Pub Date : 2025-02-10DOI: 10.1016/j.jmbbm.2025.106937
Emily S. Sullivan , Andrew Yung , Jessica Küpper , Kirsten Bale , Piotr Kozlowski , David R. Wilson
Purpose
The objective of this study was to determine the relationship between magnetization transfer ratio (MTR) and strain in ex vivo bovine cartilage using 9.4T magnetic resonance imaging (MRI) and to compare this relationship to the relationship between T2 and strain.
Methods
A previously designed custom electropneumatic loading device was used to compress together osteochondral blocks of bovine femoral and tibial cartilage and bone within a 9.4T Bruker MRI scanner. Stepwise loads were applied to compress cartilage to targets of 10%, 20% and 30% strain. Images were acquired for unloaded cartilage and after each load had been held constant for 20 min to minimize creep effects. A custom algorithm was used to quantify T2 and MTR (average, by depth, and column wise) in the region of contact, and to calculate axial cartilage strain. Repeated measures correlation was used to investigate potential correlations between MTR and strain, and T2 and strain.
Results
Mean MTR vs strain correlations were rrm = −0.90 (CI = −0.96 to −0.75) in the tibia and rrm = −0.70 (CI = −0.87 to −0.35) in the femur. Mean T2 vs strain correlations were rrm = −0.84 (CI = −0.94 to −0.59) in the tibia and rrm = −0.11 (CI = −0.57 to 0.41) in the femur. Column-wise analyses produced negligible or weak correlations (−0.07 to −0.34 for T2 and MTR).
Conclusions
MTR increases with strain in the region of contact, and MTR is more strongly correlated to strain than T2. MTR shows promise as a surrogate measure of strain, especially when averaged over the region of contact.
{"title":"Relationship between magnetization transfer ratio and axial compressive strain in tibiofemoral articular cartilage","authors":"Emily S. Sullivan , Andrew Yung , Jessica Küpper , Kirsten Bale , Piotr Kozlowski , David R. Wilson","doi":"10.1016/j.jmbbm.2025.106937","DOIUrl":"10.1016/j.jmbbm.2025.106937","url":null,"abstract":"<div><h3>Purpose</h3><div>The objective of this study was to determine the relationship between magnetization transfer ratio (MTR) and strain in <em>ex vivo</em> bovine cartilage using 9.4T magnetic resonance imaging (MRI) and to compare this relationship to the relationship between T2 and strain.</div></div><div><h3>Methods</h3><div>A previously designed custom electropneumatic loading device was used to compress together osteochondral blocks of bovine femoral and tibial cartilage and bone within a 9.4T Bruker MRI scanner. Stepwise loads were applied to compress cartilage to targets of 10%, 20% and 30% strain. Images were acquired for unloaded cartilage and after each load had been held constant for 20 min to minimize creep effects. A custom algorithm was used to quantify T2 and MTR (average, by depth, and column wise) in the region of contact, and to calculate axial cartilage strain. Repeated measures correlation was used to investigate potential correlations between MTR and strain, and T2 and strain.</div></div><div><h3>Results</h3><div>Mean MTR vs strain correlations were r<sub>rm</sub> = −0.90 (CI = −0.96 to −0.75) in the tibia and r<sub>rm</sub> = −0.70 (CI = −0.87 to −0.35) in the femur. Mean T2 vs strain correlations were r<sub>rm</sub> = −0.84 (CI = −0.94 to −0.59) in the tibia and r<sub>rm</sub> = −0.11 (CI = −0.57 to 0.41) in the femur. Column-wise analyses produced negligible or weak correlations (−0.07 to −0.34 for T2 and MTR).</div></div><div><h3>Conclusions</h3><div>MTR increases with strain in the region of contact, and MTR is more strongly correlated to strain than T2. MTR shows promise as a surrogate measure of strain, especially when averaged over the region of contact.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106937"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143463780","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.jmbbm.2025.106932
Bin Wu , Mingna Li , Fan Yang , Yi Lu , Yang Yi , Mao Liu , Ke Cheng , Di Jiang , Bin Yan
Orthodontic bone remodeling simulations offer a scientific foundation for optimizing treatment plans and predicting outcomes in orthodontics. Since alveolar bone exhibits unique regional responses and high sensitivity to tensile and compressive stresses, traditional models often fail to account for these characteristics, limiting their accuracy in predicting the microstructural changes of alveolar bone under external forces. To address this issue, this study proposes a bone remodeling model based on equivalent stress derived from the Mohr strength theory as the mechanical stimulus. The model differentiates tension and compression zones within the alveolar bone and simulates density changes driven by the orthodontic remodeling process: bone formation in tension zone and resorption in compression zone. Orthodontic experiments on rats were conducted to monitor changes in alveolar bone density at 7 and 14 days. Results revealed a density increase of around 3.16% and 9.84% in tension zone and a decrease of approximately 4.86% and 3.61% in compression zone on days 7 and 14, respectively. A comparison between the experimental data and the simulation results of the bone remodeling algorithm demonstrated a consistent trend, validating that the proposed model effectively reflects the dynamic process of bone remodeling. This study provides a new perspective for orthodontic bone remodeling simulations and lays a foundation for further exploration of the mechanisms underlying alveolar bone density changes.
