研究者詳細 - 高野　直樹

論文 - 高野　直樹

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Influence of Anisotropic Bone Properties on the Biomechanical Behavior of the Acetabular Cup Implant: A Multiscale Finite Element Study

Vu-Hieu Nguyen, Giuseppe Rosi, Salah Naili, Adrien Michel, Maria-Letizia Raffa, Romain Bosc, Jean-Paul Meningaud, Christine Chappard, Naoki Takano, Guillaume Haiat

Computer Methods in Biomechanics and Biomedical Engineerin （Computer Methods in Biomechanics and Biomedical Engineering） 20 （ 12 ） 1312 - 1325 2017年10月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 10255842

© 2017 Informa UK Limited, trading as Taylor & Francis Group. Although the biomechanical behavior of the acetabular cup (AC) implant is determinant for the surgical success, it remains difficult to be assessed due to the multiscale and anisotropic nature of bone tissue. The aim of the present study was to investigate the influence of the anisotropic properties of peri-implant trabecular bone tissue on the biomechanical behavior of the AC implant at the macroscopic scale. Thirteen bovine trabecular bone samples were imaged using micro-computed tomography (μCT) with a resolution of 18 μm. The anisotropic biomechanical properties of each sample were determined at the scale of the centimeter based on a dedicated method using asymptotic homogenization. The material properties obtained with this multiscale approach were used as input data in a 3D finite element model to simulate the macroscopic mechanical behavior of the AC implant under different loading conditions. The largest stress and strain magnitudes were found around the equatorial rim and in the polar area of the AC implant. All macroscopic stiffness quantities were significantly correlated (R2 > 0.85, p < 6.5 e-6) with BV/TV (bone volume/total volume). Moreover, the maximum value of the von Mises stress field was significantly correlated with BV/TV (R2 > 0.61, p < 1.6 e-3) and was always found at the bone-implant interface. However, the mean value of the microscopic stress (at the scale of the trabeculae) decrease as a function of BV/TV for vertical and torsional loading and do not depend on BV/TV for horizontal loading. These results highlight the importance of the anisotropic properties of bone tissue.

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Parameterization, Statistical Measurement and Numerical Modeling of Fluctuated Meso/micro-structure of Plain Woven Fabric GFRP Laminate for Quantification of Gometrical Variability

Kohei Hagiwara, Shintaro Ishijima, Naoki Takano, Akio Ohtani, Asami Nakai

Mechanical Engineering Journal （JSME） 4 （ 4 ） 2017年08月

研究論文（学術雑誌）, 共著, 査読有り

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FRPの確率的RTM成形プロセスシミュレーションにおける裾野分布の解析

高野直樹・石島慎太郎

日本機械学会論文集 83 （ 851 ） 2017年07月

研究論文（学術雑誌）, 共著, 査読有り

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Stochastic Multi-Scale Finite Element Analysis of the Drilling Force of Trabecular Bone during Oral Implant Surgery

Tawara D., Takano N., Kinoshita H., Matsunaga S., Abe S.

International Journal of Applied Mechanics （International Journal of Applied Mechanics） 8 （ 6 ） 1650075 2016年08月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 17588251

© 2016 World Scientific Publishing Europe Ltd. To avoid procedural accidents during/after oral implant surgery in a jawbone (e.g., perforation of the lingual side due to an inadequate drilling angle or scratching the mandibular canal), it is important for dentists to develop skilled drilling techniques. We have developed a stochastic multi-scale prediction of apparent elastic moduli of the jawbone with modified first-order perturbation-based stochastic homogenization in which individual differences of drilling properties relating to bone quality can be evaluated with a force-sensitive device. To establish drilling properties in various types of jawbone and the perforation case, and for drill diameters, we propose an original computational method that avoids procedural accidents by defining the drilling angle as a parameter and quantifying individual differences and the inner distribution of bone quality in several jawbones as a drilling force. Three samples demonstrated that drilling forces changed depending on the trabecular structure, with the drilling force changing little around the mandibular canal and increasing just before perforation. Drilling force also depended on the drill diameter but did not always match its size. Estimated drilling forces of the expected value and 50% and 90% probability results suggested prominent differences in drilling properties. This information enables dentists to develop a skillful surgical technique.

