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Zhong J, Huang W, Ahmad R, Chen J, Wu C, Hu J, Zheng K, Swain MV, Li Q. A Soft-Tissue Driven Bone Remodeling Algorithm for Mandibular Residual Ridge Resorption Based on Patient CT Image Data. Adv Healthc Mater 2024; 13:e2400091. [PMID: 38722148 DOI: 10.1002/adhm.202400091] [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: 01/09/2024] [Revised: 05/04/2024] [Indexed: 09/03/2024]
Abstract
The role of the biomechanical stimulation generated from soft tissue has not been well quantified or separated from the self-regulated hard tissue remodeling governed by Wolff's Law. Prosthodontic overdentures, commonly used to restore masticatory functions, can cause localized ischemia and inflammation as they often compress patients' oral mucosa and impede local circulation. This biomechanical stimulus in mucosa is found to accelerate the self-regulated residual ridge resorption (RRR), posing ongoing clinical challenges. Based on the dedicated long-term clinical datasets, this work develops an in-silico framework with a combination of techniques, including advanced image post-processing, patient-specific finite element models and unsupervised machine learning Self-Organizing map algorithm, to identify the soft tissue induced RRR and quantitatively elucidate the governing relationship between the RRR and hydrostatic pressure in mucosa. The proposed governing equation has not only enabled a predictive simulation for RRR as showcased in this study, providing a biomechanical basis for optimizing prosthodontic treatments, but also extended the understanding of the mechanobiological responses in the soft-hard tissue interfaces and the role in bone remodeling.
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Affiliation(s)
- Jingxiao Zhong
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, 2006, Australia
| | - Wenwei Huang
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, 2006, Australia
| | - Rohana Ahmad
- Faculty of Dentistry and Integrative Pharmacogenomics Institute, Universiti Teknologi MARA, Selangor, 40450, Malaysia
| | - Junning Chen
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QJ, UK
| | - Chi Wu
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, 2006, Australia
| | - Jingrui Hu
- College of Engineering, Mathematics and Physical Sciences, University of Exeter, Exeter, EX4 4QJ, UK
| | - Keke Zheng
- Institute for Mechanical, Process and Energy Engineering, School of Engineering and Physical Sciences, Heriot Watt University, Edinburgh, EH14 4AS, UK
| | - Michael V Swain
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, 2006, Australia
| | - Qing Li
- School of Aerospace, Mechanical and Mechatronic Engineering, the University of Sydney, Sydney, 2006, Australia
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Chen S, Ye Z, Hong X, Chen L, Wu L, Wang Y, Chen Y, Wu M, Wang J, Zhang Q, Wu Y, Sun X, Ding X, Huang S, Zhao S. The effect of periapical bone defects on stress distribution in teeth with periapical periodontitis: a finite element analysis. BMC Oral Health 2023; 23:980. [PMID: 38066540 PMCID: PMC10709972 DOI: 10.1186/s12903-023-03546-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Accepted: 10/17/2023] [Indexed: 12/18/2023] Open
Abstract
BACKGROUND Apical periodontitis directly affects the stress state of the affected tooth owing to the destruction of the periapical bone. Understanding the mechanical of periapical bone defects/tooth is clinically meaningful. In this study, we evaluate the effect of periapical bone defects on the stress distribution in teeth with periapical periodontitis using finite element analysis. METHODS Finite element models of normal mandibular second premolars and those with periapical bone defects (spherical defects with diameters of 5, 10, 15, and 20 mm) were created using a digital model design software. The edges of the mandible were fixed and the masticatory cycle was simplified as oblique loading (a 400 N force loaded obliquely at 45° to the long axis of the tooth body) to simulate the tooth stress state in occlusion and analyze the von Mises stress distribution and tooth displacement distribution in each model. RESULTS Overall analysis of the models: Compared to that in the normal model, the maximum von Mises stresses in all the different periapical bone defect size models were slightly lower. In contrast, the maximum tooth displacement in the periapical bone defect model increased as the size of the periapical bone defect increased (2.11-120.1% of increase). Internal analysis of tooth: As the size of the periapical bone defect increased, the maximum von Mises stress in the coronal cervix of the tooth gradually increased (2.23-37.22% of increase). while the von Mises stress in the root apical region of the tooth showed a decreasing trend (41.48-99.70% of decrease). The maximum tooth displacement in all parts of the tooth showed an increasing trend as the size of the periapical bone defect increased. CONCLUSIONS The presence of periapical bone defects was found to significantly affect the biomechanical response of the tooth, the effects of which became more pronounced as the size of the bone defect increased.
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Affiliation(s)
- ShuoMin Chen
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - ZhangYan Ye
- Department of Stomatology, Pingyang Hospital Affiliated of Wenzhou Medical University, Wenzhou, China
| | - XinHua Hong
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
| | - Liang Chen
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
| | - LinMei Wu
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
| | - Yilin Wang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
| | - YuGe Chen
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Dentistry, University of Alberta, Edmonton, Canada
| | - MengHan Wu
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Jun Wang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - QinHui Zhang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - YuTian Wu
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - XiaoYu Sun
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China
- Department of Periodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China
| | - Xi Ding
- Department of Stomatology, the First Affiliated Hospital of Wenzhou Medical University, Ouhai District, Wenzhou, PR China.
| | - ShengBin Huang
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China.
