Implante Inmediato en Zona Estética Anterior con Pérdida Parcial de la Cortical Vestibular: Reporte De Caso y Revisión de Literatura

El tratamiento con implantes dentales hoy en día es un procedimiento clínico de rutina que permite rehabilitar a los pacientes con prótesis fijas. En este caso presentamos un tratamiento complejo de implantación inmediata del sector anterior con pérdida parcial de la cortical vestibular en el que se realizó una regeneración ósea guiada y provisionalización en un tiempo quirúrgico en un paciente con patología renal. Complementamos el estudio con una revisión de la efectividad de las técnicas utilizadas y las posibles respuestas celular asociadas a la patología renal.

Treatment with dental implants nowadays is a routine clinical procedure that allows patient rehabilitation with fixed prostheses. In this case we present a complex treatment of immediate implantation of the anterior sector with partial loss of the vestibular cortex, in which guided bone regeneration and provisionalization was performed in surgical time in a patient with kidney pathology. The study was complemented with a review of the effectiveness of the techniques used and the possible cellular responses associated with kidney pathology.

Analysis of the Chemical Composition, Morphological Characterization, and Porosimetry of Allograft and Comparison with Xenograft for Dental Applications / Análisis de la Composición Química, Caracterización Morfológica y Porosimetría de Aloinjerto y Comparación con Xenoinjerto para Aplicaciones Odontológicas

SUMMARY: Tissue engineering aims to fabricate a scaffold that exhibits a suitable surface topography for a desired cellular response. Therefore, a study analyzing the characteristics of bone grafts is important for future research directions. This work aims to analyze the physical-chemical characteristics of commercially available bone grafts of human and bovine origin for dental use, using morphological analysis of the surface and chemical composition by variable pressure scanning electron microscope (VP-SEM) and energy-dispersive x-ray (EDX) spectrometry. In addition, pore diameter and surface area were analyzed by degassing method using a porosimeter, and particle size by laser diffraction. The analyzed allograft and xenograft particles differ in morphological characteristics and chemical composition. The allograft particles present a cuboidal and prismatic geometric morphology with angled edges and the absence of macropores. On the contrary, the xenograft particles present an irregular morphology with macropores in their structure. There is a statistically significant difference in C, P, and Ca between the xenograft and allografts (p < 0,05). The analyzed composition of allografts showed mainly the presence of C and O. In contrast, the composition of the xenograft was mainly Ca. These differences could influence the osteogenic properties of allografts and xenografts. This analysis provides basic information to understand the physicochemical properties of allografts and xenografts that facilitate cell-graft interaction.

La ingeniería de tejidos tiene como objetivo fabricar un andamio que muestre una topografía de superficie adecuada para una respuesta celular deseada. Por tanto, un estudio que analice las características de los injertos óseos es importante para futuros enfoques de investigación. Este trabajo tiene como objetivo analizar las características físico-químicas de injertos óseos de origen humano y bovino disponibles comercialmente para uso odontológico, mediante análisis morfológico de la superficie y composición química mediante microscopio electrónico de barrido de presión variable (VP-SEM) y x-dispersivo de energía. espectrometría de rayos (EDX). Además, el diámetro de los poros y el área superficial se analizaron mediante el método de desgasificación utilizando un porosímetro y el tamaño de las partículas mediante difracción láser. Las partículas de aloinjerto y xenoinjerto analizadas difieren en características morfológicas y composición química. Las partículas del aloinjerto presentan una morfología geométrica cúbica y prismática con bordes angulados y ausencia de macroporos. Por el contrario, las partículas de xenoinjerto presentan una morfología irregular con macroporos en su estructura. Existe una diferencia estadísticamente significativa en C, P y Ca entre el xenoinjerto y los aloinjertos (p < 0,05). La composición analizada de los aloinjertos mostró principalmente la presencia de C y O. Por el contrario, la composición del xenoinjerto fue principalmente Ca. Estas diferencias podrían influir en las propiedades osteogénicas de los aloinjertos y xenoinjertos. Este análisis proporciona información básica para comprender las propiedades fisicoquímicas de aloinjertos y xenoinjertos que facilitan la interacción célula-injerto.