{"title":"A stress-driven model for bone density evolution in rats during orthodontic tooth movement","authors":"Bin Wu , Mingna Li , Fan Yang , Yi Lu , Yang Yi , Mao Liu , Ke Cheng , Di Jiang , Bin Yan","doi":"10.1016/j.jmbbm.2025.106932","DOIUrl":"10.1016/j.jmbbm.2025.106932","url":null,"abstract":"<div><div>Orthodontic bone remodeling simulations offer a scientific foundation for optimizing treatment plans and predicting outcomes in orthodontics. Since alveolar bone exhibits unique regional responses and high sensitivity to tensile and compressive stresses, traditional models often fail to account for these characteristics, limiting their accuracy in predicting the microstructural changes of alveolar bone under external forces. To address this issue, this study proposes a bone remodeling model based on equivalent stress derived from the Mohr strength theory as the mechanical stimulus. The model differentiates tension and compression zones within the alveolar bone and simulates density changes driven by the orthodontic remodeling process: bone formation in tension zone and resorption in compression zone. Orthodontic experiments on rats were conducted to monitor changes in alveolar bone density at 7 and 14 days. Results revealed a density increase of around 3.16% and 9.84% in tension zone and a decrease of approximately 4.86% and 3.61% in compression zone on days 7 and 14, respectively. A comparison between the experimental data and the simulation results of the bone remodeling algorithm demonstrated a consistent trend, validating that the proposed model effectively reflects the dynamic process of bone remodeling. This study provides a new perspective for orthodontic bone remodeling simulations and lays a foundation for further exploration of the mechanisms underlying alveolar bone density changes.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106932"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143437301","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.jmbbm.2025.106934
Jixin Hou , Nicholas Filla , Xianyan Chen , Mir Jalil Razavi , Dajiang Zhu , Tianming Liu , Xianqiao Wang
The human brain, characterized by its intricate architecture, exhibits complex mechanical properties that underpin its critical functional capabilities. Traditional computational methods, such as finite element analysis, have been instrumental in uncovering the fundamental mechanisms governing the brain's physical behaviors. However, accurate predictions of brain mechanics require effective constitutive models to represent the nuanced mechanical properties of brain tissue. In this study, we aimed to identify well-suited material models for human brain tissue by leveraging artificial neural network and multiple regression techniques. These methods were applied to a generalized framework of widely accepted classic models, and their respective outcomes were systematically compared. To evaluate model efficacy, all setups were maintained consistent across both approaches, except for strategies employed to mitigate potential overfitting. Our findings reveal that artificial neural networks are capable of automatically identifying accurate constitutive models from given admissible estimators. However, the five-term and two-term neural network models trained under single-mode and multi-mode loading scenarios, respectively, were found to be suboptimal. These models could be further simplified into two-term and single-term formulations using multiple regression, achieving even higher predictive accuracy. This refinement underscores the importance of rigorous cross-validations of regularization parameters in neural network-based methods to ensure globally optimal model selection. Additionally, our study demonstrates that traditional multivariable regression methods, when combined with appropriate information criterion, are also highly effective in discovering optimal constitutive models. These insights contribute to the ongoing development of advanced material constitutive models, particularly for complex biological tissues.
