Journal of the Mechanical Behavior of Biomedical Materials最新文献

{"title":"Impact of a prophylactic mesh on the biomechanics of abdominal wall closure: an animal study","authors":"Anicet Le Ruyet ,&nbsp;Baptiste Pillet ,&nbsp;Anthony Végleur ,&nbsp;Arthur Jourdan ,&nbsp;Aline Bel-Brunon ,&nbsp;Ludovic Bouré ,&nbsp;Baptiste Pierrat","doi":"10.1016/j.jmbbm.2025.107014","DOIUrl":"10.1016/j.jmbbm.2025.107014","url":null,"abstract":"<div><h3>Background</h3><div>The use of a prophylactic prosthetic mesh (PPM) to reinforce a midline laparotomy suture closure improves the clinical outcomes, in comparison with primary suture technique. However, understanding how a PPM impacts the biomechanics of the repair is crucial for gaining a deeper comprehension and ultimately improving clinical outcome by decreasing incisional hernia (IH) rates post midline laparotomy. Based on a porcine IH model, this study aimed to assess the biomechanical characteristics of the abdominal wall (AW) midline over time post midline laparotomy, considering sthree repair modalities: no repair, primary suture and onlay mesh reinforcement coupled with suture.</div></div><div><h3>Methods</h3><div>31 pigs were enrolled in the study and the repair was characterized using CT-scans based on the distance between the right and left Rectus Abdominis Muscle (RAM). The AW of each animal was explanted at 48 h, 4 and 12 weeks postoperatively and a Stereo Digital Image Correlation (s-DIC)-based method was used to assess the response of the repaired AW (<em>e.g.</em>, strain, compliance) when subjected to an inflation test mimicking an increase in intra-abdominal pressure (IAP). Intact AW were included in the study and served as controls.</div></div><div><h3>Results</h3><div>AWs repaired with a primary suture exhibited a higher RAM distance compared to healthy animals, along with an increased compliance of the repair along the transverse direction over time. AWs repaired with primary suture and reinforced with a PPM exhibited a biomechanical response similar to that of healthy animals in terms of repair strain and compliance.</div></div><div><h3>Conclusion</h3><div>The use of a PPM to reinforce suture was found to better restore the biomechanical properties to the midline of the AW post midline incision. Further investigations are needed to correlate the findings of this study with clinical outcomes, especially long-term recurrence rates.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107014"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869545","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}

{"title":"Comparative study of wear properties of CAD/CAM PEEK materials, resin ceramics and dental enamel under simulated chewing conditions","authors":"Kangjie Li ,&nbsp;Meng Meng ,&nbsp;Chenghua Li ,&nbsp;Yuchen Liu ,&nbsp;Hengyan Liu ,&nbsp;Shizhu Bai ,&nbsp;Sheng Zhong ,&nbsp;Meng Li ,&nbsp;Li Chen ,&nbsp;Min Tian ,&nbsp;Lina Niu ,&nbsp;Ming Fang","doi":"10.1016/j.jmbbm.2025.107012","DOIUrl":"10.1016/j.jmbbm.2025.107012","url":null,"abstract":"<div><h3>Objectives</h3><div>To compare the impact-sliding wear properties of CAD/CAM polyetheretherketone (PEEK) materials and resin ceramics with dental enamel, and to investigate the corresponding wear mechanisms.</div></div><div><h3>Methods</h3><div>Six CAD/CAM polymer materials were assessed in comparison with human tooth enamel. Hardness, modulus and roughness values of each group were measured, prior to wear testing in a chewing simulator (ball-on-disc design, 49 N). Wear depth, volume loss and wear rate were analysed using a nanoindentation tester and an optical profiler. Wear scars were further examined by backscattered electron scanning electron microscopy to identify the tribo-mechanisms.</div></div><div><h3>Results</h3><div>No significant difference in wear rate was found among BioHPP®, BioPEAK® (two filler-containing PEEK compounds) and natural enamel, during chewing simulation. After 500,000 cycles, the former two materials exhibited lower wear depth and volume loss of material and the steatite antagonists, as well as smaller wear scars, than pure PEEK Shushijie™, resin ceramics Vita ENAMIC<strong>®</strong> and Lava™ Ultimate, despite lower baseline hardness and elastic modulus than enamel. Of all the groups, BioHPP®, a ceramic-filled PEEK compound, exhibited the greatest wear resistance and the least abrasiveness to the antagonist, comparable to enamel. PEEK materials can absorb the impact stress and undergo plastic deformation, which is different from the impact-sliding wear mechanisms of resin ceramics.</div></div><div><h3>Conclusions</h3><div>With increasing wear cycles, PEEK compounds with high filler densities showed more favourable wear properties, comparable to enamel; and formed a compacted wear debris layer, exhibiting self-lubrication, despite of three-body wear.</div></div><div><h3>Clinical significance</h3><div>Within the limitations of our results, PEEK compounds are particularly suitable for pathological wear conditions in posterior regions.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107012"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143863749","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}

