ showed higher principal stress than restoration during the application of both thermal and thermomechanical stimuli, making it more vulnerable to fracture and failure. Moreover, the study showed non-linear variations in the values and locations of principal stresses due to thermal and thermomechanical stimuli with the change in the property of the restoration composite used. Finally, this study derived an optimised restorative value for CTE and E due to the application of thermal and simultaneous thermal and mechanical stimuli. CONCLUSION This study highlights the importance of choosing the suitable material properties of the restoration composite by dental clinicians to repair a large class MOD cavity. The findings from this study also suggest that the difference in the values of E and CTE in a dental restoration composite when compared with the enamel causes a lack of uniformity in mechanical and thermal properties, thereby forming stress concentrations at the interfaces. The study establishes two optimised CTE and E values for the MOD restoration composite as 25 × 10-6 °C-1 and 20 GPa and 37 × 10-6 °C-1 and 5 GPa, respectively.
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Affiliation(s)
| | | | | | | | - B Gangadhara Prusty
- School of Mechanical and Manufacturing Engineering, UNSW, NSW, 2052, Australia; ARC Centre for Automated Manufacture of Advanced Composites, UNSW, Sydney, NSW, 2052, Australia; Australian Composite Manufacturing CRC, UNSW, Sydney, NSW, 2052, Australia
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Lin F, Feng X, Ordinola-Zapata R, VanHeel B, Fok ASL. Load capacity and fracture modes of instrumented tooth roots under axial compression. Dent Mater 2023; 39:938-945. [PMID: 37648562 DOI: 10.1016/j.dental.2023.08.177] [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: 08/19/2023] [Accepted: 08/23/2023] [Indexed: 09/01/2023]
Abstract
OBJECTIVE To investigate the influences of root canal instrumentation on the load capacity and fracture modes of tooth roots under axial compression by performing mechanical tests and finite element analysis (FEA). METHODS Thirty bovine incisor roots were trimmed into cylinders of 5.0 mm diameter. They were randomly divided into two groups, one with root canals instrumented to ∼2.0 mm in diameter, and one without instrumentation. The specimens were fractured under uniaxial compression at a crosshead speed of 0.2 mm/min, and then micro-CT was used to reveal the fracture patterns in three dimensions. FEA was further performed, using the extended finite element method (XFEM), to compare the compression-induced stress distributions and the initiation and propagation of root fractures in both groups. RESULTS The mean fracture load of the non-instrumented group (2334 ± 436 N) was statistically significantly higher than that of the instrumented group (1857 ± 377 N) (p < 0.01). Three types of root fractures were identified according to the path and length of the cracks: end-face crack, partial-length crack, and full-length crack. As to the fracture modes, the incidence of partial-length root fracture was the highest in both groups (60% for the non-instrumented group and 53.3% for the instrumented group), followed by that of full-length fracture (26.7% and 40%, respectively) and then end-face fracture (13.3% and 6.7%, respectively). The percentage of full-length fracture was slightly higher in the instrumented group. FEA showed that the compression induced higher Tresca stresses but lower maximum principal stresses in the canal walls of the instrumented group. The XFEM simulations predicted that the fracture of both groups initiated from the outer root surface near an end face and propagated axially to the middle third of the root and radially towards the root canal. These numerical results agreed well with our experimental findings. SIGNIFICANCE Within the limitation of this study, it was found that root canal instrumentation could significantly decrease the load capacity of tooth roots and potentially increase their susceptibility to full-length root fracture under uniaxial compression.
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Affiliation(s)
- Fei Lin
- Department of Cariology and Endodontology, Peking University School and Hospital of Stomatology & National Center for Stomatology & National Clinical Research Center for Oral Diseases & National Engineering Research Center of Oral Biomaterials and Digital Medical Devices, Beijing 100081, China
| | - Xiqiao Feng
- Institute of Biomechanics and Medical Engineering, Department of Engineering Mechanics, Tsinghua University, Beijing 100084, China
| | - Ronald Ordinola-Zapata
- Division of Endodontics, Department of Restorative Sciences, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Bonita VanHeel
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA
| | - Alex S L Fok
- Minnesota Dental Research Center for Biomaterials and Biomechanics, School of Dentistry, University of Minnesota, Minneapolis, MN 55455, USA.