Injertos Óseos en Quistes de los Maxilares. Reporte de un Caso

Los quistes de los maxilares son las lesiones óseas más comunes en la región maxilofacial. La enucleación de las lesiones y el cierre primario de los defectos, son en conjunto, el tratamiento óptimo hoy en día. En algunas ocasiones el defecto óseo resultante puede ser de un tamaño tan grande que afecta la estabilidad de dientes vecinos, comprometa la indemnidad del hueso o produce un retraso cicatrizal que incluso puede impedir una regeneración ósea completa. Se considera que esta falta de regeneración expone al paciente a riesgos de infección tardía, retraso de los tratamientos rehabilitadores en zonas de alta demanda estética y pérdida de vitalidad dentaria. Para disminuir el riesgo de alteraciones en la regeneración ósea completa de cavidades quísticas, se ha propuesto la posibilidad de que tras la enucleación del quiste se rellenen estos defectos con injertos óseos u otras técnicas de preservación alveolar para favorecer la cicatrización. Teóricamente el uso de estos injertos mejora la calidad y disminuye el tiempo de cicatrización ósea, permitiendo que el paciente recupere rápidamente las funciones habituales del componente dentoalveolar, acortando el periodo de cuidados postoperatorios que restringen la alimentación, los deportes o la rehabilitación oral. El actual trabajo tiene como objetivo realizar una revisión de la literatura respecto a los beneficios del uso de injertos óseos en el tratamiento quirúrgico de los quistes maxilares y presentar un caso clínico con los detalles quirúrgicos de esta técnica.

Jaw cysts are the most common bone lesions in the maxillofacial region. Enucleation of the lesions along with the primary closure of the defects are the optimal treatment nowadays. On some occasions, the resulting bone defect can be so large that it affects the stability of neighboring teeth, compromises the integrity of the bone, or produces a delayed healing that can even prevent complete bone regeneration. It is considered that the lack of regeneration exposes the patient to risk of infection, delay of rehabilitation treatments in areas of high aesthetic demand and loss of dental vitality. To reduce the risk of alterations in complete bone regeneration of cystic cavities, the possibility of filling these defects with bone grafts or other alveolar preservation techniques to promote healing, has been proposed after cyst enucleation. Theoretically, the use of these grafts improves the quality and decreases the bone healing time, allowing the patient to quickly recover the usual functions of the dentoalveolar component, limiting the period of postoperative care that restricts eating, sports or oral rehabilitation. The present work aims to carry out a review of the literature regarding the benefits of the use of bone grafts in the surgical treatment of maxillary cysts and to present a clinical case with the surgical details of this technique.

Fibroma ameloblástico mandibular: caso clínico / Fibroblastic fibroma mandibular: a clinical case

El fibroma ameloblástico (FA) se describe como una neoplasia benigna de origen odontogénico mixto que suele presentarse entre la primera y segunda década de vida, frecuentemente en los molares permanentes inferiores. Por lo general es asintomático, pero las lesiones de gran tamaño suelen acompañarse con dolor e inflamación. Su tratamiento por lo regular es conservador. Se describe el caso de un fibroma ameloblástico en un paciente de 13 años de edad, que involucraba cuerpo y ángulo mandibular izquierdo, tratado de manera conservadora, se realiza extirpación del tumor, regeneración ósea guiada y rehabilitación con implante dental (AU)

Ameloblastic fibroma (AF) is described as a benign neoplasm of mixed odontogenic origin that usually presents between the first and second decade of life, frequently in lower permanent molars. It is usually asymptomatic, but large lesions are usually accompanied by pain and inflammation. His treatment is generally conservative. The clinical case of an ameloblastic fibroma in a 13-year-old patient is described, involving the left mandibular body and angle, treated conservatively, tumor removal, guided bone regeneration and rehabilitation with dental implants are performed (AU)

Temporal evolution of postsurgical bone repair in a rabbit model: A [99mTc]Tc-MDP scintigraphic study

Abstract Bone regeneration is crucial for repairing bone tissue following various injuries. Research techniques that enable the study of metabolic changes in bone tissue under different conditions are important for understanding bone repair and remodeling. This study used bone scintigraphy to evaluate osteogenesis secondary to osteotomy in a preclinical model of New Zealand rabbits. For this purpose, we conducted a longitudinal, prospective, case-control study in which scintigraphic variables were measured in both the right forearm (case-operated) and the left forearm (control - non-operated). The study sample consisted of 10 rabbits subjected to osteotomy, followed by a 12-week postoperative evaluation period, divided into six imaging stages at 1, 2, 3, 4, 8, and 12 weeks. We observed that the operated forearm showed significantly higher external radiation than the control side, using the pinhole collimator, denoting an increase in the biodistribution and tropism of the radiopharmaceutical to the operated forearm. Among the three evaluated time points, osteoblastic activity was highest in the second week and presented a significant decline in the 8th and 12th weeks, denoting regeneration and resolution of the surgical injury; the control forearm was also influenced by the inactivity imposed by the operated forearm. This fact was notably evidenced by the reduction in the metabolic activity of osteoblasts in the left forearm. Our study suggested that bone scintigraphy was sensitive enough to semi-quantitatively differentiate the metabolic activity of osteoblasts in the operated forearm in the three temporal landmarks evaluated in the study.

