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Fatola D, Nasution ID, Sabri M, Chairunnisa R. Pain-related analysis on a resorbed ridge with various denture occlusal schemes using finite element method. Braz Dent J 2024; 35:5798. [PMID: 39045988 PMCID: PMC11262769 DOI: 10.1590/0103-6440202405798] [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: 10/28/2023] [Accepted: 03/11/2024] [Indexed: 07/25/2024] Open
Abstract
Resorbed alveolar ridges, particularly in the lower jaw, have a small denture supporting area, which may cause the stress distribution of mastication load to exceed the pressure-pain threshold (PPT) and induce pain in the mucosa or potentially worsen the ridge resorption. Thus, choosing the ideal occlusal scheme among bilateral balanced (BBO), lingualized (LO), and monoplane (MO) for such conditions becomes crucial. The experiment was conducted using the finite element method on a modeling of a resorbed alveolar ridge in the lower jaw with three dentures placed on top, each of which was given different loading points according to the tooth arrangement of BBO, LO, and MO. The axial load was 100 N, and the resultant oblique loads on BBO and LO were 119 N and 106 N, respectively. The von Mises stresses for BBO, LO, and MO were observed in nine denture-supporting areas, and the results showed that the axial load did not produce stresses that exceeded the PPT value (0.64925 MPa) for BBO, LO, and MO with the highest value on area H, 0.43229 MPa, 0.39715 MPa, and 0.31576 MPa, respectively. However, the oblique load direction showed that the BBO had more areas (area E 0.80778 MPa and area H 0.76256 MPa) that exceeded the PPT than LO (area E 0.64394 MPa). The lingualized occlusal scheme is ideal for patients with resorbed alveolar ridge conditions, especially in terms of limiting interferences when the denture is functioning while maintaining comfort but still providing good masticatory performance and satisfactory esthetics.
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Affiliation(s)
- David Fatola
- . Department of Prosthodontics, Faculty of Dentistry, Universitas Sumatera Utara, Medan, Indonesia
| | - Ismet Danial Nasution
- . Department of Prosthodontics, Faculty of Dentistry, Universitas Sumatera Utara, Medan, Indonesia
| | - Muhammad Sabri
- .Computational & Experimental System Mechanics Research Centre, Department of Mechanical Engineering, Universitas Sumatera Utara, Medan, Indonesia
| | - Ricca Chairunnisa
- . Department of Prosthodontics, Faculty of Dentistry, Universitas Sumatera Utara, Medan, Indonesia
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2
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Khamaysi I, Firman R, Martin P, Vasilyev G, Boyko E, Zussman E. Mechanical Perspective on Increasing Brush Cytology Yield. ACS Biomater Sci Eng 2024; 10:1743-1752. [PMID: 38373217 PMCID: PMC10934267 DOI: 10.1021/acsbiomaterials.3c00935] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Revised: 02/04/2024] [Accepted: 02/06/2024] [Indexed: 02/21/2024]
Abstract
Brush cytology is a sampling technique extensively used for mucosal surfaces, particularly to identify malignancies. A sample is obtained by rubbing the brush bristles over the stricture or lesion several times until cells are trapped. Brush cytology detection rate varies, with malignancy confirmed in 15-65% of cases of adenocarcinoma-associated biliary strictures and 44-80% of cases of cholangiocarcinoma. Despite the widespread use of brush cytology, there is no consensus to date defining the optimal biliary brushing parameters for the collection of suspicious lesions, such as the number of passes, brushing rate, and force applied. The aim of this work is to increase the brush cytology diagnostic yield by elucidating the underlying mechanical phenomena. First, the mechanical interactions between the brush bristles and sampled tissue are analyzed. During brushing, mucus and detached cells are transferred to the space between the bristles through the capillary rise and flow eddies. These mass transfer mechanisms and their dependence on mucus rheology as a function of pH, brush displacement rate, and bristle geometry and configuration are examined. Lastly, results from ex vivo brushing experiments performed on porcine stomachs are presented. Clinical practitioners from a variety of disciplines can apply the findings of this study to outline clear procedures for cytological brushing to increase the sensitivity and specificity of the brushings.
