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Zhao Z, Zhang Y, Lin L, Huang W, Xiao C, Liu J, Chai G. Intelligent electromagnetic navigation system for robot-assisted intraoral osteotomy in mandibular tumor resection: a model experiment. Front Immunol 2024; 15:1436276. [PMID: 39119338 PMCID: PMC11306084 DOI: 10.3389/fimmu.2024.1436276] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2024] [Accepted: 07/11/2024] [Indexed: 08/10/2024] Open
Abstract
Background Mandibular tumor surgery necessitates precise osteotomies based on tumor boundaries; however, conventional osteotomies often lack accuracy in predicting osteotomy positions and planes, potentially leading to excessive resection of normal bone tissues or residual tumors, thus compromising postoperative quality of life and clinical outcomes. Robotic-assisted surgery (RAS) augmented with artificial intelligence (AI) offers precise localization capabilities, aiding surgeons in achieving accurate osteotomy positioning. This study aimed to evaluate the feasibility and accuracy of a robotic magnetic navigation system for positioning and osteotomy in an intraoral surgical trial of a mandibular tumor model. Methods Patient computed tomography (CT) imaging data of mandibular chin and body tumors were utilized to create 3D printed models, serving as study subjects for mandibular tumor resection. Ten pairs of models were printed for the experimental and control groups. The experimental group (EG) underwent osteotomy using a robot-assisted surgical navigation system, performing osteotomy under robotic navigation following alignment based on preoperative design. The control group (CG) underwent traditional surgery, estimating osteotomy position empirically according to preoperative design. Postoperative CT scans were conducted on both models, and actual postoperative results were compared to preoperative design. Osteotomy accuracy was evaluated by positional and angular errors between preoperatively designed and actual osteotomy planes. Results For ten randomly selected spots on the left and right sides, respectively, the EG group had mean distance errors of 0.338 mm and 0.941 mm. These values were obtained from the EG group. In the EG group, on the left side, the mean angular errors were 14.741 degrees, while on the right side, they were 13.021 degrees. For the 10 randomly selected spots on the left and right sides, respectively, the CG had mean distance errors of 1.776 mm and 2.320 mm. This is in contrast to the results obtained by the EG. It was determined that the left side had a mean angle error of 16.841 degrees, while the right side had an error of 18.416 degrees in the CG group. The above results indicated significantly lower point errors of bilateral osteotomy planes in the experimental group compared to the control group. Conclusion This study demonstrates the feasibility of electromagnetic navigation robot-assisted intraoral osteotomy for mandibular tumors and suggests that this approach can enhance the precision of clinical surgery.
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Affiliation(s)
- Zhijie Zhao
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Yichi Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Li Lin
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
- Department of Stomatology, the First Affiliated Hospital of Soochow University, Suzhou, China
- National Center for Translational Medicine (Shanghai) SHU Branch, Shanghai University, Shanghai, China
| | - Wenyi Huang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
| | - Can Xiao
- Department of Stomatology, the First Affiliated Hospital of Soochow University, Suzhou, China
| | - Jiannan Liu
- Department of Oral and maxillofacial Head and neck Oncology, Shanghai Ninth People’s Hospital, Shanghai Jiao Tong University School of Medicine; College of Stomatology, Shanghai Jiao Tong University; National Center for Stomatology; National Clinical Research Center for Oral Diseases; Shanghai Key Laboratory of Stomatology; Shanghai Research Institute of Stomatology, Shanghai, China
| | - Gang Chai
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai JiaoTong University School of Medicine, Shanghai, China
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Guerra RC, de Fátima Borim Pulino B, Salomão Júnior VF, Dos Santos Pereira R, Thieringer FM, Sacco R, Sader R, Vieira EH. Finite element analysis of low-profile reconstruction plates for atrophic mandibles: a comparison of novel 3D grid and conventional plate designs. Oral Maxillofac Surg 2024; 28:595-603. [PMID: 37516667 DOI: 10.1007/s10006-023-01173-3] [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: 01/05/2023] [Accepted: 07/16/2023] [Indexed: 07/31/2023]
Abstract
OBJECTIVES This study aimed to compare the reconstruction with type 2.4 and three-dimensional (3D) grid plates relating the areas of weakness to anatomical regions of force incidence in atrophic mandibles with and without segmentation using finite element analysis (FEA). MATERIALS AND METHODS Strength and force quality in the mandible were also determined. The atrophic mandible models with and without segmentation were divided into four groups, and the behavior of each plate was analyzed using finite element analysis. In the atrophic mandible without segmentation using the type 2.4 reconstruction plate, the highest stress concentration in the plate was observed in the posterior region of the mandibular body and in the grid type 3D reconstruction plate was observed in the mandibular angle. RESULTS In the segmented atrophic mandible with the 2.4 reconstruction plate, higher stress concentration was observed in the mandibular segment defect. Analysis of the 3D grid-like reconstruction plate revealed that the geometry of the plate conferred greater stiffness to the assembly, as the most significant stress concentration was observed at the mandibular angle. CONCLUSION The width of the plate design may influence the strength, not the thickness.
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Affiliation(s)
- Raphael Capelli Guerra
- Research and Education Institute - Hospital Sírio Libanes, DASA/Leforte Group, São Paulo State University Araraquara - UNESP, São Paulo Metodista University, São Paulo, Brazil
| | - Bianca de Fátima Borim Pulino
- Research and Education Institute, Hospital Sírio Libanes; São Paulo State University Araçatuba; DASA/Leforte Group, São Paulo Metodista University, Praça Francisco Manuel, 72, São Paulo, 01541-020, Brazil.
| | | | | | | | - Roberto Sacco
- Division of Dentistry, Oral Surgery Department, School of Medical Sciences, The University of Manchester, London, UK
| | - Robert Sader
- Klinikum der Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt Am Main, Frankfurt, Hessen, Germany
| | - Eduardo Hochuli Vieira
- DASA/Leforte Group, Research and Education Institute, Hospital Sírio Libanes; São Paulo State University - UNESP, Araraquara, Brazil
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Mohammadi Khanaghah X, Pourlak T, Mortazavi A. Microplate Versus Combined Microplate-Miniplate in Fixation of Zygomaticomaxillary Complex Fractures: An In-Silico Analysis of Biomechanical Parameters. J Maxillofac Oral Surg 2024; 23:524-530. [PMID: 38911404 PMCID: PMC11189873 DOI: 10.1007/s12663-023-02109-w] [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: 10/11/2023] [Accepted: 12/22/2023] [Indexed: 06/25/2024] Open
Abstract
Introduction To compare the biomechanical parameters of microplates and the combined miniplate-microplate for fixing zygomaticomaxillary complex (ZMC) fractures using nonlinear finite element analysis (FEA). Material and Methods Two samples of ZMC fracture models were prepared. In sample 1 (S1), the fractures were stabilized with microplates, and in sample 2 (S2), with miniplates plus microplates. FEA software was used to measure the displacement, Von Mises stress distribution (VMSD), and maximum principal stress distribution (MPSD). Results The displacement was 6.7 μm in the L-shaped plate of both samples, 4.4 μm in the S1 lateral-edge plate, 4.8 μm in the S2 lateral-edge plate, 5.8 μm in the S1 bottom-edge plate, and 5.6 μm in the S2 bottom-edge plate. The VMSD was 41.1 MPa in the S1 lateral-edge plate, 24.3 MPa in the S2 lateral-edge plate, 7.6 MPa in the S1 Lshaped plate, 9.6 MPa in S2 L-shaped plate, 28.5 MPa in the S1 bottom-edge plate, and 11.8 MPa in the S2 bottom-edge plate. The MPSD was 46.2 MPa in the S1 lateral-edge plate, 26.4 MPa in the S2 lateral-edge plate, 3.6 MPa in S1 L-shaped plate, 4.2 MPa in S2 L-shaped plate, 30.9 MPa in S1 bottom-edge plate, and 14.1 MPa in the S2 bottom-edge plate. Conclusion The L-shaped and lateral-edge plates in both samples had the highest and lowest amount of displacement, respectively. The lateral-edge plates in both samples had the highest VMSD and MPSD, which was higher in S1 than S2. The L-shaped plate had the lowest VMSD and MPSD in both samples.