Clinical effect of apical microsurgery combined with guided bone regeneration on refractory apical periodontitis / 局解手术学杂志

Objective To investigate the clinical effect of apical microsurgery combined with guided bone regeneration(GBR)on refractory apical periodontitis and masticatory function.Methods A total of 82 patients with refractory apical periodontitis admitted to our hospital from June 2019 to September 2021 were selected as the study subjects,and they were divided into the control group and the com-bined group according to the random number table,with 41 cases in each group.The control group was treated with apical microsurgery,and the combined group was treated with apical microsurgery combined with GBR.The clinical efficacy,masticatory function and the levels of bone absorption markers[Wnt3a,osteoprotegerin(OPG),receptor activator of nuclear factor-κB ligand(RANKL)]of patients in the two groups were compared.Results The total effective rate of the combined group(100%)was higher than that of the control group(85.37%),the difference was statistically significant(P<0.05).The masticatory efficiency and bite force of patients in both groups increased gradually 3,6 and 12 months after operation(P<0.05),which were higher in the combined group compared with the control group(P<0.05).The tooth mobility of patients in both groups decreased gradually 3,6 and 12 months after operation,and the tooth mobility of patients 3 and 6 months after operation in the combined group were lower than those in the control group(P<0.05).The levels of Wnt3a and OPG of patients 1 week after operation in both groups increased,which were higher in the combined group compared with the control group(P<0.05).The RANKL level of gingival crevicular fluid of patients 1 week after operation in both groups decreased,and which was lower in the combined group compared with the control group(P<0.05).Conclusion The microapical surgery combined with GBR is effective for refractory apical periodontitis,which can effectively inhibit bone resorption,and improve masticatory function.

Research progress on graphene and its derivatives modulating the bone regeneration microenvironment / 口腔疾病防治

@#Graphene family nanomaterials (GFNs) are highly popular in the field of bone tissue engineering because of their excellent mechanical properties, biocompatibility, and ability to promote the osteogenic differentiation of stem cells. GFNs play a multifaceted role in promoting the bone regeneration microenvironment. First, GFNs activate the adhesion kinase/extracellularly regulated protein kinase (FAK/ERK) signaling pathway through their own micromorphology and promote the expression of osteogenesis-related genes. Second, GFNs adapt to the mechanical strength of bone tissue, which helps to maintain osseointegration; by adjusting the stiffness of the extracellular matrix, they transmit the mechanical signals of the matrix to the intracellular space with the help of focal adhesions (FAs), thus creating a favorable physiochemical microenvironment. Moreover, they regulate the immune microenvironment at the site of bone defects, thus directing the polarization of macrophages to the M2 type and influencing the secretion of relevant cytokines. GFNs also act as slow-release carriers of bioactive molecules with both angiogenic and antibacterial abilities, thus accelerating the repair process of bone defects. Multiple types of GFNs regulate the bone regeneration microenvironment, including scaffold materials, hydrogels, biofilms, and implantable coatings. Although GFNs have attracted much attention in the field of bone tissue engineering, their application in bone tissue regeneration is still in the basic experimental stage. To promote the clinical application of GFNs, there is a need to provide more sufficient evidence of their biocompatibility, elucidate the mechanism by which they induce the osteogenic differentiation of stem cells, and develop more effective form of applications.

Bionic design,preparation and clinical translation of oral hard tissue restorative materials / 北京大学学报(医学版)

Oral diseases concern almost every individual and are a serious health risk to the popula-tion.The restorative treatment of tooth and jaw defects is an important means to achieve oral function and support the appearance of the contour.Based on the principle of"learning from the nature",Deng Xu-liang's group of Peking University School and Hospital of Stomatology has proposed a new concept of"microstructural biomimetic design and tissue adaptation of tooth/jaw materials"to address the worldwide problems of difficulty in treating dentine hypersensitivity,poor prognosis of restoration of tooth defects,and vertical bone augmentation of alveolar bone after tooth loss.The group has broken through the bottle-neck of multi-stage biomimetic technology from the design of microscopic features to the enhancement of macroscopic effects,and invented key technologies such as crystalline/amorphous multi-level assembly,ion-transportation blocking,and multi-physical properties of the micro-environment reconstruction,etc.The group also pioneered the cationic-hydrogel desensitizer,digital stump and core integrated restora-tions,and developed new crown and bridge restorative materials,gradient functionalisation guided tissue regeneration membrane,and electrically responsive alveolar bone augmentation restorative membranes,etc.These products have established new clinical strategies for tooth/jaw defect repair and achieved inno-vative results.In conclusion,the research results of our group have strongly supported the theoretical im-provement of stomatology,developed the technical system of oral hard tissue restoration,innovated the clinical treatment strategy,and led the progress of the stomatology industry.