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Desktop micro-CT image-based dynamic FEM analysis of stress wave pathways between mandibular trabecular bone and cortical bone with comparisons to virtual models with eliminated materials on pathways

Nakano H., Takano N., Maki K.

Journal of Biomechanical Science and Engineering （Journal of Biomechanical Science and Engineering） 11 （ 3 ） 1 - 11 2016年08月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 18809863

© 2016 The Japan Society of Mechanical Engineers. To a nalyze the biomechanical behavior of human bone, micro-CT image-based static FEM analyse s considering trabecular architecture have been carried out. In the field of dental biomechanics, not only the static analysis but also dynamic analysis against impact load is required. In this paper, a desktop micro-CT was used for the right half of a human mandible with 0.103 mm resolution after dissecting. The lost information by a saw was recovered by the homogenization model. The impact load was applied to the implant in the molar part and the load transfer from the implant to the cortical bone and trabecular bone was considered. The stress wave pathways from the implant to the condyle were analyzed by comparison with virtual FEM models with eliminated materials on pathways. It was revealed that the stress wave transferred from the implant neck and end part to peri-implant trabecular bone played a significant mechanical role. It was also found that the apparent wave speed in the trabecular bone region was as fast as that in the cortical bone.

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Numerical Prediction of Scattered Initial Fracture Load of Perforated Thin Plate under Tension by Monte Carlo FEM Simulation with Stepwise Limited Sampling

Shusuke Akimoto and Naoki Takano

Mechanical Engineering Letters 2 1 - 8 2016年06月

研究論文（学術雑誌）, 共著, 査読有り

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Quantitative study of force sensing while drilling trabecular bone in oral implant surgery

Bin Kamisan M., Kinoshita H., Nakamura F., Homma S., Yajima Y., Matsunaga S., Abe S., Takano N.

Journal of Biomechanical Science and Engineering （Journal of Biomechanical Science and Engineering） 11 （ 3 ） 1 - 9 2016年06月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 18809863

© 2016 The Japan Society of Mechanical Engineers. A survey done recently showed that almost 30 percent of the accidents occurred during oral implant surgery were concerned with the mandibular canal in the trabecular bone region and most of them were related to the drilling process. One of the reasons known is due to the clinicians' lack of knowledge and experience. In order to overcome the problem, through the educational approach, we proposed and developed a new system mainly for dental colleges' students, by focusing on drilling the mandibular trabecular bone. The system comes in the form of an oral implant surgery training simulator that enables student to sense the reaction force during drilling. The developed system was then evaluated by expert clinicians and dental college's students. A total of 8 clinicians and 24 students tested all three samples of drilling force database. The clinicians were asked to describe the drilling force based on a stiffness scale while the students are required to drill two samples first before drilling the third sample. They were asked to sketch the third samples based on the comparison of previous samples. Based on the evaluation done, it was found that the quantification of force sensed during drilling could be derived from the combination of drilling force and speed obtained through the relative value of comparison with the previous or accumulated experience of drilling. The results of this study also indicate that the oral implant surgery training simulator could help students learn the difference of drilling force sense dependent on the bone quality through repeated usage and practices.

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Probabilistic multiscale analysis of three-phase composite material considering uncertainties in both physical and geometrical parameters at microscale

Wen P., Takano N., Kurita D.

Acta Mechanica （Acta Mechanica） 227 （ 10 ） 2735 - 2747 2016年05月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 00015970

© 2016, Springer-Verlag Wien. A probabilistic multiscale framework is proposed to characterize the probabilistic behaviors of macroscopic elastic properties of multiphase composite materials. The first-order perturbation-based stochastic homogenization method is extended to incorporate inherent randomness existed in multiphase constituents materials on basis of our previous work for porous material. Moreover, a generalized stochastic method is introduced to combine above with morphological nonparametric uncertainties. A numerical example for coated particulate composite material demonstrated the feasibility and effectiveness of proposed methods.