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Demirel MG, Mohammadi R, Keçeci M. Crack Propagation and Fatigue Performance of Partial Posterior Indirect Restorations: An Extended Finite Element Method Study. J Funct Biomater 2023; 14:484. [PMID: 37754898 PMCID: PMC10532640 DOI: 10.3390/jfb14090484] [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: 08/30/2023] [Revised: 09/13/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023] Open
Abstract
Dental ceramics are susceptible to slow, progressive crack growth after cyclic loading. The purpose of this study was to investigate the progressive patterns of cracks in two different types of CAD/CAM ceramic materials used with three different partial posterior indirect restoration (PPIR) designs and to determine the materials' failure risk using a fatigue test. Standard initial cracks were formed in Standard Tessellation Language (STL) files prepared for three different PPIRs. The materials chosen were monolithic lithium disilicate (LS) and polymer-infiltrated ceramic networks (PICNs). The extended finite element method (XFEM) was applied, and the fatigue performance was examined by applying a 600 N axial load. The cracks propagated the most in onlay restorations, where the highest displacement was observed. In contrast, the most successful results were observed in overlay restorations. Overlay restorations also showed better fatigue performance. LS materials exhibited more successful results than PICN materials. LS materials, which can be used in PPIRs, yield better results compared to PICN materials. While inlay restorations demonstrated relatively successful results, overlay and onlay restorations can be specified as the most and the least successful PPIR types, respectively.
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Affiliation(s)
| | - Reza Mohammadi
- Faculty of Dentistry, Necmettin Erbakan University, Konya 42090, Turkey;
| | - Murat Keçeci
- Department of Prosthodontics, Faculty of Dentistry, Karamanoğlu Mehmet Bey University, Karaman 70000, Turkey;
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Yan M, Ding SJ, Lin CW, Wei CL, Huang YW, Yang CC. Aging resistance of highly translucent zirconia ceramics with rapid sintering. J Oral Sci 2023; 65:15-19. [PMID: 36403959 DOI: 10.2334/josnusd.22-0264] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
PURPOSE Rapid sintering technology has become one of the most direct methods for shortening the manufacturing time of zirconia restorations. This study aimed to explore the aging resistance of rapid-sintered 5 mol% yttria-partially-stabilized zirconia (5Y-PSZ). METHODS Specimens were made from two types of 5Y-PSZ material and subjected to rapid sintering (RS) and conventional sintering (CS). After in vitro aging for 5 h, morphology observation, grain size measurement, and phase composition analysis were performed. The mechanical properties were evaluated by biaxial, three-point flexural tests, and the Vickers microhardness test. Results were analyzed by 3-way ANOVA. RESULTS Both the RS group and the CS group had a dense microstructure. The tested zirconia ceramics had different grain sizes, which were affected by the interaction between the sintering method and aging. Both groups revealed the same characteristic peaks of the cubic phase after aging. Regardless of the sintering method used, there was no significant difference in the mechanical properties of the tested zirconia before and after aging. CONCLUSION The rapid-sintered 5Y-PSZ materials had a microstructure, phase composition and mechanical properties similar to those of conventional sintered materials. The characteristics of the materials prepared using the two sintering methods did not change significantly after aging.