Risk factors of perioperative hypertension in dental implant surgeries with bone augmentation / 北京大学学报(医学版)

Objective:To investigate the characteristics and risk factors of perioperative hypertension during dental implant surgeries with bone augmentation.Methods:A retrospective cohort study was con-ducted.Seven hundred and twenty-eight cases underwent dental implant placement and bone augmenta-tion in Peking University School and Hospital of Stomatology from September 2021 to August 2022 were recruited in this study according to the inclusion and exclusion criteria.They were divided into different groups according to the exposure factors which were gender,age,surgical time,and surgical approach.The correlation between perioperative hypertension and the exposure factors was analyzed.Results:The average systolic blood pressure variability was 9.93％±6.63％(maximum 50.41％),the average dias-tolic blood pressure variability was 12.45％±8.79％(maximum 68.75％),and the average mean arte-rial pressure variability was 10.02％±6.61％(maximum 49.48％).The incidence rate of perioperative hypertension was 26.77％.Male,age ≥ 60 years,and surgical time＞60 minutes were risk factors for perioperative hypertension(P＜0.05),and the relative risks(95％CI)were 1.74(1.21-2.50),2.35(1.54-3.58),and 1.65(1.15-2.38),respectively.There was no significant difference in the inci-dence of perioperative hypertension among the guided bone regeneration,sinus floor elevation with transal-veolar approach,and sinus floor elevation with lateral window approach(P＞0.05).However,the risk factors varied according to bone augmentation approaches.For the patients underwent guided bone rege-neration,the risk factors for perioperative hypertension included male,age≥60 years,and surgical time＞60 minutes(P＜0.05).For the patients underwent maxillary sinus lift with transalveolar approach,the risk factor for perioperative hypertension was age ≥ 60 years(P＜0.05).For the patients underwent maxillary sinus lift with lateral window approach,male,age ≥60 years,and surgical time＞60 minutes were not risk factors for perioperative hypertension(P＞0.05).Conclusion:There was a certain risk of periopera-tive hypertension in oral implantation with bone augmentation.The influence of male,age ≥60 years and sur-gical time＞60 minutes on perioperative hypertension was related to the approach of bone augmentation.

Application of metal ions in bone tissue engineering / 中国组织工程研究

BACKGROUND:Metal ions play an important role in the human body.With the progress of material synthesis and processing technology,a variety of metal ions that can be used in bone tissue engineering have been developed,such as magnesium(Mg2+),zinc(Zn2+),manganese(Mn2+),strontium(Sr2+),and copper(Cu2+). OBJECTIVE:To summarize the research progress and development direction of metal ions in bone tissue engineering. METHODS:The literature collected by CNKI,PubMed and WanFang databases from 2014 to 2022 was retrieved.The Chinese and English key words were"metal ions,bone tissue engineering,osteogenic activity,magnesium ions,zinc ions,manganese ions,strontium ions,copper ions,calcium ions,lithium ions,cobalt ions". RESULTS AND CONCLUSION:Different metal ions will be released to varying degrees after the materials are implanted into the body,which can change the tissue microenvironment,thus improving the ability of materials to form blood vessels and bones.Compared with growth factors,metal ions are easier to control the release rate,have lower cost,and can also improve the mechanical properties of implant materials.The application of metal ions in bone tissue engineering is full of prospects.Although some metal ions can already be used to treat bone defects,the mechanism of action of many metal ions in the human body is not completely clear,and the application effect is a lack of clinical experiment verification.Further exploration is needed before clinical application.

Function and advantages of magnetically responsive hydrogel in bone tissue engineering / 中国组织工程研究

BACKGROUND:Magnetically responsive hydrogels have great advantages in bone tissue engineering,which is more conducive to the minimally invasive and efficient promotion of osteogenesis. OBJECTIVE:To review the application advances of magnetically responsive hydrogels in bone tissue engineering. METHODS:PubMed,Web of Science,WanFang and CNKI databases were used to search relevant literature.The English search terms were"Magnetic Hydrogels,Magnetic Nanoparticles,Superparamagnetic Nanoparticles,Fe3O4,SPIONs,Magnetic Fields,Bone Regeneration,Bone Repair,Bone Tissue Engineering".The Chinese search terms were"Magnetic Hydrogel,Magnetic Nanoparticles,Superparamagnetic Iron Oxide Nanoparticles,Magnetic Field,Iron Oxide Nanoparticles,Bone Regeneration,Bone Reconstruction,Bone Repair,Bone Tissue Engineering".After preliminary screening of all articles according to the inclusion and exclusion criteria,60 articles were finally retained for review. RESULTS AND CONCLUSION:(1)In recent years,due to the emergence of magnetic nanoparticles,more and more magnetic responsive scaffold materials have been developed.Among them,magnetic responsive hydrogels containing iron oxide nanoparticles and superparamagnetic iron oxide nanoparticles have outstanding mechanical properties and good biocompatibility.It can quickly respond to the external magnetic field and provide the magnetic-mechanical signals needed for seed cells to form bone.(2)Magnetic-responsive hydrogel can be used as a carrier to accurately regulate the release time of growth factors.(3)Under the three-dimensional microenvironment culture platform based on magnetically responsive hydrogel,the magnetic force at the interface between the magnetic response hydrogel and cells can activate cell surface sensitive receptors,enhance cell activity,and promote the integration of new bone and host bone.(4)The injectable magnetically responsive hydrogel can be used in the field of magnetic hyperthermia and biological imaging of bone tumors.(5)At present,magnetically responsive hydrogels are expected to mimic the anisotropic layered structure observed in natural bone tissue.However,most of the studies on magnetically responsive hydrogels focus on in vitro studies,and the mechanism of interaction between magnetically responsive hydrogels and the local microenvironment in vivo is still insufficient.(6)Therefore,based on the successful application of magnetic nanoparticles in magnetic resonance imaging,it is expected to optimize the properties of magnetic nanoparticles in the future to construct magnetic responsive hydrogels with suitable degradation properties,mechanical properties,and vascular functionalization,which can monitor changes in vivo in real time.