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Affiliation(s)
- Iyad Khamaysi
- Department
of Gastroenterology, The Ruth and Bruce Rappaport Faculty of Medicine, Technion—Israel Institute of Technology, Haifa 3525433, Israel
- Gastroenterology
Institute, Rambam Health
Care Campus, Haifa 3109601, Israel
| | - Ronen Firman
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Patrick Martin
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Gleb Vasilyev
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Evgeniy Boyko
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
| | - Eyal Zussman
- Faculty
of Mechanical Engineering, Technion—Israel
Institute of Technology, Haifa 3200003, Israel
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3
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Lee EJ, Kim Y, Salipante P, Kotula AP, Lipshutz S, Graves DT, Alimperti S. Mechanical Regulation of Oral Epithelial Barrier Function. Bioengineering (Basel) 2023; 10:bioengineering10050517. [PMID: 37237587 DOI: 10.3390/bioengineering10050517] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/18/2023] [Accepted: 04/21/2023] [Indexed: 05/28/2023] Open
Abstract
Epithelial cell function is modulated by mechanical forces imparted by the extracellular environment. The transmission of forces onto the cytoskeleton by modalities such as mechanical stress and matrix stiffness is necessary to address by the development of new experimental models that permit finely tuned cell mechanical challenges. Herein, we developed an epithelial tissue culture model, named the 3D Oral Epi-mucosa platform, to investigate the role mechanical cues in the epithelial barrier. In this platform, low-level mechanical stress (0.1 kPa) is applied to oral keratinocytes, which lie on 3D fibrous collagen (Col) gels whose stiffness is modulated by different concentrations or the addition of other factors such as fibronectin (FN). Our results show that cells lying on intermediate Col (3 mg/mL; stiffness = 30 Pa) demonstrated lower epithelial leakiness compared with soft Col (1.5 mg/mL; stiffness = 10 Pa) and stiff Col (6 mg/mL; stiffness = 120 Pa) gels, indicating that stiffness modulates barrier function. In addition, the presence of FN reversed the barrier integrity by inhibiting the interepithelial interaction via E-cadherin and Zonula occludens-1. Overall, the 3D Oral Epi-mucosa platform, as a new in vitro system, will be utilized to identify new mechanisms and develop future targets involved in mucosal diseases.
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Affiliation(s)
- Eun-Jin Lee
- Department of Biochemistry and Molecular & Cellular Biology, School of Medicine, Georgetown University, Washington, DC 20057, USA
- Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
- Department of Chemistry and Biochemistry, College of Computer, Mathematical and Natural Sciences, University of Maryland, College Park, MD 20742, USA
| | - Yoontae Kim
- Department of Biochemistry and Molecular & Cellular Biology, School of Medicine, Georgetown University, Washington, DC 20057, USA
| | - Paul Salipante
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Anthony P Kotula
- Materials Science and Engineering Division, Material Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Sophie Lipshutz
- Department of Biochemistry and Molecular & Cellular Biology, School of Medicine, Georgetown University, Washington, DC 20057, USA
| | - Dana T Graves
- Department of Periodontics, School of Dental Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
| | - Stella Alimperti
- Department of Biochemistry and Molecular & Cellular Biology, School of Medicine, Georgetown University, Washington, DC 20057, USA
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4
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Luo H, Shu J, Liu Z. Biomechanical effects of high acceleration on the temporomandibular joint. Comput Methods Biomech Biomed Engin 2021; 25:333-341. [PMID: 34310250 DOI: 10.1080/10255842.2021.1955105] [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: 10/20/2022]
Abstract
The symptoms of temporomandibular disorders (TMD) are easily developed in pilots after long flights, such as joint pain, anterior displacement disc and so on. Related studies have suggested that abnormal high acceleration would cause temporomandibular joint (TMJ) lesions. Therefore, the purpose of this study is to analyze the biomechanical effects of high acceleration on the TMJs. The 3D models of the maxilla, mandible, articular disc were generated by Computed Tomography (CT) and Magnetic Resonance Imaging (MRI) of a healthy volunteer without any TMD symptoms. Then, the loads were added according to the various operating conditions of the aircraft. The maximum tensile stress, occurred in the anterior band of the discs, exceeded the failure stress. Compared with the low acceleration, the contact stresses between the discs and the articular cartilages were much greater under the high acceleration. High acceleration had a negative impact on the stress distributions of the articular discs and cartilages and easily led to TMJ damage. Lateral acceleration will cause asymmetric stress distribution of the TMJs.