- Department of Prosthodontics, School and Hospital of Stomatology, Wenzhou Medical University, Wenzhou, China.
| | - ShuFan Zhao
- Institute of Stomatology, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China.
- Department of Oral Maxillofacial Surgery, School and Hospital of Stomatology, Wenzhou Medical University, No. 373, West Xueyuan Road, Lucheng District, Wenzhou, PR China.
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Gil-Marques B, Pallarés-Sabater A, Brizuela-Velasco A, Sánchez Lasheras F, Lázaro-Calvo P, Gómez-Adrián MD, Larrazábal-Morón C. A Biomechanical Analysis of the Influence of the Morfology of the Bone Blocks Grafts on the Transfer of Tension or Load to the Soft Tissue by Means of the Finite Elements Method. MATERIALS (BASEL, SWITZERLAND) 2022; 15:9039. [PMID: 36556844 PMCID: PMC9786190 DOI: 10.3390/ma15249039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Revised: 12/06/2022] [Accepted: 12/09/2022] [Indexed: 06/17/2023]
Abstract
Edentulism produces resorption of alveolar bone processes, which can complicate placement of dental implants. Guided bone regeneration techniques aim to recover the volume of bone. These treatments are susceptible to the surgical technique employed, the design of the autologous block or the tension of the suture. These factors can relate to major complications as the lack of primary closure and dehiscence. The present study, using finite element analysis, aimed to determine differences in terms of displacement of the oral mucosa, transferred stress according to Von Mises and deformation of soft tissue when two block graft designs (right-angled and rounded) and two levels of suture tension (0.05 and 0.2 N) were combined. The results showed that all the variables analyzed were greater with 0.2 N. Regarding the design of the block, no difference was found in the transferred stress and deformation of the soft tissue. However, displacement was related to a tendency to dehiscence (25% greater in the right-angled/chamfer design). In conclusion different biomechanical behavior was observed in the block graft depending on the design and suture tension, so it is recommended to use low suture tension and rounded design. A novel finite element analysis model is presented for future investigations.
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Affiliation(s)
- Blanca Gil-Marques
- Doctoral School, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - Antonio Pallarés-Sabater
- Departament Endodonthics, School of Dentistry, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | | | - Fernando Sánchez Lasheras
- Department of Mathematics, Faculty of Sciences, University of Oviedo, 33007 Oviedo, Spain
- Institute of Space Sciences and Technologies of Asturias (ICTEA), University of Oviedo, 33004 Oviedo, Spain
| | - Pedro Lázaro-Calvo
- Departament of Periodonticx, Complutense University, 28004 Madrid, Spain
| | - María Dolores Gómez-Adrián
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
| | - Carolina Larrazábal-Morón
- School of Dentistry, Departament Medical and Surgery, Catholic University of Valencia San Vicente Mártir, 46001 Valencia, Spain
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Ramakrishnan AN, Röhrle O, Ludtka C, Varghese R, Koehler J, Kiesow A, Schwan S. Numerical study of the stress state on the oral mucosa and abutment tooth upon insertion of partial dentures in the mandible. INTERNATIONAL JOURNAL FOR NUMERICAL METHODS IN BIOMEDICAL ENGINEERING 2022; 38:e3604. [PMID: 35419990 DOI: 10.1002/cnm.3604] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Revised: 10/12/2021] [Accepted: 04/04/2022] [Indexed: 06/14/2023]
Abstract
The introduction of a removable partial denture onto the dental arch significantly influences the mechanical stress characteristics of both the jawbone and oral mucosa. The aim of this study was to analyze the stress state caused by biting forces upon insertion of partial dentures into the assembly, and to understand the influence of the resulting contact pressure on its retention behavior. For this purpose, a numerical model of a removable partial denture is proposed based on 3D models developed using computer tomography data of the jawbone and the removable partial denture. The denture system rests on the oral mucosa surface and three abutment teeth. The application of bite forces on the denture generated a stick condition on the loaded regions of the denture-oral mucosa interface, which indicates positive retention of the denture onto the oral mucosa surface. Slip and negative retention were observed in the regions of the contact space that were not directly loaded. The contact pressures observed in the regions of the oral mucosa in contact with the denture were below the clinical pressure pain threshold value for soft tissue, which potentially lowers the risk of pain being experienced by denture users. Further, the variation of the retention behavior and contact pressures across different regions of the denture assembly was observed. Thus, there is a need for adhesives or restraining mechanisms for the denture system in order to avoid bending and deformation of sections of the denture as a consequence of the applied bite force.