{"title":"Exploring hyperelastic material model discovery for human brain cortex: Multivariate analysis vs. artificial neural network approaches","authors":"Jixin Hou , Nicholas Filla , Xianyan Chen , Mir Jalil Razavi , Dajiang Zhu , Tianming Liu , Xianqiao Wang","doi":"10.1016/j.jmbbm.2025.106934","DOIUrl":"10.1016/j.jmbbm.2025.106934","url":null,"abstract":"<div><div>The human brain, characterized by its intricate architecture, exhibits complex mechanical properties that underpin its critical functional capabilities. Traditional computational methods, such as finite element analysis, have been instrumental in uncovering the fundamental mechanisms governing the brain's physical behaviors. However, accurate predictions of brain mechanics require effective constitutive models to represent the nuanced mechanical properties of brain tissue. In this study, we aimed to identify well-suited material models for human brain tissue by leveraging artificial neural network and multiple regression techniques. These methods were applied to a generalized framework of widely accepted classic models, and their respective outcomes were systematically compared. To evaluate model efficacy, all setups were maintained consistent across both approaches, except for strategies employed to mitigate potential overfitting. Our findings reveal that artificial neural networks are capable of automatically identifying accurate constitutive models from given admissible estimators. However, the five-term and two-term neural network models trained under single-mode and multi-mode loading scenarios, respectively, were found to be suboptimal. These models could be further simplified into two-term and single-term formulations using multiple regression, achieving even higher predictive accuracy. This refinement underscores the importance of rigorous cross-validations of regularization parameters in neural network-based methods to ensure globally optimal model selection. Additionally, our study demonstrates that traditional multivariable regression methods, when combined with appropriate information criterion, are also highly effective in discovering optimal constitutive models. These insights contribute to the ongoing development of advanced material constitutive models, particularly for complex biological tissues.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106934"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420171","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-10DOI: 10.1016/j.jmbbm.2025.106938
Kerstin Lebahn , Jonas Keiler , Wolfram Schmidt , Julia Schubert , Maria Reumann , Andreas Wree , Niels Grabow , Sabine Kischkel
For the development of stent-based intraluminal prostheses to treat chronic venous insufficiency, comprehensive knowledge of morphometric and mechanical parameters of the femoral veins (FV) is crucial for an optimized implant design. These data is essential as input for material models for numerical simulations of venous valves prostheses. However, data on mechanical properties of native/unfixed FV tissue are scarce. Unfixed native tissue, though, has limited availableness and durability due to progressing decay. To address these challenges, this study aimed to determine stress-strain behavior and compliance from native specimens of the human FV and its valves from body donations and compared the data to chemically fixed material.
A large data set has been generated in tensile tests with a total of 313 venous wall and 78 valve leaflet specimens in different fixation groups from a total of 41 body donations. Tensile testing was conducted at cut rectangular specimens in longitudinal as well as circumferential direction of the vein walls and in one specific direction for the valve leaflets. Young's moduli E1 and E2 in two differently defined strain regions, tensile strength Rm and elongation at break A were determined. Additionally, compliance measurements were performed at whole, unfixed vein segments using optical coherence tomography to determine the vessel diameter at increasing intravascular pressure from 20 to 240 mmHg.
Significant differences were found in the tensile parameters between unfixed tissue and the different fixations (exemplary Young's modulus E1 in longitudinal direction: E1, unfixed = 5.7 ± 5.1 N/mm2, E1, FA = 13.1 ± 11.9 N/mm2, E1, PFA = 2.3 ± 1.0 N/mm). A distinct anisotropy of the mechanical properties could only be detected for PFA fixed material when comparing longitudinal and circumferential tensile direction. Resultant mean compliance values over all segments and measuring positions of the vein segments for the analyzed pressure stages were in the range from 18.16 to 3.78 %/100 mmHg and showed a distinct decrease with increasing pressure.
Fixation (FA, PFA) alters the elastomechanical behavior, but the parameters were still in a similar order of magnitude considering the naturally occurring variability. Thus, testing of fixed tissue appears to be as appropriate as the use of this material for ex vivo testing. The provided material data of femoral veins (longitudinal and circumferential) as well as venous valve leaflets may serve as basis for numerical models, e.g. for the development of artificial venous valves.