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Affiliation(s)
- Min Yan
- Institute of Oral Sciences, Chung Shan Medical University.,Department of Dentistry, Chung Shan Medical University Hospital, Chung Shan Medical University
| | - Shinn-Jyh Ding
- Institute of Oral Sciences, Chung Shan Medical University.,Department of Dentistry, Chung Shan Medical University Hospital, Chung Shan Medical University
| | - Cheng-Wei Lin
- Department of Dental Technology and Materials Science, Central Taiwan University of Science and Technology
| | - Cian-Li Wei
- Institute of Oral Sciences, Chung Shan Medical University
| | - Yi-Wen Huang
- Institute of Oral Sciences, Chung Shan Medical University
| | - Chun-Chuan Yang
- Department of Dental Technology, Shu-Zen Junior College of Medicine and Management
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Lassila L, Mangoush E, Vallittu PK, Garoushi S. Fracture behavior of discontinuous fiber-reinforced composite inlay-retained fixed partial denture before and after fatigue aging. J Prosthodont Res 2022; 67:271-277. [PMID: 35896342 DOI: 10.2186/jpr.jpr_d_22_00050] [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: 11/06/2022]
Abstract
PURPOSE To evaluate the fracture behavior of inlay-retained fixed partial dentures (IRFPDs) made of experimental short fiber-reinforced composite (SFRC) computer-aided design/computer-aided manufacturing (CAD/CAM) block before and after cyclic fatigue aging. METHODS Five groups (n=20/group) of three-unit posterior IRFPDs were fabricated. The first and second groups were CAD/CAM fabricated from experimental SFRC blocks or lithium-disilicate (IPS e.max CAD, IVOCLAR) materials, the third group comprised a three-dimensional-printed composite (Temp PRINT, GC), and the fourth and fifth groups comprised conventional laboratory flowable composite (Gradia Plus, GC) and commercial flowable SFRC (everX Flow, GC), respectively. All IRFPDs were luted into a metal jig with adhesive dual-cure resin cement (RelyX Ultimate, 3M ESPE). Half the IRFPDs per group (n=10) were subjected to fatigue aging for 10,000 cycles. The remaining half were statically loaded until fracture without fatigue aging. The load was applied vertically between triangular ridges of the buccal and lingual cusps. The fracture mode was visually examined using optical and scanning electron microscopy (SEM). Data were statistically analyzed using a two-way analysis of variance (ANOVA) followed by Tukey's HSD test. RESULTS ANOVA revealed that IRFPDs made of experimental SFRC CAD/CAM had the highest (p<0.05) load-bearing capacity before (2624±463 N) and after (2775±297 N) aging among all groups. Cyclic fatigue aging decreased the load-bearing capacity (p>0.05) of all tested prostheses, except for the experimental SFRC CAD/CAM and conventional laboratory composite IRFPDs (p>0.05). SEM images showed the ability of discontinuous short fibers in the experimental SFRC CAD/CAM composite to redirect and hinder crack propagation. CONCLUSION CAD/CAM-fabricated IRFPDs made of experimental SFRC blocks showed promising performance in clinical testing in terms of fracture behavior.
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Affiliation(s)
- Lippo Lassila
- Department of Biomaterials Science and Turku Clinical Biomaterials Centre -TCBC Institute of Dentistry, University of Turku, Turku, Finland
| | - Enas Mangoush
- Department of Biomaterials Science and Turku Clinical Biomaterials Centre -TCBC Institute of Dentistry, University of Turku, Turku, Finland
| | - Pekka K Vallittu
- Department of Biomaterials Science and Turku Clinical Biomaterials Centre -TCBC Institute of Dentistry, University of Turku, Turku, Finland.,City of Turku Welfare Division, Oral Health Care, Turku, Finland
| | - Sufyan Garoushi
- Department of Biomaterials Science and Turku Clinical Biomaterials Centre -TCBC Institute of Dentistry, University of Turku, Turku, Finland
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Hypo and hyperbaric pressure effect on the fracture resistance of three types of dental crowns: PFM, LD, and Y-TZP. J Oral Biosci 2022; 64:245-252. [DOI: 10.1016/j.job.2022.04.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Revised: 04/06/2022] [Accepted: 04/06/2022] [Indexed: 11/18/2022]
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Mallek A, Miloudi A, Khaldi M, Bouziane MM, Bouiadjra BB, Bougherara H, Gill RHS. Quasi-static analysis of hip cement spacers. J Mech Behav Biomed Mater 2021; 116:104334. [PMID: 33497959 DOI: 10.1016/j.jmbbm.2021.104334] [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: 11/09/2020] [Revised: 01/11/2021] [Accepted: 01/13/2021] [Indexed: 11/25/2022]