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Affiliation(s)
- Haotian Luo
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Jingheng Shu
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Zhan Liu
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
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Shu J, Luo H, Zhang Y, Liu Z. 3D Printing Experimental Validation of the Finite Element Analysis of the Maxillofacial Model. Front Bioeng Biotechnol 2021; 9:694140. [PMID: 34336806 PMCID: PMC8322983 DOI: 10.3389/fbioe.2021.694140] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2021] [Accepted: 06/18/2021] [Indexed: 11/29/2022] Open
Abstract
Contacts used in finite element (FE) models were considered as the best simulation for interactions in the temporomandibular joint (TMJ). However, the precision of simulations should be validated through experiments. Three-dimensional (3D) printing models with the high geometric and loading similarities of the individuals were used in the validation. This study aimed to validate the FE models of the TMJ using 3D printing models. Five asymptomatic subjects were recruited in this study. 3D models of mandible, disc, and maxilla were reconstructed according to cone-beam CT (CBCT) image data. PLA was chosen for 3D printing models from bottom to top. Five pressure forces corresponding to the central occlusion were applied to the 3D printing models. Ten strain rosettes were distributed on the mandible to record the horizontal and vertical strains. Contact was used in the FE models with the same geometries, material properties, loadings, and boundary conditions as 3D printing models to simulate the interaction of the disc-condyle, disc-temporal bone, and upper-lower dentition. The differences of the simulated and experimental results for each sample were less than 5% (maximum 4.92%) under all five loadings. In conclusion, it was accurate to use contact to simulate the interactions in TMJs and upper-lower dentition.
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Affiliation(s)
- Jingheng Shu
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Haotian Luo
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
| | - Yuanli Zhang
- Department of Medical Technology, Chongqing Three Gorges Medical College, Chongqing, China
| | - Zhan Liu
- Key Lab for Biomechanical Engineering of Sichuan Province, Sichuan University, Chengdu, China.,Yibin Institute of Industrial Technology, Sichuan University Yibin Park, Yibin, China
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Paras A, Ma S, Waddell JN, Choi JJE. Real-time in vitro measurement of denture-mucosa pressure distribution in a typical edentulous patient with and without implants: Development of a methodology. J Mech Behav Biomed Mater 2021; 119:104531. [PMID: 33894527 DOI: 10.1016/j.jmbbm.2021.104531] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/05/2021] [Accepted: 04/12/2021] [Indexed: 11/19/2022]
Abstract
PURPOSE To measure the pressure distribution on the oral mucosa in vitro by comparing the pressure distributions under a complete denture and that of an implant overdenture. MATERIALS AND METHOD Anatomically accurate models and conventional Class I complete denture (CD) were produced and subjected to cyclic loading using a 100 N vertical centric and unilateral masticatory load with the universal testing machine (Instron 3369). Four miniature pressure sensors were positioned at four different locations in the intaglio surface of the denture and recorded pressure at 100 Hz frequency measured during a 10-cycle load at 1 Hz. Testing was repeated in different clinical combinations; CD vs. single implant overdentures (1-IOD), CD vs. two, three and four implant overdentures (2-IOD, 3-IOD vs. 4-IOD). The pressure profile (kPa) of complete dentures were measured and compared to the implant overdenture combinations. Collected data was statically analysed using SPSS and one-way analysis of variance. RESULTS The highest mean pressure was observed in CD group, with the mean mandible buccal ridge pressure value of 212.82 kPa ± 136.9 due to its surface area. There were no statistically significant differences between the group combinations (p = 0.146) but between various locations in the mean pressure recorded across the five denture/overdenture combinations. CONCLUSION CD experienced large pressure values on mandibular denture. 1-IOD demonstrated the most pressure in comparison to CD where with an increase in the number of implants used, it transformed the denture from being pure-borne mucosa to an implant overdenture, providing support and distributing the pressure amongst the implants.