{"title":"Mechanical characterization of the human femoral vein wall and its valves","authors":"Kerstin Lebahn , Jonas Keiler , Wolfram Schmidt , Julia Schubert , Maria Reumann , Andreas Wree , Niels Grabow , Sabine Kischkel","doi":"10.1016/j.jmbbm.2025.106938","DOIUrl":"10.1016/j.jmbbm.2025.106938","url":null,"abstract":"<div><div>For the development of stent-based intraluminal prostheses to treat chronic venous insufficiency, comprehensive knowledge of morphometric and mechanical parameters of the femoral veins (FV) is crucial for an optimized implant design. These data is essential as input for material models for numerical simulations of venous valves prostheses. However, data on mechanical properties of native/unfixed FV tissue are scarce. Unfixed native tissue, though, has limited availableness and durability due to progressing decay. To address these challenges, this study aimed to determine stress-strain behavior and compliance from native specimens of the human FV and its valves from body donations and compared the data to chemically fixed material.</div><div>A large data set has been generated in tensile tests with a total of 313 venous wall and 78 valve leaflet specimens in different fixation groups from a total of 41 body donations. Tensile testing was conducted at cut rectangular specimens in longitudinal as well as circumferential direction of the vein walls and in one specific direction for the valve leaflets. Young's moduli <em>E</em><sub><em>1</em></sub> and <em>E</em><sub><em>2</em></sub> in two differently defined strain regions, tensile strength <em>R</em><sub><em>m</em></sub> and elongation at break <em>A</em> were determined. Additionally, compliance measurements were performed at whole, unfixed vein segments using optical coherence tomography to determine the vessel diameter at increasing intravascular pressure from 20 to 240 mmHg.</div><div>Significant differences were found in the tensile parameters between unfixed tissue and the different fixations (exemplary Young's modulus E<sub>1</sub> in longitudinal direction: <em>E</em><sub><em>1, unfixed</em></sub> = 5.7 ± 5.1 N/mm<sup>2</sup>, <em>E</em><sub><em>1, FA</em></sub> = 13.1 ± 11.9 N/mm<sup>2</sup>, <em>E</em><sub><em>1, PFA</em></sub> = 2.3 ± 1.0 N/mm). A distinct anisotropy of the mechanical properties could only be detected for PFA fixed material when comparing longitudinal and circumferential tensile direction. Resultant mean compliance values over all segments and measuring positions of the vein segments for the analyzed pressure stages were in the range from 18.16 to 3.78 %/100 mmHg and showed a distinct decrease with increasing pressure.</div><div>Fixation (FA, PFA) alters the elastomechanical behavior, but the parameters were still in a similar order of magnitude considering the naturally occurring variability. Thus, testing of fixed tissue appears to be as appropriate as the use of this material for <em>ex vivo</em> testing. The provided material data of femoral veins (longitudinal and circumferential) as well as venous valve leaflets may serve as basis for numerical models, e.g. for the development of artificial venous valves.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106938"},"PeriodicalIF":3.3,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420169","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-08DOI: 10.1016/j.jmbbm.2025.106931
Kétlin Fagundes Teixeira , Pablo Machado Soares , Luiza Freitas Brum Souza , Gabriel Bauken , Fernanda Cocco , Cornelis Johannes Kleverlaan , João Paulo Mendes Tribst , Gabriel Kalil Rocha Pereira , Luiz Felipe Valandro , Ana Carolina Cadore-Rodrigues
The study aims to evaluate the effect of finishing and polishing protocol after CAD/CAM grinding and surface treatments of bonding surface on the topographical characteristics and fatigue behavior of 4YSZ adhesively luted to an epoxy resin substrate. Ninety 4YSZ discs (IPS e.max ZirCAD MT, Ivoclar AG) (Ø = 10 mm, thickness = 1 mm) were obtained, submitted to in-lab simulation with a CAD/CAM system bur, and randomly allocated into six groups (n = 15) based on 'Surface condition' (with or without finishing and polishing) and 'Surface treatments' (no treatment, air abrasion with 45 μm aluminum oxide and glaze spray application). The surface roughness of all samples was measured, and the discs were luted with resin cement onto an epoxy resin substrate to be tested under cyclic fatigue (step-stress approach: 20 Hz, 5,000 cycles for piston accommodation in the first step, followed by 10,000 cycles per step with a step size of 100 N, starting at 100 N until failure). The results indicated that surface roughness (Ra and Rz) decreased in the groups with polishing and finishing protocol, with no significant differences between surface treatments in groups without finishing and polishing. The air abrasion groups (whit and without finishing and polishing) showed superior fatigue performance, comparable to no treatment with polishing and finishing. While the groups no treatment without finishing and polishing, treated with glaze spray without finishing and polishing and treated with glaze spray with finishing and polishing exhibited inferior fatigue behavior. In conclusion, while the finishing and polishing protocol can minimize defects and influence the fatigue behavior of 4YSZ, its effect is not significant when combined with surface treatments. The surface treatment, particularly air abrasion, plays a more decisive role in improving fatigue performance, proving to be the most effective approach.