Abstract
The use of temporary hip prosthesis made of orthopedic cement (spacer) in conjunction with antibiotics became a widespread method used for treating prosthetic infections despite the fact that this method makes bone cement (PMMA) more fragile. The necessity to incorporate reinforcement is therefore crucial to strengthen the bone cement. In this study, a validated Finite Element Modelling (FEM) was used to analyze the behavior of spacers. This FEM model uses a non-linear dynamic explicit integration to simulate the mechanical behavior of the spacer under quasi-static loading. In addition to this FEM, Extended Finite Element Method (XFEM) was also used to investigate the fracture behavior of the spacers reinforced with titanium, ceramic and stainless-steel spacer stems. The effect of the material on the performance of the reinforced spacers was also analyzed. The results showed that numerical modelling based on explicit finite element using ABAQUS/Explicit is an effective method to predict the different spacers' mechanical behavior. The simulated crack initiation and propagation were in a good agreement with experimental observations. The FEM models developed in this study can help mechanical designers and engineers to improve the prostheses' quality and durability.
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Affiliation(s)
- Abdelhafid Mallek
- LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Cité Ben M'hidi, Sidi Bel Abbes, 22000, Algeria
| | - Abdelkader Miloudi
- LMSR, Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Cité Ben M'hidi, Sidi Bel Abbes, 22000, Algeria
| | - Mokhtar Khaldi
- Laboratory of Applied Biomechanics and Biomaterials (LABAB), ENP Oran-MA, Oran, Algeria; Department of Mechanical Engineering, Faculty of Technology, University of Mascara, BP 305 Route de Mamounia, Mascara, 29000, Algeria
| | - Mohammed-Mokhtar Bouziane
- LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Cité Ben M'hidi, Sidi Bel Abbes, 22000, Algeria; Department of Mechanical Engineering, Faculty of Technology, University of Mascara, BP 305 Route de Mamounia, Mascara, 29000, Algeria.
| | - Belabbes Bachir Bouiadjra
- LMPM, Department of Mechanical Engineering, University of Sidi Bel Abbes, BP 89, Cité Ben M'hidi, Sidi Bel Abbes, 22000, Algeria
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Ontario, Canada
| | - Richie H S Gill
- Centre for Orthopedic Biomechanics, Department of Mechanical Engineering, University of Bath, Bath, United Kingdom
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Tasopoulos T, Pachiou A, Kouveliotis G, Karaiskou G, Ottenga M, Zoidis P. An 8-Year Clinical Outcome of Posterior Inlay Retained Resin Bonded Fixed Dental Prosthesis Utilizing High Performance Polymer Materials: A Clinical Report. J Prosthodont 2020; 30:19-23. [PMID: 32991007 DOI: 10.1111/jopr.13266] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/22/2020] [Indexed: 12/26/2022] Open
Abstract
This clinical report presents the use of a modified polyetheretherketone (PEEK) Inlay Retained Resin Bonded Fixed Dental Prosthesis (IRRBFDP) framework, veneered with indirect high impact composite for the bilateral restoration of mandibular first molar teeth, as the most conservative treatment option for a medically compromised patient. When used as a framework, PEEK's elastic modulus (approximately 4 GPa), could result in the reduction of stresses transferred to the abutment teeth and the cementation interface accordingly, therefore it could result in lower de-bonding rates and higher success rates. Furthermore, the high bond strength with the veneering composite material and the luting cements permit its use for resin-bonded restorations. Preparation guidelines, indications and advantages for the fabrication of IRRBFDPs are described in this clinical report. No technical complications such as de-bonding of the framework, connector or retainer fracture of the adhesive frameworks or loss of retention were observed during the course of 8 years. Prosthetic replacement of single missing posterior mandibular teeth utilizing IRRBFDPs with high performance polymer materials could potentially offer long-term high survival rate outcomes. Further clinical evidence is required in order to justify the above statement.