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Affiliation(s)
- Anantha Narayanan Ramakrishnan
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Halle, Germany
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Oliver Röhrle
- Institute for Modelling and Simulation of Biomechanical Systems, University of Stuttgart, Stuttgart, Germany
| | - Christopher Ludtka
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | | | - Josephine Koehler
- Department of Prosthodontics, School of Dental Medicine, Martin-Luther-University Halle-Wittenberg, Halle, Germany
| | - Andreas Kiesow
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Halle, Germany
| | - Stefan Schwan
- Department of Biological and Macromolecular Materials, Fraunhofer Institute for Microstructure of Materials and Systems IMWS, Halle, Germany
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Kouadio AA, Fabienne J, Soueidan A, Volteau C, Koffi NJ, Djérédou KB, Le Bars P. Effects of wearing removable dentures and aging on palatal mucosa blood flow by laser doppler. J Indian Prosthodont Soc 2022; 22:161-168. [PMID: 36511027 PMCID: PMC9132508 DOI: 10.4103/jips.jips_292_21] [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: 12/30/2022] Open
Abstract
Aim The purpose of this work is to analyze the effects of removable dental prostheses and aging on blood microcirculation in the palatal mucosa. Settings and Design Blood flow was measured in two groups using the Laser Doppler Flowmeter at three specific anatomical sites: Retro incisive papilla, medial raphe, and Schroeder area. Materials and Methods Group 1 included young, healthy dentulous individuals (mean age: 23 ± 3 years), and Group 2 contained elderly edentulous individuals (mean age: 62 ± 11.69 years). For Group 1, measurements were taken in a single session; for Group 2, the measurements were taken in two sessions: The first just before the prosthetic load (E1) and again 1 week after new dentures were provider (E2). Statistical Analysis Used Statistical analyses were performed using SAS software, Version 9.4 of the SAS System for Windows, Copyright © 2017 SAS Institute Inc. (Cary, NC, USA). A P < 0.05 was classified as statistically significant. Results Measurements of blood flow of the palatal mucosa showed that the healthy young dentulous participants had significantly lower perfusion unit values than the elderly edentulous participants at all three anatomical sites (P < 0.05). For Group 2, the comparisons between the measurements taken before (E1) and after (E2) new dentures were provided showed no significant differences. Conclusion Our results indicate that the process of aging significantly modifies the blood flow of the palatal mucosa while wearing removable dental prostheses does not modify the blood flow of the palatal mucosa in a 1week period. These results are not influenced by systemic pathology (e.g., diabetes, cardiovascular diseases) or smoking.
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Affiliation(s)
- Ayepa Alain Kouadio
- Department of Prosthodontics, UIC Odontology, Nantes Dental School, Abidjan, Cote d’Ivoire,Odontostomatology Faculty, Félix Houphouët Boigny University, Abidjan, Cote d’Ivoire
| | - Jordana Fabienne
- Department of Prosthodontics, UIC Odontology, Nantes Dental School, Abidjan, Cote d’Ivoire
| | - Assem Soueidan
- Department of Periodontology, UIC Odontology, CHU, Nantes Cedex, France
| | | | - N’goran Justin Koffi
- Odontostomatology Faculty, Félix Houphouët Boigny University, Abidjan, Cote d’Ivoire
| | | | - Pierre Le Bars
- Department of Prosthodontics, UIC Odontology, Nantes Dental School, Abidjan, Cote d’Ivoire,Address for correspondence: Dr. Pierre Le Bars, Nantes Dental School, 1 Place Alexis-Ricordeau, 44042 Nantes Cedex 1, France. E-mail: pierre.le-bars@univ-nantes
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Jacob S, Nair AB, Boddu SHS, Gorain B, Sreeharsha N, Shah J. An Updated Overview of the Emerging Role of Patch and Film-Based Buccal Delivery Systems. Pharmaceutics 2021; 13:1206. [PMID: 34452167 PMCID: PMC8399227 DOI: 10.3390/pharmaceutics13081206] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2021] [Revised: 07/28/2021] [Accepted: 08/03/2021] [Indexed: 12/17/2022] Open
Abstract
Buccal mucosal membrane offers an attractive drug-delivery route to enhance both systemic and local therapy. This review discusses the benefits and drawbacks of buccal drug delivery, anatomical and physiological aspects of oral mucosa, and various in vitro techniques frequently used for examining buccal drug-delivery systems. The role of mucoadhesive polymers, penetration enhancers, and enzyme inhibitors to circumvent the formulation challenges particularly due to salivary renovation cycle, masticatory effect, and limited absorption area are summarized. Biocompatible mucoadhesive films and patches are favored dosage forms for buccal administration because of flexibility, comfort, lightness, acceptability, capacity to withstand mechanical stress, and customized size. Preparation methods, scale-up process and manufacturing of buccal films are briefed. Ongoing and completed clinical trials of buccal film formulations designed for systemic delivery are tabulated. Polymeric or lipid nanocarriers incorporated in buccal film to resolve potential formulation and drug-delivery issues are reviewed. Vaccine-enabled buccal films have the potential ability to produce both antibodies mediated and cell mediated immunity. Advent of novel 3D printing technologies with built-in flexibility would allow multiple drug combinations as well as compartmentalization to separate incompatible drugs. Exploring new functional excipients with potential capacity for permeation enhancement of particularly large-molecular-weight hydrophilic drugs and unstable proteins, oligonucleotides are the need of the hour for rapid advancement in the exciting field of buccal drug delivery.
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Affiliation(s)
- Shery Jacob
- Department of Pharmaceutical Sciences, College of Pharmacy, Gulf Medical University, Ajman 4184, United Arab Emirates
| | - Anroop B. Nair
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa 31982, Saudi Arabia; (A.B.N.); (N.S.)
| | - Sai H. S. Boddu
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Ajman University, Ajman 346, United Arab Emirates;
| | - Bapi Gorain
- School of Pharmacy, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya 47500, Selangor, Malaysia;
- Centre for Drug Delivery and Molecular Pharmacology, Faculty of Health and Medical Sciences, Taylor’s University, Subang Jaya 47500, Selangor, Malaysia
| | - Nagaraja Sreeharsha
- Department of Pharmaceutical Sciences, College of Clinical Pharmacy, King Faisal University, Al-Ahsa 31982, Saudi Arabia; (A.B.N.); (N.S.)
