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Gao LT, Chen YM, Aziz Y, Wei W, Zhao XY, He Y, Li J, Li H, Miyatake H, Ito Y. Tough, self-healing and injectable dynamic nanocomposite hydrogel based on gelatin and sodium alginate. Carbohydr Polym 2024; 330:121812. [PMID: 38368083 DOI: 10.1016/j.carbpol.2024.121812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2023] [Revised: 12/13/2023] [Accepted: 01/08/2024] [Indexed: 02/19/2024]
Abstract
Biomacromolecules based injectable and self-healing hydrogels possessing high mechanical properties have widespread potential in biomedical field. However, dynamic features are usually inversely proportional to toughness. It is challenging to simultaneously endow these properties to the dynamic hydrogels. Here, we fabricated an injectable nanocomposite hydrogel (CS-NPs@OSA-l-Gtn) stimultaneously possessing excellent autonomous self-healing performance and high mechanical strength by doping chitosan nanoparticles (CS-NPs) into dynamic polymer networks of oxidized sodium alginate (OSA) and gelatin (Gtn) in the presence of borax. The synergistic effect of the multiple reversible interactions combining dynamic covalent bonds (i.e., imine bond and borate ester bond) and noncovalent interactions (i.e., electrostatic interaction and hydrogen bond) provide effective energy dissipation to endure high fatigue resistance and cyclic loading. The dynamic hydrogel exhibited excellent mechanical properties like maximum 2.43 MPa compressive strength, 493.91 % fracture strain, and 89.54 kJ/m3 toughness. Moreover, the integrated hydrogel after injection and self-healing could withstand 150 successive compressive cycles. Besides, the bovine serum albumin embedded in CS-NPs could be sustainably released from the nanocomposite hydrogel for 12 days. This study proposes a novel strategy to synthesize an injectable and self-healing hydrogel combined with excellent mechanical properties for designing high-strength natural carriers with sustained protein delivery.
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Affiliation(s)
- Li Ting Gao
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Yong Mei Chen
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China.
| | - Yasir Aziz
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Wei Wei
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Xin Yi Zhao
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Yuan He
- College of Bioresources Chemical and Materials Engineering, National Demonstration Center for Experimental Light Chemistry Engineering Education, Shaanxi University of Science & Technology, Xi'an, Shaanxi 710021, China
| | - Jianhui Li
- Department of Surgical Oncology, Shaanxi Provincial People's Hospital, Xi'an, Shaanxi 710068, China.
| | - Haopeng Li
- Second Affiliated Hospital of Xi'an Jiaotong University, Xi'an Jiaotong University, Xi'an. Shaanxi 710049, China
| | - Hideyuki Miyatake
- Nano Medical Engineering Laboratory, RIKEN Cluster for Pioneering Research, Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 3510198, Japan
| | - Yoshihiro Ito
- Nano Medical Engineering Laboratory, RIKEN Cluster for Pioneering Research, Emergent Bioengineering Materials Research Team, RIKEN Center for Emergent Matter Science, 2-1 Hirosawa, Wako, Saitama 3510198, Japan
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Stevenson JD, Kilding AE, Plews DJ, Maunder E. Prolonged exercise shifts ventilatory parameters at the moderate-to-heavy intensity transition. Eur J Appl Physiol 2024; 124:309-315. [PMID: 37495864 PMCID: PMC10786968 DOI: 10.1007/s00421-023-05285-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Accepted: 07/13/2023] [Indexed: 07/28/2023]
Abstract
PURPOSE To quantify the effects of prolonged cycling on the rate of ventilation ([Formula: see text]), frequency of respiration (FR), and tidal volume (VT) associated with the moderate-to-heavy intensity transition. METHODS Fourteen endurance-trained cyclists and triathletes (one female) completed an assessment of the moderate-to-heavy intensity transition, determined as the first ventilatory threshold (VT1), before (PRE) and after (POST) two hours of moderate-intensity cycling. The power output, [Formula: see text], FR, and VT associated with VT1 were determined PRE and POST. RESULTS As previously reported, power output at VT1 significantly decreased by ~ 10% from PRE to POST. The [Formula: see text] associated with VT1 was unchanged from PRE to POST (72 ± 12 vs. 69 ± 13 L.min-1, ∆ - 3 ± 5 L.min-1, ∆ - 4 ± 8%, P = 0.075), and relatively consistent (within-subject coefficient of variation, 5.4% [3.7, 8.0%]). The [Formula: see text] associated with VT1 was produced with increased FR (27.6 ± 5.8 vs. 31.9 ± 6.5 breaths.min-1, ∆ 4.3 ± 3.1 breaths.min-1, ∆ 16 ± 11%, P = 0.0002) and decreased VT (2.62 ± 0.43 vs. 2.19 ± 0.36 L.breath-1, ∆ - 0.44 ± 0.22 L.breath-1, ∆ - 16 ± 7%, P = 0.0002) in POST. CONCLUSION These data suggest prolonged exercise shifts ventilatory parameters at the moderate-to-heavy intensity transition, but [Formula: see text] remains stable. Real-time monitoring of [Formula: see text] may be a useful means of assessing proximity to the moderate-to-heavy intensity transition during prolonged exercise and is worthy of further research.
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Affiliation(s)
- Julian D Stevenson
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Andrew E Kilding
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Daniel J Plews
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand
| | - Ed Maunder
- Sports Performance Research Institute New Zealand, Auckland University of Technology, Auckland, New Zealand.
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Marin E. Forged to heal: The role of metallic cellular solids in bone tissue engineering. Mater Today Bio 2023; 23:100777. [PMID: 37727867 PMCID: PMC10506110 DOI: 10.1016/j.mtbio.2023.100777] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2023] [Revised: 08/21/2023] [Accepted: 08/23/2023] [Indexed: 09/21/2023] Open
Abstract
Metallic cellular solids, made of biocompatible alloys like titanium, stainless steel, or cobalt-chromium, have gained attention for their mechanical strength, reliability, and biocompatibility. These three-dimensional structures provide support and aid tissue regeneration in orthopedic implants, cardiovascular stents, and other tissue engineering cellular solids. The design and material chemistry of metallic cellular solids play crucial roles in their performance: factors such as porosity, pore size, and surface roughness influence nutrient transport, cell attachment, and mechanical stability, while their microstructure imparts strength, durability and flexibility. Various techniques, including additive manufacturing and conventional fabrication methods, are utilized for producing metallic biomedical cellular solids, each offering distinct advantages and drawbacks that must be considered for optimal design and manufacturing. The combination of mechanical properties and biocompatibility makes metallic cellular solids superior to their ceramic and polymeric counterparts in most load bearing applications, in particular under cyclic fatigue conditions, and more in general in application that require long term reliability. Although challenges remain, such as reducing the production times and the associated costs or increasing the array of available materials, metallic cellular solids showed excellent long-term reliability, with high survival rates even in long term follow-ups.
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Affiliation(s)
- Elia Marin
- Ceramic Physics Laboratory, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, 606-8585, Kyoto, Japan
- Department of Dental Medicine, Graduate School of Medical Science, Kyoto Prefectural University of Medicine, Kamigyo-ku, Kyoto, 602-8566, Japan
- Department Polytechnic of Engineering and Architecture, University of Udine, 33100, Udine, Italy
- Biomedical Research Center, Kyoto Institute of Technology, Sakyo-ku, Matsugasaki, Kyoto, 606-8585, Japan
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Wang Z, Zhang W, Bai G, Lu Q, Li X, Zhou Y, Yang C, Xiao Y, Lang M. Highly resilient and fatigue-resistant poly(4-methyl- ε-caprolactone) porous scaffold fabricated via thiol-yne photo-crosslinking/salt-templating for soft tissue regeneration. Bioact Mater 2023; 28:311-325. [PMID: 37334070 PMCID: PMC10275743 DOI: 10.1016/j.bioactmat.2023.05.020] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Revised: 05/12/2023] [Accepted: 05/30/2023] [Indexed: 06/20/2023] Open
Abstract
Elastomeric scaffolds, individually customized to mimic the structural and mechanical properties of natural tissues have been used for tissue regeneration. In this regard, polyester elastic scaffolds with tunable mechanical properties and exceptional biological properties have been reported to provide mechanical support and structural integrity for tissue repair. Herein, poly(4-methyl-ε-caprolactone) (PMCL) was first double-terminated by alkynylation (PMCL-DY) as a liquid precursor at room temperature. Subsequently, three-dimensional porous scaffolds with custom shapes were fabricated from PMCL-DY via thiol-yne photocrosslinking using a practical salt template method. By manipulating the Mn of the precursor, the modulus of compression of the scaffold was easily adjusted. As evidenced by the complete recovery from 90% compression, the rapid recovery rate of >500 mm min-1, the extremely low energy loss coefficient of <0.1, and the superior fatigue resistance, the PMCL20-DY porous scaffold was confirmed to harbor excellent elastic properties. In addition, the high resilience of the scaffold was confirmed to endow it with a minimally invasive application potential. In vitro testing revealed that the 3D porous scaffold was biocompatible with rat bone marrow stromal cells (BMSCs), inducing BMSCs to differentiate into chondrogenic cells. In addition, the elastic porous scaffold demonstrated good regenerative efficiency in a 12-week rabbit cartilage defect model. Thus, the novel polyester scaffold with adaptable mechanical properties may have extensive applications in soft tissue regeneration.
