Cooling and Crack Suppression of Bone Material Drilling Based on Microtextured Bit Modeled on Dung Beetle

In recent years,the number of patients with orthopedic diseases such as cervical spondylosis has increased,resulting in an increase in the demand for orthopedic surgery.However,thermal necrosis and bone cracks caused by surgery severely restrict the development and progression of orthopedic surgery.For the material of cutting tool processing bone in bone surgery of drilling high temperature lead to cell death,easy to produce the problem such as crack cause secondary damage effects to restore,in this paper,a bionic drill was designed based on the micro-structure of the dung beetle's head and back.The microstructure configuration parameters were optimized by numerical analysis,and making use of the optical fiber laser marking machine preparation of bionic bit;through drilling test,the mathematical model of drilling temperature and crack generation based on micro-structure characteristic parameters was established by infrared thermal imaging technology and acoustic emission signal technology,and the cooling mechanism and crack suppression strategy were studied.The experimental results show that when the speed is 60 m/min,the cooling effects of the bionic bit T1 and T2 are 15.31%and 19.78%,respectively,and both kinds of bits show obvious crack suppression effect.The research in this paper provides a new idea for precision and efficient machining of bone materials,and the research results will help to improve the design and manufacturing technology and theoretical research level in the field of bone drilling tools.

Experimental Investigation of Material Removal in Elliptical Vibration Cutting of Cortical Bone

To benefit tissue removal and postoperative rehabilitation,increased efficiency and accuracy and reduced operating force are strongly required in the osteotomy.A novel elliptical vibration cutting(EVC)has been introduced for bone cutting compared with conventional cutting(CC)in this paper.With the assistance of high-speed microscope imaging and the dynamometer,the material removals of cortical bone and their cutting forces from two cutting regimes were recorded and analysed comprehensively,which clearly demonstrated the chip morphology improvement and the average cutting force reduction in the EVC process.It also revealed that the elliptical vibration of the cutting tool could promote fracture propagation along the shear direction.These new findings will be of important theoretical and practical values to apply the innovative EVC process to the surgical procedures of the osteotomy.

Biodegradable materials for bone defect repair

Compared with non-degradable materials,biodegradable biomaterials play an increasingly important role in the repairing of severe bone defects,and have attracted extensive attention from researchers.In the treatment of bone defects,scaffolds made of biodegradable materials can provide a crawling bridge for new bone tissue in the gap and a platform for cells and growth factors to play a physiological role,which will eventually be degraded and absorbed in the body and be replaced by the new bone tissue.Traditional biodegradable materials include polymers,ceramics and metals,which have been used in bone defect repairing for many years.Although these materials have more or fewer shortcomings,they are still the cornerstone of our development of a new generation of degradable materials.With the rapid development of modern science and technology,in the 21 st century,more and more kinds of new biodegradable materials emerge in endlessly,such as new intelligent micro-nano materials and cell-based products.At the same time,there are many new fabrication technologies of improving biodegradable materials,such as modular fabrication,3 D and 4 D printing,interface reinforcement and nanotechnology.This review will introduce various kinds of biodegradable materials commonly used in bone defect repairing,especially the newly emerging materials and their fabrication technology in recent years,and look forward to the future research direction,hoping to provide researchers in the field with some inspiration and reference.

Bone Remodeling, Biomaterials And Technological Applications: Revisiting Basic Concepts

Presently, several different graft materials are employed in regenerative or corrective bone surgery. However current misconceptions about these biomaterials, their use and risks may compromise their correct application and development. To unveil these misconceptions, this work briefly reviewed concepts about bone remodeling, grafts classification and manufacturing processes, with a special focus on calcium phosphate materials as an example of a current employed biomaterial. Thus a search on the last decade was performed in Medline, LILACS, Scielo and other scientific electronic libraries using as keywords biomaterials, bone remodeling, regeneration, biocompatible materials, hydroxyapatite and therapeutic risks. Our search showed not only an accelerated biotechnological development that brought significant advances to biomaterials use on bone remodeling treatments but also several therapeutic risks that should not be ignored. The biomaterials specificity and limitations to clinical application point to the current need for developing safer products with better interactions with the biological microenvironments.