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Prediction of apparent properties with uncertain material parameters using high-order fictitious domain methods and PGD model reduction

Legrain G., Chevreuil M., Takano N.

International Journal for Numerical Methods in Engineering （International Journal for Numerical Methods in Engineering） 109 （ 3 ） 345 - 367 2016年04月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 00295981

Copyright © 2016 John Wiley & Sons, Ltd. This contribution presents a numerical strategy to evaluate the effective properties of image-based microstructures in the case of random material properties. The method relies on three points: (1) a high-order fictitious domain method; (2) an accurate spectral stochastic model; and (3) an efficient model-reduction method based on the proper generalized decomposition in order to decrease the computational cost introduced by the stochastic model. A feedback procedure is proposed for an automatic estimation of the random effective properties with a given confidence. Numerical verifications highlight the convergence properties of the method for both deterministic and stochastic models. The method is finally applied to a real 3D bone microstructure where the empirical probability density function of the effective behaviour could be obtained. Copyright © 2016 John Wiley & Sons, Ltd.

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Macro/micro simultaneous validation for multiscale analysis of semi-periodically perforated plate using full-field strain measurement

Matsuda T., Ito T., Akimoto S., Kobori H., Goto K., Takano N.

International Journal of Mechanical Sciences （International Journal of Mechanical Sciences） 110 34 - 40 2016年03月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 00207403

© 2016 Elsevier Ltd. Multiscale analysis of a semi-periodically perforated plate based on a homogenization theory is experimentally validated both macroscopically and microscopically, using a full-field strain measurement. To do this, a plate-fin-type perforated plate with a misaligned microstructure is considered as a semi-periodically perforated plate. Then, a homogenization theory that can analyze macroscopic behavior and microscopic stress and strain distributions of the perforated plate is presented. To validate the theory, a tensile test of a plate-fin-type semi-periodically perforated plate made of epoxy resin is conducted. During the test, the microscopic deformation of the specimen is observed with a digital image correlation (DIC) full-field measurement system, from which microscopic strain distribution of the specimen is calculated. It is shown that the obtained strain distribution satisfies the unit-cell periodicity except at edges of the periodic structure, and that the strain distribution is in good agreement with the result of analysis using the homogenization theory. It is also shown that the macroscopic stress-strain relationships obtained by the experiment and analysis agree well, supporting the macroscopic and microscopic validity of the multiscale analysis using the homogenization theory.

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Drilling Force and Speed for Mandibular Trabecular Bone in Oral Implant Surgery

Mohammad Aimaduddin Atiq bin Kamisan, Kenichiro Yokota, Takayuki Ueno, Hideaki Kinoshita, Shinya Homma, Yasutomo Yajima, Sinichi Abe and Naoki Takano

Biomaterials and Biomechanics in Bioengineering （TECHNO Press） 3 （ 1 ） 15 - 26 2016年03月

研究論文（学術雑誌）, 共著, 査読有り

Probabilistic homogenization and sensitivity analysis for robust design of coated particulate composite material considering non-parametric geometrical uncertainty at microscale

Wen P., Kamijo K., Kurita D., Takano N.

Transactions of the Japan Society for Computational Engineering and Science （Transactions of the Japan Society for Computational Engineering and Science） 2016 （ 20160005 ） 1 - 10 2016年02月

研究論文（学術雑誌）, 共著, 査読有り

© 2016 by the Japan Society for Computational Engineering and Science. The aim of this study is that with consideration of geometrical fluctuation, robust design is made to assure performance of material more reliable to fabrication process. Firstly a target microstructure is defined as the optimum solution for coated particulate material. Then a slightly fluctuated computational models are generated in which some random variables are defined. Multiscale analysis is done to obtain homogenized Young’s modulus, shear modulus and an index with respect to strength. Probabilistic sensitivity for those quantities of interest against design variables is analyzed by means of response surface method. For response surface, this paper studies a case where the scattering of sampling points is clustered. The characteristics of cluster sampling points determine the response surface strategy as quadratic polynomial and least square regression method. Finally the numerical result of a specific robust design for coated particulate composite material reveals that when the mean radius of particle is bigger and mean coating thickness is smaller, the less sensitive index is. It will provide a reliable guidance and save cost in the development of wide range of composite materials.