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Affiliation(s)
- Zhaochuang Wang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Wenhao Zhang
- Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Department of Oral Surgery of Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, PR China
| | - Guo Bai
- Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Department of Oral Surgery of Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, PR China
| | - Qiaohui Lu
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Xiaoyu Li
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Yan Zhou
- State Key Laboratory of Bioreactor Engineering, School of Biotechnology, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Chi Yang
- Shanghai Key Laboratory of Stomatology, Shanghai Research Institute of Stomatology, Department of Oral Surgery of Ninth People's Hospital, College of Stomatology, Shanghai Jiao Tong University School of Medicine, Shanghai, 200011, PR China
| | - Yan Xiao
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
| | - Meidong Lang
- Shanghai Key Laboratory of Advanced Polymeric Materials, Key Laboratory for Ultrafine Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai, 200237, PR China
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Grünheid T, Bitner TF. Wear and fatigue resistance: An in-vitro comparison of three polyethylene terephthalate glycol and thermoplastic polyurethane materials for vacuum-formed retainers. Int Orthod 2023; 21:100748. [PMID: 36934632 DOI: 10.1016/j.ortho.2023.100748] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 02/27/2023] [Accepted: 03/04/2023] [Indexed: 03/19/2023]
Abstract
OBJECTIVE To test the wear and fatigue resistance of three materials (Essix ACE®, Taglus®, and Zendura A®) for the fabrication of vacuum-formed retainers in an artificial oral environment. MATERIAL AND METHODS Wear resistance was tested by subjecting 21 retainers of each Essix ACE®, Taglus®, and Zendura A® to 12,000 wear cycles at 75N to simulate one year of retainer wear with moderate nighttime bruxing. Post-wear retainer thickness was compared to baseline measurements to calculate wear depth. Fatigue resistance was tested by flexing 15 retainers of each material at an angle of 25 degrees for 1,825 cycles to simulate one year of removing and reinserting a retainer five times per day. Retainers were visually inspected for fractures. Pairwise t-tests with correction using Tukey's method were used to determine significant differences between materials. RESULTS The mean wear depths were 0.155±0.021mm, 0.168±0.031mm, and 0.096±0.033mm for Essix ACE®, Taglus®, and Zendura A®, respectively. The wear depth of Zendura A® was significantly lower than that of both Essix ACE® (P<0.001) and Taglus® (P<0.001). There was no significant difference in wear depth between Essix ACE® and Taglus® (P=0.312). Under the parameters set for the fatigue resistance test, fractures did not occur on any of the tested materials. CONCLUSIONS Under the assumption of moderate nighttime bruxing for one year, Zendura A® is the most wear-resistant among the materials tested. With the assumption of retainer removal and reinsertion five times per day for one year, all three materials tested have the same ability to resist fatigue.
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Affiliation(s)
- Thorsten Grünheid
- Division of Orthodontics, School of Dentistry, University of Minnesota, Minneapolis, Minnesota, USA.
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Langlois J, Hamadouche M. What have we learned from 20 years of using highly crosslinked PE in total hip arthroplasty? Orthop Traumatol Surg Res 2023; 109:103457. [PMID: 36302450 DOI: 10.1016/j.otsr.2022.103457] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Revised: 05/11/2022] [Accepted: 05/12/2022] [Indexed: 11/07/2022]
Abstract
Slightly more than 20 years after its first clinical use, highly cross-linked polyethylene (HXLPE) has been widely adopted. Despite initial concerns about oxidation and lack of fatigue resistance, first generation HXLPE, with 15 years of follow-up and widespread use, continues to provide excellent results, even in a young, active population. Remelted HXLPE might have a lower wear rate than annealed HXLPE and will no doubt have a better resistance to oxidation. Second generation materials, consisting of polyethylene (PE) that is sequentially irradiated then annealed and PE that is infused with antioxidants, also have provided encouraging short- and medium-term results. Data from national joint registers confirm data from clinical trials. Even in more challenging cases (dual mobility, hip resurfacing, revision surgery and thin liners), HXLPE has generated promising results. However, failures (rim fractures) have been documented, including for all the latest HXLPE generations. Consequently, certain precautions must be taken during its use and close patient monitoring is necessary.
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Affiliation(s)
- Jean Langlois
- Centre Orthopédique Santy, 24, avenue Paul Santy, Lyon, France; Hôpital Privé Jean-Mermoz, 55, avenue Jean-Mermoz, Lyon, France.
| | - Moussa Hamadouche
- Département de Chirurgie Orthopédique, Université de Paris, Assistance Publique-Hôpitaux de Paris, Hôpital Cochin, 27, rue du Faubourg Saint-Jacques, Paris, France
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He R, Zhao L, Silberschmidt VV. Effect of balloon pre-dilation on performance of self-expandable nitinol stent in femoropopliteal artery. Biomech Model Mechanobiol 2023; 22:189-205. [PMID: 36282361 PMCID: PMC9957922 DOI: 10.1007/s10237-022-01641-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2022] [Accepted: 09/19/2022] [Indexed: 11/24/2022]
Abstract
Balloon pre-dilation is usually performed before implantation of a nitinol stent in a femoropopliteal artery in a case of severe blockage or calcified plaque. However, its effect on performance of the nitinol stent in a diseased femoropopliteal artery has not been studied yet. This study compares the outcomes of stenting with pre-dilation and without it by modelling the entire processes of stent deployment. Fatigue deformation of the implanted stent is also modelled under diastolic-systolic blood pressure, repetitive bending, torsion, axial compression and their combination. Reduced level of stress in the stent occurs after stenting with pre-dilation, but causing the increased damage in the media layer, i.e. the middle layer of the arterial wall. Generally, pre-dilation increases the risk of nitinol stent's fatigue failure. Additionally, the development of in-stent restenosis is predicted based on the stenting-induced tissue damage in the media layer, and no severe mechanical irritation is induced to the media layer by pre-dilation, stent deployment or fatigue loading.
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Affiliation(s)
- Ran He
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Epinal Way, Loughborough, LE11 3TU, UK.
| | - Liguo Zhao
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Epinal Way, Loughborough, LE11 3TU UK ,College of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing, 210016 People’s Republic of China
| | - Vadim V. Silberschmidt
- Wolfson School of Mechanical, Electrical and Manufacturing Engineering, Loughborough University, Epinal Way, Loughborough, LE11 3TU UK
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Chen Y, Maghami E, Bai X, Huang C, Pow EHN, Tsoi JKH. Which dentine analogue material can replace human dentine for crown fatigue test? Dent Mater 2023; 39:86-100. [PMID: 36503862 DOI: 10.1016/j.dental.2022.11.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 11/19/2022] [Accepted: 11/25/2022] [Indexed: 12/13/2022]
Abstract
OBJECTIVE To seek dentine analogue materials in combined experimental, analytical, and numerical approaches on the mechanical properties and fatigue behaviours that could replace human dentine in a crown fatigue laboratory test. METHODS A woven glass fibre-filled epoxy (NEMA grade G10; G10) and a glass fibre-reinforced polyamide-nylon (30% glass fibre reinforced polyamide-nylon 6,6; RPN) were investigated and compared with human dentine (HD). Flexural strength and elastic modulus (n = 10) were tested on beam-shaped specimens via three-point bending, while indentation hardness (n = 3) was tested after fracture. Abutment substrates of G10, RPN and HD were prepared and resin-bonded with monolithic lithium disilicate crowns (n = 10), then subjected to wet cyclic loading in a step-stress manner (500 N initial load, 100 N step size, 100,000 cycles per step, 20 Hz frequency). Data were statistically analysed using Kruskal-Wallis one-way ANOVA followed by post-hoc comparisons (α = 0.05). Survival probability estimation was performed by Mantel-Cox Log-Rank test with 95% confidence intervals. The fatigue failure load (FFL) and the number of cycles until failure (NCF) were evaluated with Weibull statistics. Finite Element Models of the fatigue test were established for stress distribution analysis and lifetime prediction. Fractographic observations were qualitatively analysed. RESULTS The flexural strength of HD (164.27 ± 14.24 MPa), G10 (116.48 ± 5.93 MPa), and RPN (86.73 ± 3.56 MPa) were significantly different (p < 0.001), while no significant difference was observed in their flexural moduli (p = 0.377) and the indentation hardness between HD and RPN (p = 0.749). The wet cyclic fatigue test revealed comparable mean FFL and NCF of G10 and RPN to HD (p = 0.237 and 0.294, respectively) and similar survival probabilities for the three groups (p = 0.055). However, RPN promotes higher stability and lower deviation of fatigue test results than G10 in Weibull analysis and FEA. SIGNIFICANCE Even though dentine analogue materials might exhibit similar elastic properties and fatigue performance to human dentine, different reliabilities of fatigue on crown-dentine analogues were shown. RPN seems to be a better substrate that could provide higher reliability and predictability of laboratory study results.