Characteristics of hydrogel microspheres in bone tissue engineering / 中国组织工程研究

BACKGROUND:Hydrogel microparticles,due to their porous and injectable properties,have demonstrated unique advantages in biomedical fields,such as the delivery of cells and bioactive factors/drugs,the construction of tissue repair scaffolds.They have broad application prospects. OBJECTIVE:To review the latest research progress and discuss the key problems and challenges in the research of bone tissue engineering based on hydrogel microparticles. METHODS:The relevant articles in PubMed and CNKI were searched by computer.The English key words were"hydrogels,microparticles,microspheres,microcarriers,bone,bone defect,bone repair,bone healing,bone tissue engineering"while the Chinese key words were"hydrogels,microparticles,microspheres,bone tissue engineering,bone defect,bone repair,bone regeneration".The retrieval period was from 2002 to 2022,and 127 articles were finally included for review. RESULTS AND CONCLUSION:(1)At present,various hydrogel microparticles have been developed for use in bone tissue engineering strategies,for example,hydrogel microparticles carrying cells or bioactive factors/drugs,hydrogel microparticles as biological scaffolds,stimulus-responsive hydrogel microparticles,biomineralized hydrogel microparticles,hydrogel microparticles combined with other biological materials.(2)Bone tissue engineering repair strategies based on hydrogel microparticles mainly regulate bone repair by promoting stem cell recruitment and osteogenic differentiation,regulating the local inflammatory microenvironment and promoting angiogenesis at the site of injury.However,the present studies did not deeply explore the effect of bone tissue engineering based on hydrogel microparticles on the recruitment and differentiation of endogenous stem cells and the regulation of the inflammatory microenvironment by the physical and chemical properties of hydrogel microparticles.The long-term in vivo adverse reactions of hydrogel microparticles have not been explored yet,and it is difficult to mass-produce them,thus future research needs to strengthen the mechanism exploration and technical route,so as to provide a reasonable reference for the development of hydrogel microparticles that can be used for clinical transformation.

Application of near infrared responsive hydrogels in tissue engineering / 中国组织工程研究

BACKGROUND:Near infrared responsive hydrogels,have a variety of excellent properties such as high spatial and temporal precision,remote tunability,and safety and non-invasiveness,providing a new direction of exploration for the development of tissue engineering. OBJECTIVE:To summarize the application progress of near infrared responsive hydrogels in the field of tissue engineering in recent years. METHODS:The literature search was performed on PubMed and CNKI databases.The keywords were"near infrared responsive hydrogels,tissue engineering,bone defect,bone repair,bone regeneration,wound healing,wound dressing,angiogenesis"in Chinese and English.The search time limit was from May 2006 to October 2022 and extended for some classical literature.The abstracts and contents of the retrieved literature were analyzed,and the relevant literature was obtained according to inclusion and exclusion criteria.Finally,97 articles were included for review. RESULTS AND CONCLUSION:(1)Near infrared responsive materials are involved in tissue repair by controlling infection and reducing inflammation,promoting angiogenesis,osteoblast differentiation and new bone formation.(2)Near infrared responsive hydrogel can be prepared by constructing a thermosensitive hydrogel with a photothermal effect or by using a photochemical reaction.(3)Near infrared responsive hydrogels as wound dressings perform various functions such as rapid hemostasis,tissue adhesion through polymerization of polymer monomers,antibacterial and anti-inflammatory effects,and promotion of angiopoiesis and epithelial regeneration through the local photothermal effect of photothermal nanomaterials during soft tissue healing and regeneration.(4)Near infrared responsive hydrogels function during bone reconstruction and repair by promoting osteogenic differentiation of mesenchymal stem cells,stimulating the expression of heat shock proteins,and increasing angiogenesis.(5)Near infrared responsive hydrogels present a combination of multiple therapeutic strategies with significant synergistic therapeutic functions and are also being progressively developed for application in other tissue reconstruction and disease treatment scenarios.