Development of a drilling simulator for dental implant surgery

Kinoshita H., Nagahata M., Takano N., Takemoto S., Matsunaga S., Abe S., Yoshinari M., Kawada E.

Journal of Dental Education （Journal of Dental Education） 80 （ 1 ） 83 - 90 2016年01月

研究論文（学術雑誌）, 共著, 査読有り, ISSN 00220337

The aim of this study was to develop and evaluate a dental implant surgery simulator that allows learners to experience the drilling forces necessary to perform an osteotomy in the posterior mandibular bone. The simulator contains a force-sensing device that receives input and counteracts this force, which is felt as resistance by the user. The device consists of an actuator, a load cell, and a control unit. A mandibular bone model was fabricated in which the predicted forces necessary to drill the cortical and trabecular bone were determined via micro CT image-based 3D finite element analysis. The simulator was evaluated by five dentists from the Department of Implantology at Tokyo Dental College. The ability of the evaluators to distinguish the drilling resistance through different regions of the mandibular bone was investigated. Of the five dentists, four sensed the change in resistance when the drill perforated the upper cortical bone. All five dentists were able to detect when the drill made contact with lingual cortical bone and when the lingual bone was perforated. This project successfully developed a dental implant surgery simulator that allows users to experience the forces necessary to drill through types of bone encountered during osteotomy. Furthermore, the researchers were able to build a device by which excessive drilling simulates a situation in which the lingual cortical bone is perforated-A situation that could lead to negative repercussions in a clinical setting. The simulator was found to be useful to train users to recognize the differences in resistance when drilling through the mandibular bone.

The “Sea” Should Not Be Operated on in Scar Revision for “Island-Like” Scars

Tomohisa Nagasao, Yusuke Hamamoto, Motoki Tamai, Hiroo Kudo, Toshiya Ensako, Tetsukuni Kogure, Naoki Takano, Yoshio Tanaka

Medical Hypotheses 2015年04月

研究論文（学術雑誌）, 共著, 査読有り

Probabilistic analysis of mechanical behaviour of mandibular trabecular bone using a calibrated stochastic homogenization model

Tawara D., Nagahata M., Takano N., Kinoshita H., Abe S.

Acta Mechanica （Acta Mechanica） 226 （ 7 ） 3275 - 3287 2015年

研究論文（学術雑誌）, 共著, 査読有り, ISSN 00015970

© 2015, Springer-Verlag Wien. Surgical success of drilling in oral implantology depends on the sense of force on the fingers or feeling of a dental clinician, which is related to the quality of trabecular bone in the jawbone expressed by apparent mechanical characteristics. As the mechanical properties of trabecular bone depend on the bone volume fraction, microstructure, and many other factors closely related to individual differences, a probabilistic numerical procedure to assess drilling force is proposed. Using a micro-CT-based jawbone model, a first-order perturbation-based stochastic homogenization method was employed to estimate the possible scattering of apparent mechanical properties of the trabecular bone region. The complicated drilling problem was simplified to sequential linear static FEAs, to which the predicted apparent Young’s modulus and shearing moduli in the drilling direction were applied. The FEAs demonstrated that the homogenized mechanical properties showed anisotropy, which might lead to differences in the drilling forces at different drilling angles. The numerically estimated drilling forces were shown by the expected value, 50 %-probability result, and 90%-probability result and revealed that one patient among two or ten patients would probably have poor bone quality. There was a remarkable difference in the drilling forces between the expected value and the 90%-probability result.

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Scoring of Deformed Costal Cartilages Reduces Postoperative Pain after Nuss Procedure for Pectus Excavatum

Nagasao T., Hamamoto Y., Tamai M., Kogure T., Jiang H., Takano N., Tanaka Y.

