Tarek M. Elshazly, D. Salvatori, Hanaa Elattar, C. Bourauel, L. Keilig
{"title":"Effect of trimming line design and edge extension of orthodontic aligners on force transmission: A 3D finite element study.","authors":"Tarek M. Elshazly, D. Salvatori, Hanaa Elattar, C. Bourauel, L. Keilig","doi":"10.2139/ssrn.4343120","DOIUrl":"https://doi.org/10.2139/ssrn.4343120","url":null,"abstract":"OBJECTIVES\u0000To investigate in a numerical study the effect of the geometry and the extension of orthodontic aligner edges and the aligner thickness on force transmission to upper right central incisor tooth (Tooth 11).\u0000\u0000\u0000METHODS\u0000A three-dimensional (3D) digital model, obtained from a 3D data set of a complete dentulous maxilla, was imported into 3-matic software. Aligners with four different trimming line designs (scalloped, straight, scalloped extended, straight extended) were designed, each with four different thicknesses (0.3, 0.4, 0.5, and 0.6 mm). The models were exported to a finite element (FE) software (Marc/Mentat). A facial 0.2 mm bodily malposition of tooth 11 was simulated.\u0000\u0000\u0000RESULTS\u0000The maximum resultant force was in the range of (7.5 - 55.2) N. The straight trimming designs had higher resultant force than the scalloped designs. The resultant force increases with increasing the edge extension of the aligner. The normal contact forces were unevenly distributed over the entire surface and were concentrated in six areas: Incisal, Mesio-Incisal, Disto-Incisal, Middle, Mesio-Cervical, and Disto-Cervical. The resultant force increases super linearly with increasing thickness.\u0000\u0000\u0000CONCLUSIONS\u0000The design of the trimming line, the edge extension, and the thickness of the aligner affect significantly the magnitude of the resultant force and the distribution of normal contact force. The straight extended trimming design exhibited better force distribution that may favor a bodily tooth movement.\u0000\u0000\u0000CLINICAL RELEVANCE\u0000A straight extended trimming design of an orthodontic aligner may improve the clinical outcomes. In addition, the manufacturing procedures of the straight design are much simpler compared to the scalloped design.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"140 1","pages":"105741"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44473764","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
K. Cheikho, J. Ganghoffer, A. Baldit, E. Labbe, S. Alix, H. Kerdjoudj, C. Mauprivez, A. Lebée, C. Laurent
{"title":"A flexible design framework to design graded porous bone scaffolds with adjustable anisotropic properties.","authors":"K. Cheikho, J. Ganghoffer, A. Baldit, E. Labbe, S. Alix, H. Kerdjoudj, C. Mauprivez, A. Lebée, C. Laurent","doi":"10.2139/ssrn.4147190","DOIUrl":"https://doi.org/10.2139/ssrn.4147190","url":null,"abstract":"Since the success of bone regenerative medicine depends on scaffold morphological and mechanical properties, numerous scaffolds designs have been proposed in the last decade, including graded structures that are suited to enhance tissue ingrowth. Most of these structures are based either on foams with a random pore definition, or on the periodic repetition of a unit cell (UC). These approaches are limited by the range of target porosities and obtained effective mechanical properties, and do not permit to easily generate a pore size gradient from the core to the periphery of the scaffold. In opposition, the objective of the present contribution is to propose a flexible design framework to generate various three-dimensional (3D) scaffolds structures including cylindrical graded scaffolds from the definition of a UC by making use of a non-periodic mapping. Conformal mappings are firstly used to generate graded circular cross-sections, while 3D structures are then obtained by stacking the cross-sections with or without a twist between different scaffold layers. The effective mechanical properties of different scaffold configurations are presented and compared using an energy-based efficient numerical method, pointing out the versatility of the design procedure to separately govern longitudinal and transverse anisotropic scaffold properties. Among these configurations, a helical structure exhibiting couplings between transverse and longitudinal properties is proposed and permits to extend the adaptability of the proposed framework. In order to investigate the capacity of common additive manufacturing techniques to fabricate the proposed structures, a subset of these configurations is elaborated using a standard SLA setup, and subjected to experimental mechanical testing. Despite observed geometric differences between the initial design and the actual obtained structures, the effective properties are satisfyingly predicted by the proposed computational method. Promising perspectives are offered concerning the design of self-fitting scaffolds with on-demand properties depending on the clinical application.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"140 1","pages":"105727"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46171639","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Potts, N. Bennion, S. Zappalá, David Marshall, Rob Harrison, S. L. Evans