- Department of Pharmaceutics, Vidya Siri College of Pharmacy, Off Sarjapura Road, Bangalore 560035, India
| | - Jigar Shah
- Department of Pharmaceutics, Institute of Pharmacy, Nirma University, Ahmedabad 382481, India;
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Choi JJE, Chen S, Waddell JN. Investigation of dental elastomers as oral mucosa simulant materials. Clin Exp Dent Res 2021; 7:754-762. [PMID: 33512785 PMCID: PMC8543465 DOI: 10.1002/cre2.399] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2020] [Revised: 12/29/2020] [Accepted: 12/30/2020] [Indexed: 12/19/2022] Open
Abstract
Objective To measure mechanical properties of dental soft liners in tensional stress to identify their suitability as human oral mucosa simulant materials. Methods Eleven different dental elastomers were subjected to tensile testing to obtain their tensile strength and elastic moduli (n = 15/group) according to the ISO‐527 method. Fractured surfaces of one specimen per sample group were examined under the light microscope and scanning electron microscope (SEM). Energy‐dispersive X‐ray spectroscopy (EDS) was performed for the elemental analysis or chemical characterization of each sample group. The obtained data were quantitatively and qualitatively analysed. They were also statistically analysed using SPSS version 25. Results The tensile strength of dental elastomers ranged from 0.43 MPa (±0.09) to 7.41 MPa (±1.11) and had statistically significant differences between tested groups (p = 0.001). Vertex soft heat‐cure soft liner, GC impression silicones and Silagum soft liners were found to have tensile strengths close to that of the oral mucosa reported by previous studies. SEM analysis revealed that the elastomers with higher filler contents showed rough fractured surface with plucking of particles after tensile fracture. Conclusion This is the first study assessing the suitability of dental elastomers as human oral mucosa simulant materials which can be used for in vitro, mathematical modeling and finite element analysis (FEA) to study masticatory force distribution in oral mucosa. Out of 11 studied, six (Vertex Soft, GC heavy and Light body, Molloplast B, Algin X Ultra and Exaclear) dental elastomers showed similar mechanical properties to the Theil embalmed gingival tissues. Vertex Soft, GC Light body, and Molloplast B may be used for the majority of oral mucosal model when considering tensile strength as the primary factor for mechanical stimulation.
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Affiliation(s)
- Joanne Jung Eun Choi
- Faculty of Dentistry, Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand
| | - Shiyao Chen
- Faculty of Dentistry, Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand
| | - John Neil Waddell
- Faculty of Dentistry, Sir John Walsh Research Institute, University of Otago, Dunedin, New Zealand
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8
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Denture induced mechanotransduction can contribute to oral carcinogenesis. Med Hypotheses 2021; 148:110507. [PMID: 33524846 DOI: 10.1016/j.mehy.2021.110507] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 01/13/2021] [Accepted: 01/20/2021] [Indexed: 01/28/2023]
Abstract
Mechanical stresses in the form of substrate rigidity, hydrostatic pressure, compressive, tensile and shear stress has been regarded as an important motive for the epithelial carcinogenesis brought about by the activation of Hippo signaling pathways. Masticatory forces generated in edentulous patients with dentures are transferred directly to the palatal mucosa (maxillary denture) and alveolar mucosa (mandibular denture). Thus, the oral mucosa present underneath the dentures experiences compressive, shear and tensile stresses on a day-to-day basis. These stresses can induce carcinogenesis by mechano-transduction and subsequent activation of numerous carcinogenesis relevant signaling pathways such as the HIPPO pathway. With this contention in mind, we proposed a hypothesis, which explains the pathogenesis for the presence of oral squamous cell carcinoma in denture wearer patients. Efforts were made to envisage the appropriate experimentations for the evaluation of the hypothesis. As a therapeutic implication, flexible dentures, soft denture, or medicated dentures could be prescribed for the high-risk groups having potentially malignant lesions in the oral cavity.
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9
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Nogawa T, Saito M, Murashima N, Takayama Y, Yokoyama A. Influence of rigidity of retainers on dynamic behavior of implant-supported removable partial dentures. Int J Implant Dent 2020; 6:60. [PMID: 33089410 PMCID: PMC7578214 DOI: 10.1186/s40729-020-00260-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2020] [Accepted: 09/02/2020] [Indexed: 01/14/2023] Open
Abstract
Background Implant-supported removable partial dentures (ISRPDs) are an effective treatment for partially edentulous patients. ISRPDs improve patients’ satisfaction and oral function to a greater extent than RPDs by improving denture stability and enhancing support. However, the effect of a type of direct retainer on displacement of the abutment teeth and dentures in ISRPDs remains unclear. Therefore, we made a resin mandibular model of unilateral mandibular distal-extension partial edentulism for mechanical simulation and compared the dynamic behavior of the abutment teeth and the denture base among different tooth-borne retainers with various rigidities for RPDs and ISRPDs. Methods A resin mandibular model for mechanical simulation that had unilateral mandibular distal-extension edentulism and was missing the first molar, second molar, first premolar, and second premolar, and a denture fabricated from the patient’s computed tomography images were used. Three types of direct retainers with different connecting rigidities were evaluated. The vertical displacement of the denture base and buccal and lingual sides and the mesial displacement of the abutment teeth were measured. Results Regardless of the rigidity of the direct retainers and loading positions, the displacement of the denture bases in the ISRPDs was significantly smaller than that in the RPDs (P < 0.001). There was no significant difference in vertical displacement of the denture bases among direct retainers with various connecting rigidities in the ISRPDs. Conversely, horizontal displacement of the abutment teeth in both the RPDs and ISRPDs tended to be larger with the cone crown telescope, which has high rigidity, than with the cast cingulum rest and wire clasp, which have much lower rigidities. Conclusion Our results suggested that cast cingulum rest and wire clasps as direct retainers are appropriate ISRPDs to minimize denture movement and suppress displacement of the remaining teeth in patients with unilateral mandibular distal-extension partial edentulism.