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Affiliation(s)
- Xaniar Mohammadi Khanaghah
- Maxillofacial Surgery Resident, Maxillofacial Surgery Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Tannaz Pourlak
- Maxillofacial Surgery Department, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Ali Mortazavi
- Maxillofacial Surgery Department, Tabriz University of Medical Sciences, Tabriz, Iran
- Maxillofacial Surgery Department, Tabriz Dentistry School, Golgasht Street, Azadai Street, Tabriz, Iran
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Demir E, Yalçın G, Kalaycı A. Finite element analysis of biplanar customized reconstruction plates for lateral and central segmental defects of mandible. Comput Methods Biomech Biomed Engin 2024; 27:489-497. [PMID: 36920278 DOI: 10.1080/10255842.2023.2188105] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 03/02/2023] [Indexed: 03/16/2023]
Abstract
The purpose of this study is to compare biplanar custom mandibular reconstruction plates with locking reconstruction plates in bridging central and lateral mandibular segmental defects by using the finite element method. Central and two different types of lateral segmental defects were created on mandibular model that was generated from computed tomography of a male patient. Segmental defects were fixed with conventional locking reconstruction plates and two different custom designed plates with caudobuccal and dorsobuccal cover. Stress formation on hardware and screws, strain on bone under masticatory simulation were evaluated with a finite element model. The stress values on plate and screws were higher in conventional reconstruction plate than custom plates. Simulations of central segmental defect revealed maximum von Mises stresses of 643.62 MPa and 101.83 MPa in conventional reconstruction plate and biplanar plate, respectively. Biplanar plates revealed slightly higher von Mises stresses than extended surfaced biplanar plates. The screws close to resection area were exposed to higher stress than farther screws for whole groups. In conventional reconstruction plate, the maximum von Mises stress values of fixation screws were 268.66 MPa and 95 MPa for central segmental defect and lateral segmental defect, respectively. The study reveals that the biplanar custom reconstruction plates had a favourable effect on stress distribution and can enhance function and aesthetics as supporting mandible and flaps from two different planes.
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Affiliation(s)
- Esin Demir
- Department of Oral and Maxillofacial Surgery, Selçuk University Faculty of Dentistry, Konya, Turkey
| | - Gökhan Yalçın
- Department of Mechanics of Materials, Selçuk University Faculty of Technology, Konya, Turkey
| | - Abdullah Kalaycı
- Department of Oral and Maxillofacial Surgery, Selçuk University Faculty of Dentistry, Konya, Turkey
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Wang CF, Liu S, Hu LH, Yu Y, Peng X, Zhang WB. Biomechanical behavior of the three-dimensionally printed surgical plates for mandibular defect reconstruction: a finite element analysis. Comput Assist Surg (Abingdon) 2023; 28:2286181. [PMID: 38010807 DOI: 10.1080/24699322.2023.2286181] [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] [Indexed: 11/29/2023] Open
Abstract
The aim of the study was to investigate the biomechanical behavior of three-dimensionally (3D)-printed surgical plates used for mandibular defect reconstruction, compare them with conventional surgical plates, and provide experimental evidence for their clinical application. Three-dimensional models were created for the normal mandible and for mandibular body defects reconstructed using free fibula and deep circumflex iliac artery flaps. Three-dimensional finite element models of reconstructed mandibles fixed using 3D-printed and conventional surgical plates were established. Vertical occlusal forces were applied to the remaining teeth and the displacement and Von Mises stress distributions were studied using finite element analysis. The normal and reconstructed mandibles had similar biomechanical behaviors. The displacement distributions for the surgical plates were similar, and the maximum total deformation occurred at the screw hole of the anterior segment of the surgical plates. However, there were differences in the Von Mises stress distributions for the surgical plates. In reconstructed mandibles fixed using 3D-printed surgical plates, the maximum equivalent Von Mises stress occurred at the screw hole of the posterior segment, while in those fixed using conventional surgical plates, the maximum equivalent Von Mises stress was at the screw hole of the anterior segment. In the mandible models reconstructed with the same free flap but fixed with different surgical plates, the plates had similar biomechanical behaviors. The biomechanical behavior of 3D-printed surgical plates was similar to conventional surgical plates, suggesting that 3D-printed surgical plates used to reconstruct mandibular body defects with vascularized autogenous bone grafts could lead to secure and stable fixation.
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Affiliation(s)
- Chao-Fei Wang
- Department of Stomatology, Beijing Chao-Yang Hospital, Capital Medical University, Beijing, China
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Shuo Liu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Lei-Hao Hu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Yao Yu
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Xin Peng
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
| | - Wen-Bo Zhang
- Department of Oral and Maxillofacial Surgery, Peking University School and Hospital of Stomatology, Beijing, China
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Ghezta NK, Bhardwaj Y, Ram R, Parmar M, Basi RN, Thakur P. Nine Years of Retrospective Study of Mandibular Fractures in Semi-urban Teaching Hospital, Shimla, Himachal Pradesh, India. Craniomaxillofac Trauma Reconstr 2023; 16:138-146. [PMID: 37222980 PMCID: PMC10201191 DOI: 10.1177/19433875221095984] [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: 09/20/2023] Open
Abstract
Study Design Retrospective study. Objective To evaluate current trends in maxillofacial trauma, a retrospective study of mandibular fractures at Government Dental College and Hospital Shimla H.P was carried out. Methods In this retrospective study, records of 910 patients with mandibular fractures were reviewed between 2007 and 2015 in the Department of Oral and Maxillofacial Surgery out of total 1656 facial fractures. These mandibular fractures were assessed according to age, sex, aetiology in addition to monthly and yearly distribution. Post-operative complications such as malocclusion, neurosensory disturbances and infection were recorded. Results It was observed that mandibular fractures were most frequent in males (67.5%) and in the age group of 21-30 years; accidental fall was the most common etiological factor (43.8%) in the present study and in stark difference to already published reports. The most common fracture site was that of condylar region 239 (26.2%). Open reduction and internal fixation (ORIF) were done in 67.3% cases whereas 32.6% were managed by maxillomandibular fixation and circummandibular wiring. Miniplate osteosynthesis was the most favoured technique. The complication with ORIF was 16%. Conclusions To treat mandibular fractures, currently there are many techniques. However, in minimizing complications and in achieving satisfactory functional and aesthetic results experienced surgical team plays an important role.
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Affiliation(s)
- Narotam K. Ghezta
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
| | - Yogesh Bhardwaj
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
| | - Rangila Ram
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
| | - Monika Parmar
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
| | - Rowena N. Basi
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
| | - Pooja Thakur
- Department of Oral and
Maxillofacial Surgery, H.P. Government Dental College and
Hospital, Shimla, India
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Rothweiler RM, Zankovic S, Brandenburg LS, Fuessinger MA, Gross C, Voss PJ, Metzger MC. Feasibility of Implant Strain Measurement for Assessing Mandible Bone Regeneration. MICROMACHINES 2022; 13:1602. [PMID: 36295956 PMCID: PMC9610677 DOI: 10.3390/mi13101602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 09/21/2022] [Accepted: 09/23/2022] [Indexed: 06/16/2023]
Abstract
Nonunion is one of the most dreaded complications after operative treatment of mandible fractures or after mandible reconstruction using vascularized and non-vascularized bone grafts. Often diagnosis is made at advanced stage of disease when pain or complications occur. Devices that monitor fracture healing and bone regeneration continuously are therefore urgently needed in the craniomaxillofacial area. One promising approach is the strain measurement of plates. An advanced prototype of an implantable strain measurement device was tested after fixation to a locking mandible reconstruction plate in multiple compression experiments to investigate the potential functionality of strain measurement in the mandibular region. Compression experiments show that strain measurement devices work well under experimental conditions in the mandibular angle and detect plate deformation in a reliable way. For monitoring in the mandibular body, the device used in its current configuration was not suitable. Implant strain measurement of reconstruction plates is a promising methodical approach for permanent monitoring of bone regeneration and fracture healing in the mandible. The method helps to avoid or detect complications at an early point in time after operative treatment.