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Affiliation(s)
- Alessandra Paras
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Sunyoung Ma
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - John Neil Waddell
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand
| | - Joanne Jung Eun Choi
- Sir John Walsh Research Institute, Faculty of Dentistry, University of Otago, Dunedin, New Zealand.
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7
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Shewan HM, Pradal C, Stokes JR. Tribology and its growing use toward the study of food oral processing and sensory perception. J Texture Stud 2019; 51:7-22. [PMID: 31149733 DOI: 10.1111/jtxs.12452] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2019] [Revised: 05/13/2019] [Accepted: 05/23/2019] [Indexed: 01/28/2023]
Abstract
Here we provide a comprehensive review of the knowledge base of soft tribology, the study of friction, lubrication, and wear on deformable surfaces, with consideration for its application toward oral tribology and food lubrication. Studies on "soft-tribology" have emerged to provide knowledge and tools to predict oral behavior and assess the performance of foods and beverages. We have shown that there is a comprehensive set of fundamental literature, mainly based on soft contacts in the Mini-traction machine with rolling ball on disk configuration, which provides a baseline for interpreting tribological data from complex food systems. Tribology-sensory relationships do currently exist. However, they are restricted to the specific formulations and tribological configuration utilized, and cannot usually be applied more broadly. With a careful and rigorous formulation/experimental design, we envisage tribological tools to provide insights into the sensory perception of foods in combination with other in vitro technique such as rheology, particle sizing or characterization of surface interactions. This can only occur with the use of well characterized tribopairs and equipment; a careful characterization of simpler model foods before considering complex food products; the incorporation of saliva in tribological studies; the removal of confounding factors from the sensory study and a global approach that considers all regimes of lubrication.
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Affiliation(s)
- Heather M Shewan
- School of Chemical Engineering, The University of Queensland, Brisbane, Australia
| | - Clementine Pradal
- School of Chemical Engineering, The University of Queensland, Brisbane, Australia
| | - Jason R Stokes
- School of Chemical Engineering, The University of Queensland, Brisbane, Australia
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8
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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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9
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Ex-Vivo Force Spectroscopy of Intestinal Mucosa Reveals the Mechanical Properties of Mucus Blankets. Sci Rep 2017; 7:7270. [PMID: 28779181 PMCID: PMC5544714 DOI: 10.1038/s41598-017-07552-7] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Accepted: 06/27/2017] [Indexed: 01/03/2023] Open
Abstract
Mucus is the viscous gel that protects mucosal surfaces. It also plays a crucial role in several diseases as well as in mucosal drug delivery. Because of technical limitations, mucus properties have mainly been addressed by in-vitro studies. However, this approach can lead to artifacts as mucus collection can alter its structure. Here we show that by using an implemented atomic force microscope it is possible to measure the interactions between micro-particles and mucus blankets ex-vivo i.e., on fresh excised mucus-covered tissues. By applying this method to study the small intestine, we were able to quantify the stiffness and adhesiveness of its mucus blanket at different pH values. We also demonstrate the ability of mucus blankets to bind and attract particles hundreds of µm away from their surface, and to trap and bury them even if their size is as big as 15 µm.