Update on the use of 45S5 bioactive glass in the treatment of bone defects in regenerative medicine

Bone regeneration is a critical area in regenerative medicine,particularly in orthopedics,demanding effective biomedical materials for treating bone defects.45S5 bioactive glass(45S5 BG)is a promising material because of its osteoconductive and bioactive properties.As research in this field continues to advance,keeping up-to-date on the latest and most successful applications of this material is imperative.To achieve this,we conducted a comprehensive search on Pub-Med/MEDLINE,focusing on English articles published in the last decade.Our search used the keywords“bioglass 45S5 AND bone defect”in combination.We found 27 articles,and after applying the inclusion criteria,we selected 15 studies for detailed examination.Most of these studies compared 45S5 BG with other cement or scaffold materials.These comparisons demonstrate that the addition of various composites enhances cellular biocompatibility,as evidenced by the cells and their osteogenic potential.Moreover,the use of 45S5 BG is enhanced by its antimicrobial properties,opening avenues for additional investigations and applications of this biomaterial.

Preparation and characterization of hemihydrate calcium sulfate-calcium hydroxide composite bone repair materials

Objective:To prepare a bone repair material with certain mechanical strength and biological activity,this paper used calcium sulfate hemihydrate(CSH)powder compounded with calcium hydroxide(Ca(OH)2)powder to prepare a bone repair scaffold material for physicochemical property characterization and testing.Methods:The physical and chemical properties and characterization of the dried and cured bone repair materials were determined by Fourier infrared spectroscopy(FT-IR),X-ray diffraction(XRD),and scanning electron microscopy;Universal material testing machine to determine the mechanical and mechanical strength of composite materials.Results:XRD showed that the structure of the composite material phase at 5%concentration was calcium sulfate hemihydrate and calcium hydroxide after hydration.The FT-IR and XRD analyses were consistent.Scanning electron microscopy(SEM)results showed that calcium hydroxide was uniformly dispersed in the hemihydrate calcium sulfate material.0%,1%,5%,and 10%specimen groups had compressive strengths of 3.86±3.1,5.27±1.28,8.22±0.96,and 14.4±3.28 MPa.10%addition of calcium hydroxide significantly improved the mechanical strength of the composites,but also reduced the the porosity of the material.Conclusion:With the addition of calcium hydroxide,the CSH-Ca(OH)2 composite was improved in terms of mechanical material and is expected to be a new type of bone repair material.

The Effects of Absorbable Materials in the Treatment for Non-Weight-Bearing Bone Fractures of Extremities

Objective:To study the effects of absorbable materials in non-weight-bearing bone fractures of extremities.Methods:After 66 patients with nonweight-bearing bone fractures of extremities were selected,absorbable materials were used in the observation group and metal materials were used in the control group.Results:After treatment,the bone healing in the observation group was significantly improved(P<0.05).Conclusion:the application of absorbable materials in non-weight-bearing bone fractures of extremities is effective.

Nanostructured hybrid materials for bone-tooth unit regeneration

As a part of regenerative medicine, biomaterials are largely used in this field of nanotechnology and tissue engineering research. We have recently developed a new scaffold using electrospun nanofibers of Poly (ε-caprolactone), PCL which is able to mimic the collagen extracellular matrix of cells. The aim of this study was to engineer a biological and implantable structure leading the regeneration of the tooth-bone unit. For this aim, we have cultured mouse osteoblasts embedded in a collagen gel on the nanofibrous membrane and coupled this structure with an embryonic dental germ before implantation. To follow bone and tooth regeneration, we have performed RT-PCR, histology and immunofluorescence analysis. We showed here that this leaving implantable structure represents an accurate strategy for bone-tooth unit regeneration. We report here the first demonstration of bone-tooth unit regeneration by using a strategy based on a synthetic nanostructured membrane. This electrospun membrane is manufactured by using an FDA approved polymer, PCL and functionalized with osteoblasts before incorporation of the tooth germs at ED14 (the first lower molars) to generate bone-tooth unit in vivo after implantation in mice. Our technology represents an excellent platform on which other sophisticated products could be based.