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Affiliation(s)
- René Marcel Rothweiler
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Sergej Zankovic
- G.E.R.N. Center for Tissue Replacement, Regeneration & Neogenesis, Faculty of Medicine, Albert-Ludwigs-University of Freiburg, 79108 Freiburg, Germany
| | - Leonard Simon Brandenburg
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Marc-Anton Fuessinger
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Christian Gross
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Pit Jacob Voss
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
| | - Marc-Christian Metzger
- Department of Oral and Maxillofacial Surgery, Faculty of Medicine, University of Freiburg, 79106 Freiburg, Germany
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Chen CF, Chen CM, Chen HS, Huang WC, Chen YC, Chang HC, Liu SH, Yang TL, Wang LL, Chen PH. The Use of Customized Three-Dimensionally Printed Mandible Prostheses with a Pressure-Reducing Device: A Finite Element Analysis in Different Chewing Positions, Biomechanical Testing, and In Vivo Animal Study Using Lanyu Pigs. BIOMED RESEARCH INTERNATIONAL 2022; 2022:9880454. [PMID: 35342763 PMCID: PMC8942632 DOI: 10.1155/2022/9880454] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Revised: 02/06/2022] [Accepted: 02/11/2022] [Indexed: 01/05/2023]
Abstract
Segmental bony defects of the mandible constitute a complete loss of the regional part of the mandible. Although several types of customized three-dimension-printed mandible prostheses (CMPs) have been developed, this technique has yet to be widely used. We used CMP with a pressure-reducing device (PRD) to investigate its clinical applicability. First, we used the finite element analysis (FEA). We designed four models of CMP (P1 to P4), and the result showed that CMP with posterior PRD deployment (P4 group) had the maximum total deformation in the protrusion and right excursion positions, and in clenching and left excursion positions, posterior screws had the minimum von Mises stress. Second, the P4 CMP-PRD was produced using LaserCUSING from titanium alloy (Ti-6Al-4V). The fracture test result revealed that the maximum static pressure that could be withstood was 189 N, and a fatigue test was conducted for 5,000,000 cycles. Third, animal study was conducted on five male 4-month-old Lanyu pigs. Four animals completed the experiment. Two animals had CMP exposure in the oral cavity, but there was no significant inflammation, and one animal had a rear wing fracture. According to a CT scan, the lingual cortex of the mandible crawled along the CMP surface, and a bony front-to-back connection was noted in one animal. A histological examination indicated that CMP was significantly less reactive than control materials (p = 0.0170). Adequate PRD deployment in CMP may solve a challenge associated with CMP, thus promoting its use in clinical practice.
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Affiliation(s)
- Chun-Feng Chen
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
- Department of Oral and Maxillofacial Surgery, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
- Dental Laboratory Technology, Shu Zen College of Medicine and Management, Kaohsiung, Taiwan
| | - Chun-Ming Chen
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Han-Sheng Chen
- Dental Department, Kaohsiung Municipal Siaogang Hospital, Kaohsiung, Taiwan
| | - Wei-Chin Huang
- Laser and Additive Manufacturing Technology Center, Industrial Technology Research Institute, Taiwan
| | - Yung-Chung Chen
- School of Dentistry and Institute of Oral Medicine, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Hung-Chih Chang
- Department of biomedical engineering, Hungkuang University, Taichung, Taiwan
| | - Sung-Ho Liu
- Laser and Additive Manufacturing Technology Center, Industrial Technology Research Institute, Taiwan
| | - Tsung-Lung Yang
- KSVGH Originals & Enterprises, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Ling-Lin Wang
- KSVGH Originals & Enterprises, Kaohsiung Veterans General Hospital, Kaohsiung, Taiwan
| | - Ping-Ho Chen
- School of Dentistry, College of Dental Medicine, Kaohsiung Medical University, Kaohsiung, Taiwan
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Bone Remodeling Following Mandibular Reconstruction using Fibula Free Flap. J Biomech 2022; 133:110968. [DOI: 10.1016/j.jbiomech.2022.110968] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2020] [Revised: 12/11/2021] [Accepted: 01/17/2022] [Indexed: 01/08/2023]
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Kargarnejad S, Ghalichi F, Pourgol-Mohammad M, Garajei A. Mandibular reconstruction system reliability analysis using probabilistic finite element method. Comput Methods Biomech Biomed Engin 2021; 24:1437-1449. [PMID: 34657530 DOI: 10.1080/10255842.2021.1892660] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The aim of this study was to design for mandibular reconstruction of large lateral defect with minimum target reliability with designated confidence interval under bite force range of 300 ± 102 N. The performance of the models has been evaluated by numerical analysis considering the uncertainty of input parameters. Computer-Aided design was used to develop the models of three designs according to the patient's anatomy and to achieve to near symmetry of the mandible. Stress-strength modeling was utilized for the probabilistic physics of failure analysis under assumption of a quasi-static load. Monte-Carlo simulation was also applied for probabilistic finite element analysis and reliability assessment. The sensitivity analysis of the models was developed to reflect the significance of the variables in the models. The deterministic stress analysis shows that the highest stress and the second maximum stress are 110 MPa and 85 MPa for cortical bone around the screws, respectively. Also, it is determined that the maximum plate stress of the titanium conventional plate model is 580 MPa. The reconstruction system success rate was improved in all models by observing the anatomy of the patient's mandible in the plate designs by computer-aided design and additive manufacturing techniques. Based on the results, the reliability of plate strength and pull-out screws strength are 99.99% and 96.71% for the fibula free flap model, respectively, and 99.99% and 94.17%, respectively, for the customized prosthesis model. Probability sensitivity factors showed that uncertainty in the elastic modulus of the cortical bone has the greatest effect on the probability of screws loosening.
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Affiliation(s)
- S Kargarnejad
- Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - F Ghalichi
- Faculty of Biomedical Engineering, Sahand University of Technology, Tabriz, Iran
| | - M Pourgol-Mohammad
- Mechanical Engineering Department, Sahand University of Technology, Tabriz, Iran
| | - A Garajei
- Department of Oral and Maxillofacial Surgery, School of Dentistry and Department of Head and Neck Surgical Oncology and Reconstructive Surgery, Tehran University of Medical Sciences, Tehran, Iran
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Demir E, Yalçın G, Kalaycı A, Sağlam H. Biomechanical evaluation of caudally and buccally screwed customised reconstruction plates for lateral segmental defects of mandible. Br J Oral Maxillofac Surg 2021; 59:928-934. [PMID: 34454776 DOI: 10.1016/j.bjoms.2020.10.017] [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: 09/21/2020] [Accepted: 10/23/2020] [Indexed: 10/23/2022]
Abstract
The aim of this study was to compare locking reconstruction plates with caudobuccally screwed custom mandibular reconstruction plates in bridging lateral mandibular segmental defects. The in vitro study was conducted on 13 polyurethane mandibles. A total of 7 mandibles with lateral segmental defects were bridged with locking reconstruction plates in group I, 6 mandibles with the same standard defect were bridged with caudobuccally screwed customised reconstruction plates in group II. Mean yield displacement, yield load, and displacement at 80 N (Newtons), 100 N, 200 N, 300 N loading were compared among the 2 groups. The mean (SD) displacement for Group I was 11.27 (3.6) mm, Group II was 21.08 (2.5) mm. Group II had significantly greater (p=0.0001) displacement when compared with Group I. The mean (SD) force before failure for Group I was 638.4 N (127.2), Group II was 1398. 3 N (162.7). Group II withstood significantly greater force than Group I (p=0.0001). The study reveals that the caudobuccally screwed custom reconstruction plates can significantly enhance yield load as preserving the preoperative shape of the face and mandible.