Thoracic and Cardiovascular Surgeon （Thoracic and Cardiovascular Surgeon） 64 （ 1 ） 62 - 69 2015年

研究論文（学術雑誌）, 共著, 査読有り, ISSN 01716425

© 2016 Georg Thieme Verlag KG Stuttgart · New York. Objective The present study aims to elucidate whether or not scoring deformed cartilages reduces postoperative pain after the Nuss procedure for pectus excavatum patients. Methods A total of 46 pectus excavatum patients for whom the Nuss procedure was conducted were included in the study. The patients were categorized into two groups, depending on whether or not the supplementary maneuver of scoring deformed cartilages was performed in addition to the Nuss procedure. Patients for whom deformed costal cartilages were scored were categorized as the Scoring Group (n = 24); those who received no such scoring were categorized as the Non-Scoring Group (n = 22). After evaluating the maximum stresses occurring on the thoraces by means of dynamic simulation using finite element analyses, intergroup comparison of the maximum von-Mises stress values was performed. Furthermore, after quantifying postoperative pain as the frequency with which patients injected anesthetics through an epidural pain-control system within 2 postoperative days, the degree of pain was compared between the two groups. Results The maximum stresses occurring on the thorax were significantly greater for the Non-Scoring Group than for the Scoring Group; injection frequency was also greater for the Non-Scoring Group (average 4.9 times for 2 days) than for the Scoring Group (average 2.5 times for 2 days). Conclusion High stresses occur due to the performance of the Nuss procedure, causing postoperative pain. The stresses can be reduced by performing supplementary scoring on deformed cartilages. Accordingly, postoperative pain is reduced.

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Multiscale Stress Analysis of Trabecular Bone Around Acetabular Cup Implant by Finite Element Mesh Superposition Method

Makoto Tsukino, Naoki Takano, Adrien Michel and Guillaume Haiat

Mechanical Engineering Letters （JSME） 1 （ 15-00354 ） 1 - 8 2015年

研究論文（学術雑誌）, 共著, 査読有り

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Stochastic Homogenization Analysis of FIB-SEM Image-based Hierarchical Model of Sprayed Porous ZrO2

Yuma Miyauchi, Naoki Takano and Pin Wen

Mechanical Engineering Letters （JSME） 1 （ 15-00389 ） 1 - 8 2015年

研究論文（学術雑誌）, 共著, 査読有り

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Probabilistic prediction of homogenized property and update of prediction for spherical porous material considering microstructural uncertainties

Pin Wen, Kenichiro Yokota and Naoki Takano

Journal of Multiscale Modelling （Imperial College Press） 6 （ 4 ） 1 - 19 2015年

研究論文（学術雑誌）, 共著, 査読有り

The "Sea" should not be operated on in scar revision for "Island-Like" scars

Nagasao T., Hamamoto Y., Tamai M., Kudo H., Ensako T., Kogure T., Takano N., Tanaka Y.

Medical Hypotheses （Medical Hypotheses） 85 （ 2 ） 215 - 218 2015年

ISSN 03069877

© 2015 Elsevier Ltd. Scars developing on body surfaces not only restrict body movement, but are also problematic from a cosmetic standpoint. Hence, revision is conducted by removing the scar and re-suturing the resultant defects. In performing scar revision, care should be taken to prevent the re-sutured wounds from developing hypertrophy again. Scars often present a pattern where hard, red parts are separated by soft parts in between. As the hard and soft parts may be analogized as islands and seas respectively, we call this the "Island-Like" scar. Two strategies can be taken to treat scars of this type. The first is to remove the entire scar-including both hard and soft parts; the second is to remove only the hard parts and leave the soft parts untouched. The authors conducted a biomechanical study using finite element analyses and found that as a body moves, greater stresses occur in the peri-wound regions with the first strategy than with the second strategy. A wound's likelihood to develop hypertrophy increases as the stresses working on it increase. Hence, it is hypothesized that the second strategy carries less risk of the operated wounds developing re-hypertrophy than the first strategy. Based on this logic, in performing scar revision for scars consisting of hard and soft parts, it is recommended only to remove only hard parts and not to operate on soft parts in between.

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