Biologically Inspired Self-assembling Synthesis of Bone-like Nano-hydroxyapatite/PLGA-(PEG-ASP)_n Composite: A New Biomimetic Bone Tissue Engineering Scaffold Material

A new biomimetic bone tissue engineering scaffold material, nano-HAI PLGA-（ PEG-Asp ）n composite, was synthesized by a biologically inspired self-assembling approach. A novel biodegradable PLGA- （ PEG-Asp ）n copolymer with pendant amine functional groups and enhanced hydrophilicity woo synthesized by bulk ring-opening copolymerization by DL-lactide（ DLLA） and glycolide（ GA ） with Aspartic acid （ Asp ）-Polyethylene glycol（PEG） alt-prepolymer. A Three-dimensional, porous scaffold of the PLGA-（ PEG- Asp）n copolymer was fabricated by a solvent casting , particulate leaching process. The scaffold woo then incubated in modified simulated body fluid （naSBF）. Growth of HA nanocrystals on the inner pore surfaces of the porous scaffold is confirmed by calcium ion binding analyses, SEM , mass increooe meoourements and quantification of phosphate content within scaffolds. SEM analysis demonstrated the nucleation and growth of a continuous bonelike, low crystalline carbonated HA nanocrystals on the inner pore surfaces of the PLGA- （ PEG-Asp ）n scaffolds. The amount of calcium binding, total mass and the mass of phosphate on experimental PLGA- （ PEG-Asp ） n scaffolds at different incubation times in mSBF was significantly greater than that of control PLGA scaffolds. This nano-HA/ PLGA-（ PEG- Asp ）n composite stunts some features of natural bone both in main composition and hierarchical microstrueture. The Asp- PEG alt-prepolymer modified PleA copolymer provide a controllable high surface density and distribution of anionic functional groups which would enhance nucleation and growth of bonelike mineral following exposure to mSBF. This biomimetic treatment provides a simple method for surface functionalization and sabsequent mineral nucleation and self-oosembling on bodegradable polymer scaffolds for tissue engineering.

Constructive and biomechanical properties of material of decalcified bone matrix impregnated with bone cement

AIM:To analyze constructive and biomechanical properties of different quality ratio material impregnated decalcified bone matrix (DBM) with bone cement (BC).M ETHODS:The DBM particles and the materials impregnated 0 mg/g, 300 mg/g and 400 mg/g mass ratio DBM particles with BC were made according to the methods of Uris t et al.The compound material constructions were observed by scanning electron m icroscope and the biomechanical properties were measured by Instron mechanics te sting-machine.RESULTS:The DBM particles with irregular gaps existing within int erspace were connected with BC by the multipoint mode in the compound material. The ultimate compressive strength were 0 mg/g DBM in (59.3±2.2) MPa, 300 mg/g i n (27.1±1.8) MPa, 400 mg/g in (19.3±1.6) MPa.The ultimate bending strength wer e 0 mg/g in (54.3±3.7) MPa, 300 mg/g in (18.5±1.1) MPa, 400 mg/g in (13.3±1.4 ) MPa.CONCLUSION:The materials of DBM impregnated with BC had perfect plastic pr operty with much more irregular gaps existing within interspace.The materials co uld provide abundant biomechanical support.