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Affiliation(s)
- E Demir
- Department of Oral and Maxillofacial Surgery, Selçuk University Faculty of Dentistry, Konya, Turkey.
| | - G Yalçın
- Department of Mechanics of Materials, Selçuk University Faculty of Technology, Konya, Turkey
| | - A Kalaycı
- Department of Oral and Maxillofacial Surgery, Selçuk University Faculty of Dentistry, Konya, Turkey
| | - H Sağlam
- Department of Mechanics of Materials, Selçuk University Faculty of Technology, Konya, Turkey
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12
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Development, conception and modulization of patient-specific miniplate in maxillofacial surgery. ADVANCES IN ORAL AND MAXILLOFACIAL SURGERY 2021. [DOI: 10.1016/j.adoms.2021.100136] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] Open
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13
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Wang M, Yu D, Zheng L, Hong B, Li H, Hu X, Zhang K, Mou Y. Mechanical Stress Affects Circadian Rhythm in Skeletal Muscle (C2C12 Myoblasts) by Reducing Per/Cry Gene Expression and Increasing Bmal1 Gene Expression. Med Sci Monit 2021; 27:e928359. [PMID: 33444293 PMCID: PMC7814509 DOI: 10.12659/msm.928359] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2020] [Accepted: 10/21/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Circadian rhythm can modulate normal activity of humans in adapting to daily environment changes. Mechanical stress loading affects skeletal muscle development and bio-functions. This study aimed to investigate the effects of mechanical stress loading on circadian rhythm in skeletal muscle (C2C12 cells) and to explore the associated mechanism. MATERIAL AND METHODS C2C12 myoblasts were cultured and treated with mechanical stress loading. After mechanical stress loading for 6 h,12 h, and 24 h, we observed the C2C12 myoblasts and determined gene transcription and protein expression of Clock genes, including Clock, Bmal1, Per, and Cry using RT-PCR and western blot assay. RESULTS Mechanical stress loading triggered C2C12 cells growing by force direction and enhanced the cell proliferation at 6 h, 12 h, and 24 h. Gene transcription and protein expression of the core Clock-associated molecules, Clock and Bmal1, increased from start of loading to 12 h, and decreased from 12 h to 24 h. Gene transcription and protein expression of core Clock-associated molecules, Cry and Per, decreased in the first 12 h (from 6 h to 12 h) and increased in the last 12 h (from 12 h to 24 h). CONCLUSIONS Our study revealed that mechanical stress loading affected circadian rhythm in skeletal muscle (C2C12 myoblasts) through reducing Per/Cry and enhancing Clock/Bmal1 gene expression. This study provides insights for investigating circadian rhythm and associated bio-functions of humans.
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Affiliation(s)
- Mengjia Wang
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Da Yu
- Sir Run Run Hospital, Nanjing Medical University, Nanjing, Jiangsu, P.R. China
| | - Lichun Zheng
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Bing Hong
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Houxuan Li
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Xiaobei Hu
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Kun Zhang
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
| | - Yongbin Mou
- Nanjing Stomatological Hospital, Medical School of Nanjing University, Nanjing, Jiangsu, P.R. China
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Muftuoglu G, Bayram B, Aydin P. Comparison of locking and non-locking reconstruction plate-screw system in lateral mandibular defects by finite element analysis. JOURNAL OF STOMATOLOGY, ORAL AND MAXILLOFACIAL SURGERY 2020; 122:e65-e69. [PMID: 33161169 DOI: 10.1016/j.jormas.2020.10.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 10/03/2020] [Accepted: 10/26/2020] [Indexed: 10/23/2022]
Abstract
PURPOSE The purpose of this study is to analyze and compare stress distribution on bone screws and plate systems in locking and non-locking screw-plates design in lateral mandibular defects. MATERIAL AND METHODS Solid mathematical model of mandible was created by three-dimensional finite elements analysis and 25 mm length of lateral resection (L defect) was performed on the model. Models were reconstructed with 2.4 locking and non-locking reconstruction plate system. Each masticator muscles attached to mandible were simulated as direction, attachment area and magnitude on 3D model to compare with reality. The stress formation on bone and hardware system were evaluated. RESULT The stress values on the cortical bone, plate and screw system were higher in conventional plate model than the locking system model. The highest stress values were measured in the proximal segment especially in conjunction with conventional screw system. Furthermore, the distribution of stress on the bone surface was more homogenous in the locking system. CONCLUSION It is evident that the use of the locking system in 25 mm length lateral mandibular defects provides an additional advantage over conventional systems in reconstruction models.
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Affiliation(s)
- G Muftuoglu
- Private Practice, Dentgroup, Istanbul, Turkey
| | - B Bayram
- Baskent University Faculty of Dentistry Department of Oral and Maxillofacial Surgery, Ankara, Turkey
| | - P Aydin
- Baskent University Faculty of Dentistry Department of Oral and Maxillofacial Surgery, Ankara, Turkey.
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Koper DC, Leung CAW, Smeets LCP, Laeven PFJ, Tuijthof GJM, Kessler PAWH. Topology optimization of a mandibular reconstruction plate and biomechanical validation. J Mech Behav Biomed Mater 2020; 113:104157. [PMID: 33187871 DOI: 10.1016/j.jmbbm.2020.104157] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 10/18/2020] [Accepted: 10/22/2020] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Reconstruction plates, used to bridge segmental defects of the mandible after tumor resection or traumatic bone tissue loss, are subjected to repeated stresses of mastication. High stress concentrations in these plates can result in hardware failure. Topology optimization (TO) could reduce the peak stress by computing the most optimal material distribution in a patient-specific implant (PSI) used for mandibular reconstruction. The objective of this study was biomechanical validation of a TO-PSI. METHODS A computer-aided design (CAD) model with a segmental defect was created based on the geometry of a polyurethane mandible model. A standard-PSI was designed to bridge the defect. A TO-PSI was then designed with a maximum stress equal to the ultimate tensile stress of Ti6Al4V (930 MPa) during a loading condition of 378 N. Finite element analysis (FEA) was used to analyze stresses in both PSI designs during loading. The standard-PSI and TO-PSI designs were produced in triplicate by selective laser melting of Ti6Al4V, fixated to polyurethane mandible models with segmental defects identical to the CAD model, and subsequently subjected to continuous compression with a speed of 1 mm/min on a universal testing machine, while recording the load. Peak loads before failure in the TO-PSI group within a 30% range of the predicted peak load (378 N) were considered a successful biomechanical validation. RESULTS Fracture of the TO-PSI occurred at a median peak load of 334 N (range 304-336 N). These values are within the 30% range of the predicted peak load. Fracture of the mandible model in the standard-PSI group occurred at a median peak load of 1100 N (range 1010-1460 N). Failure locations during biomechanical testing of TO-PSI and standard-PSI samples corresponded to regions in the FEA where stresses exceeded the ultimate tensile strength of titanium and polyurethane, respectively. CONCLUSION This study demonstrates a successful preliminary biomechanical validation of TO in the design process for mandibular reconstruction plates. Further work is needed to refine the finite element model, which is necessary to ultimately design TO-PSIs for clinical use.
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Affiliation(s)
- David C Koper
- Department of Cranio-Maxillofacial Surgery, Maastricht University Medical Center, PO Box 5800, 6202 AZ, Maastricht, the Netherlands; Department of Instructive Biomaterials Engineering, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands; Department of Complex Tissue Regeneration, MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands; GROW School for Oncology and Developmental Biology, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands.
| | - Carine A W Leung
- Department of Cranio-Maxillofacial Surgery, Maastricht University Medical Center, PO Box 5800, 6202 AZ, Maastricht, the Netherlands
| | - Lars C P Smeets
- Department of Instrument Design, Engineering and Evaluation, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands
| | - Paul F J Laeven
- Department of Instrument Design, Engineering and Evaluation, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands
| | - Gabriëlle J M Tuijthof
- Department of Instrument Design, Engineering and Evaluation, Maastricht University, PO Box 616, 6200 MD, Maastricht, the Netherlands
| | - Peter A W H Kessler
- Department of Cranio-Maxillofacial Surgery, Maastricht University Medical Center, PO Box 5800, 6202 AZ, Maastricht, the Netherlands
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Prasadh S, Suresh S, Hong KL, Bhargav A, Rosa V, Wong RCW. Biomechanics of alloplastic mandible reconstruction using biomaterials: The effect of implant design on stress concentration influences choice of material. J Mech Behav Biomed Mater 2020; 103:103548. [DOI: 10.1016/j.jmbbm.2019.103548] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2019] [Revised: 11/19/2019] [Accepted: 11/19/2019] [Indexed: 12/28/2022]
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Evaluation of labial versus labio-inferior lines of osteosynthesis using 3D miniplate for fractures of anterior mandible: A finite element analysis with a pilot clinical trial. Chin J Traumatol 2019; 22:261-269. [PMID: 31493976 PMCID: PMC6823702 DOI: 10.1016/j.cjtee.2019.08.001] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2019] [Revised: 06/29/2019] [Accepted: 07/10/2019] [Indexed: 02/04/2023] Open
Abstract
PURPOSE The fractures of anterior mandible are subject to severe torsional forces due to muscles acting in opposite directions. 3D miniplate has been suggested as a good alternative by some researchers. However, finite element model (FEM) studies indicate that labio-inferior positioning of two miniplates perpendicular to each other offers better stability as compared to labial positioning. This study aims at combining the advantages of a single 3D miniplate and labio-inferior positioning of two conventional miniplates, which was assessed by finite element analysis along with a pilot clinical trial. METHODS Two FEM models were created using CT data of a 24-year-old patient with Angle class I occlusion: control model with labial plating and study model with labio-inferior plating. The models were processed with MIMICS® (materialise, Leuven, Belgium), CATIA® (Dassault Systemes) and finite element analysis softwares. Parameters adopted for analysis were (1) displacement (mm) of fracture fragments during each screw fixation, (2) lingual splay and post fixation stability of fracture fragments with masticatory load, and (3) stress distribution (MPa) across fracture fragments. Moreover, a pilot clinical trial including five patients with anterior mandible fracture was conducted. The fractures were managed by intraoral open reduction and 3D miniplate fixation in labio-inferior position. Intraoperative interfragmentary gap, post fixation lingual splay and radiographic fracture union and complications were assessed clinically. RESULTS Labio-inferior plating demonstrated less displacement (mm) of fracture fragments during screw fixation (0.059 vs. 0.079) as well as after application of masticatory load (1.805 vs. 1.860). Negligible lingual splay and less stress distribution (MPa) across fracture fragments (1.860 vs. 1.847) were appreciated in the study group as compared to control group. Clinical trial support the favorable outcome related to intraoperative and postoperative assessment parameters. CONCLUSION FEM analysis and clinical trial reveal better results with labio-inferior positioning of 3D miniplate when compared to labial positioning.