{"title":"3D-printed programmable bistable mechanisms for customized wearable devices in tremor attenuation","authors":"Moslem Mohammadi ,&nbsp;Abbas Z. Kouzani ,&nbsp;Mahdi Bodaghi ,&nbsp;Ali Zolfagharian","doi":"10.1016/j.jmbbm.2025.107006","DOIUrl":"10.1016/j.jmbbm.2025.107006","url":null,"abstract":"<div><div>This research proposes a computational framework for designing a compliant bistable mechanism and fabricating it using 3D printing for customized medical applications. The proposed method reduces upper limb tremors, taking advantage of the nonlinear mechanical properties of flexible structures. The model's development and execution on a single platform streamlines integrated inverse design and simulation, simplifying the customization process. A synthetic human arm model, built to imitate a human wrist, was scanned with a light detection and ranging (LiDAR) sensor to customize the 3D model of the bistable structure. Afterwards, the arm model was used to test the bistable mechanism. Automating the inverse design process with a deep neural network (DNN) and evolutionary optimization decides the optimal bistable mechanism configurations for stiffness and vibration attenuation. The pseudo-rigid-body model (PRBM) of the bistable mechanism was developed to train the machine learning (ML) model in the inverse design, making it computationally affordable to find the optimal parameters of bistable structure for a specific mechanical response based on tremor characteristics. Experimental results showing up to 87.11 % reduction in tremor power while weighing only 27 g to reduce vibrations in various situations suggest its use in 4D printing of wearable orthotic devices for Parkinsonian tremors and related diseases.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107006"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143859158","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}

{"title":"Adhesion of bone cement to porous and nonporous 3D printed surfaces","authors":"Caroline Alting ,&nbsp;William R. Walsh ,&nbsp;Robert Tait ,&nbsp;Ken Gall","doi":"10.1016/j.jmbbm.2025.107019","DOIUrl":"10.1016/j.jmbbm.2025.107019","url":null,"abstract":"<div><div>Bone cement is an adhesive commonly used to bond orthopedic implants to bone during a surgical procedure. Total joint replacements such as total knee, hip, shoulder, or ankle arthroplasties have metal or polymer components that are commonly cemented. However, implant failures can occur via debonding at the implant-cement interface, suggesting sub-optimal adhesion of the cement to the implant. In parallel, the orthopedic implant industry is seeing a significant rise in additive manufacturing (AM), which enables the seamless integration of surface porosity enhanced osseointegration in cementless procedures. However, there is a lack of foundational data or understanding of how bone cement adheres to 3D printed surfaces as a function of varying topography. This study evaluates adhesion of cement to clinically relevant printed implant surfaces, porous topographies, and materials. Adhesion strength of cemented samples was tested in shear. Surface porous layers were compared to traditional implant surface finishes (blasted, machined, polished). The impact of 3D printed surface porosity size and depth was also investigated. Testing revealed that the adhesive strength of porous surfaces (26.3 ± 3.1 MPa) was more than double the adhesive strength of all non-porous surfaces (the highest being the as-printed surface with a strength of 11.3 ± 2.5 MPa). The study also demonstrated porosity and layer-depth dependent performance trade-offs, with the best performing group having a 2x2x2 mm³ unit cell size and 0.50 mm layer depth and a shear strength of 26.31 ± 3.10 MPa. These results provide a foundation for improving designs of emerging 3D printed orthopedic implants that can be both cemented and cementless.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107019"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869544","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}