3D/4D printed bio-piezoelectric smart scaffolds for next-generation bone tissue engineering

Piezoelectricity in native bones has been well recognized as the key factor in bone regeneration.Thus,bio-piezoelectric materials have gained substantial attention in repairing damaged bone by mimicking the tissue’s electrical microenvironment(EM).However,traditional manufacturing strategies still encounter limitations in creating personalized bio-piezoelectric scaffolds,hindering their clinical applications.Three-dimensional(3D)/four-dimensional(4D)printing technology based on the principle of layer-by-layer forming and stacking of discrete materials has demonstrated outstanding advantages in fabricating bio-piezoelectric scaffolds in a more complex-shaped structure.Notably,4D printing functionality-shifting bio-piezoelectric scaffolds can provide a time-dependent programmable tissue EM in response to external stimuli for bone regeneration.In this review,we first summarize the physicochemical properties of commonly used bio-piezoelectric materials(including polymers,ceramics,and their composites)and representative biological findings for bone regeneration.Then,we discuss the latest research advances in the 3D printing of bio-piezoelectric scaffolds in terms of feedstock selection,printing process,induction strategies,and potential applications.Besides,some related challenges such as feedstock scalability,printing resolution,stress-to-polarization conversion efficiency,and non-invasive induction ability after implantation have been put forward.Finally,we highlight the potential of shape/property/functionality-shifting smart 4D bio-piezoelectric scaffolds in bone tissue engineering(BTE).Taken together,this review emphasizes the appealing utility of 3D/4D printed biological piezoelectric scaffolds as next-generation BTE implants.

Evaluation of 4 different bone graft substitutes and autogenous bone grafting in root-end resection osteotomies after retrograde root-filling with Intermediate Restorative Material(IRM):An experimental study in dogs

Purpose: To investigate the periapical tissue response after root end filling with intermediate restorative material (IRM) and filling of the root-end resection bone defects with autogenous bone or a bone graft substitute in comparison to empty controls. Materials and Methods: Vital roots of the second, third and fourth mandibular premolars in six healthy mongrel dogs were apectomized. The root canals were prepared and sealed with IRM following a standardized surgical procedure. The resection bone defects were either filled with autogenous bone (PB) or one of the bone graft substitutes;CERAMENTTM|BONE VOID FILLER, ChronOS?, TigranTM PTG, Easygraft? CLASSIC or left empty. After 120 days the animals were sacrificed and the specimens were analyzed radiologically and histologically. Kruskal-Wallis and Mann-Whitney tests were performed for statistical evaluation. Results: 34 sections were analyzed histologically. The evaluation revealed a variation in the outcome amongst the tested options, regarding reestablishment of the periapical bone healing and inflammatory infiltration in the sections. According to the tested variables, there was no statistical significant difference between the materials when comparing all groups as a whole. When comparing individual materials to each other there was statistical differences among some of the tested materials. Conclusion: The healing outcome after periapical surgery of a five-wall resection defect could not be increased by infill with autogenous bone or bone graft substitutes. The most important factor for the healing outcome in periapical surgery is the quality of the root-end sealing. The healing outcome after some of the tested bone substitutes, might be improved by longer healing time.

硼硅酸盐生物活性玻璃的矿化及机理初探

目的探讨硼硅酸盐生物活性玻璃体外矿化成类骨层状结构的机理。方法模拟体内环境,将硅酸盐玻璃(0B)、硼硅酸盐玻璃(2B)和硼酸盐玻璃(3B)浸泡于SBF溶液和含有明胶的SBF溶液中1周;随后采用质量损失分析、SEM、EDS、XRD及FTIR等测试方法对多种生物活性玻璃的矿化产物进行系统分析与比较;采用固体核磁NMR对生物玻璃进行玻璃结构分析。结果浸泡1周后,SEM观察到硼硅酸盐玻璃(2B)和不含硅的硼酸盐玻璃(3B)表面产生层状矿化产物,而硅酸盐玻璃(0B)表面只有一层矿化产物层;XRD和FTIR结果显示3种玻璃的表面产物均为含有部分羟基磷灰石的钙磷化合物;固体核磁波谱(11B)测试结果表明硼硅酸盐玻璃(2B)和不含硅的硼酸盐玻璃(3B)都存在大量[BO_(3)]平面三角体。最后,当硼硅酸盐玻璃(2B)浸泡在含有明胶的SBF溶液后,其矿化产物仍能维持层状结构;通过EDS分析可知形成明胶有机层和含羟基磷灰石的无机层相互堆积的特殊层状结构。结论2B和3B玻璃内部存在大量[BO_(3)]平面三角体所构造的二维平面结构。矿化过程中,不溶性反应物沉积在二维平面结构上,从而使矿化产物呈现层状结构。在浸泡液中添加一定量的明胶后,其可以有效地与硼硅酸盐玻璃的层状矿化结构相互匹配结合,最终堆叠形成有机相层与无机层相互交错的特殊结构。