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Affiliation(s)
- Yanning Chen
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Ebrahim Maghami
- Department of Mechanical Engineering and Mechanics, College of Engineering, Drexel University, Philadelphia, PA 19104, USA
| | - Xuedong Bai
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - Cui Huang
- The State Key Laboratory Breeding Base of Basic Science of Stomatology (Hubei-MOST) & Key Laboratory for Oral Biomedicine Ministry of Education, School and Hospital of Stomatology, Wuhan University, Wuhan, China
| | - Edmond Ho Nang Pow
- Prosthodontics, Restorative Dental Sciences, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China
| | - James Kit Hon Tsoi
- Dental Materials Science, Applied Oral Sciences and Community Dental Care, Faculty of Dentistry, The University of Hong Kong, Hong Kong, China.
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Stevenson JD, Kilding AE, Plews DJ, Maunder E. Prolonged cycling reduces power output at the moderate-to-heavy intensity transition. Eur J Appl Physiol 2022. [PMID: 36127418 DOI: 10.1007/s00421-022-05036-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Accepted: 09/02/2022] [Indexed: 12/01/2022]
Abstract
Purpose To determine the effect of prolonged exercise on moderate-to-heavy intensity transition power output and heart rate. Methods Fourteen endurance-trained cyclists and triathletes took part in the present investigation (13 males, 1 female, V·O2peak 59.9 ± 6.8 mL.kg−1.min−1). Following a characterisation trial, participants undertook a five-stage incremental step test to determine the power output and heart rate at the moderate-to-heavy intensity transition before and after two hours of cycling at 90% of the estimated power output at first ventilatory threshold (VT1). Results Power output at the moderate-to-heavy intensity transition significantly decreased following acute prolonged exercise when determined using expired gases (VT1, 217 ± 42 W vs. 196 ± 42 W, P < 0.0001) and blood lactate concentrations (LoglogLT, 212 ± 47 W vs. 190 ± 47 W, P = 0.004). This was attributable to loss of efficiency (VT1, -8 ± 10 W; LoglogLT, − 7 ± 9 W) and rates of metabolic energy expenditure at the transition (VT1, − 14 ± 11 W; LoglogLT, − 15 ± 22 W). The heart rate associated with the moderate-to-heavy intensity transition increased following acute prolonged exercise (VT1, 142 ± 9 beats.min−1 vs. 151 ± 12 beats.min−1, P < 0.001; LoglogLT, 140 ± 13 beats.min−1 vs. 150 ± 15 beats.min−1, P = 0.006). Conclusion These results demonstrate the external work output at the moderate-to-heavy intensity transition decreases during prolonged exercise due to decreased efficiency and rates of metabolic energy expenditure, but the associated heart rate increases. Therefore, individual assessments of athlete ‘durability’ are warranted. Supplementary Information The online version contains supplementary material available at 10.1007/s00421-022-05036-9.
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Aragonez GC, Pilecco RO, Dapieve KS, Burgo TAL, Guilardi LF, Prochnow C, Valandro LF, Rippe MP. Simulation of CAD/CAM milling on lithium disilicate: Mechanical and topographic analyses of surface grinding different protocols. J Mech Behav Biomed Mater 2022; 132:105278. [PMID: 35653917 DOI: 10.1016/j.jmbbm.2022.105278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 05/14/2022] [Accepted: 05/17/2022] [Indexed: 10/18/2022]
Abstract
The aim of this study was to evaluate the topography and the fatigue performance of lithium disilicate glass-ceramic after surface grinding through different laboratory protocols used to simulate the Computer-aided design/Computer-aided manufacturing (CAD/CAM) milling. Ceramic discs (IPS e.max CAD, Ø = 13.5 mm × 1.2 mm of thickness) were produced through different methodologies: milling in CAD/CAM system (CAD/CAM group); produced in-lab with a polished surface (POL group); or produced through in-lab methods and randomly distributed into five groups according to different grinding protocols to simulate the CAD/CAM milling [grinding with a CAD/CAM bur coupled to a mandrel (CAD/CAM Bur group); fine diamond bur using oscillatory movements (DBO group); fine diamond bur in x and y axes of the disc (DBXY group); #60-grit silicon carbide sandpaper (SiC group); and #60-grit wood sandpaper (WS group)]. The specimens were fatigue tested (n = 15) according to the step-stress method (initial load: 60 N; step-size: 20 N; 10,000 cycles/step; 20 Hz frequency). A roughness analysis was performed on all specimens, while fractal dimension (FD) and fractography were performed on representative samples. The Kaplan-Meier analysis showed that the POL (293.3 N) group presented better fatigue performance (higher load and number of cycles for failure) (p < 0.05) than the other groups (CAD/CAM = 222.7 N; CAD/CAM Bur = 181.3 N; DBO = 184.0 N; DBXY = 192.0 N; SiC = 182.6 N; WS = 182.6 N). For roughness, only the SiC (Ra = 1.616; Rz = 10.465) and WS (Ra = 1.673; Rz = 10.655) groups produced statistically similar Ra (μm) and Rz (μm) values to the CAD/CAM (Ra = 1.628; Rz = 9.571) group (p > 0.05). The surface created by CAD/CAM milling and POL group exhibited more complexity (FD) higher values than the experimental groups. For the ceramic surface topography images, the CAD/CAM milling visibly produced a uniform surface compared to the other groups; however, the POL group was the smoothest. The DBO, DBXY, SiC, and WS groups resulted in similar characteristics of surface topography. Therefore, although the SiC and WS groups showed similar roughness to the control group (CAD/CAM), no in-lab simulation method was fully capable to mimic the mechanical performance of the CAD/CAM-milled lithium disilicate glass-ceramic.
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Affiliation(s)
- Gabriela Carrão Aragonez
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Rafaela Oliveira Pilecco
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Kiara Serafini Dapieve
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Thiago Augusto Lima Burgo
- Department of Physics, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Luís Felipe Guilardi
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Catina Prochnow
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Luiz Felipe Valandro
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
| | - Marília Pivetta Rippe
- MSciD and PhD Graduate Programs in Oral Science - Prosthodontic Units, Faculty of Odontology, Federal University of Santa Maria - UFSM, Santa Maria, Rio Grande do Sul State, Brazil.
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11
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Ling Z, Ma J, Zhang S, Shao L, Wang C, Ma J. Stretchable and fatigue resistant hydrogels constructed by natural galactomannan for flexible sensing application. Int J Biol Macromol 2022; 216:193-202. [PMID: 35788003 DOI: 10.1016/j.ijbiomac.2022.06.185] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 06/14/2022] [Accepted: 06/28/2022] [Indexed: 12/28/2022]
Abstract
Exploration of sustainable and functional materials from biomolecules has received much interest, while the limited mechanical property and possible bacterial contamination were proved to be their major shortages. Here, we proposed novel double network (DN) hydrogels based on galactomannan (GM) polysaccharide as backbone. Folic acid (FA) and polyacrylamide (PAM) were introduced to form hydrogen bond linkages and covalent bond networks respectively. The three-dimensional hydrogel networks showed greatly improved mechanical strength. Impressive compressive fatigue resistance was present for 100 cycles' compression forming only 0.7 % shape deformation. The phenomenon was mainly attributed to promoted stress-bearing and energy dissipation from the DN cross-linking. The GM hydrogels also exhibited good electronic conductivity and excellent anti-bacterial capabilities with inhibition against more than 80 % of E. coli., attributing to the tunable attachments of FA. Thus, we provided multi-functional hydrogels of high potential serving as anti-fatigue/bacterial and conductive strain sensors on the fields of wearable devices.
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Affiliation(s)
- Zhe Ling
- International Center for Bamboo and Rattan, Key Lab of Bamboo and Rattan Science & Technology, Beijing 100102, China; Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | - Junmei Ma
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Shuai Zhang
- Jiangsu Co-Innovation Center of Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Nanjing 210037, China
| | - Lupeng Shao
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | - Chao Wang
- State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China
| | - Jianfeng Ma
- International Center for Bamboo and Rattan, Key Lab of Bamboo and Rattan Science & Technology, Beijing 100102, China; State Key Laboratory of Biobased Material and Green Papermaking, Qilu University of Technology, Shandong Academy of Sciences, Jinan 250353, China.