{"title":"A novel diffusion tensor based three-dimensional constitutive model for human breast tissue","authors":"Michael S. Sacks ,&nbsp;Benjamin Thomas ,&nbsp;Christian Goodbrake ,&nbsp;Aldan Webb ,&nbsp;Charles V. Kingsley ,&nbsp;Jason Stafford ,&nbsp;Gregory P. Reece ,&nbsp;Kristy Brock","doi":"10.1016/j.jmbbm.2025.106996","DOIUrl":"10.1016/j.jmbbm.2025.106996","url":null,"abstract":"<div><div>There is a lack of understanding how human breast tissue internal structure connects to its bulk level 3D mechanical behaviors. An attractive method to quantify tissue structure is diffusion tensor imaging (DTMRI), which produces compact, local, quantitative information in the form of a second rank symmetric tensor <strong>D</strong>. As <strong>D</strong> contains rich information about local 3D tissue structure, we developed a novel constitutive model form for human fibroglandular (FG) and adipose (AD) breast tissues that directly utilized the complete <span><math><mi>D</mi></math></span>. Our modeling approach included separate extensional/compression and shear-like interactions terms. To develop the necessary mathematical forms we utilized a neural network modeling approach trained using pure-shear loading paths from the extant triaxial data for the AD and FG groups. A final model form was formulated and model parameters determined using the same data set. The resultant constitutive model was able to simulate the unique anisotropic tension/compression behaviors, including directionally dependent non-linearities for the FG tissue group. The constitutive model was validated in two steps. First, we used the model to predict <strong>D</strong> and compared it to <strong>D</strong> as measured directly by DTMRI on excised breast tissue, which compared very well. Secondly, validation of the predictive capabilities of the model were demonstrated by accurate predictions of breast tissue in simple compression for both AD and FG tissue groups. The present modeling approach was able to predict human breast tissue 3D mechanical behavior accurately, as well as shed insight into connections to the underlying tissue structure via the use of <strong>D</strong>.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 106996"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143851684","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}

{"title":"Towards the development of reliable finite element models of Ti6Al4V trabecular structures fabricated via laser powder bed fusion for biomedical applications","authors":"Francesca Danielli ,&nbsp;Qingbo Wang ,&nbsp;Francesca Berti ,&nbsp;Adelaide Nespoli ,&nbsp;Tomaso Villa ,&nbsp;Lorenza Petrini ,&nbsp;Chao Gao","doi":"10.1016/j.jmbbm.2025.107022","DOIUrl":"10.1016/j.jmbbm.2025.107022","url":null,"abstract":"<div><div>Additive manufacturing technologies are commonly adopted for the fabrication of trabecular-based orthopedic prostheses made of titanium alloys due to their ability in producing complex and intricate designs. In this scenario, the use of finite element models represents a powerful tool for designing such devices and assessing their biomechanical behavior. Nevertheless, the usefulness of a numerical approach depends on the reliability of the adopted models, a crucial aspect when dealing with trabecular structures present within orthopedic implants. Indeed, the description of their effective geometry and the characterization of the material mechanical properties represent a tough challenge that hinders the development of high-fidelity numerical models. Specifically, the small dimensions of the trabeculae approach the accuracy limit of additive manufacturing leading to relevant uncertainties in their production. The existing studies dealing with the finite element modeling of 3D-printed trabecular structures often neglect the geometrical and material peculiarities of thin struts, making questionable the reliability of the developed numerical models. Namely, they either make simplifications in describing the mechanical properties of the material or do not account for realistic geometries. To address this gap, the present work aims to propose a systematic approach that achieves the development of accurate finite element models of trabecular structures, by integrating experimental activities with numerical simulations. This approach is exemplified by using two distinct trabecular structures used in the design of a custom talus prosthesis.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107022"},"PeriodicalIF":3.3,"publicationDate":"2025-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143876823","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}