人体骨骼生物力学测试研究综述

骨骼是由矿物质和胶原蛋白等成分构成的多尺度层级结构,其在生理载荷作用下的自适应特性造就了骨骼复杂的非均匀性、各项异性等特性。为适应机械、生物力学、医学、航空航天、法医等多领域中骨骼生物力学特性的表征,需要利用多种不同的材料力学测试方法,准确地获取骨骼的材料本构参数。全面介绍了骨骼试样的保存、制备、测试及材料本构参数识别方法,分析了各种力学测试方法的特点及其对骨骼试样的要求。还介绍了新测试技术在骨骼力学特性表征方面的应用,基于三点弯曲测试方法提出了一套人体骨骼的材料参数获取流程。可为骨骼生物力学特性的系统表征提供理论和方法参考。

晶须在骨组织工程中的应用进展

晶须是高纯度单晶生长而成的微纳米级短纤维,其卓越的理化性能与生物学性能在骨组织工程中展现出巨大的应用潜力。本文旨在系统综述晶须的分类、生长机制、制备方法和特性,深入探讨其在骨组织工程中的应用,并展望晶须的研究方向及在骨组织工程中的应用前景。

骨增量材料中血管新生性能的作用及认识

骨增量是种植治疗中解决骨量不足状况的必要手段,骨增量成功的关键之一是植入的骨增量材料应能发生血管新生,形成与宿主组织有效血氧交换的网络。本文就骨增量材料的血管新生作用研究进展进行阐述,为促进骨增量材料的研发及其临床转化提供建议和参考。