{"title":"Fatigue performance of 4YSZ: Effect of finishing/polishing protocol and surface treatments of the bonding surface","authors":"Kétlin Fagundes Teixeira , Pablo Machado Soares , Luiza Freitas Brum Souza , Gabriel Bauken , Fernanda Cocco , Cornelis Johannes Kleverlaan , João Paulo Mendes Tribst , Gabriel Kalil Rocha Pereira , Luiz Felipe Valandro , Ana Carolina Cadore-Rodrigues","doi":"10.1016/j.jmbbm.2025.106931","DOIUrl":"10.1016/j.jmbbm.2025.106931","url":null,"abstract":"<div><div>The study aims to evaluate the effect of finishing and polishing protocol after CAD/CAM grinding and surface treatments of bonding surface on the topographical characteristics and fatigue behavior of 4YSZ adhesively luted to an epoxy resin substrate. Ninety 4YSZ discs (IPS e.max ZirCAD MT, Ivoclar AG) (Ø = 10 mm, thickness = 1 mm) were obtained, submitted to in-lab simulation with a CAD/CAM system bur, and randomly allocated into six groups (n = 15) based on 'Surface condition' (with or without finishing and polishing) and 'Surface treatments' (no treatment, air abrasion with 45 μm aluminum oxide and glaze spray application). The surface roughness of all samples was measured, and the discs were luted with resin cement onto an epoxy resin substrate to be tested under cyclic fatigue (step-stress approach: 20 Hz, 5,000 cycles for piston accommodation in the first step, followed by 10,000 cycles per step with a step size of 100 N, starting at 100 N until failure). The results indicated that surface roughness (Ra and Rz) decreased in the groups with polishing and finishing protocol, with no significant differences between surface treatments in groups without finishing and polishing. The air abrasion groups (whit and without finishing and polishing) showed superior fatigue performance, comparable to no treatment with polishing and finishing. While the groups no treatment without finishing and polishing, treated with glaze spray without finishing and polishing and treated with glaze spray with finishing and polishing exhibited inferior fatigue behavior. In conclusion, while the finishing and polishing protocol can minimize defects and influence the fatigue behavior of 4YSZ, its effect is not significant when combined with surface treatments. The surface treatment, particularly air abrasion, plays a more decisive role in improving fatigue performance, proving to be the most effective approach.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106931"},"PeriodicalIF":3.3,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420897","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-08DOI: 10.1016/j.jmbbm.2025.106930
Camilla Johansson , Christel Larsson , Evaggelia Papia
Purpose
To evaluate how laboratory polishing and glazing and clinical adjustments, i.e., by grinding and polishing affect the biaxial flexural strength and surface characterization of multilayer zirconia.
Methods
Specimens of KATANA™ Zirconia YML, containing Enamel–Body 1 or Body 2–3 layers, and UTML were divided into 18 groups (n = 11) according to material/layer and finish treatment: laboratory polishing, glazing, or both, or followed by clinical adjustments. The surface roughness, surface structure and elemental composition were evaluated. Thermocyclic-mechanical cyclic loading and biaxial flexural strength test were performed. Three- and two-way ANOVA were used (α = 0.05).
Results
The yttrium amount decreased in the order UTML, YML Enamel–Body 1, and YML Body 2–3. Body 2–3 showed higher flexural strength than Enamel–Body 1 and UTML, in that order. Flexural strength after clinical adjustments was higher in Body 2–3 but lower in Enamel–Body 1 and UTML. Finish treatments had indistinguishable impact on Enamel–Body 1. Body 2–3 had higher strength after polishing, polishing and glazing, and glazing, in that order. UTML displayed the highest strength after polishing and glazing or glazing. The surface roughness was lowest after polishing regardless of material/layer.
Conclusions
Laboratory treatments and clinical adjustments of multilayer zirconia affect the flexural strength and surface roughness differently depending on the zirconia type. Composition-gradient zirconia should be polished, and shade-gradient zirconia (≥ 5 mol% yttria) should be polished and glazed. Clinical adjustments of zirconia with higher yttria content are detrimental for the flexural strength and should be performed with caution.
{"title":"Biaxial flexural strength and surface characterization of multilayer zirconium dioxide after polishing, glazing and clinical adjustments","authors":"Camilla Johansson , Christel Larsson , Evaggelia Papia","doi":"10.1016/j.jmbbm.2025.106930","DOIUrl":"10.1016/j.jmbbm.2025.106930","url":null,"abstract":"<div><h3>Purpose</h3><div>To evaluate how laboratory polishing and glazing and clinical adjustments, i.e., by grinding and polishing affect the biaxial flexural strength and surface characterization of multilayer zirconia.</div></div><div><h3>Methods</h3><div>Specimens of KATANA™ Zirconia YML, containing Enamel–Body 1 or Body 2–3 layers, and UTML were divided into 18 groups (<em>n</em> = 11) according to material/layer and finish treatment: laboratory polishing, glazing, or both, or followed by clinical adjustments. The surface roughness, surface structure and elemental composition were evaluated<em>.</em> Thermocyclic-mechanical cyclic loading and biaxial flexural strength test were performed. Three- and two-way ANOVA were used (<em>α</em> = 0.05).