Role and application of early transient presence of M1 macrophages in bone tissue engineering / 中国组织工程研究

BACKGROUND:Early transient presence of M1 macrophages can play a beneficial role after the implantation of bone tissue engineering materials.Recently,strategies for manipulating M1 macrophages to produce an early moderate inflammatory response have been extensively studied and many research advances have been made in the design of bone tissue engineering materials. OBJECTIVE:To review the role of early transient presence of M1 macrophages in bone tissue engineering and recent research advances in the strategy for activating early transient presence of M1 macrophages in the field of bone tissue engineering. METHODS:Relevant literature included in PubMed,WanFang database,and CNKI Database from January 2012 to October 2022 was searched.Search terms were"M1,macrophage,bone immunoregulation,bone defect,osteogenesis,osteoimmunology,angiogenesis"in English and Chinese.After excluding articles irrelevant to the research purpose and repetitive articles,63 papers were finally included for review. RESULTS AND CONCLUSION:The early transient presence of M1 macrophages play a key role in bone tissue engineering by promoting angiogenesis,facilitating osteogenic differentiation of bone marrow mesenchymal stem cells and promoting an M2 macrophage phenotype.Strategies for inducing and activating early transient presence of M1 macrophages can modulate the local immune microenvironment for bone defect repair in a manner consistent with early natural bone healing,including modulation of the physicochemical properties of bone tissue engineering materials to promote appropriate M1 macrophage-mediated inflammatory responses,sequential delivery of cytokines,microRNAs or bioactive ions to facilitate the M1-to-M2 transition of macrophages,and controlled release of anti-inflammatory substances to achieve the maintenance of early inflammatory responses.

Application value of nanocomposite gelatin methacryloyl hydrogels in different bone defect environments / 中国组织工程研究

BACKGROUND:At present,nanocomposite gelatin methacryloyl hydrogels have been extensively studied in bone tissue engineering. OBJECTIVE:To review the latest research progress of nanocomposite gelatin methacryloyl hydrogels,and introduce the application of nanocomposite gelatin methacryloyl hydrogels in different bone defect environments. METHODS:The computer retrieval was conducted for relevant literature published in CNKI,WanFang,PubMed,and Web of Science databases from 2016 to 2023.The Chinese and English search terms were"gelatin,methacryl*,nano*,bone,bone tissue engineering,bone regeneration,osteogenesis". RESULTS AND CONCLUSION:(1)Up to now,inorganic nanomaterials,organic nanomaterials and organic-inorganic hybrid nanomaterials are the main nanomaterials used as fillers for gelatin methacryloyl.(2)Inorganic nanomaterials enhance the mechanical strength of gelatin methacryloyl,improve its thixotropic properties and degradation rate,and realize the antibacterial,osteogenic,immunoregulatory,angiogenic and other functions of gelatin methacryloyl hydrogel through its surface charge regulation,drug/factor loading,metal ion self-degradation release,etc.(3)Organic nanomaterial and organic-inorganic hybrid nanomaterial composite gelatin methacryloyl hydrogel are two emerging materials.At present,there are relatively few studies,but from the published research,compared with inorganic nanomaterial gelatin methacryloyl hydrogel,organic nanomaterial gelatin methacryloyl hydrogel has better biocompatibility and drug-loading performance.The interaction between nano phase and organic polymer phase is stronger,and the dispersion of nano particles is better.(4)Organic-inorganic hybrid nanomaterial composite gelatin methacryloyl combines the advantages of the previous two,and has better controllability of metal ion release,which proves great research potential.(5)Nanomaterials can enhance the antibacterial,immune regulation,osteogenesis and other biological properties of gelatin methacryloyl,so as to promote bone regeneration in the complex bone defect microenvironment,such as infected bone defect,diabetes,osteosarcoma resection and so on.However,the relevant research of nanocomposite gelatin methacryloyl hydrogel in bone repair is still limited to animal experiments.Further safety testing and clinical studies are still needed.

Application of core-shell structured nanofibers in oral tissue regeneration / 中国组织工程研究

BACKGROUND:The combination of good biomechanical properties,controlled drug release and multi-functionality of core-shell structured nanofibers is receiving more and more attention,which also makes them promising for a wide range of applications in the field of oral tissue regeneration. OBJECTIVE:To summarize the preparation,drug loading and release mechanisms of core-shell structured nanofibers and their application in the regenerative repair of oral tissues. METHODS:A computer search of the literature collected in CNKI and PubMed from January 2000 to November 2022 was applied,and the search terms in English and Chinese were"electrospinning,core-shell structures,drug delivery systems,jaw bone regeneration,cartilage regeneration,periodontal tissue regeneration". RESULTS AND CONCLUSION:(1)There are various methods for the preparation of core-shell structured nanofibers,but the coaxial and emulsion methods of electrostatic spinning have unique advantages such as simple operation,diverse material selection and good biocompatibility.(2)Core-shell structured nanofibers can be used as bacteriostatic agents,carriers of different types of drugs,and scaffolds for cell adhesion,providing new therapeutic options for oral tissue regeneration.(3)Controlled degradation and drug release rate of core-shell structured nanofibers can better adapt to the healing process of oral tissue defect repair and achieve ideal tissue regeneration.