骨免疫调节特性骨组织工程支架在修复骨缺损中的应用和发展

背景:在使用骨支架修复骨缺损时,注意骨免疫反应的调节对骨再生具有重要意义。目的:综述骨免疫反应对骨修复的影响和具有调节骨免疫功能的骨组织工程支架的设计和其在骨修复中的应用。方法:从Science Direct、PubMed、Web of Science与中国知网数据库中检索1973-2023年发表的相关文献。英文检索词:“Osteoimmunology,Macrophages,Bone repair materials,Bone scaffold,Bone defects,Bone regeneration”;中文检索词:“骨免疫,巨噬细胞,骨修复材料,骨支架,骨缺损,骨再生”,对筛选出该领域最新研究进展的80篇文献进行归纳分析。结果与结论:①文章详细梳理了骨免疫的起源和发展进程中的重要时间点,并阐述了巨噬细胞作为骨免疫调控体系中重要成员,可分为M1(促炎)和M2(抗炎)两类表型,并在骨再生的不同时期发挥着关键作用。在炎症期,M1型巨噬细胞一方面能激活破骨细胞,启动组织修复进程,同时参与骨内微血管网的重建,另一方面炎症后期的骨组织再生过程中,持续高表达M1型巨噬细胞会阻碍新骨形成;而在修复期,M2型巨噬细胞一方面可分泌成骨细胞因子,刺激骨髓间充质干细胞的成骨分化和矿化,进而促进骨形成,另一方面,长期激活的M2型巨噬细胞会增加促纤维化分子的分泌,导致瘢痕组织的过度形成,从而延迟愈合过程。因此调控巨噬细胞在适宜的阶段进行表型转换,构建有益于成骨的免疫微环境对骨再生意义巨大。②在设计具备骨免疫调控特性的骨支架过程中,可通过改变支架粗糙度、孔隙结构、刚度、亲水性、表面电荷、表面官能团等理化性质影响非特异性蛋白质和细胞黏附,从而影响骨支架与免疫系统的相互作用。而将羟基磷灰石,生物活性玻璃、金属离子、细胞外基质、药物、细胞因子和外泌体等生物活性物质进行表面功能涂层设计,则可在植入机体之后通过释放生物活性物质,主动调控免疫微环境,影响巨噬细胞极化和巨噬细胞与骨骼细胞之间的串扰,促进巨噬细胞更多的M2极化,构建出有利于骨再生的骨免疫微环境。③基于骨组织工程支架的研发,除了关注干细胞成骨分化的直接调控因素外,还应注重对干细胞分化的免疫微环境的管理,通过调控适宜的骨免疫微环境,诱导更多的干细胞成骨分化,增强支架的成骨效能,并凝练出“骨免疫调节特性”的理念,深入阐明了骨免疫微环境的多向调节作用并介绍了现有改变支架理化性能和表面功能涂层策略赋予支架骨免疫调控潜能的策略,为指导新一代具有骨免疫调控特性的骨组织工程支架的研发提供新思路。但是骨免疫微环境是一个动态平衡状态,现有研究的调控策略多数未顾虑到调控的动态匹配性,因此针对具有高效且靶向调控免疫微环境的智能骨免疫调控支架的研发,是未来学者研究的重点关注方向。

纳米复合甲基丙烯酰明胶水凝胶在不同骨缺损环境中应用的价值

背景:近年来,纳米复合甲基丙烯酰明胶水凝胶在修复骨组织损伤方面的研究备受关注。目的:综述应用于骨组织工程的纳米复合甲基丙烯酰明胶水凝胶近年来的最新进展,举例说明纳米复合甲基丙烯酰明胶水凝胶在不同骨缺损环境中的应用。方法:应用计算机检索中国知网、万方、PubMed和Web of Science数据库2016-2023年发表的相关文献,中文检索词为:“明胶,甲基丙烯,纳米,骨,骨组织工程,骨再生,成骨”,英文检索关键词为“gelatin,methacryl*,nano*,bone,bone tissue engineering,bone regeneration,osteogenesis”。结果与结论:①当前作为甲基丙烯酰明胶填料的纳米材料包括无机纳米材料、有机纳米材料以及有机-无机纳米杂化材料。②无机纳米材料可有效提高水凝胶的力学强度、触变性能,调节其降解时间,同时还可通过调节自身表面电荷、搭载药物/因子、自身降解释放金属离子等方式,实现水凝胶的抗菌、促骨形成、免疫调节、促血管生成等功能。③有机纳米材料、有机-无机纳米杂化材料复合甲基丙烯酰明胶水凝胶是两类新兴的材料,目前研究相对较少,但从已发表的研究来看,相比无机纳米材料复合甲基丙烯酰明胶水凝胶,有机纳米材料复合甲基丙烯酰明胶水凝胶的生物相容性及载药性能更佳,纳米相与有机聚合物相间的相互作用更强,纳米粒子的分散性更好。④有机-无机纳米杂化材料复合甲基丙烯酰明胶水凝胶结合了前二者的优势,且金属离子释放可控性更佳,具有巨大的研究潜力。⑤纳米材料可增强甲基丙烯酰明胶水凝胶的抗菌、免疫调控、促成骨等生物学性能,以促进感染性骨缺损、伴糖尿病骨缺损、骨肉瘤切除术后等复杂骨缺损环境下的骨再生。然而,纳米复合甲基丙烯酰明胶水凝胶用于骨缺损修复中的研究还仅限于动物实验,仍需要进行更多的安全性评价和临床试验。