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12
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Koike TE, Dell Aquila RA, Silva KS, Aoki MS, Miyabara EH. Glutamine supplementation improves contractile function of regenerating soleus muscles from rats. J Muscle Res Cell Motil 2022; 43:87-97. [PMID: 35201551 DOI: 10.1007/s10974-022-09615-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Accepted: 02/02/2022] [Indexed: 10/19/2022]
Abstract
This study evaluated the effects of glutamine supplementation immediately after freezing injury on morphological and contractile function of regenerating soleus muscles from rats. Young male Wistar rats were subjected to cryolesion of soleus muscles, and immediately after received a daily supplementation of glutamine (1 g/kg/day). The muscles were evaluated on post-injury days 3 and 10. Glutamine-supplemented injured muscles had a lower number of CD11b positive immune cells and higher mRNA levels of IL-4 compared to those from the cryolesioned muscles analyzed on post-injury day 3. The mRNA and protein expression levels of the myogenic transcription factor MyoD were also higher in glutamine-supplemented injured muscles than in injured muscles examined on post-cryolesion day 3. In addition, glutamine-supplemented injured muscles had a higher size of their regenerating myofibers, attenuated decline in maximum tetanic strength and improved fatigue resistance compared to those from injured muscles evaluated on post-cryolesion day 10. No effect was observed in uninjured muscles supplemented with glutamine. Our results suggest that glutamine supplementation improves the resolution of inflammation, as well as the size and functional recovery of regenerating myofibers from soleus muscles by accelerating the up-regulation of IL-4 and MyoD expression. Future non-pharmacological rehabilitation studies are warranted to investigate the effect of glutamine supplementation on the outcome of injured skeletal muscles.
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Affiliation(s)
- Tatiana E Koike
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Av Prof. Lineu Prestes, 2415, São Paulo, SP, 05508-000, Brazil
| | - Rodrigo A Dell Aquila
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Av Prof. Lineu Prestes, 2415, São Paulo, SP, 05508-000, Brazil
| | - Kellana S Silva
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Av Prof. Lineu Prestes, 2415, São Paulo, SP, 05508-000, Brazil
| | - Marcelo S Aoki
- School of Arts, Sciences and Humanities, University of Sao Paulo, Sao Paulo, SP, 03828-000, Brazil
| | - Elen H Miyabara
- Department of Anatomy, Institute of Biomedical Sciences, University of Sao Paulo, Av Prof. Lineu Prestes, 2415, São Paulo, SP, 05508-000, Brazil.
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13
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Krech E, LaPierre L, Tuncdemir S, Gurdal AE, Haas E, Arnold P, Friis E. Design considerations for piezoelectrically powered electrical stimulation: The balance between power generation and fatigue resistance. J Mech Behav Biomed Mater 2022; 126:104976. [PMID: 34864397 PMCID: PMC8792359 DOI: 10.1016/j.jmbbm.2021.104976] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2020] [Revised: 08/13/2021] [Accepted: 11/12/2021] [Indexed: 02/03/2023]
Abstract
Quality and timing of bone healing from orthopedic surgeries, especially lumbar spinal fusion procedures, is problematic for many patients. To address this issue, clinicians often use electrical stimulation to improve surgery success rates and decrease healing time in patients with increased risk of pseudarthrosis, including smokers and diabetics. Current invasive electrical stimulation devices require an implantable battery and a second surgery for removal. Piezoelectric composites within an interbody implant generate sufficient power under physiologic loads to deliver pulsed electrical stimulation without a battery and have demonstrated promising preclinical bone growth and fusion success. The objective of the current study was to assess the power generation and fatigue resistance of three commercially manufactured piezocomposite configurations in a modified implant design to demonstrate efficacy as a robust biomaterial within osteogenic implants. The three configurations were electromechanically assessed under physiological lumbar loading conditions, and all configurations produced sufficient power to promote bone healing. Additionally, electrical and mechanical fatigue performance was assessed under high load, low cycle conditions. All configurations demonstrated runout with no gross mechanical failure and two configurations demonstrated electrical fatigue resistance. Future piezoelectric implant design decisions should be based on power generation needs to stimulate bone growth, as mechanical fatigue efficacy was proven for all piezocomposite configurations tested.
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Affiliation(s)
- E.D. Krech
- University of Kansas, Bioengineering Graduate Program, Lawrence, KS, USA,Evoke Medical, LLC, Lawrence, KS, USA
| | | | | | | | - E.G. Haas
- University of Kansas, Department of Mechanical Engineering, Lawrence, KS, USA
| | - P.M. Arnold
- Evoke Medical, LLC, Lawrence, KS, USA,University of Illinois Carle College of Medicine, Champaign, IL, USA
| | - E.A. Friis
- University of Kansas, Bioengineering Graduate Program, Lawrence, KS, USA,Evoke Medical, LLC, Lawrence, KS, USA,University of Kansas, Department of Mechanical Engineering, Lawrence, KS, USA
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14
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Hao J, Murakami N, Yamazaki T, Iwasaki N, Yatabe M, Takahashi H, Wakabayashi N. Flexural and fatigue properties of polyester disk material for milled resin clasps. Dent Mater J 2021; 40:1359-1364. [PMID: 34234049 DOI: 10.4012/dmj.2021-037] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
To evaluate the flexural and fatigue properties of a polyester disk material used in milled resin clasps of removable partial dentures, experimental polyester disk (mPE), injection-molded polyester (iPE), and polymethyl methacrylate disk (mPMMA) were examined by three-point bending tests and cyclic fatigue tests at 0.75 or 1.50 mm deflection. The mPE exhibited significantly higher flexural strength than the iPE (p<0.05). Meanwhile, the mPMMA displayed higher flexural modulus and strength than the polyesters. The mPE exhibited a significantly lower residual strain than the iPE at the cyclic 0.75 mm deflection (p<0.05); however, microcracks were observed in the mPE at the 1.50 mm deflection. The mPMMA showed a high residual strain at the 0.75 mm deflection and fractured within 1,000 cycles at the 1.5 mm deflection. The higher flexural strength and lower residual strain of the mPE compared with the iPE suggest the advantages of milled resin clasps within a limited deflection.
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Affiliation(s)
- Jialin Hao
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Natsuko Murakami
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Toshiki Yamazaki
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Naohiko Iwasaki
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Masaru Yatabe
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Hidekazu Takahashi
- Oral Biomaterial Development Engineering, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
| | - Noriyuki Wakabayashi
- Removable Partial Prosthodontics, Oral Health Sciences, Graduate School of Medical and Dental Sciences, Tokyo Medical and Dental University
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15
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Baldissara P, Koci B, Monaco C, Scotti N, Breschi L, Ciocca L. Fatigue failure and success rate of lithium disilicate table-tops as a function of cement thickness. J Prosthodont Res 2021; 65:528-534. [PMID: 34108297 DOI: 10.2186/jpr.jpr_d_20_00220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
PURPOSE Under thin, partial coverage restoration the proper cement thickness to be clinically employed still remains an issue. The aim of this study was to determine the failure and success rates of simplified lithium disilicate occlusal veneers as a function of cement thickness. The null hypothesis was that cement thickness has no effect on the fatigue resistance. METHODS Sound human molars were severed in a plane parallel to the occlusal surface to create a flat dentin surface surrounded by enamel edges. Forty-five occlusal veneers 1.0 mm thick (IPS e.max CAD LT) were luted to the teeth with Multilink Automix resin cement, creating 3 experimental groups (n=15) with cement thicknesses of 50, 100, and 200 µm. The restorations were fatigue-cycled using a ball mill machine containing zirconia and stainless steel spheres. Twelve 60 min cycles were performed. Survival statistics were applied to "failure" and "success" events, comparing the three groups using a log-rank Mantel-Cox test and a log-rank test for trends (alpha = 0.05). RESULTS The failure and success rates were not significantly influenced by cement thickness (P = 0.137 and P = 0.872, respectively); thus, the null hypothesis was accepted. However, when log-rank test for trends was applied to failure events, the tendency to have less failures with increasing thicknesses was found statistically significant (P = 0.047). CONCLUSIONS The cement thickness within the range adopted here did not have a significant effect on the failure or success rate of lithium disilicate occlusal veneers when exposed to randomized impact stresses generating fatigue phenomena.
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Affiliation(s)
- Paolo Baldissara
- Section of Prosthodontics, Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna
| | - Brunilda Koci
- Faculty of Dental Sciences, Aldent University, Tirana
| | - Carlo Monaco
- Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna
| | - Nicola Scotti
- Department of Surgical Sciences, University of Turin
| | - Lorenzo Breschi
- Section of Prosthodontics, Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna
| | - Leonardo Ciocca
- Section of Prosthodontics, Department of Biomedical and Neuromotor Science, Alma Mater Studiorum University of Bologna
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16
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Wang K, Yin R, Lu Y, Qiao H, Zhu Q, He J, Zhou W, Zhang H, Tang T, Zhang W. Soft-hard hybrid covalent-network polymer sponges with super resilience, recoverable energy dissipation and fatigue resistance under large deformation. Mater Sci Eng C Mater Biol Appl 2021; 126:112185. [PMID: 34082984 DOI: 10.1016/j.msec.2021.112185] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 05/03/2021] [Accepted: 05/12/2021] [Indexed: 11/20/2022]
Abstract
Energy absorption or dissipation ability has been widely developed in tough hydrogels and 3D nano-structured sponges for a variety of applications. However, fully recoverable energy dissipation and fatigue resistance under large deformation is still challenging yet highly desirable. Polymer network with homogeneous chemical crosslinking structures is an efficient way to construct hydrogels with high resilience and fatigue resistance. Unfortunately, such polymer network usually has poor energy dissipation capability. In this paper, we propose a new approach to build the ability of fully recoverable energy dissipation into covalent-crosslink polymer network by integrating soft and hard chains in a uniform crosslinking network and present the one-pot synthesis method for constructing corresponding polymer sponges by low-temperature phase-separation photopolymerization. The application of such polymer sponges as a tissue engineering scaffold, fabricated by using cyclic acetal units and PEG based monomers in particular is demonstrated. For the first time, we show the feasibility of building a synthetic scaffold with the characteristics of high porosity, super compressibility and resilience, fast recovery, completely recoverable energy dissipation, high fatigue resistance, biodegradability and biocompatibility. Such a scaffold is promising in tissue engineering especially in load-bearing applications.