Angiogenesis mechanism of metal ions and their application in bone tissue engineering / 中国组织工程研究

BACKGROUND:Owing to excellent angiogenesis activity and their participation in the physiological processes such as angiogenesis in osteogenesis,the researches and applications of a variety of metal ions are getting deeper in the field of bone tissue engineering. OBJECTIVE:To systematically explain the mechanism of angiogenesis of different metal ions such as copper ion(Cu2+),magnesium ion(Mg2+),strontium ion(Sr2+),zinc ion(Zn2+),cobalt ion(Co2+)and their current research situation as well as application in the treatment of diseases in the field of bone tissue engineering. METHODS:The two authors used PubMed and CNKI to search the literature published between 2017 and 2022 with the search terms"copper ion,magnesium ion,strontium ion,zinc ion,cobalt ion,bone,angiogenesis"in Chinese and"copper,cuprum,Cu,magnesium,Mg,strontium,Sr,zinc,Zn,cobalt,Co,metal ion,angiogenesis,bone"in English.After reading titles and abstracts,the articles were initially screened,and irrelevant articles were excluded.Finally,114 articles were included for review. RESULTS AND CONCLUSION:(1)Metal ions can regulate angiogenesis by acting on vascular endothelial growth factors,hypoxia-inducible factors,angiogenesis-related genes,endothelial cells and conducting immune regulation of macrophages.(2)Metal ions such as copper,magnesium,strontium,zinc and cobalt are often used to improve the performance of tissue engineering scaffolds due to their significant angiogenic effect.Among them,hydrogels,bioceramics and synthetic polymer materials are widely used at present,and magnesium and its alloys also have advantages due to their excellent bearing capacity.However,these materials all have some defects.Currently,there is no ideal bone replacement material.(3)Various metal ions show different application potentials in bone replacement materials:Copper has antibacterial,angiogenic and osteogenic properties,and is mainly used for bone defects caused by infection and tumors.Magnesium and zinc have strong biodegradability,so the degradation rate should be controlled.Magnesium is corrosive and is mainly used as an alloy.The angiogenesis mechanism of zinc is less involved.Magnesium and strontium are effective in treating osteoporotic bone defects.(4)The above five metal ions(copper,magnesium,strontium,zinc and cobalt)have a significant role in promoting angiogenesis and then promote osteogenesis through angiogenesis.Some ions,such as copper ions,have a bactericidal effect.These ions can be used as a new strategy for the treatment of bone defects caused by tumors,osteoporosis,infection and trauma,but the current clinical trials and application studies of products are relatively insufficient.

Application and prospects of erythropoietin in bone tissue engineering / 中国组织工程研究

BACKGROUND:Bone defects are caused by many factors,such as inflammation,tumor,trauma or bone diseases.Erythropoietin can promote the differentiation of mesenchymal stem cells into osteoblasts and osteoclasts and act on vascular endothelial cells to induce angiogenesis and accelerate the repair of bone and cartilage defects.Erythropoietin is a growth factor with potential application in bone tissue engineering construction. OBJECTIVE:To expound the application and potential mechanism of erythropoietin in bone tissue engineering. METHODS:The first author searched the related articles published in CNKI,WanFang,VIP,and PubMed databases from 2004 to 2022 by computer.Search terms were"erythropoietin,bone defect,bone regeneration,angiogenesis,osteogenesis,osteoblast,osteoclast,bone tissue engineering"in Chinese and English.Finally,64 articles were included for review. RESULTS AND CONCLUSION:(1)Erythropoietin can directly act on osteoblasts and osteoclasts in the bone marrow microenvironment by promoting the differentiation of mesenchymal stem cells into osteoblasts,osteoclasts,adipocytes,nerve cells and stromal cells.The activation of Wnt/β-catenin,hypoxia-inducible factor 1α/vascular endothelial growth factor,p38 MAPK and EphrinB2/EphB4 signaling pathways mediates the osteogenic differentiation of mesenchymal stem cells.(2)Erythropoietin can not only regulate the production of erythrocytes to alter the oxygen-carrying capacity of blood but also stimulate vascular endothelial cells to promote angiogenesis.The new blood vessels can carry oxygen,nutrients,growth factors,and bone progenitor cells necessary for osteogenesis to the osteogenic site,thereby promoting bone formation and fracture healing.(3)Currently,erythropoietin is being used as a growth factor with osteogenic and angiogenic effects in various types of scaffold materials such as chitosan,polycaprolactone,bioceramics,and nanofibers through various drug delivery methods.Erythropoietin,along with other growth factors such as bone morphogenetic protein-2 and bone morphogenetic protein-9,has been applied to the surface of scaffold materials to participate in the repair of bone defects.Erythropoietin has demonstrated excellent practicality in the construction of new tissue-engineered bone and has potential clinical application value.