</div></div><div><h3>Results</h3><div>The yttrium amount decreased in the order UTML, YML Enamel–Body 1, and YML Body 2–3. Body 2–3 showed higher flexural strength than Enamel–Body 1 and UTML, in that order. Flexural strength after clinical adjustments was higher in Body 2–3 but lower in Enamel–Body 1 and UTML. Finish treatments had indistinguishable impact on Enamel–Body 1. Body 2–3 had higher strength after polishing, polishing and glazing, and glazing, in that order. UTML displayed the highest strength after polishing and glazing or glazing. The surface roughness was lowest after polishing regardless of material/layer.</div></div><div><h3>Conclusions</h3><div>Laboratory treatments and clinical adjustments of multilayer zirconia affect the flexural strength and surface roughness differently depending on the zirconia type. Composition-gradient zirconia should be polished, and shade-gradient zirconia (≥ 5 mol% yttria) should be polished and glazed. Clinical adjustments of zirconia with higher yttria content are detrimental for the flexural strength and should be performed with caution.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"166 ","pages":"Article 106930"},"PeriodicalIF":3.3,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143471276","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-08DOI: 10.1016/j.jmbbm.2025.106923
Hüray Ilayda Kök , Miriam Kick , Osman Akbas , Sebastian Stammkötter , Andreas Greuling , Meike Stiesch , Frank Walther , Philipp Junker
To improve longevity and performance of dental implants by reducing stress-shielding, a modification of the internal structure of the implant can be a solution. In this paper the inner design of the implant is generated either using a topology optimization approach or an approach based on TPMS lattice structures. These approaches aim to maintain long-term stability and to reduce stress-shielding. For both approaches, the mechanostat model was applied to investigate the influence of the inner structure to the surrounding bone tissue and compare the standard uniform implant. For the investigation an ANSYS model was used with material parameters obtained from a mechanical test of additively manufactured Ti6Al4V. Compared to the uniform implant, the topology-optimized implant showed 20% less stress-shielding, and the implant with triply periodic minimal surface structures (TPMS) showed 15% less stress-shielding. Further, the long-term-stability was investigated by introducing a high-cycle fatigue material model. Despite a change in the internal structure and a 45% reduction in the mass of the topology-optimized implant, the cycle numbers specified in the DIN EN ISO 14801 standard were fulfilled.
{"title":"Reduction of stress-shielding and fatigue-resistant dental implant design through topology optimization and TPMS lattices","authors":"Hüray Ilayda Kök , Miriam Kick , Osman Akbas , Sebastian Stammkötter , Andreas Greuling , Meike Stiesch , Frank Walther , Philipp Junker","doi":"10.1016/j.jmbbm.2025.106923","DOIUrl":"10.1016/j.jmbbm.2025.106923","url":null,"abstract":"<div><div>To improve longevity and performance of dental implants by reducing stress-shielding, a modification of the internal structure of the implant can be a solution. In this paper the inner design of the implant is generated either using a topology optimization approach or an approach based on TPMS lattice structures. These approaches aim to maintain long-term stability and to reduce stress-shielding. For both approaches, the mechanostat model was applied to investigate the influence of the inner structure to the surrounding bone tissue and compare the standard uniform implant. For the investigation an ANSYS model was used with material parameters obtained from a mechanical test of additively manufactured Ti<img>6Al<img>4V. Compared to the uniform implant, the topology-optimized implant showed 20% less stress-shielding, and the implant with triply periodic minimal surface structures (TPMS) showed 15% less stress-shielding. Further, the long-term-stability was investigated by introducing a high-cycle fatigue material model. Despite a change in the internal structure and a 45% reduction in the mass of the topology-optimized implant, the cycle numbers specified in the DIN EN ISO 14801 standard were fulfilled.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106923"},"PeriodicalIF":3.3,"publicationDate":"2025-02-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143402497","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-07DOI: 10.1016/j.jmbbm.2025.106927
Xingyue Wang , Susu Wang , Akoumay Tehoungue , Yurong Li , Xiang Li , Yanhui , Mingkun Zhu , Guozheng Zhang , Yeshun Zhang
Oxidative stress and infection significantly obstruct the process of diabetic wound healing. Herein, we developed a new sericin hydrogel with excellent antioxidative and antimicrobial features for the treatment of diabetic wounds. This hydrogel was prepared from a native sericin solution collected from silk fibroin-deficient mutant silkworm bodies; it also possesses exceptional ductility, high transparency, and excellent biocompatibility, enabling the hydrogel dressing to effectively eliminate excessive reactive oxygen species, while preventing bacterial infections within the diabetic wound microenvironment. Additionally, the hydrogel facilitates real-time monitoring of wounds and surgical sutures. Furthermore, it demonstrates pH-responsive swelling and degradation properties, along with a microporous structure, which collectively foster a moist, flexible, and breathable environment conducive to tissue regeneration, thereby promoting wound healing. Moreover, the hydrogel promotes the adhesion and proliferation of NIH3T3 cells, and in vivo studies highlight its ability to expedite wound healing. These findings suggest that the formic acid-treated sericin hydrogel dressing holds great promise as an advanced solution for managing diabetic wounds.