{"title":"Fabrication of a positional brain shift phantom through the utilization of the frozen intermediate hydrogel state.","authors":"M. Potts, N. Bennion, S. Zappalá, David Marshall, Rob Harrison, S. L. Evans","doi":"10.2139/ssrn.4264247","DOIUrl":"https://doi.org/10.2139/ssrn.4264247","url":null,"abstract":"Synthetic models (phantoms) of the brain-skull system are useful tools for the study of surgical events that are otherwise difficult to study directly in humans. To date, very few studies can be found which replicate the full anatomical brain-skull system. Such models are required to study the more global mechanical events that can occur in neurosurgery, such as positional brain shift. Presented in this work is a novel workflow for the fabrication of a biofidelic brain-skull phantom which features a full hydrogel brain with fluid-filled ventricle/fissure spaces, elastomer dural septa and fluid-filled skull. Central to this workflow is the utilization of the frozen intermediate curing state of an established brain tissue surrogate, which allows for a novel moulding and skull installation approach that permits a much fuller recreation of the anatomy. The mechanical realism of the phantom was validated through indentation testing of the phantom's brain and simulation of the supine to prone brain shift event, while the geometric realism was validated through magnetic resonance imaging. The developed phantom captured a novel measurement of the supine to prone brain shift event with a magnitude that accurately reproduces that seen in the literature.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"140 1","pages":"105704"},"PeriodicalIF":0.0,"publicationDate":"2023-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42748247","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"A lumped model for long bone behavior based on poroelastic deformation and Darcy flow.","authors":"J. Tichy, B. Bou-Saïd","doi":"10.2139/ssrn.4270103","DOIUrl":"https://doi.org/10.2139/ssrn.4270103","url":null,"abstract":"The present paper provides a simplified model for compact bone behavior by accounting for bone fluid flow coupled to the elasticity of the porous structure. The lumped model considers the bone material as a layered poroelastic structure and predicts normal pressure versus displacement, i.e, a stress-strain curve. There is a parametric dependency on porosity and permeability but, in addition, on pressure history. Specifically, the pressure impulse (the integral of pressure versus time) plays a key role. This factor is alluded to in several past studies, but not highlighted in a simplified fashion. Based on a global flow balance, bone displacement depends on the fluid flow in a channel according to the classical Darcy model of 1856, and on the rate of change of fluid within the porous solid according to the 1941 classical model of Biot. The present results agree with those of Perrin et al. which, in turn, agree with results of a detailed numerical simulation.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"139 1","pages":"105649"},"PeriodicalIF":0.0,"publicationDate":"2023-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47163300","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Finite element analysis of FGM dental crowns using phase-field approach.","authors":"Ferit Sait, N. Saeidi, Turan Korkmaz","doi":"10.2139/ssrn.4264241","DOIUrl":"https://doi.org/10.2139/ssrn.4264241","url":null,"abstract":"Functionally graded materials (FGMs) - categorized in advanced composite materials - are specially designed to reduce the stresses and failure due to material mismatches. Advances in manufacturing techniques have brought FGMs into use in a variety of applications. However, the numerical analysis is still challenging due to the difficulties in simulations of non-homogeneous material domains of complex parts. Presenting a numerical procedure that both facilitates the implementation of material non-homogeneity in geometrically complex mediums, and increases the accuracy of the calculations using a phase-field approach, this study investigates the usage of FGMs in dental prostheses. For this purpose, a porcelain fused to metal (PFM) mandibular first molar FGM crown is simulated and analyzed under the maximum masticatory bite force, and eventually the results are compared to a PFM crown prepared conventionally.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105629"},"PeriodicalIF":0.0,"publicationDate":"2022-12-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47046092","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