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Patussi C, Sassi LM, Cruz R, Klein Parise G, Costa D, Rebellato NLB. Evaluation of different stable internal fixation in unfavorable mandible fractures under finite element analysis. Oral Maxillofac Surg 2019; 23:317-324. [PMID: 31240571 DOI: 10.1007/s10006-019-00774-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2018] [Accepted: 05/02/2019] [Indexed: 06/09/2023]
Abstract
INTRODUCTION The mandibular angle fracture is the most common fracture between this type of injury in jaw bone and also is the type of fracture treatment that presents a larger number of complications, and a series different osteosynthesis types have been studied over the years by the world literature. The finite element method is a form of mathematical analysis, which is based on dividing a structure into a finite number of small areas. It has the ability tomathematically model structures, making it possible to apply forces anywhere. MATERIAL AND METHODS For this study, a three-dimensional mandible with an unfavorable angle fracture was simulated. Five different types of fixations were evaluated: group 1, Champy technique with one 4-holes miniplate, 2.0 system; group 2, technique with two parallel 4-holes conventional miniplates, 2.0 system; group 3, technique with two parallel 4-holes locking miniplates, 2.0 system; group 4, technique with one reconstruction 6-holes plate, 2.8 system in base jaw; and group 5, technique with one reconstruction 6-holes plates, 2.8 system in jaw body + one parallel 4-holes conventional miniplate, 2.0 system. RESULTS The results showed that strains are better distributed through the locking miniplate and screws system and presented less stress concentration when compared with the conventional ones. The Champy technique had the worst results about of all groups. The use of the locking system shows less stress compared to the non-locking system, and the presence of a reconstruction plate associated with a mini plate does not lead to increased stability compared with an isolated reconstruction plate.
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Affiliation(s)
- Cleverson Patussi
- Cirurgia Bucomaxilofacial, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
| | - Laurindo Moacir Sassi
- Oral Maxillofacial Surgery, Erasto Gaertner Hospital, Rua Dr. Ovande do Amaral, 201 Jardim das Américas, Curitiba, PR, Brazil
| | - Rafael Cruz
- Cirurgia Bucomaxilofacial, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
| | - Guilherme Klein Parise
- Oral Maxillofacial Surgery, Erasto Gaertner Hospital, Rua Dr. Ovande do Amaral, 201 Jardim das Américas, Curitiba, PR, Brazil
| | - Delson Costa
- Cirurgia Bucomaxilofacial, Universidade Federal do Paraná, Curitiba, Paraná, Brazil
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Which plate results in better stability after segmental mandibular resection and fibula free flap reconstruction? Biomechanical analysis. Oral Surg Oral Med Oral Pathol Oral Radiol 2018; 126:380-389. [DOI: 10.1016/j.oooo.2018.05.048] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2018] [Revised: 05/21/2018] [Accepted: 05/29/2018] [Indexed: 11/17/2022]
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Clinical experience with a novel structure designed bridging plate system for segmental mandibular reconstruction: The TriLock bridging plate. J Craniomaxillofac Surg 2018; 46:1679-1690. [DOI: 10.1016/j.jcms.2018.07.001] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2018] [Revised: 06/05/2018] [Accepted: 07/02/2018] [Indexed: 11/17/2022] Open
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Determining the Patient-Specific Optimum Osteotomy Line for Severe Mandibular Retrognathia Patients. J Craniofac Surg 2018. [DOI: 10.1097/scs.0000000000004470] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
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22
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Hoefert S, Taier R. Mechanical stress in plates for bridging reconstruction mandibular defects and purposes of double plate reinforcement. J Craniomaxillofac Surg 2018; 46:785-794. [PMID: 29567342 DOI: 10.1016/j.jcms.2018.01.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2017] [Revised: 01/03/2018] [Accepted: 01/25/2018] [Indexed: 10/18/2022] Open
Abstract
PURPOSE To evaluate the biomechanical performance of a commercially available bridging plate (2.4) as well as screws and bone simulating the reconstruction of hemimandibular defects and to indicate alternatives of reinforcement to prevent plate fractures either by strength or fatigue. MATERIAL AND METHODS Two common hemimandibular defects are investigated using computed finite element analysis (FEA) approach. Simplified and refined computational models are developed for the geometry of the screw. Conditions of non-locking and locking plate-screw interfaces are considered. Static loads of 120 N are applied. Von Mises stresses and fatigue are calculated. As reinforcement, a second complete or partial plate is placed onto the original plate. RESULTS Results demonstrate that reconstruction plates are often subjected to excessive stress that may lead to fracture either by strength or by fatigue. An attached complete or partial second plate is able to reduce stress in the plate, in screws and bone so that stress remains below the allowable limit of the materials. CONCLUSION A simplified technique of attaching a whole or sectioned second plate onto the original plate can reduce the stress calculated and may reduce the frequency of plate fractures for the patient's comfort, security and financial savings.
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Affiliation(s)
- Sebastian Hoefert
- Department of Oral and Maxillofacial Surgery, University Hospital Tuebingen, Osianderstrasse 2-8, 72076 Tuebingen, Germany.
| | - Roberto Taier
- Rua Gustavo Sampaio 223/1001, 22010.010 Rio de Janeiro, Brazil
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Stability of the permanently bent plates used in mandibular reconstructive surgery. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2017; 2016:2198-2201. [PMID: 28268767 DOI: 10.1109/embc.2016.7591165] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
In mandibular reconstructive surgery, straight surgical plates are predominantly used for osteotomy. In this process, a straight plate is bent to fit to the shape of the patient's defect. This potentially compromises the stability of the plate because of changes in mechanical properties resulting from plastic deformation; however, the effect of plastic deformation on stability has yet been investigated. In this study, we assess the stability of three types of commonly used bent plates for two types of mandible defect cases, using three-dimensional finite element analysis (FEA). We compare the stability of plastically deformed plates with customized plates having the same shape, but not the residual stresses from plastic deformation. The results indicate that while the bearing strength of the bent plate is sufficient, there is much higher stress in the plate due to the residual stresses from the bending process that may significantly decrease the safety of the reconstruction surgery.
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Gutwald R, Jaeger R, Lambers FM. Customized mandibular reconstruction plates improve mechanical performance in a mandibular reconstruction model. Comput Methods Biomech Biomed Engin 2016; 20:426-435. [PMID: 27887036 PMCID: PMC5359746 DOI: 10.1080/10255842.2016.1240788] [Citation(s) in RCA: 48] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The purpose of this paper was to analyze the biomechanical performance of customized mandibular reconstruction plates with optimized strength. The best locations for increasing bar widths were determined with a sensitivity analysis. Standard and customized plates were mounted on mandible models and mechanically tested. Maximum stress in the plate could be reduced from 573 to 393 MPa (−31%) by increasing bar widths. The median fatigue limit was significantly greater (p < 0.001) for customized plates (650 ± 27 N) than for standard plates (475 ± 27 N). Increasing bar widths at case-specific locations was an effective strategy for increasing plate fatigue performance.