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Affiliation(s)
| | | | | | | | - Marc Ottenga
- Division of Operative Dentistry, Department of Restorative Dental Sciences, University of Florida - College of Dentistry, Gainesville, FL
| | - Panagiotis Zoidis
- Division of Prosthodontics, Department of Restorative Dental Sciences, University of Florida - College of Dentistry, Gainesville, FL
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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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Effect of different implant configurations on biomechanical behavior of full-arch implant-supported mandibular monolithic zirconia fixed prostheses. J Mech Behav Biomed Mater 2019; 102:103490. [PMID: 31877512 DOI: 10.1016/j.jmbbm.2019.103490] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2018] [Revised: 09/17/2019] [Accepted: 10/10/2019] [Indexed: 02/06/2023]
Abstract
Mechanical failure of zirconia-based full-arch implant-supported fixed dental prostheses (FAFDPs) remains a critical issue in prosthetic dentistry. The option of full-arch implant treatment and the biomechanical behaviour within a sophisticated screw-retained prosthetic structure have stimulated considerable interest in fundamental and clinical research. This study aimed to analyse the biomechanical responses of zirconia-based FAFDPs with different implant configurations (numbers and distributions), thereby predicting the possible failure sites and the optimum configuration from biomechanical aspect by using finite element method (FEM). Five 3D finite element (FE) models were constructed with patient-specific heterogeneous material properties of mandibular bone. The results were reported using volume-averaged von-Mises stresses (σVMVA) to eliminate numerical singularities. It was found that wider placement of multi-unit copings was preferred as it reduces the cantilever effect on denture. Within the limited areas of implant insertion, the adoption of angled multi-unit abutments allowed the insertion of oblique implants in the bone and wider distribution of the multi-unit copings in the prosthesis, leading to lower stress concentration on both mandibular bone and prosthetic components. Increasing the number of supporting implants in a FAFDPs reduced loading on each implant, although it may not necessarily reduce the stress concentration in the most posterior locations significantly. Overall, the 6-implant configuration was a preferable configuration as it provided the most balanced mechanical performance in this patient-specific case.
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Gustafsson A, Wallin M, Khayyeri H, Isaksson H. Crack propagation in cortical bone is affected by the characteristics of the cement line: a parameter study using an XFEM interface damage model. Biomech Model Mechanobiol 2019; 18:1247-1261. [PMID: 30963356 PMCID: PMC6647448 DOI: 10.1007/s10237-019-01142-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2018] [Accepted: 03/22/2019] [Indexed: 01/25/2023]
Abstract
Bulk properties of cortical bone have been well characterized experimentally, and potent toughening mechanisms, e.g., crack deflections, have been identified at the microscale. However, it is currently difficult to experimentally measure local damage properties and isolate their effect on the tissue fracture resistance. Instead, computer models can be used to analyze the impact of local characteristics and structures, but material parameters required in computer models are not well established. The aim of this study was therefore to identify the material parameters that are important for crack propagation in cortical bone and to elucidate what parameters need to be better defined experimentally. A comprehensive material parameter study was performed using an XFEM interface damage model in 2D to simulate crack propagation around an osteon at the microscale. The importance of 14 factors (material parameters) on four different outcome criteria (maximum force, fracture energy, crack length and crack trajectory) was evaluated using ANOVA for three different osteon orientations. The results identified factors related to the cement line to influence the crack propagation, where the interface strength was important for the ability to deflect cracks. Crack deflection was also favored by low interface stiffness. However, the cement line properties are not well determined experimentally and need to be better characterized. The matrix and osteon stiffness had no or low impact on the crack pattern. Furthermore, the results illustrated how reduced matrix toughness promoted crack penetration of the cement line. This effect is highly relevant for the understanding of the influence of aging on crack propagation and fracture resistance in cortical bone.