{"title":"Quantification of the mechanical effects of saline on human ex vivo stratum corneum","authors":"L. Moogan,&nbsp;G.K. German","doi":"10.1016/j.jmbbm.2025.107016","DOIUrl":"10.1016/j.jmbbm.2025.107016","url":null,"abstract":"<div><div>The <em>stratum corneum</em> (SC) acts as the body's inert barrier to the outside world, protecting viable tissue from potentially damaging environmental factors. One of the fundamental functions of the SC is to maintain water in the skin by minimizing trans-epidermal water loss (TEWL). When the SC degrades, the ability to hold water in the underlying tissue is reduced, increasing TEWL, exposing the skin to xerosis and potential fracture if left untreated. It is a widely described urban myth that people experience dry and tight ‘weathered’ skin after swimming in the ocean during trips to the beach. It is unknown, however, to what degree saltwater is responsible for the barrier disruption that leads to the feeling of this dry skin. In this initial investigation, we study the impact of saline water treatment on the elastic modulus and drying stress build up within ex vivo SC in comparison with pure water using an established high-throughput mechanical method. Saline was found to cause significantly higher elastic moduli (<span><math><mrow><msub><mi>E</mi><mrow><mi>S</mi><mi>C</mi></mrow></msub><mo>=</mo><mn>5.13</mn><mo>±</mo><mn>1.20</mn></mrow></math></span> MPa) and drying stresses (<span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>C</mi></mrow></msub><mo>=</mo><mn>208.5</mn><mo>±</mo><mn>24.0</mn></mrow></math></span> kPa) in the SC as opposed to deionized water (<span><math><mrow><msub><mi>E</mi><mrow><mi>S</mi><mi>C</mi></mrow></msub><mo>=</mo><mn>2.75</mn><mo>±</mo><mn>0.89</mn></mrow></math></span> MPa, <span><math><mrow><msub><mi>P</mi><mrow><mi>S</mi><mi>C</mi></mrow></msub><mo>=</mo><mn>91.23</mn><mo>±</mo><mn>25.55</mn></mrow></math></span> kPa) (<span><math><mrow><mi>p</mi><mo>=</mo><mn>0.018</mn><mo>,</mo><mi>p</mi><mo>=</mo><mn>0.003</mn></mrow></math></span>), indicating that exposure to saltwater significantly alters the drying behavior of the SC. This disrupted barrier could lead to xerotic skin. It also appears to explain the anecdotal experience of dry and tight-feeling skin following swimming in the ocean or seawater.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107016"},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869542","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}

{"title":"The multi-factor effects study on mechanical properties of rat skin using orthogonal experimental design","authors":"Shuaijun Yang ,&nbsp;Xuewei Song ,&nbsp;Hui Zhao ,&nbsp;Zhikang Liao ,&nbsp;Xiyan Zhu ,&nbsp;Nan Wang ,&nbsp;Jingru Xie ,&nbsp;Danfeng Yuan ,&nbsp;Jinlong Qiu","doi":"10.1016/j.jmbbm.2025.107018","DOIUrl":"10.1016/j.jmbbm.2025.107018","url":null,"abstract":"<div><div>Skin is highly susceptible to damage and laceration in various scenarios such as traffic accidents, sports or daily falls. These injuries can occur at anywhere on the body, in any direction, and at varying stretching speeds, making skin a kind of material influenced by multiple factors. To obtain a comprehensive understanding of the mechanical properties of skin across the entire body, a multi-factor effects study was conducted using Rats. An experiment design utilizing an orthogonal table was established, incorporating three pivotal factors: Site, Strain Rate, and Sampling Orientation, each with multiple levels to explore their respective impacts. Skin samples collected from four different anatomical locations, with each location being sampled in three directions, were tested using uniaxial tensile test at three different stretching speeds to obtain stress-strain curves. From these curves, key mechanical indices were derived, including ultimate stress, ultimate strain, failure strain energy, and elastic modulus, were acquired from the curves as the indices. By utilizing Analysis of Variance with these four parameters as indices, the sum of squares of deviations was calculated, and this enabled the precise quantification of each factor's contribution rate to the indices, the variability among the levels within each factor, and the impact of errors on the experimental results.</div><div>The results indicate that the site factor has the greatest impact on the mechanical properties of rat skin, followed by the Strain rate factor, and then the Sampling orientation factor. Specifically, their integrated contribution rates are 59.00 %, 27.88 %, and 1.93 %, respectively.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107018"},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143869543","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}