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Affiliation(s)
- Ralf Gutwald
- a Department of Oral and Maxillofacial Surgery , University Hospital of Freiburg , Freiburg , Germany
| | - Raimund Jaeger
- b Fraunhofer Institute for Mechanics of Materials IWM , Polymer Tribology & Biomedical Materials - Group , Freiburg , Germany
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Kwon IJ, Eo MY, Park SJ, Kim SM, Lee JH. Newly designed retentive posts of mandibular reconstruction plate in oral cancer patients based on preliminary FEM study. World J Surg Oncol 2016; 14:292. [PMID: 27871294 PMCID: PMC5117542 DOI: 10.1186/s12957-016-1043-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2016] [Accepted: 11/07/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The reconstruction of a large mandibular defect poses a challenging issue in oral cancer ablation surgery. One popular option for mandibular continuity reconstruction after tumor resection involves the use of a reconstruction plate (R-plate), which maintains space and contour without bone harvesting. An R-plate, however, cannot provide final functional loading rehabilitation with implants or dentures. METHODS We suggest a new method of functional mandibular reconstruction using retentive posts and an upper prosthesis. The finite element method (FEM) was used to optimize the design. Surgery was needed to adapt the retentive posts. Prosthodontic procedures were required for the upper prosthesis. RESULTS Eight patients were treated with retentive posts and prostheses. All patients underwent wide resections of the mandible, and reconstruction with an R-plate and microvascular soft tissue transfer. We adapted the retentive posts on an R-plate and fabricated the upper prostheses with a flexible denture or a fixed resin prosthesis. Finally, the patients had functional rehabilitation, which restored proper mastication. CONCLUSIONS The retentive posts of the R-plate and upper prosthesis allow functional dental rehabilitation without the need for a bone graft. Virtual simulation using FEM will help to design and optimize the retentive posts. Two or three regular size posts are suitable for the quadrant jaw. This first preliminary step will allow improved patient-specific retentive post designs in the near future.
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Affiliation(s)
- Ik Jae Kwon
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 110-768, South Korea
| | - Mi Young Eo
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 110-768, South Korea
| | | | - Soung Min Kim
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 110-768, South Korea.
| | - Jong Ho Lee
- Department of Oral and Maxillofacial Surgery, Dental Research Institute, School of Dentistry, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 110-768, South Korea
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Kwon IJ, Lee BH, Eo MY, Kim SM, Lee JH, Lee SK. Pathologic mandibular fracture after biting crab shells following ramal bone graft. Dent Traumatol 2016; 32:421-4. [DOI: 10.1111/edt.12263] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/05/2016] [Indexed: 10/22/2022]
Affiliation(s)
- Ik Jae Kwon
- Department of Oral and Maxillofacial Surgery; Dental Research Institute; School of Dentistry; Seoul National University; Seoul Korea
| | | | - Mi Young Eo
- Department of Oral and Maxillofacial Surgery; Dental Research Institute; School of Dentistry; Seoul National University; Seoul Korea
| | - Soung Min Kim
- Department of Oral and Maxillofacial Surgery; Dental Research Institute; School of Dentistry; Seoul National University; Seoul Korea
| | - Jong Ho Lee
- Department of Oral and Maxillofacial Surgery; Dental Research Institute; School of Dentistry; Seoul National University; Seoul Korea
| | - Suk Keun Lee
- Department of Oral Pathology; College of Dentistry; Gangneung-Wonju National University; Gangneung Korea
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Biomechanical Evaluation of Different Fixation Methods for Mandibular Anterior Segmental Osteotomy Using Finite Element Analysis, Part Two. J Craniofac Surg 2016; 27:36-40. [DOI: 10.1097/scs.0000000000002173] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Hirota M, Shima T, Sato I, Ozawa T, Iwai T, Ametani A, Sato M, Noishiki Y, Ogawa T, Hayakawa T, Tohnai I. Development of a biointegrated mandibular reconstruction device consisting of bone compatible titanium fiber mesh scaffold. Biomaterials 2016; 75:223-236. [DOI: 10.1016/j.biomaterials.2015.09.034] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2015] [Revised: 09/21/2015] [Accepted: 09/23/2015] [Indexed: 11/30/2022]
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Effect of Photofunctionalization on Ti6Al4V Screw Stability Placed in Segmental Bone Defects in Rat Femurs. J Oral Maxillofac Surg 2015; 74:861.e1-16. [PMID: 26704430 DOI: 10.1016/j.joms.2015.11.016] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2015] [Revised: 11/18/2015] [Accepted: 11/18/2015] [Indexed: 11/24/2022]
Abstract
PURPOSE Ultraviolet-mediated photofunctionalization is a new technology to improve bone and titanium integration. We hypothesized that photofunctionalization would enhance the stability of titanium screws used for segmental bone defects. MATERIALS AND METHODS Disks were prepared of a titanium alloy (Ti6Al4V) for an in vitro study to evaluate the attachment, proliferation, and differentiation of osteoblasts. Commercially available Ti6Al4V screws were used in vivo. Segmental bone defects were created in rat femurs as an immediate loading reconstruction model. The defects were reconstructed with commercially available titanium plates and Ti6Al4V screws, with or without photofunctionalization. The screw survival rates and mechanical stability were evaluated at 2 and 4 weeks, and the bone formation around the screws was analyzed. RESULTS Osteoblasts showed greater attachment, proliferation, and differentiation on the photofunctionalized Ti6Al4V disks. Photofunctionalized screws had significantly greater survival rates and mechanical stability at 2 and 4 weeks. The bone formation around the photofunctionalized screws was significantly greater than that around the untreated screws at 4 weeks. CONCLUSIONS The results of the present study have demonstrated the efficacy of photofunctionalization on enhancing the survival and stability of Ti6Al4V screws under a loaded condition in the reconstruction of segmental defects. This was associated with increased bioactivity and bone formation around the photofunctionalized Ti6Al4V material.
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Pinheiro M, Alves JL. The feasibility of a custom-made endoprosthesis in mandibular reconstruction: Implant design and finite element analysis. J Craniomaxillofac Surg 2015; 43:2116-28. [PMID: 26596361 DOI: 10.1016/j.jcms.2015.10.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Revised: 09/09/2015] [Accepted: 10/02/2015] [Indexed: 11/15/2022] Open
Abstract
This work studies the feasibility of custom-made endoprosthesis in the reconstruction of major mandibular defects. The natural anatomical and occlusal relations are used to accurately reconstruct a mandibular defect. The customized implant allows the accurate restoration of the facial profile and aesthetics. The biomechanical behaviour of mandibular endoprosthesis was validated with Finite Element Analysis for three masticatory tasks, namely incisal, right molar and left group clenching. The implanted mandible shows displacement fields and stress distributions very similar to the intact mandible. The strain fields observed along the bone-implant interface may promote bone maintenance and ingrowth. The preliminary results show that this implant may be a reliable alternative to other prosthetic mandibular reconstruction approaches.
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Affiliation(s)
- Manuel Pinheiro
- Department of Mechanical Engineering, University of Minho, Guimarães, Braga, Portugal.
| | - J L Alves
- Department of Mechanical Engineering, University of Minho, Guimarães, Braga, Portugal
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Mandibular Nonvascularized Bone Grafts of Critical Sizes and Complex Warfare Defects With Interrami Intraoral Fixation. J Craniofac Surg 2015; 26:1173-7. [DOI: 10.1097/scs.0000000000001564] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Risk factors and surgical refinements of postresective mandibular reconstruction: a retrospective study. PLASTIC SURGERY INTERNATIONAL 2014; 2014:893746. [PMID: 25228992 PMCID: PMC4150385 DOI: 10.1155/2014/893746] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 07/18/2014] [Accepted: 07/18/2014] [Indexed: 11/17/2022]
Abstract
Background. Postresective mandibular reconstruction is common in cases of oral and mandibular tumors. However, complications such as infection, plate exposure, or plate fracture can occur. We identified several significant risk factors of complications after reconstructive surgery and compared the effectiveness of different surgical techniques for reducing the incidence of complications. Methods. This study is a retrospective analysis of 28 oromandibular cancer cases that required reconstructive surgery between January 1999 and December 2011 at Kobe University Graduate School of Medicine in Japan. All cases were classified using Hashikawa's CAT and Eichner's classification methods. Then, we determined whether these classifications and different treatment or surgical methods were significantly related to complications. Results. Complications after mandibular reconstruction occurred in 10/28 patients (36%). Specifically, five patients had plate fractures, four had plate exposures, and one had an infection. Radiation therapy and closure without any flaps were significantly related to infection or plate exposure. The wrap-around technique of securing reconstruction plates was used in 14 cases, whereas the run-through technique was used in two cases. Conclusions. The success of mandibular reconstruction depends on both mechanical and biological factors, such as the location of defects, presence of occlusions, and the amount of vascularization of the flap.