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Affiliation(s)
- Anna Gustafsson
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden
| | - Mathias Wallin
- Division of Solid Mechanics, Lund University, Box 118, 221 00 Lund, Sweden
| | - Hanifeh Khayyeri
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden
| | - Hanna Isaksson
- Department of Biomedical Engineering, Lund University, Box 118, 221 00 Lund, Sweden
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Wan B, Shahmoradi M, Zhang Z, Shibata Y, Sarrafpour B, Swain M, Li Q. Modelling of stress distribution and fracture in dental occlusal fissures. Sci Rep 2019; 9:4682. [PMID: 30886223 PMCID: PMC6423029 DOI: 10.1038/s41598-019-41304-z] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2018] [Accepted: 02/27/2019] [Indexed: 12/15/2022] Open
Abstract
The aim of this study was to investigate the fracture behaviour of fissural dental enamel under simulated occlusal load in relation to various interacting factors including fissure morphology, cuspal angle and the underlying material properties of enamel. Extended finite element method (XFEM) was adopted here to analyse the fracture load and crack length in tooth models with different cusp angles (ranging from 50° to 70° in 2.5° intervals), fissural morphologies (namely U shape, V shape, IK shape, I shape and Inverted-Y shape) and enamel material properties (constant versus graded). The analysis results showed that fissures with larger curved morphology, such as U shape and IK shape, exhibit higher resistance to fracture under simulated occlusal load irrespective of cusp angle and enamel properties. Increased cusp angle (i.e. lower cusp steepness), also significantly enhanced the fracture resistance of fissural enamel, particularly for the IK and Inverted-Y shape fissures. Overall, the outcomes of this study explain how the interplay of compositional and structural features of enamel in the fissural area contribute to the resistance of the human tooth against masticatory forces. These findings may provide significant indicators for clinicians and technicians in designing/fabricating extra-coronal dental restorations and correcting the cuspal inclinations and contacts during clinical occlusal adjustment.
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Affiliation(s)
- Boyang Wan
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Mahdi Shahmoradi
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Zhongpu Zhang
- School of Computing, Engineering and Mathematics, Western Sydney University, Penrith, NSW, 2751, Australia
| | - Yo Shibata
- Department of Conservative Dentistry, Division of Biomaterials and Engineering, Showa University School of Dentistry, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo, 142-8555, Japan
| | - Babak Sarrafpour
- The University of Sydney, Discipline of Oral Surgery, Medicine and Diagnostics, School of Dentistry, Faculty of Medicine and Health, The University of Sydney, Westmead Centre for Oral Health, Westmead Hospital, Sydney, NSW, 2145, Australia
| | - Michael Swain
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, NSW, 2006, Australia.
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An interface damage model that captures crack propagation at the microscale in cortical bone using XFEM. J Mech Behav Biomed Mater 2019; 90:556-565. [DOI: 10.1016/j.jmbbm.2018.09.045] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2018] [Revised: 09/05/2018] [Accepted: 09/26/2018] [Indexed: 11/23/2022]
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Waldecker M, Rues S, Rammelsberg P, Bömicke W. Validation of in-vitro tests of zirconia-ceramic inlay-retained fixed partial dentures: A finite element analysis. Dent Mater 2019; 35:e53-e62. [PMID: 30686709 DOI: 10.1016/j.dental.2019.01.017] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2018] [Revised: 12/13/2018] [Accepted: 01/13/2019] [Indexed: 10/27/2022]
Abstract
OBJECTIVE In the past, discrepancies between laboratory results and clinical behavior have been observed for all-ceramic restorations. This analysis of fracture resistance of zirconia-based inlay-retained fixed partial dentures (IRFPDs) aimed at identifying correlations between an in-vitro test setup and the clinical situation. The effects of tooth material, tooth mobility, restoration design, load direction, and different cements were taken into account. METHODS The in-vitro test model and IRFPD were reverse engineered (Geomagic DesignX) and meshed predominantly with hexahedral elements (approx. 230,000 elements). Homogenous, linear-elastic behavior was assumed for all materials. On the basis of the calculated stresses (ANSYS 18.2) and already known strength distributions for the restorative materials fracture resistance of the complete restoration and force at initial damage (fracture within the veneer) was estimated on the basis of the principal stress hypothesis. Differences depending on the assumed clinical situation and effects of different variables on fracture resistance were evaluated. RESULTS All variables tested in the finite element analysis affected the calculated fracture resistance of the IRFPD. Use of resin teeth led to an underestimation of fracture resistance by up to -57%, whereas fracture resistance of IRFPDs on metal abutment teeth was close to the clinical reference (-6% to +15%). Good correlation between the clinical scenario and that using metal teeth could only be achieved when the natural resilience of the abutment teeth was simulated. SIGNIFICANCE When testing fracture resistance of zirconia-based IRFPDs, metal abutment teeth in combination with simulated tooth resilience can reflect the clinical situation accurately.