{"title":"Corroboration in vivo mechanical strain distribution in soft tissues for pressure ulcer prevention: A comparative analysis between a simplified finite element analysis and experimental strain fields","authors":"Alexandre Segain ,&nbsp;Helene Pillet ,&nbsp;Stefano Zappalá ,&nbsp;Giuseppe Sciume ,&nbsp;Pierre-Yves Rohan","doi":"10.1016/j.jmbbm.2025.107017","DOIUrl":"10.1016/j.jmbbm.2025.107017","url":null,"abstract":"<div><div>Basic research into the aetiology of pressure ulcers suggests that the concentration of mechanical strain in biological soft tissues is critical to their development. Direct measurement of <em>in vivo</em> strain is not compatible with clinical routine. To overcome this problem, several finite element models (FEM) have been proposed by the biomechanical community to estimate strain from imaging data. However, no direct experimental validation of the underlying relationships between mechanical loading and soft tissue strain distribution predicted by the model has been performed, and such validation evidence must be obtained prior to any clinical evaluation. Building on the experimental results obtained in N = 10 healthy volunteers (Zappalá et al., 2024), the relevance of the modelling hypotheses of the finite element model proposed in this study, which is based on a simplified geometric representation of the ischial region (Macron et al., 2020), was investigated. A methodology was proposed to estimate the different parameters needed to construct the model from the available MRI masks. The FEM was then used to estimate <em>in vivo</em> compressive and shear strains. The resulting strains were then compared with experimental data. The results show that the model assumptions lead to an overall overestimation of the compressive and shear strains in the muscle tissue, especially directly under the ischial tuberosity. Similarly, the model underestimates the strain in adipose tissue (mean error in shear strain of −0.2). This study highlights the fact that the assumptions usually made for the geometric modelling of muscle tissue (homogeneous soft tissue layer) lead to an incorrect estimation of peak strain localisation. Further work should be done to improve the representation of muscle tissue.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107017"},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143850662","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}

{"title":"Degradation of experimental composites containing calcium orthophosphate particles in different immersion media","authors":"Handially dos Santos Vilela,&nbsp;Tarsila Vaz Marcolino Alves,&nbsp;Amanda Lopes Campos,&nbsp;Rafael Bergamo Trinca,&nbsp;Roberto Ruggiero Braga","doi":"10.1016/j.jmbbm.2025.107009","DOIUrl":"10.1016/j.jmbbm.2025.107009","url":null,"abstract":"<div><div>The aim of the present study was to evaluate the effect of prolonged immersion in different media on the mechanical properties of composites containing dicalcium phosphate dihydrate particles (DCPD, CaHPO₄.2H₂O). Three formulations with the same resin phase (BisGMA/TEGMA, 1:1 in moles) were prepared. The total inorganic content was 50 vol%, consisting of barium glass (BG) or a mixture of BG and DCPD (15:35 or 35:15 vol%). The degree of conversion (DC) of the composites was determined using FTIR spectroscopy (n = 3). Biaxial flexural strength (BFS) and flexural modulus (FM) were determined using the “piston-on-three-spheres” method (n = 13) after 24 h and 6 months in deionized water (DW), citric acid (CA, pH 5) or 75 % ethanol solution (EtOH). Knoop microhardness (KHN, n = 6) was determined in fragments of the flexural test specimens. Data were analysed using ANOVA/Tukey's test (alpha: 5 %). DC was statistically higher for the 35 % DCPD composite (p &lt; 0.001). Overall, mechanical properties were inversely related to DCPD fraction in all three media and both storage times. The 15 % DCPD composite had BFS statistically similar to the control in most of the tested conditions, and similar FM after 24h in all media. However, CA had a severe negative effect on the KHN of composites containing DCPD both after 24h and 6 months, while EtOH caused the highest reduction in KHN for the control, in comparison to DW. Based on these results, it is concluded that composites containing DCPD presented higher surface degradation than the control, which may limit their use as bulk restoratives.</div></div>","PeriodicalId":380,"journal":{"name":"Journal of the Mechanical Behavior of Biomedical Materials","volume":"168 ","pages":"Article 107009"},"PeriodicalIF":3.3,"publicationDate":"2025-04-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143887497","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}