{"title":"A robust visualized sericin hydrogel dressing with excellent antioxidative and antimicrobial activities facilitates diabetic wound healing","authors":"Xingyue Wang , Susu Wang , Akoumay Tehoungue , Yurong Li , Xiang Li , Yanhui , Mingkun Zhu , Guozheng Zhang , Yeshun Zhang","doi":"10.1016/j.jmbbm.2025.106927","DOIUrl":"10.1016/j.jmbbm.2025.106927","url":null,"abstract":"<div><div>Oxidative stress and infection significantly obstruct the process of diabetic wound healing. Herein, we developed a new sericin hydrogel with excellent antioxidative and antimicrobial features for the treatment of diabetic wounds. This hydrogel was prepared from a native sericin solution collected from silk fibroin-deficient mutant silkworm bodies; it also possesses exceptional ductility, high transparency, and excellent biocompatibility, enabling the hydrogel dressing to effectively eliminate excessive reactive oxygen species, while preventing bacterial infections within the diabetic wound microenvironment. Additionally, the hydrogel facilitates real-time monitoring of wounds and surgical sutures. Furthermore, it demonstrates pH-responsive swelling and degradation properties, along with a microporous structure, which collectively foster a moist, flexible, and breathable environment conducive to tissue regeneration, thereby promoting wound healing. Moreover, the hydrogel promotes the adhesion and proliferation of NIH3T3 cells, and in vivo studies highlight its ability to expedite wound healing. These findings suggest that the formic acid-treated sericin hydrogel dressing holds great promise as an advanced solution for managing diabetic wounds.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106927"},"PeriodicalIF":3.3,"publicationDate":"2025-02-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143395882","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-06DOI: 10.1016/j.jmbbm.2025.106929
Joyce R. de Souza , Caroline Anselmi , Lais M. Cardoso , Letícia T. Kito , Alexandre H. dos Reis-Prado , Pedro H.C. de Oliveira , Renan Dal-Fabbro , Maedeh Rahimnejad , Tiago M.B. Campos , Luciano T.A. Cintra , Alexandre L.S. Borges , Marco C. Bottino
Bone regeneration remains a critical challenge in regenerative medicine, particularly in dentistry, where conditions such as periodontal disease and trauma can lead to significant bone defects. Traditional treatment methods, such as autogenous bone grafting, face limitations, including donor site morbidity and postoperative complications. Recent advancements in biomaterials, particularly silk fibroin-based scaffolds, have shown promise due to their excellent biocompatibility and tunable mechanical properties. Incorporating bioactive glass and metal ions, such as cobalt, into these scaffolds can enhance osteogenic properties and antibacterial effects, creating an optimal environment for bone regeneration. The primary objective of this study was to develop and characterize SilkMA/silicated-chlorinated cobalt-doped bioactive glass composites with the potential for bone regeneration applications. Utilizing the sol-gel method, we synthesized cobalt-doped bioglass, enhancing its bioactivity and antibacterial properties. Mechanical testing, swelling assessments, degradation analysis, and in vitro evaluations using alveolar bone-derived mesenchymal stem cells (aBMSCs) demonstrated the scaffolds' cytocompatibility and favorable physical properties. The structural integrity of the electrospun fibers was confirmed through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy analyses. Incorporating bioglass reduced swelling ratios, while in vitro assays showed that cobalt ions effectively inhibited the biofilm formation of Porphyromonas gingivalis. In vivo analysis using hematoxylin-eosin and von Kossa (vK) staining demonstrated that the SilkMA + 20% BGCo scaffold elicited a minimal inflammatory response, confirming its biocompatibility. However, the absence of positively stained structures in the vK analysis indicated its lack of mineralization potential. In sum, SilkMA/BGCo scaffolds showed promising in vitro potential for bone tissue regeneration and excellent biocompatibility in vivo despite lacking calcium deposition. Further studies with alternative in vivo models are needed to confirm their efficacy.