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17
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Becerra LHC, Rodríguez MALH, Arroyo RL, Solís HE, Castro AT. Effect of sterilization on 3-point dynamic response to in vitro bending of an Mg implant. Biomater Res 2021; 25:9. [PMID: 33823939 PMCID: PMC8025350 DOI: 10.1186/s40824-021-00207-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/17/2021] [Indexed: 11/10/2022] Open
Abstract
Background The aim of the study is to characterize a biomedical magnesium alloy and highlighting the loss of mechanical integrity due to the sterilization method. Ideally, when using these alloys is to delay the onset of degradation so that the implant can support body loads and avoid toxicological effects due to the release of metal ions into the body. Methods Standardized procedures according to ASTM F-1264 and ISO-10993-5 were used, respecting detailed methodological controls to ensure accuracy and reproducibility of the results, this testing methodology is carried out in accordance with the monographs of the Pharmacopoeia for the approval of medical devices and obtaining a health registration. An intramedullary implant (IIM) manufactured in magnesium (Mg) WE43 can support loads of the body in the initial period of bone consolidation without compromising the integrity of the fractured area. A system with these characteristics would improve morbidity and health costs by avoiding secondary surgical interventions. Results As a property, the fatigue resistance of Mg in aggressive environments such as the body environment undergoes progressive degradation, however, the autoclave sterilization method drastically affects fatigue resistance, as demonstrated in tests carried out under in vitro conditions. Coupled with this phenomenon, the relatively poor biocompatibility of Mg WE43 alloys has limited applications where they can be used due to low acceptance rates from agencies such as the FDA. However, Mg alloy with elements such as yttrium and rare earth elements (REEs) have been shown to delay biodegradation depending on the method of sterilization and the physiological solution used. With different sterilization techniques, it may be possible to keep toxicological effects to a minimum while still ensuring a balance between the integrity of fractured bone and implant degradation time. Therefore, the evaluation of fatigue resistance of WE43 specimens sterilized and tested in immersion conditions (enriched Hank’s solution) and according to ASTM F-1264, along with the morphological, crystallinity, and biocompatibility characterization of the WE43 alloy allows for a comprehensive evaluation of the mechanical and biological properties of WE43. Conclusions These results will support decision-making to generate a change in the current perspective of biomaterials utilized in medical devices (MDs), to be considered by manufacturers and health regulatory agencies. An implant manufactured in WE43 alloy can be used as an intramedullary implant, considering keeping elements such as yttrium-REEs below as specified in its designation and with the help of a coating that allows increasing the life of the implant in vivo.
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Affiliation(s)
- Luis Humberto Campos Becerra
- Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León (UANL), Pedro de Alba S/N, ciudad universitaria, San Nicolás de los Garza, NL, Mexico.
| | | | - Raúl Lesso Arroyo
- Departamento de Ingeniería Mecánica., Biomecánica, Instituto Tecnológico de Celaya (ITC), Av. Tecnológico Esq. A. García Cubas S/N Col. Bonfil, Celaya, 38010, Guanajuato, CP, Mexico
| | - Hugo Esquivel Solís
- Centro de Investigación y Asistencia en Tecnología y Diseño del Estado de Jalisco (CIATEJ), Av. Normalistas No.800, Colinas de la normal C.P, 44270, Guadalajara, Jalisco, Mexico
| | - Alejandro Torres Castro
- Facultad de Ingeniería Mecánica y Eléctrica, Universidad Autónoma de Nuevo León (UANL), Pedro de Alba S/N, ciudad universitaria, San Nicolás de los Garza, NL, Mexico
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18
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He R, Zhao LG, Silberschmidt VV, Willcock H. A computational study of fatigue resistance of nitinol stents subjected to walk-induced femoropopliteal artery motion. J Biomech 2021; 118:110295. [PMID: 33578053 DOI: 10.1016/j.jbiomech.2021.110295] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 01/20/2021] [Accepted: 01/23/2021] [Indexed: 11/21/2022]
Abstract
Fatigue resistance of nitinol stents implanted in femoropopliteal arteries is a critical issue because of their harsh biomechanical environment. Limb flexions due to daily walk expose the femoropopliteal arteries and, subsequently, the implanted stents to large cyclic deformations, which may lead to fatigue failure of the smart self-expandable stents. For the first time, this paper utilised the up-to-date measurements of walk-induced motion of a human femoropopliteal artery to investigate the fatigue behaviour of nitinol stent after implantation. The study was carried out by modelling the processes of angioplasty, stent crimping, self-expansion and deformation under diastolic-systolic blood pressure, repetitive bending, torsion and axial compression as well as their combination. The highest risk of fatigue failure of the nitinol stent occurs under a combined loading condition, with the bending contributing the most, followed by compression and torsion. The pulsatile blood pressure alone hardly causes any fatigue failure of the stent. The work is significant for understanding and improving the fatigue performance of nitinol stents through innovative design and procedural optimisation.
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Uslu G, Gundogar M, Özyurek T, Plotino G. Cyclic fatigue resistance of reduced-taper nickel-titanium (NiTi) instruments in doubled-curved (S-shaped) canals at body temperature. J Dent Res Dent Clin Dent Prospects 2020; 14:111-115. [PMID: 32908652 PMCID: PMC7464224 DOI: 10.34172/joddd.2020.024] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Accepted: 02/12/2020] [Indexed: 11/09/2022] Open
Abstract
Background. This study was conducted to compare the cyclic fatigue resistance of VDW.ROTATE, TruNatomy Prime, HyFlex CM, and 2Shape nickel-titanium (NiTi) rotary instruments in double-curved canals in a simulated clinical environment. Methods. Eighty NiTi files were used for the fatigue testing in stainless steel canals compatible with instrument sizes until fracture occurred (n=20): VDW.ROTATE (04./25#), TruNatomy Prime (04./26#), HyFlex CM (04./25#) and 2Shape TS04./25#( 1). For each instrument, the number of cycles to fracture (NCF) was calculated, and the fractured fragment length (FL) was measured. To verify that the files were fractured due to cyclic fatigue, the fractured surfaces of the files were evaluated under a scanning electron microscope. Data were statistically analyzed using the Kruskal-Wallis and Student's t-tests at the %95 confidence level. Results. The failure of the files due to cyclic fatigue was first seen in the apical curvature before the coronal curvature (P<0.05). The highest fatigue resistance was observed in VDW.ROTATE and HyFlex CM files in both curvatures (P<0.05). There were no significant differences in the fatigue resistance between the HyFlex CM and VDW.ROTATE files or between the 2Shape and the TruNatomy files (P>0.05). There was no difference in the fractured lengths of the files between the apical and coronal curvatures (P>0.05). Conclusion. In artificial S-shaped root canals, VDW.ROTATE and HyFlex CM files exhibited higher fatigue resistance compared to 2Shape and TruNatomy files.
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Affiliation(s)
- Gülşah Uslu
- Department of Endodontics, Faculty of Dentistry, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
| | - Mustafa Gundogar
- Department of Endodontics, Faculty of Dentistry, Istanbul Medipol University, İstanbul, Turkey
| | - Taha Özyurek
- Department of Endodontics, Faculty of Dentistry, Çanakkale Onsekiz Mart University, Çanakkale, Turkey
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Sobotkiewicz T, Huang X, Haapasalo M, Mobuchon C, Hieawy A, Hu J, Zhou H, Wang Z, Shen Y. Effect of canal curvature location on the cyclic fatigue resistance of reciprocating files. Clin Oral Investig 2020; 25:169-177. [PMID: 32488488 DOI: 10.1007/s00784-020-03348-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 05/15/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVES To determine the effect of the location of the canal curvature on the fatigue resistance of WaveOne (WO), WaveOne Gold (WOG), Reciproc (Rec), and Reciproc Blue (RecB) files, and to examine the phase transformation behaviors of the reciprocating file systems. MATERIAL AND METHODS The instruments were subjected to fatigue testing in five artificial canals with a curvature of 60° angle and a 3-mm radius. The location of the curvature was unique for each canal. Each file was inserted 16 mm into the canal and operated until fracture occurred. The time to fracture was recorded and the length of the fragment was measured. Differential scanning calorimetry was used to characterize the thermal behavior of the files. The number of cycles to failure was analyzed using two-way analysis of variance and the post hoc Tukey test. The Kruskal-Wallis test was used to compare the mean fragment lengths between groups. RESULTS The instruments had significantly lower fatigue resistance in canals with curvatures in the middle and coronal canals compared with those with apical curvatures (p < 0.05). At all tested curvature locations, RecB had superior fatigue resistance compared with WO and Rec (p < 0.05). There were no significant differences between WOG and Rec in canals with curvatures in the middle and coronal canals. The DSC thermograms for RecB exhibit a single exothermic peak during cooling but double endothermic peaks during heating indicating that a two-step phase transformation from martensite to R-phase to austenite takes place. CONCLUSIONS The reciprocating instruments experience decreased cyclic fatigue resistance when operated in canals with coronal- and middle-third curvatures when compared with curvatures in the apical-third. Instrumenting coronally positioned curvatures with reciprocating files needs to be performed with caution. CLINICAL RELEVANCE The location of the root canal's curvature influences the fracture resistance of rotary files that are used with reciprocating movements. Therefore, caution needs to be exercised when using reciprocating instruments in canals with coronal or middle curvatures.