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Affiliation(s)
- Toshifumi Nogawa
- Preventive Dentistry, Hokkaido University Hospital, Sapporo, Japan.
| | - Masayasu Saito
- Oral Functional Prosthodontics, Division of Oral Functional Science, Facility of Dental Medicine, Hokkaido University, Sapporo, Japan
| | - Naomichi Murashima
- Oral Functional Prosthodontics, Division of Oral Functional Science, Graduate School of Dental Medicine, Hokkaido University, Sapporo, Japan
| | | | - Atsuro Yokoyama
- Oral Functional Prosthodontics, Division of Oral Functional Science, Facility of Dental Medicine, Hokkaido University, Sapporo, Japan
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10
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Matsuoka A, Yoshioka F, Ozawa S, Takebe J. Development of three-dimensional facial expression models using morphing methods for fabricating facial prostheses. J Prosthodont Res 2018; 63:66-72. [PMID: 30220620 DOI: 10.1016/j.jpor.2018.08.003] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2018] [Revised: 07/17/2018] [Accepted: 08/10/2018] [Indexed: 11/17/2022]
Abstract
PURPOSE It is essential to fabricate a best-fit three-dimensional (3D) facial prosthesis model capable of facial expressions. In order for the facial prosthesis to remain in position, especially around marginal areas subject to movement, a new method of making 3D facial expression models using time-series data allowing changes in facial expression by morphing technique was developed. METHODS Seven normal subjects and seven patients with nasal defects or nasal deformities participated in this study. Three distinct facial expressions (i.e., a neutral expression, smiled, and open mouthed) were digitally acquired with a facial scanner. Prepared template models were transformed to homologous models, which can represent the form as shape data with the same number of point cloud data of the same topology referring to the scanning data. Finally, 3D facial expression models were completed by generating a morphing image based on two sets of homologous models, and the accuracy of the homologous models of all subjects was evaluated. RESULTS 3D facial expression models of both normal subjects and patients with nasal defects were successfully generated. No significant differences in shape between the scanned models and homologous models were shown. CONCLUSIONS The high accuracy of this 3D facial expression model in both normal subjects and patients suggests its use for fabricating facial prostheses.
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Affiliation(s)
- Ayumi Matsuoka
- Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Fumi Yoshioka
- Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan.
| | - Shogo Ozawa
- Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
| | - Jun Takebe
- Department of Removable Prosthodontics, School of Dentistry, Aichi Gakuin University, Nagoya, Japan
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Alsrouji MS, Ahmad R, Abdul Razak NH, Shuib S, Kuntjoro W, Baba NZ. Premaxilla Stress Distribution and Bone Resorption Induced by Implant Overdenture and Conventional Denture. J Prosthodont 2018; 28:e764-e770. [PMID: 30044033 DOI: 10.1111/jopr.12954] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/29/2018] [Indexed: 11/29/2022] Open
Abstract
PURPOSE To relate the principal stress, strain, and total deformation in the premaxilla region beneath a complete denture to the pattern of premaxilla bone resorption when opposed by a conventional complete denture (CD) or by a two-implant-retained overdenture (IOD) using finite element analysis (FEA). MATERIALS AND METHODS Three-dimensional solid models of the maxilla, mucosa, and denture of a selected edentulous patient were created using Mimics and CATIA software. The FEA model was created and duplicated in ANSYS 16.0 to perform two simulations for the IOD and the CD models. The values of maximum stress and strain and total deformation were obtained and compared to the outcomes of premaxilla resorption from a parallel clinical study. RESULTS The maximum principal stress in the premaxilla in the IOD model ranged from 0.019 to 0.336 MPa, while it ranged from 0.011 to 0.193 MPa in the CD model. The maximum principal strain in the IOD model was 1.75 times greater than that in the CD model. Total deformation was 1.8 times higher in the IOD model. Greater bone resorption was observed in regions of higher stress, which were on the occlusal and buccal sides of the premaxilla residual ridge. CONCLUSION Stress, strain, and total deformation values present in the premaxilla area beneath a CD were approximately two times greater in a comparison between an opposing mandibular two-IOD and an opposing mandibular CD. The results were consistent with a parallel clinical study in which the rate of premaxilla bone resorption was almost three times greater in the IOD group.