{"title":"Electrospun SilkMA/silicate-chlorinated cobalt-doped bioactive glass composite for bone regeneration","authors":"Joyce R. de Souza , Caroline Anselmi , Lais M. Cardoso , Letícia T. Kito , Alexandre H. dos Reis-Prado , Pedro H.C. de Oliveira , Renan Dal-Fabbro , Maedeh Rahimnejad , Tiago M.B. Campos , Luciano T.A. Cintra , Alexandre L.S. Borges , Marco C. Bottino","doi":"10.1016/j.jmbbm.2025.106929","DOIUrl":"10.1016/j.jmbbm.2025.106929","url":null,"abstract":"<div><div>Bone regeneration remains a critical challenge in regenerative medicine, particularly in dentistry, where conditions such as periodontal disease and trauma can lead to significant bone defects. Traditional treatment methods, such as autogenous bone grafting, face limitations, including donor site morbidity and postoperative complications. Recent advancements in biomaterials, particularly silk fibroin-based scaffolds, have shown promise due to their excellent biocompatibility and tunable mechanical properties. Incorporating bioactive glass and metal ions, such as cobalt, into these scaffolds can enhance osteogenic properties and antibacterial effects, creating an optimal environment for bone regeneration. The primary objective of this study was to develop and characterize SilkMA/silicated-chlorinated cobalt-doped bioactive glass composites with the potential for bone regeneration applications. Utilizing the sol-gel method, we synthesized cobalt-doped bioglass, enhancing its bioactivity and antibacterial properties. Mechanical testing, swelling assessments, degradation analysis, and <em>in vitro</em> evaluations using alveolar bone-derived mesenchymal stem cells (aBMSCs) demonstrated the scaffolds' cytocompatibility and favorable physical properties. The structural integrity of the electrospun fibers was confirmed through Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and Raman Spectroscopy analyses. Incorporating bioglass reduced swelling ratios, while <em>in vitro</em> assays showed that cobalt ions effectively inhibited the biofilm formation of <em>Porphyromonas gingivalis</em>. <em>In vivo</em> analysis using hematoxylin-eosin and von Kossa (vK) staining demonstrated that the SilkMA + 20% BGCo scaffold elicited a minimal inflammatory response, confirming its biocompatibility. However, the absence of positively stained structures in the vK analysis indicated its lack of mineralization potential. In sum, SilkMA/BGCo scaffolds showed promising <em>in vitro</em> potential for bone tissue regeneration and excellent biocompatibility <em>in vivo</em> despite lacking calcium deposition. Further studies with alternative <em>in vivo</em> models are needed to confirm their efficacy.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"164 ","pages":"Article 106929"},"PeriodicalIF":3.3,"publicationDate":"2025-02-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143372384","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-02-05DOI: 10.1016/j.jmbbm.2025.106904
Fatemeh Khorami , Numaira Obaid , Carolyn J. Sparrey
Hip injuries are a frequent outcome of falls. Studying the biomechanics of hip injuries requires a comprehensive understanding of soft tissue properties and their responses to external loads. Particularly, muscle activity is crucial in arresting a fall and is likely to affect soft tissue properties. Failing to consider muscle activation might result in incorrect conclusions regarding the processes underlying injuries and the efficacy of preventive strategies. Soft tissue response is also affected by loading rate, sex, and mechanical testing protocols, highlighting the need for precise experimental design and interpretation.
Forty individuals (age = 25.53 ± 3.41 years) were recruited (20 males and 20 females) to investigate the hip soft tissue response during a high-speed cyclic indentation testing. Muscle activity was recorded using electromyography (EMG) and soft tissue thickness was measured using ultrasound imaging. Peak force, energy, and tissue stiffness were measured using tissue indentation.
The hip soft tissue exhibited hysteresis and was nonlinear during loading. Sex differences in trochanteric soft tissue stiffness resulted in males having 38% higher peak force than females and absorbed energy was 32% higher in the active state than the passive state (in combined participants).
Characterizing the range of tissue responses for in vivo hip soft tissues emphasizes the natural variability in healthy human tissues and the need to consider the range of tissue behaviors in models, not just the average response. Both sex and muscle activation increased tissue mechanical variability and need to be considered in future physical and computational models of hip impact.
{"title":"Sex differences in in vivo soft tissue compressive properties of the human hip in young adults: a comparison between passive vs active state","authors":"Fatemeh Khorami , Numaira Obaid , Carolyn J. Sparrey","doi":"10.1016/j.jmbbm.2025.106904","DOIUrl":"10.1016/j.jmbbm.2025.106904","url":null,"abstract":"<div><div>Hip injuries are a frequent outcome of falls. Studying the biomechanics of hip injuries requires a comprehensive understanding of soft tissue properties and their responses to external loads. Particularly, muscle activity is crucial in arresting a fall and is likely to affect soft tissue properties. Failing to consider muscle activation might result in incorrect conclusions regarding the processes underlying injuries and the efficacy of preventive strategies. Soft tissue response is also affected by loading rate, sex, and mechanical testing protocols, highlighting the need for precise experimental design and interpretation.</div><div>Forty individuals (age = 25.53 ± 3.41 years) were recruited (20 males and 20 females) to investigate the hip soft tissue response during a high-speed cyclic indentation testing. Muscle activity was recorded using electromyography (EMG) and soft tissue thickness was measured using ultrasound imaging. Peak force, energy, and tissue stiffness were measured using tissue indentation.</div><div>The hip soft tissue exhibited hysteresis and was nonlinear during loading. Sex differences in trochanteric soft tissue stiffness resulted in males having 38% higher peak force than females and absorbed energy was 32% higher in the active state than the passive state (in combined participants).</div><div>Characterizing the range of tissue responses for in vivo hip soft tissues emphasizes the natural variability in healthy human tissues and the need to consider the range of tissue behaviors in models, not just the average response. Both sex and muscle activation increased tissue mechanical variability and need to be considered in future physical and computational models of hip impact.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"165 ","pages":"Article 106904"},"PeriodicalIF":3.3,"publicationDate":"2025-02-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143420167","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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