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Affiliation(s)
- Tyler Sobotkiewicz
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Xiangya Huang
- Department of Conservative Dentistry & Endodontics, Guanghua School of Stomatology, Guangdong Province Key Laboratory of Stomatology, Sun Yat-Sen University Guangzhou, Guangzhou, China
| | - Markus Haapasalo
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | | | - Ahmed Hieawy
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Jinghao Hu
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Huimin Zhou
- Center for Biomedical Materials and Engineering, College of Material Science and Chemical Engineering, Harbin Engineering University, Harbin, China
| | - Zhejun Wang
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada
| | - Ya Shen
- Division of Endodontics, Faculty of Dentistry, The University of British Columbia (UBC), 2199 Wesbrook Mall, Vancouver, V6T1Z3, Canada.
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Abstract
More than two decades after their clinical introduction, crosslinked polyethylenes (XLPE) have been widely adopted. Though concerns were initially raised regarding oxidation and brittleness, on a large scale, the first generation of XLPE continues to be highly effective 15 years after the surgery, even in a young and active population. Remelted XLPE might display lower wear rates than annealed XLPE. Second generation XLPEs, not only including sequentially irradiated and annealed but also associated with antioxidants, demonstrate encouraging short- to mid-term results. Registry data support clinical trial reports. Even in less favorable settings (lipped liners, dual mobility cups, revision surgery, hip resurfacing) results are promising. However, failures (fractures) have already been described. Therefore, a high level of surveillance remains crucial.
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Affiliation(s)
- Jean Langlois
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Centre Orthopédique Santy 24, avenue Paul Santy 69008 Lyon France
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Hôpital Privé Jean-Mermoz 55, avenue Jean-Mermoz 69008 Lyon France
| | - Moussa Hamadouche
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Département de Chirurgie Orthopédique, Université Paris-Descartes, Assistance Publique-Hôpitaux de Paris, Hôpital Cochin 27, rue du Faubourg Saint-Jacques 75014 Paris France
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Algahtani F, Huang X, Haapasalo M, Wang Z, Hieawy A, Zhang D, Aleksejuniene J, Shen Y. Fatigue resistance of ProTaper gold exposed to high-concentration sodium hypochlorite in double curvature artificial canal. Bioact Mater 2019; 4:245-248. [PMID: 31528756 PMCID: PMC6739284 DOI: 10.1016/j.bioactmat.2019.07.003] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/10/2019] [Accepted: 07/30/2019] [Indexed: 01/28/2023] Open
Abstract
This study aimed to evaluate and compare the fatigue resistance of ProTaper Gold (PTG) and ProTaper Universal (PTU) in artificial single and double curvature canals in 5% sodium hypochlorite (NaOCl) at body temperature (37 °C). PTG and PTU files (size F1) were subjected to fatigue tests in two different artificial ceramic canals. The single curvature model had a 60° curvature angle with a 5 mm radius. The double curvature model had a 60° curvature angle with a 5 mm radius and a second 30° curvature with a 2 mm radius. A file segment was introduced into the artificial canal and immersed in water or 5% NaOCl at 37 °C. The total number of cycles to fracture (NCF) was recorded. Data were analyzed using t-test and linear regression analysis. The NCF of all files was significantly influenced by the type of NiTi metal alloy (P < .01), canal curvatures (P < .01), and the environmental conditions (P < .05). PTG had higher fatigue resistance than PTU files in both single and double curvature canals (P < .05). The NCF of PTU files in 5% NaOCl was shorter than that in water (P < .05). The mean length of broken PTG was significantly shorter than those of PTU files in both single and double curvature canals (P < .01). The fatigue performance of PTG is better than that of PTU in both single and double curvature. Environmental conditions may affect the fatigue behavior of PTU files with single curvature.
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Affiliation(s)
- Fahda Algahtani
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada.,College of Dentistry, Princess Nourah Bint Abdulrahman University, Saudi Arabia
| | - Xiangya Huang
- Department of Conservative Dentistry and Endodontics, Guanghua School of Stomatology, Sun Yat-Sen University, Guangzhou, China.,Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Markus Haapasalo
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Zhejun Wang
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Ahmed Hieawy
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Duo Zhang
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Jolanta Aleksejuniene
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
| | - Ya Shen
- Department of Oral Biological and Medical Sciences, Faculty of Dentistry, The University of British Columbia, Vancouver, Canada
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Tang X, Sun H, Nie J, Han X, Zhao Y, Zhang R, Ni Z. An o-hydroxyl aldehyde structure based naphthalimide derivative: Reversible photochromic properties and its application in ClO - detection in living cells. Spectrochim Acta A Mol Biomol Spectrosc 2019; 219:154-163. [PMID: 31035125 DOI: 10.1016/j.saa.2019.04.049] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2019] [Revised: 04/12/2019] [Accepted: 04/18/2019] [Indexed: 06/09/2023]
Abstract
A bifunctional organic compound 2-butyl-6-hydroxy-1,3-dioxo-2,3-dihydro-1H-benzo[de] isoquinoline-5-carbaldehyde (BHC) with photochromic properties in solid state and probe detection for ClO- in complete water solution was synthesized and fully characterized. A 'white-yellow-white' reversible photochromic behavior could be observed when alternating UV/vis light irradiation on the solid BHC powder. Good fatigue resistance and adjustable bleaching rate were shown when heating conditions changes. In addition, BHC displayed a high selectivity and low detection limit (1.16 × 10-8 M) for ClO-. The photoluminescent fluorescence "on-off" recognition result can be easily identified and BHC has been tested for safely imaging living cells and detecting hypochlorite anion in vitro and vivo. A better water solubility of BHC effectively reduces damage caused by organic solvent in cell imaging progress.
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Affiliation(s)
- Xinxue Tang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Hao Sun
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Jing Nie
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Xiang'en Han
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
| | - Yun Zhao
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Ran Zhang
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China
| | - Zhonghai Ni
- School of Chemical Engineering and Technology, China University of Mining and Technology, Xuzhou 221116, People's Republic of China.
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Abstract
This study evaluates the reinforcement of semi-interpenetrating network composites of 2,2-bis[4-(2-hydroxy-3-methacryloyloxypropyl)phenyl] propane (Bis-GMA)/ triethyleneglycol dimethacrylate (TEGDMA)/polymethyl methacrylate (PMMA) and 25% titanium dioxide (TiO2) nanofiller with surface treated Kevlar fibers for potential application as dental posts. The post material was subjected to thermo-cycling and flexural strength determined, characterised by dynamic mechanical analysis, water sorption, radiopacity and cytotoxicity tests. The results were compared with everStick®POST. Kevlar pre-treatment with acetic acid and silane coupling agent demonstrated a clear effect on the flexural strength of the composites with a significant increase compared to composites with fibers without surface treatment. The inclusion of TiO2 into the final formulation provided the desired radiopacity and improved both aesthetics and flexural strength, which exhibits a higher resistance on thermocycling. The ratios of fatigue limit to static flexural strength were about 0.73 for Kevlar and 0.58 for everStick®POST; MTT assay confirmed the absence of any toxic eluents, indicating its feasibility as new intracanal post material.