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Affiliation(s)
- M Waldecker
- Department of Prosthodontics, Heidelberg University Hospital, University of Heidelberg, Heidelberg, Germany.
| | - S Rues
- Department of Prosthodontics, Heidelberg University Hospital, University of Heidelberg, Heidelberg, Germany
| | - P Rammelsberg
- Department of Prosthodontics, Heidelberg University Hospital, University of Heidelberg, Heidelberg, Germany
| | - W Bömicke
- Department of Prosthodontics, Heidelberg University Hospital, University of Heidelberg, Heidelberg, Germany
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15
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All-ceramic inlay-retained fixed dental prostheses for replacing posterior missing teeth: A systematic review. J Prosthodont Res 2018; 62:10-23. [DOI: 10.1016/j.jpor.2017.06.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2016] [Revised: 04/14/2017] [Accepted: 06/28/2017] [Indexed: 11/22/2022]
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16
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Zhang D, Han X, Zhang Z, Liu J, Jiang C, Yoda N, Meng X, Li Q. Identification of dynamic load for prosthetic structures. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2017; 33. [PMID: 28425209 DOI: 10.1002/cnm.2889] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Accepted: 04/15/2017] [Indexed: 06/07/2023]
Abstract
Dynamic load exists in numerous biomechanical systems, and its identification signifies a critical issue for characterizing dynamic behaviors and studying biomechanical consequence of the systems. This study aims to identify dynamic load in the dental prosthetic structures, namely, 3-unit implant-supported fixed partial denture (I-FPD) and teeth-supported fixed partial denture. The 3-dimensional finite element models were constructed through specific patient's computerized tomography images. A forward algorithm and regularization technique were developed for identifying dynamic load. To verify the effectiveness of the identification method proposed, the I-FPD and teeth-supported fixed partial denture structures were investigated to determine the dynamic loads. For validating the results of inverse identification, an experimental force-measuring system was developed by using a 3-dimensional piezoelectric transducer to measure the dynamic load in the I-FPD structure in vivo. The computationally identified loads were presented with different noise levels to determine their influence on the identification accuracy. The errors between the measured load and identified counterpart were calculated for evaluating the practical applicability of the proposed procedure in biomechanical engineering. This study is expected to serve as a demonstrative role in identifying dynamic loading in biomedical systems, where a direct in vivo measurement may be rather demanding in some areas of interest clinically.
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Affiliation(s)
- Dequan Zhang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Xu Han
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
| | - Zhongpu Zhang
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales, 2006, Australia
| | - Jie Liu
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
| | - Chao Jiang
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
| | - Nobuhiro Yoda
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4-1 Seiryo-machi, Aoba-ku, Sendai, 980-8575, Japan
| | - Xianghua Meng
- State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body, College of Mechanical and Vehicle Engineering, Hunan University, Changsha, 410082, China
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, Sydney, New South Wales, 2006, Australia
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