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Affiliation(s)
- Mohamed Samih Alsrouji
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sg. Buloh Campus, Selangor, Malaysia
| | - Rohana Ahmad
- Centre of Restorative Dentistry Studies, Faculty of Dentistry, Universiti Teknologi MARA, Sg. Buloh Campus, Selangor, Malaysia.,Integrative Pharmacogenomics Institute, Universiti Teknologi MARA, Puncak Alam Campus, Selangor, Malaysia
| | - Noor Hayati Abdul Razak
- Oral and Maxillofacial Surgery Unit, School of Dental Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Solehuddin Shuib
- Faculty of Mechanical Engineering, Universiti Teknologi MARA, Shah Alam, Malaysia
| | - Wahyu Kuntjoro
- Faculty of Mechanical Engineering, Universiti Teknologi MARA, Shah Alam, Malaysia
| | - Nadim Z Baba
- Advanced Specialty Education Program in Prosthodontics, Loma Linda University, School of Dentistry, Loma Linda, CA
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Nonlinear Biomechanical Characteristics of the Schneiderian Membrane: Experimental Study and Numerical Modeling. BIOMED RESEARCH INTERNATIONAL 2018; 2018:2829163. [PMID: 30035119 PMCID: PMC6033247 DOI: 10.1155/2018/2829163] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 05/24/2018] [Indexed: 01/21/2023]
Abstract
Objective The aim of this study is to quantify the nonlinear mechanical behavior of the Schneiderian membrane. Methods Thirty cadaveric maxillary sinus membrane specimens were divided into the elongation testing group and the perforation testing group. Mechanical experimental measurements were taken via ex vivo experiments. Theoretical curves were compared with experimental findings to assess the effectiveness of the nonlinear mechanical properties. The FE model with nonlinear mechanical properties was used to simulate the detachment of the Schneiderian membrane under loading. Results The mean thickness of the membrane samples was 1.005 mm. The mean tensile strength obtained by testing was 6.81 N/mm2. In membrane perforation testing, the mean tensile strength and the linear elastic modulus were significantly higher than those in membrane elongation testing (P < 0.05). The mean adhesion force between the Schneiderian membrane and the bone was 0.052 N/mm. By FE modeling, the squared correlation coefficients of theoretical stress-strain curves for the nonlinear and linear models were 0.99065 and 0.94656 compared with the experimental data. Conclusions The biomechanical properties of the Schneiderian membrane were implemented into the FE model, which was applied to simulate the mechanical responses of the Schneiderian membrane in sinus floor elevation.
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New Gene Markers for Metabolic Processes and Homeostasis in Porcine Buccal Pouch Mucosa during Cells Long Term-Cultivation-A Primary Culture Approach. Int J Mol Sci 2018; 19:ijms19041027. [PMID: 29596348 PMCID: PMC5979461 DOI: 10.3390/ijms19041027] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Revised: 03/26/2018] [Accepted: 03/27/2018] [Indexed: 01/22/2023] Open
Abstract
The oral mucosal tissue is a compound structure composed of morphologically and physiologically different cell types. The morphological modification involves genetically determined lifespan, which may be recognized as the balance between cell survival and apoptosis. Although the biochemical processes and pathways in oral mucosa, with special regards to drug transport, delivery, and metabolism, are well known, the cellular physiological homeostasis in this tissue requires further investigation. The porcine buccal pouch mucosal cells (BPMCs) collected from 20 pubertal crossbred Landrace gilts, were used in this study. Immediately after recovery, the oral mucosa was separated micro-surgically, and treated enzymatically. The dispersed cells were transferred into primary in vitro culture systems for a long-term cultivation of 30 days. After each step of in vitro culture (IVC), the cells were collected for isolation of total RNA at 24 h, 7, 15, and 30 days of IVC. While the expression was analyzed for days 7, 15, and 30, the 24th hour was used as a reference for outcome calibration. The gene expression profile was determined using Affymetrix microarray assays and necessary procedures. In results, we observed significant up-regulation of SCARB1, PTGS2, DUSP5, ITGB3, PLK2, CCL2, TGFB1, CCL8, RFC4, LYN, ETS1, REL, LIF, SPP1, and FGER1G genes, belonging to two ontological groups, namely "positive regulation of metabolic process", and "regulation of homeostatic process" at 7 day of IVC as compared to down-regulation at days 15 and 30. These findings suggest that the metabolic processes and homeostatic regulations are much more intense in porcine mucosal cells at day 7 of IVC. Moreover, the increased expression of marker genes, for both of these ontological groups, may suggest the existence of not only "morphological lifespan" during tissue keratinization, but also "physiological checkpoint" dedicated to metabolic processes in oral mucosa. This knowledge may be useful for preclinical experiments with drugs delivery and metabolism in both animals and humans.