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Bujtár P, Simonovics J, Váradi K, Sándor GK, Avery C. The biomechanical aspects of reconstruction for segmental defects of the mandible: A finite element study to assess the optimisation of plate and screw factors. J Craniomaxillofac Surg 2014; 42:855-62. [DOI: 10.1016/j.jcms.2013.12.005] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Revised: 11/09/2013] [Accepted: 12/13/2013] [Indexed: 10/25/2022] Open
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Markwardt J, Weber T, Modler N, Sembdner P, Lesche R, Schulz MC, Reitemeier B. One vs. two piece customized implants to reconstruct mandibular continuity defects: A preliminary study in pig cadavers. J Craniomaxillofac Surg 2014; 42:790-5. [DOI: 10.1016/j.jcms.2013.11.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2013] [Revised: 08/24/2013] [Accepted: 11/04/2013] [Indexed: 10/26/2022] Open
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Local and systemic risk factors influencing the long-term success of angular stable alloplastic reconstruction plates of the mandible. J Craniomaxillofac Surg 2014; 42:e271-6. [DOI: 10.1016/j.jcms.2013.10.004] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Revised: 07/27/2013] [Accepted: 10/08/2013] [Indexed: 11/17/2022] Open
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Biomechanical analysis of a curvilinear distractor device for correcting mandibular symphyseal defects. J Oral Maxillofac Surg 2014; 72:1158-67. [PMID: 24388177 DOI: 10.1016/j.joms.2013.10.014] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2013] [Revised: 10/19/2013] [Accepted: 10/23/2013] [Indexed: 11/21/2022]
Abstract
PURPOSE The local mechanical environment is a determinant of successful transport disc distraction osteogenesis. This study assessed the biomechanics of a curvilinear distractor device for correcting mandibular symphyseal defects. MATERIALS AND METHODS The finite element method was used to analyze an intact mandible, mandibular distractor bodies with different rail thicknesses (4, 6, 8, and 10 mm), and mandibular distractor bodies with rails and auxiliary lingual brackets. RESULTS Rail thickness was positively correlated with maximum von Mises stress in the distractor and negatively correlated with maximum displacement of the mandibular distractor bodies. The maximum von Mises stress occurred at the junction of the rails and fixed arms. It also exceeded the yield strength of the titanium material. Compared with the maximum displacement of the intact mandible, that of the mandibular distractor bodies was visibly increased. CONCLUSION An auxiliary lingual bracket can effectively decrease stress in such devices and displacement of mandibular distractor bodies. Rail fixation alone cannot achieve stability for distraction osteogenesis. Using an auxiliary lingual bracket effectively prevents distractor breakage and exposure.
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Chang YW, Liu PH. Biomechanical effects of screw fixation in second mandibular reconstruction plate. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2013:3167-70. [PMID: 24110400 DOI: 10.1109/embc.2013.6610213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The purpose of this study was to investigate biomechanical effects of second reconstruction plate with different combinations of fixed screws in patient with mandibular tumor resection by three-dimensional finite element analysis (FEA). The FEA models were consisted of defected mandible, reconstruction plate with different screw holes, and bone screws. The results indicated that application of the second reconstruction plate appeared to increase stability and decrease stress magnitude on the plates and screws accompanying with increasing screw number. For clinical cost consideration in usage of the second reconstruction plate, the conclusion showed that the second reconstruction plate could offer a better mechanical efficacy accompanying with increase of screw quantity, but single screw applied for the second plate fixation to defected mandible of tumor resection was enough to stabilize without increase of screw quantities.
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Locking versus nonlocking plates in mandibular reconstruction with fibular graft—a biomechanical ex vivo study. Clin Oral Investig 2013; 18:1291-1298. [DOI: 10.1007/s00784-013-1105-1] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2013] [Accepted: 09/09/2013] [Indexed: 10/26/2022]
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The modular endoprosthesis for mandibular body replacement. Part 2: Finite element analysis of endoprosthesis reconstruction of the mandible. J Craniomaxillofac Surg 2012; 40:e487-97. [DOI: 10.1016/j.jcms.2012.03.010] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2011] [Revised: 03/12/2012] [Accepted: 03/12/2012] [Indexed: 11/24/2022] Open
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40
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Wong RC, Tideman H, Merkx MA, Jansen J, Goh SM. The modular endoprosthesis for mandibular body replacement. Part 1: Mechanical testing of the reconstruction. J Craniomaxillofac Surg 2012; 40:e479-86. [DOI: 10.1016/j.jcms.2012.03.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2011] [Revised: 02/01/2012] [Accepted: 03/09/2012] [Indexed: 10/28/2022] Open
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Katona TR. A qualitative engineering analysis of occlusion effects on mandibular fracture repair mechanics. JOURNAL OF DENTAL BIOMECHANICS 2011; 2011:752741. [PMID: 22073042 PMCID: PMC3182375 DOI: 10.4061/2011/752741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/05/2011] [Revised: 06/30/2011] [Accepted: 08/22/2011] [Indexed: 11/20/2022]
Abstract
Objectives. The purpose of this analytical study was to examine and critique the engineering foundations of commonly accepted biomechanical principles of mandible fracture repair. Materials and Methods. Basic principles of static equilibrium were applied to intact and plated mandibles, but instead of the traditional lever forces, the mandibles were subjected to more realistic occlusal forces. Results. These loading conditions produced stress distributions within the intact mandible that were very different and more complex than the customary lever-based gradient. The analyses also demonstrated the entirely different mechanical environments within intact and plated mandibles. Conclusions. Because the loading and geometry of the lever-idealized mandible is incomplete, the associated widely accepted bone stress distribution (tension on top and compression on the bottom) should not be assumed. Furthermore, the stress gradients within the bone of an intact mandible should not be extrapolated to the mechanical environment within the plated regions of a fractured mandible.
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Affiliation(s)
- Thomas R. Katona
- Indiana University School of Dentistry, Indiana University—Purdue University, Indianapolis (IUPUI), 1121 W. Michigan Street, Indianapolis, IN 46202, USA
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Review of biomechanical models used in studying the biomechanics of reconstructed mandibles. Int J Oral Maxillofac Surg 2011; 40:393-400. [PMID: 21195588 DOI: 10.1016/j.ijom.2010.11.023] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2010] [Accepted: 11/23/2010] [Indexed: 11/20/2022]
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Kovan V. The development of a new mandibular osteosynthesis plate: an application of the Ashby approach. Proc Inst Mech Eng H 2011; 225:199-205. [PMID: 21428154 DOI: 10.1243/09544119jeim849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Mandible fractures are among the most common bone injuries in facial traumas. Currently, mandibular fracture repair is carried out with an appropriate osteosynthesis plate. These osteosynthesis plates are also used to provide mastication function as soon as possible after operation. Therefore, the plates employed should ensure functional, mechanical, and morphological rehabilitation. Many researchers have reported that the titanium osteosynthesis plates currently used for mandibular defects are often subject to excessive stress. This excessive stress may lead to unexpected fractures of the plates. Unexpected fractures have been indicated as a mechanical weakness of titanium osteosynthesis plates. The aim of the present study is to investigate the mechanical stability and deformation behaviour of commercially available titanium mandibular osteosynthesis plates, as well as to design and develop a new osteosynthesis plate with better mechanical stability. In the first stage of this investigation, an analytical study was carried out to determine the optimum cross-sectional shape for the new plates. Subsequently, the cross-sectional shapes for the new plates were validated by numerical methods. Finally, the project was completed by manufacturing the plates and conducting static mechanical experiments of the developed plates. The mandibular osteosynthesis plates developed here are shown to exhibit improved mechanical stability.