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Affiliation(s)
- Ahmed Almaroof
- Division of Tissue Engineering & Biophotonics, King's College London Dental Institute.,Department of Conservative Dentistry, College of Dentistry, University of Baghdad
| | - Ahmed Ali
- Division of Tissue Engineering & Biophotonics, King's College London Dental Institute.,Department of Conservative Dentistry, College of Dentistry, University of Baghdad
| | - Francesco Mannocci
- Department of Conservative Dentistry, King's College London Dental Institute
| | - Sanjukta Deb
- Division of Tissue Engineering & Biophotonics, King's College London Dental Institute
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Heck K, Paterno H, Lederer A, Litzenburger F, Hickel R, Kunzelmann KH. Fatigue resistance of ultrathin CAD/CAM ceramic and nanoceramic composite occlusal veneers. Dent Mater 2019; 35:1370-7. [PMID: 31351578 DOI: 10.1016/j.dental.2019.07.006] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 06/06/2019] [Accepted: 07/10/2019] [Indexed: 11/21/2022]
Abstract
OBJECTIVE The fracture resistance of different ultrathin occlusal computer-aided design/computer-aided manufacturing (CAD/CAM) veneers was investigated under cyclic mechanical loading to restore combined enamel-dentin defects. METHODS Eighty-four molars were reduced occlusally until extensive dentin exposure occurred with a remaining enamel ring. Twenty-four molars were ground flat for examination of highly standardized specimens, of which 8 were treated with uniformly flat 0.3mm IPS Empress CAD and 0.3 and 0.5mm IPS e.max CAD restorations. Sixty-four molars were anatomically prepared until dentin exposure and were restored using occlusal veneers with fissure/cusp thicknesses of 0.3/0.5mm from 3 different dental CAD/CAM materials: IPS Empress CAD, IPS e.max CAD and Lava Ultimate CAD/CAM. Teeth were etched with 37% phosphoric acid, and occlusal veneers were bonded using an adhesive luting system (Syntac Primer, Adhesive, Heliobond and Variolink II). Specimens were placed under cyclic mechanical loading in a chewing simulator (1 million cycles at 50N) and were examined for cracks after each cyclic loading sequence. The anatomical 0.3/0.5mm IPS e.max CAD specimens experienced an additional 1 million cycles at 100N. Kaplan-Meier survival curves and log-rank tests were used for data analysis. RESULTS All highly standardized and 0.3/0.5mm IPS e.max CAD specimens tolerated cyclic loading. One anatomical Lava Ultimate CAD/CAM and 10 IPS Empress CAD specimens showed cracks. SIGNIFICANCE Ultrathin occlusal veneers of lithium disilicate ceramic and nanoceramic composite showed remarkably high fracture strength under cyclic mechanical loading. These veneers might be a tooth substance preserving option for restoring combined dentin-enamel defects.
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Zadpoor AA. Mechanical performance of additively manufactured meta-biomaterials. Acta Biomater 2019; 85:41-59. [PMID: 30590181 DOI: 10.1016/j.actbio.2018.12.038] [Citation(s) in RCA: 71] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2018] [Revised: 11/27/2018] [Accepted: 12/21/2018] [Indexed: 12/11/2022]
Abstract
Additive manufacturing (AM) (=3D printing) and rational design techniques have enabled development of meta-biomaterials with unprecedented combinations of mechanical, mass transport, and biological properties. Such meta-biomaterials are usually topologically ordered and are designed by repeating a number of regular unit cells in different directions to create a lattice structure. Establishing accurate topology-property relationships is of critical importance for these materials. In this paper, we specifically focus on AM metallic meta-biomaterials aimed for application as bone substitutes and orthopaedic implants and review the currently available evidence regarding their mechanical performance under quasi-static and cyclic loading conditions. The topology-property relationships are reviewed for regular beam-based lattice structures, sheet-based lattice structures including those based on triply periodic minimal surface, and graded designs. The predictive models used for establishing the topology-property relationships including analytical and computational models are covered as well. Moreover, we present an overview of the effects of the AM processes, material type, tissue regeneration, biodegradation, surface bio-functionalization, post-manufacturing (heat) treatments, and loading profiles on the quasi-static mechanical properties and fatigue behavior of AM meta-biomaterials. AM meta-biomaterials exhibiting unusual mechanical properties such as negative Poisson's ratios (auxetic meta-biomaterials), shape memory behavior, and superelasitcity as well as the potential applications of such unusual behaviors (e.g. deployable implants) are presented too. The paper concludes with some suggestions for future research. STATEMENT OF SIGNIFICANCE: Additive manufacturing enables fabrication of meta-biomaterials with rare combinations of topological, mechanical, and mass transport properties. Given that the micro-scale topological design determines the macro-scale properties of meta-biomaterials, establishing topology-property relationships is the central research question when rationally designing meta-biomaterials. The interest in understanding the relationship between the topological design and material type on the one hand and the mechanical properties and fatigue behavior of meta-biomaterials on the other hand is currently booming. This paper presents and critically evaluates the most important trends and findings in this area with a special focus on the metallic biomaterials used for skeletal applications to enable researchers better understand the current state-of-the-art and to guide the design of future research projects.
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Heintze SD, Monreal D, Reinhardt M, Eser A, Peschke A, Reinshagen J, Rousson V. Fatigue resistance of all-ceramic fixed partial dentures - Fatigue tests and finite element analysis. Dent Mater 2018; 34:494-507. [PMID: 29395474 DOI: 10.1016/j.dental.2017.12.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Revised: 12/11/2017] [Accepted: 12/16/2017] [Indexed: 10/18/2022]
Abstract
OBJECTIVE To estimate the fatigue resistance of a new translucent zirconia material in comparison to lithium disilicate for 3-unit fixed partial dentures (FPDs). METHODS Eighteen 3-unit FPDs (replacement of first upper molar) with a connector size of 4mm×4mm were dry milled with a five-axis milling machine (Zenotec Select, Wieland, Germany) using discs made of a new translucent zirconia material (IPS e.max ZirCAD MT, Ivoclar Vivadent). Another 9 FPDs with a reduced connector size (3mm×4mm) were milled. The zirconia FPDs were sintered at 1500°C. For a comparison, 9 FPDs were made of IPS e.max Press, using the same dimensions. These IPS e.max Press FPDs were ground from a wax disc (Wieland), invested and pressed at 920°C. All FPDs were glazed twice. The FPDs were adhesively luted to PMMA dies with Multilink Automix. Dynamic cyclic loading was carried out on the molar pontic using Dyna-Mess testing machines (Stolberg, Germany) with 2×106 cycles at 2Hz in water (37°C). Two specimens per group and load were subjected to decreasing load levels (at least 4) until the two specimens no longer showed any failures. Another third specimen was subjected to this load to confirm the result. All the specimens were evaluated under a stereo microscope (20× magnification). The number of cycles reached before observing a failure, and their dependence on the load and on the material, were modeled, using a Weibull model. This made it possible to estimate the fatigue resistance as the maximum load for which one would observe less than 1% failure after 2×106 cycles. In addition to the experimental study, Finite Element Modeling (FEM) simulations were conducted to predict the force to failure for IPS e.max ZirCAD MT and IPS e.max Press with a reduced cross-section of the connectors. RESULTS The failure mode of the zirconia FPDs was mostly the fracture of the distal connector, whereas the failure mode of the lithium disilicate FPDs observed to be the fracture of the connectors or multiple cracks of the pontic. The fatigue resistance with 1% fracture probability was estimated to be 488N for the IPS e.max ZirCAD MT FPDs (453N for repeated test), 365N for IPS e.max ZirCAD MT FPDs with reduced connector size and 286N for the e.max Press FPDs. All three IPS e.max ZirCAD groups statistically performed significantly better than IPS e.max Press (p<0.001). On the other hand, no significant difference could be established between the two IPS e.max ZirCAD MT3 groups with a 4mm×4mm connector size (p>0.05). The allowable maximum principal stress (σmax) which did not lead to failure during fatigue testing for IPS e.max ZirCAD MT3 was calculated between 208MPa and 223MPa for FPDs with 4mm×4mm connectors for 2×106 cycles. This value could also be verified for the FPDs of the same material with 3mm×4mm connectors. On the other hand fatigue strength in terms of σmax at 2×106 cycles of IPS e.max Press was calculated to be between 78 and 90MPa. SIGNIFICANCE The fatigue resistance of the translucent zirconia 3-unit FPDs was about 60-70% higher than that of the lithium disilicate 3-unit FPDs, which may justify their use for molar replacements, provided that a minimal connector size of 4mm×4mm is observed. Even with a limited number of specimens (n=9) per group it was possible to statistically differentiate between the tested groups.
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Affiliation(s)
- S D Heintze
- R&D, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein.
| | - D Monreal
- R&D, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | - M Reinhardt
- R&D, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | - A Eser
- R&D, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | - A Peschke
- R&D, Ivoclar Vivadent AG, Bendererstrasse 2, FL-9494 Schaan, Liechtenstein
| | | | - V Rousson
- University Hospital Lausanne, Biostatistical Division, Institute for Social and Preventive Medicine, Switzerland
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Soares LM, Razaghy M, Magne P. Optimization of large MOD restorations: Composite resin inlays vs. short fiber-reinforced direct restorations. Dent Mater 2018; 34:587-597. [PMID: 29366492 DOI: 10.1016/j.dental.2018.01.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Revised: 11/29/2017] [Accepted: 01/08/2018] [Indexed: 01/25/2023]
Abstract
OBJECTIVE To compare mechanical performance and enamel-crack propensity of direct, semi-direct, and CAD/CAM approaches for large MOD composite-resin restorations. METHODS 45 extracted maxillary molars underwent standardized slot-type preparation (5-mm depth and bucco-palatal width) including immediate dentin sealing (Optibond FL) for the inlays (30 teeth). Short-fiber reinforced composite-resin (EverX Posterior covered by Gradia Direct Posterior) was used for the direct approach, Gradia Direct Posterior for the semi-direct, and Cerasmart composite resin blocks for CAD/CAM inlays. All inlays were adhesively luted with light-curing composite-resin (preheated Gradia Direct Posterior). Shrinkage-induced enamel cracks were tracked by transillumination photography. Cyclic axial isometric chewing (5-Hz) was simulated, starting with a load of 200N (5000 cycles), followed by stages of 400, 600, 800, 1000, 1200, and 1400N (maximum 30,000 cycles each) until fracture or to a maximum of 185,000 cycles. Survived specimens were subjected to cyclic-load-to-failure test at 30-degree angle on the palatal cusp. RESULTS Only small shrinkage-induced cracks were found in 47% of the direct restorations compared to 7% and 13% of semi-direct and CAD/CAM inlays, respectively. Survival to accelerated fatigue was similar for all three groups (Kaplan-Meier p>.05) and ranged between 87% (direct) and 93% (semi-direct and CAD/CAM). Cyclic-load-to-failure tests did not yield significant differences either (Life Table analysis, p>.05) with median values of 1675N for CAD/CAM inlays, 1775N for fiber-reinforced direct restorations and 1900N for semi-direct inlays. SIGNIFICANCE All three restorative techniques yielded excellent mechanical performance above physiological masticatory loads. Direct restorations performed as good as inlays when a short-fiber reinforced composite-resin base was used.