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Biomechanical investigation into the role of the periodontal ligament in optimising orthodontic force: a finite element case study. Arch Oral Biol 2016; 66:98-107. [DOI: 10.1016/j.archoralbio.2016.02.012] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 09/09/2015] [Accepted: 02/19/2016] [Indexed: 11/23/2022]
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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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Fisher PD, Clemens J, Zach Hilt J, Puleo DA. Multifunctional poly(β-amino ester) hydrogel microparticles in periodontal in situ forming drug delivery systems. ACTA ACUST UNITED AC 2016; 11:025002. [PMID: 26947556 DOI: 10.1088/1748-6041/11/2/025002] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
In situ forming implants (ISIs) formed from poly(lactic-co-glycolic acid) (PLGA) have been commercialized for local drug delivery to treat periodontitis, but drug release from these bulk materials is typically subject to an initial burst. In addition, PLGA has inferior material properties for the dynamic mechanical environment of gingival tissue. In this work, poly(β-amino ester) (PBAE) hydrogel microparticles were incorporated into a PLGA matrix to provide several new functions: mechanical support, porosity, space-filling, and controlled co-delivery of antimicrobial and osteogenic drugs. First, the effects of PBAE microparticles on ISI architecture and material properties throughout degradation were investigated. Second, the influence of PBAE microparticles on drug release kinetics was quantified. Over a 15 d period, ISIs containing PBAE microparticles possessed greater porosity, ranging from 42-80%, compared to controls, which ranged from 24-54% (p < 0.001), and these ISIs also developed significantly greater accessible volume to simulated cell-sized spheres after 5 d or more of degradation (p < 0.001). PBAE-containing ISIs possessed a more uniform microarchitecture, which preserved mechanical resilience after cyclical loading (p < 0.001), and the materials swelled to fill the injected space, which significantly increased interfacial strength in an artificial periodontal pocket (p < 0.0001). PBAE microparticles eliminated the burst of freely-mixed simvastatin compared to 36% burst from controls (p < 0.0001), and high-dose doxycycline release was prolonged from 2 d to 7 d by pre-loading drug into the microparticles. PBAE-containing PLGA ISIs are more effective space-filling scaffolds and offer improved release kinetics compared to existing ISIs used to treat periodontitis.
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Affiliation(s)
- Paul D Fisher
- Department of Biomedical Engineering, University of Kentucky, Lexington, KY 40506, USA
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Jo DW, Dong JK. Effects of posterior ridge resorption and attachment wear on periimplant strain in mandibular two-implant-supported overdentures. J Prosthet Dent 2015; 114:839-47. [PMID: 26372626 DOI: 10.1016/j.prosdent.2015.06.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/06/2015] [Accepted: 06/11/2015] [Indexed: 11/29/2022]
Abstract
STATEMENT OF PROBLEM Progressive resorption of the posterior residual ridge and attachment wear increase the rotational movement of mandibular 2-implant-supported overdentures (IODs). Limited information is available regarding the biomechanical effects of rotational movement on anterior implants during mastication. PURPOSE The purpose of this in vitro investigation was to analyze the effects of posterior ridge resorption and attachment wear, using simulated IODs to examine periimplant strain changes under dynamic loading conditions. MATERIAL AND METHODS Two dental implants were positioned in the canine regions of a mandibular edentulous cast. Two mandibular edentulous models were fabricated from the cast by using a fixture-level impression technique, and IODs reinforced with a cobalt-chromium cast framework were prepared using the laboratory models. Two different types of stud attachments (Locator and O-ring) were connected to each paired model and to the IOD. Using a dynamic load of 100 N, continuous stress-strain changes were recorded under 3 conditions: the original condition of the paired laboratory models and the IODs, following a 1-mm reduction of the posterior residual ridge support, and after performing a fatigue test to simulate attachment wear after reduction of the posterior ridge support. After these measurements, a scanning electron microscope (SEM) was used to analyze attachment wear. RESULTS In all implants, the 1-mm posterior ridge reduction and attachment wear procedure did not remarkably elevate tensile forces compared with their original condition. All stress-strain curves showed phased strain changes caused by the rotational movement of the IODs. After the fatigue test, the shape of the stress-strain curve changed from a smooth curve to a polygonal line compared with that in the previous records. The Locator matrices showed more wear than the other attachment components. CONCLUSIONS Neither attachment wear nor an increase of the IOD rotational movement caused by an approximately 1-mm decrease in the posterior mucosal support led to significant changes in the periimplant strain in IODs.
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Affiliation(s)
- Deuk-Won Jo
- Assistant Professor, Department of Prosthodontics, Section of Dentistry, Seoul National University Bundang Hospital, Seongnam, Korea
| | - Jin-Keun Dong
- Professor, Department of Prosthodontics, College of Dentistry, Wonkwang University, Iksan, Korea.