R. W. Veale, Tarek Kollmetz, Navid Taghavi, Claudia G. Duston-Fursman, Matthew T. Beeson, Dorrin Asefi, Henry D Chittock, A. Vikranth, S. Dowling, S. Dempsey, H. Rose, Isaac Mason, B. C. May
{"title":"Influence of advanced wound matrices on observed vacuum pressure during simulated negative pressure wound therapy.","authors":"R. W. Veale, Tarek Kollmetz, Navid Taghavi, Claudia G. Duston-Fursman, Matthew T. Beeson, Dorrin Asefi, Henry D Chittock, A. Vikranth, S. Dowling, S. Dempsey, H. Rose, Isaac Mason, B. C. May","doi":"10.2139/ssrn.4264243","DOIUrl":"https://doi.org/10.2139/ssrn.4264243","url":null,"abstract":"Biomaterials and negative pressure wound therapy (NPWT) are treatment modalities regularly used together to accelerate soft-tissue regeneration. This study evaluated the impact of the design and composition of commercially available collagen-based matrices on the observed vacuum pressure delivered under NPWT using a custom test apparatus. Specifically, testing compared the effect of the commercial products; ovine forestomach matrix (OFM), collagen/oxidized regenerated cellulose (collagen/ORC) and a collagen-based dressing (CWD) on the observed vacuum pressure. OFM resulted in an ∼50% reduction in the observed target vacuum pressure at 75 mmHg and 125 mmHg, however, this effect was mitigated to a ∼0% reduction when fenestrations were introduced into the matrix. Both collagen/ORC and CWD reduced the observed vacuum pressure at 125 mmHg (∼15% and ∼50%, respectively), and this was more dramatic when a lower vacuum pressure of 75 mmHg was delivered (∼20% and ∼75%, respectively). The reduced performance of the reconstituted collagen products is thought to result from the gelling properties of these products that may cause occlusion of the delivered vacuum to the wound bed. These findings highlight the importance of in vitro testing to establish the impact of adjunctive therapies on NPWT, where effective delivery of vacuum pressure is paramount to the efficacy of this therapy.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105620"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46511122","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Rahul Vellaparambil, W. Han, Pierluigi Di Giovanni, S. Avril
{"title":"Potential of auxetic designs in endovascular aortic repair: A computational study of their mechanical performance.","authors":"Rahul Vellaparambil, W. Han, Pierluigi Di Giovanni, S. Avril","doi":"10.2139/ssrn.4258753","DOIUrl":"https://doi.org/10.2139/ssrn.4258753","url":null,"abstract":"With the rising popularity of endovascular aortic repair (EVAR) for aortic aneurysms and dissections, there is a crucial need for investigating the delayed appearance of post-EVAR complications such as stent-graft kinking, fracture and migration respectively. These complications have been noted to be influenced by the radial stiffness and bending flexibility attributes of stent-grafts. Auxetic designs with negative Poisson's ratio offer interesting advantages such as enhanced fracture toughness, superior indentation resistance and adaptive stiffness in response to intricate morphology for stenting applications over conventional stent designs. The objective of this study is to propose different auxetic stent candidates and to compare their mechanical performance with two conventional stent candidates for endovascular applications using numerical simulation through crimp/crushing tests for their radial stiffness and three-point bending/kinking tests for their flexibility, respectively. The results demonstrate that the novel hybrid auxetic designs (CRE and CSTAR) possess the best trade-off between radial stiffness and bending flexibility characteristics among all candidates for stent-graft applications.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105644"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47561881","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A. Knutsen, S. Vidhate, Grace McIlvain, J. Luster, Eric J. Galindo, Curtis L. Johnson, D. Pham, J. Butman, R. Mejía-Alvarez, M. Tartis, A. Willis
{"title":"Characterization of material properties and deformation in the ANGUS phantom during mild head impacts using MRI.","authors":"A. Knutsen, S. Vidhate, Grace McIlvain, J. Luster, Eric J. Galindo, Curtis L. Johnson, D. Pham, J. Butman, R. Mejía-Alvarez, M. Tartis, A. Willis","doi":"10.2139/ssrn.4117081","DOIUrl":"https://doi.org/10.2139/ssrn.4117081","url":null,"abstract":"Traumatic brain injury (TBI) is a major health concern affecting both military and civilian populations. Despite notable advances in TBI research in recent years, there remains a significant gap in linking the impulsive loadings from a blast or a blunt impact to the clinical injury patterns observed in TBI. Synthetic head models or phantoms can be used to establish this link as they can be constructed with geometry, anatomy, and