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Affiliation(s)
- V Kovan
- Department of Mechanical Engineering, Akdeniz University, Antalya 07058, Turkey.
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Freitas EP, Rahal SC, Gioso MA, Vulcano LC, Shimano AC, da Silva JVL, Noritomi PY, El Warrak AO. Finite element modeling for development and optimization of a bone plate for mandibular fracture in dogs. J Vet Dent 2011; 27:212-21. [PMID: 21322428 DOI: 10.1177/089875641002700402] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
This study aimed to develop a plate to treat fractures of the mandibular body in dogs and to validate the project using finite elements and biomechanical essays. Mandible prototypes were produced with 10 oblique ventrorostral fractures (favorable) and 10 oblique ventrocaudal fractures (unfavorable). Three groups were established for each fracture type. Osteosynthesis with a pure titanium plate of double-arch geometry and blocked monocortical screws of free angulation were used. The mechanical resistance of the prototype with unfavorable fracture was lower than that of the favorable fracture. In both fractures, the deflection increased and the relative stiffness decreased proportionally to the diminishing screw number The finite element analysis validated this plate study, since the maximum tension concentration observed on the plate was lower than the resistance limit tension admitted by the titanium. In conclusion, the double-arch geometry plate fixed with blocked monocortical screws has sufficient resistance to stabilize oblique fractures, without compromising mandibular dental or neurovascular structures.
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Affiliation(s)
- Elisângela P Freitas
- Department of Veterinary Surgery and Anesthesiology, College of Veterinary Medicine and Animal Science, São Paulo State University, Botucatu, SP, Brazil.
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Wong RCW, Tideman H, Kin L, Merkx MAW. Biomechanics of mandibular reconstruction: a review. Int J Oral Maxillofac Surg 2009; 39:313-9. [PMID: 19944568 DOI: 10.1016/j.ijom.2009.11.003] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2008] [Revised: 09/07/2009] [Accepted: 11/03/2009] [Indexed: 12/23/2022]
Abstract
Knowledge of the biomechanics of the mandible allows the surgeon to understand the forces acting on the mandible during function and the resulting deformation that can occur. This allows the appropriate selection and placement of osteosynthesis plates to neutralize these forces. Many methods have been proposed for mandibular reconstruction, each of which has strengths and weaknesses. Most papers evaluating these techniques have focused on survival rates and the quality of the grafted bones, and there have been few studies of the biomechanics (stress distribution and strength) of the various types of reconstructed mandibles. This paper reviews the biomechanics of the mandible and the various methods of reconstruction reported in past studies.
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Affiliation(s)
- R C W Wong
- Department of Oral and Maxillofacial Surgery, National Dental Centre, Singapore.
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Parthasarathy J, Starly B, Raman S. Computer Aided Biomodeling and Analysis of Patient Specific Porous Titanium Mandibular Implants. J Med Device 2009. [DOI: 10.1115/1.3192104] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Custom implants for the reconstruction of mandibular defects have recently gained importance due to their better performance over their generic counterparts. This is attributed to their precise adaptation to the region of implantation, reduced surgical times, and better cosmesis. Recent introduction of direct digital manufacturing technologies, which enable the fabrication of implants from patient specific data, has opened up a new horizon for the next generation of customized maxillofacial implants. In this article, we discuss a representative volume element based technique in which precisely defined porous implants with customized stiffness values are designed to match the stiffness and weight characteristics of surrounding healthy bone tissue. Dental abutment structures have been incorporated into the mandibular implant. Finite element analysis is used to assess the performance of the implant under masticatory loads. This design strategy lends itself very well to rapid manufacturing technologies based on metal sintering processes.
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Affiliation(s)
- Jayanthi Parthasarathy
- Center for Shape Engineering and Advanced Manufacturing, School of Industrial Engineering, University of Oklahoma, 202 W. Boyd Street, Room 124, Norman, OK 73019-0631
| | - Binil Starly
- Center for Shape Engineering and Advanced Manufacturing, School of Industrial Engineering, University of Oklahoma, 202 W. Boyd Street, Room 124, Norman, OK 73019-0631
| | - Shivakumar Raman
- Center for Shape Engineering and Advanced Manufacturing, School of Industrial Engineering, University of Oklahoma, 202 W. Boyd Street, Room 124, Norman, OK 73019-0631
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Comparison of computed tomography and microradiography for graft evaluation after reconstruction of critical size bone defects using beta-tricalcium phosphate. J Craniomaxillofac Surg 2009; 38:38-46. [PMID: 19700333 DOI: 10.1016/j.jcms.2009.07.010] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2008] [Revised: 05/21/2009] [Accepted: 07/28/2009] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION The aim of the study was to evaluate the accuracy of computed tomography (CT) for in vivo follow up after mandibular reconstruction. MATERIAL AND METHODS Unilateral mandibular defects were surgically created in ten sheep and either reconstructed using blood soaked beta-tricalcium phosphate (beta-TCP) cylinders (group A, n=5) or blood soaked beta-TCP cylinders that were additionally loaded with autologous bone marrow (group B, n=5). The two graft designs resulted in different stages of graft ossification representative of different stages of healing. CT datasets were fused with microradiographs and measurements of ceramic area based on both methods were compared. RESULTS Two animals (groups A (n=1) and B (n=1)) presented infection and graft dislocation that was visible on CT and were excluded from statistical evaluation. Group A grafts underwent moderate degradation (53.55%+/-9.7) and incomplete bony incorporation representing an intermediate state of healing while ceramic grafts within group B developed a high grade of osseointegration and degradation (94.2%+/-3.3) consistent with progressive healing. Statistical comparison of measurements based on both methods revealed a significant bias (p<0.05) and a non-significant variance for group A and a significant variance (p<0.05) and non-significant bias for group B. CONCLUSION Our results indicate that conventional CT is not suitable to objectively evaluate ossification and degradation of a beta-TCP graft in vivo and further attempts to improve clinical visualization of beta-TCP need to be undertaken.
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An assessment of impact strength of the mandible. J Biomech 2008; 41:3488-91. [DOI: 10.1016/j.jbiomech.2008.09.026] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2008] [Revised: 09/18/2008] [Accepted: 09/25/2008] [Indexed: 11/20/2022]
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Nagasao M, Nagasao T, Imanishi Y, Tomita T, Tamaki T, Ogawa K. Experimental evaluation of relapse-risks in operated zygoma fractures. Auris Nasus Larynx 2008; 36:168-75. [PMID: 18635326 DOI: 10.1016/j.anl.2008.05.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2008] [Revised: 03/29/2008] [Accepted: 05/22/2008] [Indexed: 11/30/2022]
Abstract
OBJECTIVES Prevention of relapse, or postoperative dislocation, of the fixed zygoma is necessary to achieve optimal results in the treatment of zygoma fractures. Assuming that the occurrence of intensified stresses on mastication at the screw-bone interface (SBI) constitutes the essential cause of the relapse, we evaluated the stresses for three different fixation methods-fixation at the frontal process (FP), inferior orbital rim (IOR), and zygomatico-maxillary buttress (ZMB). METHODS We used 10 computer-aided design (CAD) models simulating zygoma fractures in the experiment. For each CAD model, we fixed the fractured zygoma with four screws and one mini-plate at the FP, IOR, or ZMB. After applying a 5.5kg force simulating mastication, we calculated the intensity and distribution patterns of the stresses occurring at the SBIs of the fixation screws using the finite element method. Thereby, we evaluated dynamic stability of the fixed zygoma for each of the three fixation methods. RESULTS Greater stresses occur at the SBIs with IOR fixation than at those with FP and ZMB fixation. Although the stresses occurring at the SBIs on mastication demonstrated evenly distributed patterns with the FP and ZMB fixation, the stresses demonstrated concentration on one screw with the IOR fixation. CONCLUSIONS The fixed zygoma is more likely to cause relapse with the IOR fixation than with the FP or ZMB fixation. Hence, in performing zygoma fixation at the IOR, care should be taken to minimize the likelihood of postoperative relapse that is caused by skewed distribution of the stresses on the fixation screws.
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Affiliation(s)
- Maki Nagasao
- Department of Otolaryngology, Keio University, Tokyo, Japan
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