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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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Chen J, Suenaga H, Hogg M, Li W, Swain M, Li Q. Determination of oral mucosal Poisson’s ratio and coefficient of friction fromin-vivocontact pressure measurements. Comput Methods Biomech Biomed Engin 2015; 19:357-65. [DOI: 10.1080/10255842.2015.1028925] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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Suenaga H, Chen J, Yamaguchi K, Li W, Sasaki K, Swain M, Li Q. Mechanobiological Bone Reaction Quantified by Positron Emission Tomography. J Dent Res 2015; 94:738-44. [DOI: 10.1177/0022034515573271] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
While nuclear medicine has been proven clinically effective for examination of the change in bone turnover as a result of stress injury, quantitative correlation between tracer uptake and mechanical stimulation in the human jawbone remains unclear. This study aimed to investigate the relationship between bone metabolism observed by 18F-fluoride positron emission tomography (PET) images and mechanical stimuli obtained by finite element analysis (FEA) in the residual ridge induced by the insertion of a removable partial denture (RPD). An 18F-fluoride PET/CT (computerized tomography) scan was performed to assess the change of bone metabolism in the residual ridge under the denture before and after RPD treatment. Corresponding patient-specific 3D finite element (FE) models were created from CT images. Boundary conditions were prescribed by the modeling of condylar contacts, and muscular forces were derived from the occlusal forces measured in vivo to generate mechanobiological reactions. Different mechanobiological stimuli, e.g., equivalent von Mises stress (VMS), equivalent strain (EQV), and strain energy density (SED), determined from nonlinear FEA, were quantified and compared with the standardized uptake values (SUVs) of PET. Application of increased occlusal force after RPD insertion induced higher mechanical stimuli in the residual bone. Accordingly, SUV increased in the region of residual ridge with higher mechanical stimuli. Thus, with SUV, a clear correlation was observed with VMS and SED in the cancellous bone, especially after RPD insertion (R2 > 0.8, P < 0.001). This study revealed a good correlation between bone metabolism and mechanical stimuli induced by RPD insertion. From this patient-specific study, it was shown that metabolic change detected by PET in the loaded bone, in a much shorter duration than conventional x-ray assessment, is associated with mechanical stimuli. The nondestructive nature of PET/CT scans and FEA could potentially provide a new method for clinical examination and monitoring of prosthetically driven bone remodeling.
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Affiliation(s)
- H. Suenaga
- Division of Preventive Dentistry, Tohoku University Graduate School of Dentistry, Sendai, Japan
| | - J. Chen
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, Australia
| | - K. Yamaguchi
- Department of Radiology, Sendai Kousei Hospital, Sendai, Japan
| | - W. Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, Australia
| | - K. Sasaki
- Division of Advanced Prosthetic Dentistry, Tohoku University Graduate School of Dentistry Sendai, Japan
| | - M. Swain
- Faculty of Dentistry, The University of Sydney, NSW, Australia
| | - Q. Li
- School of Aerospace, Mechanical and Mechatronic Engineering, The University of Sydney, NSW, Australia
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A comparative study on complete and implant retained denture treatments – A biomechanics perspective. J Biomech 2015; 48:512-9. [DOI: 10.1016/j.jbiomech.2014.11.043] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2014] [Revised: 11/24/2014] [Accepted: 11/26/2014] [Indexed: 02/01/2023]
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Wakabayashi N, Suzuki T. Patient-specific finite element analysis of viscoelastic masticatory mucosa. JOURNAL OF DENTAL BIOMECHANICS 2013; 4:1758736013483298. [PMID: 23580171 PMCID: PMC3619231 DOI: 10.1177/1758736013483298] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/03/2022]
Abstract
The purpose of this study was to analyze the stress and strain inside of the oral mucosa in partially-edentulous patients. The patient-specific finite element models of the mucosa and the bone were constructed using the CT images and in-vivo surface measurement during a continuous load. The mean initial shear modulus of 8.3 × 10–5 (GPa) and the mean relaxation time of 503 (s) were determined as the viscoelastic properties of the mucosa. The increase of the highest maximum compressive strain during the continuous loading was observed in all the patients, however; the intensity of strain was not in accordance with the thickness of the mucosa. It is suggested that the variations of the morphology and the initial modulus of the mucosa should be considered in the mathematical approaches to detect the mechanical responses of the oral mucosa.
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Affiliation(s)
- Noriyuki Wakabayashi
- Department of Removable Partial Prosthodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan
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Jasinoski SC, Reddy BD. Mechanics of cranial sutures during simulated cyclic loading. J Biomech 2012; 45:2050-4. [PMID: 22703899 DOI: 10.1016/j.jbiomech.2012.05.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2011] [Revised: 03/27/2012] [Accepted: 05/01/2012] [Indexed: 11/24/2022]
Abstract
Previous computational and experimental analyses revealed that cranial sutures, fibrous joints between the bones, can reduce the strain experienced by the surrounding skull bones during mastication. This damping effect reflects the importance of including sutures in finite element (FE) analyses of the skull. Using the FE method, the behaviour of three suture morphologies of increasing complexity (butt-ended, moderate interdigitated, and complex interdigitated) during static loading was recently investigated, and the sutures were assumed to have linear elastic properties. In the current study, viscoelastic properties, derived from published experimental results of the nasofrontal suture of young pigs (Sus scrofa), are applied to the three idealised bone-suture models. The effects of suture viscoelasticity on the stress, strain, and strain energy in the models were computed for three different frequencies (corresponding to periods of 1, 10, and 100s) and compared to the results of a static, linear elastic analysis. The range of applied frequencies broadly represents different physiological activities, with the highest frequency simulating mastication and the lowest frequency simulating growth and pressure of the surrounding tissues. Comparing across all three suture morphologies, strain energy and strain in the suture decreased with the increase in suture complexity. For each suture model, the magnitude of strain decreased with an increase in frequency, and the magnitudes were similar for both the elastic and 1s frequency analyses. In addition, a viscous response is less apparent in the higher frequency analyses, indicating that viscous properties are less important to the behaviour of the suture during those analyses. The FE results suggest that implementation of viscoelastic properties may not be necessary for computational studies of skull behaviour during masticatory loading but instead might be more relevant for studies examining lower frequency physiological activities.
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Affiliation(s)
- S C Jasinoski
- Centre for Research in Computational and Applied Mechanics, University of Cape Town, Private Bag, 7701 Rondebosch, South Africa.
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