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Affiliation(s)
- Luciana Mara Soares
- Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USC, 925 W 34th St, Los Angeles, CA 90089, USA.
| | - Mehrdad Razaghy
- Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USC, 925 W 34th St, Los Angeles, CA 90089, USA.
| | - Pascal Magne
- Herman Ostrow School of Dentistry, University of Southern California, Los Angeles, USC, 925 W 34th St, Los Angeles, CA 90089, USA.
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Thorpe CT, Riley GP, Birch HL, Clegg PD, Screen HRC. Fascicles and the interfascicular matrix show decreased fatigue life with ageing in energy storing tendons. Acta Biomater 2017; 56:58-64. [PMID: 28323176 DOI: 10.1016/j.actbio.2017.03.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2016] [Revised: 02/09/2017] [Accepted: 03/14/2017] [Indexed: 12/27/2022]
Abstract
Tendon is composed of rope-like fascicles bound together by interfascicular matrix (IFM). The IFM is critical for the function of energy storing tendons, facilitating sliding between fascicles to allow these tendons to cyclically stretch and recoil. This capacity is required to a lesser degree in positional tendons. We have previously demonstrated that both fascicles and IFM in energy storing tendons have superior fatigue resistance compared with positional tendons, but the effect of ageing on the fatigue properties of these different tendon subunits has not been determined. Energy storing tendons become more injury-prone with ageing, indicating reduced fatigue resistance, hence we tested the hypothesis that the decline in fatigue life with ageing in energy storing tendons would be more pronounced in the IFM than in fascicles. We further hypothesised that tendon subunit fatigue resistance would not alter with ageing in positional tendons. Fascicles and IFM from young and old energy storing and positional tendons were subjected to cyclic fatigue testing until failure, and mechanical properties were calculated. The results show that both IFM and fascicles from the SDFT exhibit a similar magnitude of reduced fatigue life with ageing. By contrast, the fatigue life of positional tendon subunits was unaffected by ageing. The age-related decline in fatigue life of tendon subunits in energy storing tendons is likely to contribute to the increased risk of injury in aged tendons. Full understanding of the mechanisms resulting in this reduced fatigue life will aid in the development of treatments and interventions to prevent age-related tendinopathy. Statement of Significance Understanding the effect of ageing on tendon-structure function relationships is crucial for the development of effective preventative measures and treatments for age-related tendon injury. In this study, we demonstrate for the first time that the fatigue resistance of the interfascicular matrix decreases with ageing in energy storing tendons. This is likely to contribute to the increased risk of injury in aged tendons. Full understanding of the mechanisms that result in this reduced fatigue resistance will aid in the development of treatments and interventions to prevent age-related tendinopathy.
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30
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Thorpe CT, Riley GP, Birch HL, Clegg PD, Screen HR. Fascicles and the interfascicular matrix show adaptation for fatigue resistance in energy storing tendons. Acta Biomater 2016; 42:308-315. [PMID: 27286677 PMCID: PMC5015572 DOI: 10.1016/j.actbio.2016.06.012] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2016] [Revised: 05/06/2016] [Accepted: 06/07/2016] [Indexed: 11/27/2022]
Abstract
Tendon is composed of rope-like fascicles, bound together by interfascicular matrix (IFM). Our previous work shows that the IFM is critical for tendon function, facilitating sliding between fascicles to allow tendons to stretch. This function is particularly important in energy storing tendons, which experience extremely high strains during exercise, and therefore require the capacity for considerable inter-fascicular sliding and recoil. This capacity is not required in positional tendons. Whilst we have previously described the quasi-static properties of the IFM, the fatigue resistance of the IFM in functionally distinct tendons remains unknown. We therefore tested the hypothesis that fascicles and IFM in the energy storing equine superficial digital flexor tendon (SDFT) are more fatigue resistant than those in the positional common digital extensor tendon (CDET). Fascicles and IFM from both tendon types were subjected to cyclic fatigue testing until failure, and mechanical properties were calculated. The results demonstrated that both fascicles and IFM from the energy storing SDFT were able to resist a greater number of cycles before failure than those from the positional CDET. Further, SDFT fascicles and IFM exhibited less hysteresis over the course of testing than their counterparts in the CDET. This is the first study to assess the fatigue resistance of the IFM, demonstrating that IFM has a functional role within tendon and contributes significantly to tendon mechanical properties. These data provide important advances into fully characterising tendon structure-function relationships. Statement of Significance Understanding tendon-structure function relationships is crucial for the development of effective preventative measures and treatments for tendon injury. In this study, we demonstrate for the first time that the interfascicular matrix is able to withstand a high degree of cyclic loading, and is specialised for improved fatigue resistance in energy storing tendons. These findings highlight the importance of the interfascicular matrix in the function of energy storing tendons, and potentially provide new avenues for the development of treatments for tendon injury which specifically target the interfascicular matrix.
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Krämer M, Schilling M, Eifler R, Hering B, Reifenrath J, Besdo S, Windhagen H, Willbold E, Weizbauer A. Corrosion behavior, biocompatibility and biomechanical stability of a prototype magnesium-based biodegradable intramedullary nailing system. Mater Sci Eng C Mater Biol Appl 2015; 59:129-135. [PMID: 26652357 DOI: 10.1016/j.msec.2015.10.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Revised: 09/10/2015] [Accepted: 10/01/2015] [Indexed: 11/29/2022]
Abstract
Implants made of degradable magnesium alloys are a potential alternative to conventional orthopaedic implant materials, e.g. stainless steel or titanium. Intramedullary nails made of the magnesium alloy LAE442 were subjected to cyclic fatigue tests in both distilled water and Hank's Balanced Salt Solution (HBSS) at 37.5°C until implant failure or a limit of 500,000cycles was reached. In distilled water, four of the five nails were still intact after the end of the biomechanical test. In HBSS, a breakage within the first 70,000 bending cycles was observed. Additionally, the degradation rate of this alloy was determined in HBSS according to the weight loss method (0.24±0.12mmyear(-1)) and based on gas release (0.21±0.03mmyear(-1)) with a standard eudiometer. A cytotoxicity test with L929 cells was carried out in accordance with EN ISO 10993-5/12. This test demonstrated sufficient cell viability of the diluted extracts (50%, 25% and 12.5%). The relative metabolic activity of the 100% extract was reduced slightly below 70%, which is classified as a threshold value for cytotoxicity. In conclusion, this in vitro study indicates that intramedullary nails made of LAE442 may not have the required fatigue resistance for load-bearing applications and the development of a corrosion-protective coating may be necessary to prevent early failure of the implant.
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Affiliation(s)
- Manuel Krämer
- Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borrie-Straße 1-7, 30625 Hannover, Germany
| | - Markus Schilling
- Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borrie-Straße 1-7, 30625 Hannover, Germany
| | - Rainer Eifler
- Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, An der Universität 2, 30823 Garbsen, Germany
| | - Britta Hering
- Institute of Production Engineering and Machine Tools (IFW), Leibniz Universität Hannover, Lise-Meitner-Straße 1, 30823 Garbsen, Germany
| | - Janin Reifenrath
- Small Animal Clinic, University of Veterinary Medicine Hannover, Bünteweg 9, 30559 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany
| | - Silke Besdo
- Institute of Continuum Mechanics, Leibniz Universität Hannover, Appelstraße 11, 30167 Hannover, Germany
| | - Henning Windhagen
- Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borrie-Straße 1-7, 30625 Hannover, Germany
| | - Elmar Willbold
- Laboratory for Biomechanics and Biomaterials, Department of Orthopedic Surgery, Hannover Medical School, Anna-von-Borrie-Straße 1-7, 30625 Hannover, Germany; CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany
| | - Andreas Weizbauer
- CrossBIT, Center for Biocompatibility and Implant-Immunology, Department of Orthopedic Surgery, Hannover Medical School, Feodor-Lynen-Straße 31, 30625 Hannover, Germany.
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