Application of biomaterials in Masquelet technology / 中国组织工程研究

BACKGROUND:The remediation and treatment of bone defects present considerable challenges,with a variety of clinical intervention strategies available.One such approach,the Masquelet technique,has demonstrated high rates of success and reliable outcomes and is currently employed in clinical practice.However,the underlying mechanisms of this technique remain incompletely understood,and certain challenges persist in its clinical application,indicating that this technique is not yet fully mature. OBJECTIVE:To compile and categorize the biomaterials currently employed in research aimed at improving the Masquelet technique,in order to provide insights and references for the further development of this technique. METHODS:A literature search of the China National Knowledge Infrastructure and PubMed databases was conducted,spanning publications from January 2013 to November 2022.The search terms used included"Masquelet technique;induced membrane technique;induced membrane;biomaterial;bone defect"in both Chinese and English.A total of 58 articles meeting the inclusion criteria were reviewed. RESULTS AND CONCLUSION:(1)The emergence and continual development of the Masquelet technique provide a therapeutic strategy for treating bone defects.Some researchers are focusing on developing superior spacer materials,autograft substitutes,and membrane materials that mimic the properties of the induced membrane,to simplify the two-stage procedure,shorten treatment duration,and reduce patient distress.(2)Calcium sulfate,silicone,poly(lactic-co-glycolic acid),and polypropylene can replace polymethylmethacrylate bone cement to form induced membranes in animal experiments or clinical applications,each with their advantages.Contrary to expectations,common materials such as titanium and polyvinyl alcohol sponge cannot replace polymethylmethacrylate bone cement.(3)Autograft substitutes are diverse,with allograft bone,β-tricalcium phosphate,absorbable gelatin sponge,α-calcium sulfate hemihydrate,bioactive glass,titanium,and tantalum demonstrating their ability to reduce the quantity of autologous cancellous bone graft required in the second stage of the procedure.Among them,allograft bone,β-tricalcium phosphate,bioactive glass,titanium and tantalum can replace autogenous bone as grafts,and other materials need to be mixed with autogenous bone,in both clinical and fundamental experiments.(4)Biomimetic-induced membranes,human amnion,human decellularized dermis,polytetrafluoroethylene,and even autogenous cortical bone have been shown to possess properties similar to the induced membrane.(5)Most of the application and research of biomaterials in this technology still exist in the stage of basic research and have not been applied in clinical practice or popularized on a large scale,but the above materials can provide more sufficient theoretical basis and new ideas for the exploration of Masquelet technical mechanism,the improvement of surgical methods and clinical application.

The effective components of Chinese medicine combined with scaffold materials promote bone tissue regeneration / 中国组织工程研究

BACKGROUND:With the proven ability of traditional Chinese medicine such as icariin and berberine to promote bone regeneration by regulating various mechanisms and targets,researchers have combined active ingredients of traditional Chinese medicine with bone tissue engineering and found that they have unique advantages in treating bone defects. OBJECTIVE:Starting from the active ingredients of traditional Chinese medicines that promote bone formation,to screen cases of their effective combination with different drug-carrying scaffold materials,and summarize the active ingredients of traditional Chinese medicines that have the potential to be applied to bone tissue engineering. METHODS:CNKI,WanFang,PubMed,and Web of Science were searched for relevant literature published from 2000 to 2023,using the keywords of"bone tissue engineering,bone tissue-engineered scaffold materials,bone defect,bone repair,bone regeneration,traditional Chinese medicine"in Chinese and English.According to the inclusion and exclusion criteria,87 papers were finally included for review. RESULTS AND CONCLUSION:There are various kinds of active ingredients of traditional Chinese medicine to promote bone regeneration,mainly including flavonoids,non-flavonoid polyphenols,alkaloids,glycosides.These active ingredients have anti-inflammatory and analgesic effects,promote osteoblasts,inhibit osteoclasts and promote early angiogenesis.The combination of active ingredients of traditional Chinese medicine with bone tissue engineering is effective in anti-inflammation,accelerating collagen and bone formation,and promoting the expression of osteogenic genes,which provides a theoretical basis for the application of traditional Chinese medicine in bone tissue regeneration,and at the same time provides a new idea for the repair of bone defects.