material properties that match the human brain, and can be used as an alternative to animal models. This study presents one such phantom called the Anthropomorphic Neurologic Gyrencephalic Unified Standard (ANGUS) phantom, which is an idealized gyrencephalic brain phantom composed of polyacrylamide gel. Here we mechanically characterized the ANGUS phantom using tagged magnetic resonance imaging (MRI) and magnetic resonance elastography (MRE), and then compared the outcomes to data obtained in healthy volunteers. The direct comparison between the phantom's response and the data from a cohort of in vivo human subjects demonstrate that the ANGUS phantom may be an appropriate model for bulk tissue response and gyral dynamics of the human brain under small amplitude linear impulses. However, the phantom's response differs from that of the in vivo human brain under rotational impacts, suggesting avenues for future improvements to the phantom.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105586"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49044459","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"The occurrence of squeaking under wear testing standards for ceramic on ceramic total hip replacements.","authors":"O. O'Dwyer Lancaster-Jones, Rebecca Reddiough","doi":"10.2139/ssrn.4147189","DOIUrl":"https://doi.org/10.2139/ssrn.4147189","url":null,"abstract":"Ceramic on ceramic total hip replacement clinical reports may on occasion note a noise or squeaking. There is much debate on whether this is an actual concern, but some medical centres want to avoid any possible negative impact on the patients' wellbeing due to the noise generated. The aim of this study was to determine what sound frequencies can be picked up from hip testing standards for ceramic on ceramic under different lubrication conditions. The ISO-14242-1 (35° cup angle) and ISO-14242-4 (55° cup angle with a 4 mm translational mismatch) standards were used for testing with dry, water and serum lubrication conditions up to 10000 cycles. No sound was detected for water and serum conditions under standard walking (ISO-14242-1) testing. An audible noise with a frequency range of 0.4-0.8 kHz was picked up within 600 cycles under water and edge loading (ISO-14242-4) conditions. All dry testing produced a high pitch squeak when the frequency was higher than 2 kHz. One sample under dry edge loading conditions had an audible noise of 0.8 kHz, considered not as squeaking, as it was not high pitch. Dry testing for both, standard walking (ISO-14242-1) and edge loading (ISO-14242-4) conditions, which resulted in a high pitch noise, had a frequency range of 2-8 kHz and 5-9 kHz respectively. One sample tested with edge loading and serum produced a faint squeak noise after 6000 cycles with a frequency of 7 kHz. Edge loading due to ISO-14242-4 conditions had an increased torque which may be playing a role in increased friction leading to noise. Edge loading conditions were more prone to the generation of audible noise and squeaking whilst under lubricated conditions.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105616"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"44279836","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
C. Quinn, Kerstin van Gaalen, P. McHugh, A. Kopp, T. Vaughan
{"title":"An enhanced phenomenological model to predict surface-based localised corrosion of magnesium alloys for medical use.","authors":"C. Quinn, Kerstin van Gaalen, P. McHugh, A. Kopp, T. Vaughan","doi":"10.2139/ssrn.4146343","DOIUrl":"https://doi.org/10.2139/ssrn.4146343","url":null,"abstract":"This study developed an enhanced phenomenological model for the predictions of surface-based localised corrosion of magnesium alloys for use in medical applications. The modelling framework extended previous surface-based approaches by considering the role of β-phase components throughout the material volume to better predict spatial and temporal aspects of surface-based corrosion in magnesium alloys. This enhanced surface-based corrosion model offers many advantages as it (i) captures multi-directional pitting, (ii) captures various pit morphologies, (iii) eliminates mesh sizing effects, (iv) reduces computational cost through custom time controls (v) offers control of pit sizing and (vi) produces corrosion rates that are independent of pitting parameter values. The model was fully implemented in three dimensions within the finite element framework and shows excellent potential to enable robust predictions of the long-term performance of magnesium-based implants undergoing corrosion.","PeriodicalId":94117,"journal":{"name":"Journal of the mechanical behavior of biomedical materials","volume":"138 1","pages":"105637"},"PeriodicalIF":0.0,"publicationDate":"2022-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43437610","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}