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10
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Pradal C, Stokes JR. Oral tribology: bridging the gap between physical measurements and sensory experience. Curr Opin Food Sci 2016. [DOI: 10.1016/j.cofs.2016.04.008] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Abstract
The prevalence of prosthodontic treatment has been well recognized, and the need is continuously increasing with the ageing population. While the oral mucosa plays a critical role in the treatment outcome, the associated biomechanics is not yet fully understood. Using the literature available, this paper provides a critical review on four aspects of mucosal biomechanics, including static, dynamic, volumetric and interactive responses, which are interpreted by its elasticity, viscosity/permeability, apparent Poisson's ratio and friction coefficient, respectively. Both empirical studies and numerical models are analysed and compared to gain anatomical and physiological insights. Furthermore, the clinical applications of such biomechanical knowledge on the mucosa are explored to address some critical concerns, including stimuli for tissue remodelling (interstitial hydrostatic pressure), pressure–pain thresholds, tissue displaceability and residual bone resorption. Through this review, the state of the art in mucosal biomechanics and their clinical implications are discussed for future research interests, including clinical applications, computational modelling, design optimization and prosthetic fabrication.
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Affiliation(s)
- Junning Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Rohana Ahmad
- Unit of Prosthodontics, Faculty of Dentistry, Universiti Teknologi MARA, Shah Alam 40450, Malaysia
| | - Wei Li
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Michael Swain
- Faculty of Dentistry, University of Sydney, Sydney, New South Wales 2006, Australia
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, University of Sydney, Sydney, New South Wales 2006, Australia
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12
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Chen J, Ahmad R, Suenaga H, Li W, Sasaki K, Swain M, Li Q. Shape Optimization for Additive Manufacturing of Removable Partial Dentures--A New Paradigm for Prosthetic CAD/CAM. PLoS One 2015; 10:e0132552. [PMID: 26161878 PMCID: PMC4498620 DOI: 10.1371/journal.pone.0132552] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Accepted: 06/17/2015] [Indexed: 01/29/2023] Open
Abstract
With ever-growing aging population and demand for denture treatments, pressure-induced mucosa lesion and residual ridge resorption remain main sources of clinical complications. Conventional denture design and fabrication are challenged for its labor and experience intensity, urgently necessitating an automatic procedure. This study aims to develop a fully automatic procedure enabling shape optimization and additive manufacturing of removable partial dentures (RPD), to maximize the uniformity of contact pressure distribution on the mucosa, thereby reducing associated clinical complications. A 3D heterogeneous finite element (FE) model was constructed from CT scan, and the critical tissue of mucosa was modeled as a hyperelastic material from in vivo clinical data. A contact shape optimization algorithm was developed based on the bi-directional evolutionary structural optimization (BESO) technique. Both initial and optimized dentures were prototyped by 3D printing technology and evaluated with in vitro tests. Through the optimization, the peak contact pressure was reduced by 70%, and the uniformity was improved by 63%. In vitro tests verified the effectiveness of this procedure, and the hydrostatic pressure induced in the mucosa is well below clinical pressure-pain thresholds (PPT), potentially lessening risk of residual ridge resorption. This proposed computational optimization and additive fabrication procedure provides a novel method for fast denture design and adjustment at low cost, with quantitative guidelines and computer aided design and manufacturing (CAD/CAM) for a specific patient. The integration of digitalized modeling, computational optimization, and free-form fabrication enables more efficient clinical adaptation. The customized optimal denture design is expected to minimize pain/discomfort and potentially reduce long-term residual ridge resorption.
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Affiliation(s)
- Junning Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, NSW 2006, Australia
| | - Rohana Ahmad
- Unit of Prosthodontics, Faculty of Dentistry, Shah Alam & Integrative Pharmacogenomics Institute (iPROMISE), Universiti Teknologi MARA, Bandar Puncak Alam, Selangor, 42300, Malaysia
| | - Hanako Suenaga
- Division of Preventive Dentistry, Tohoku University Graduate School of Dentistry, 4–1 Seiryo-machi, Aoba-ku, Sendai, 980–8575, Japan
| | - Wei Li
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, NSW 2006, Australia
| | - Keiichi Sasaki
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry, 4–1 Seiryo-machi, Aoba-ku, Sendai, 980–8575, Japan
| | - Michael Swain
- Faculty of Dentistry, 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
- * E-mail:
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