3D Printing characteristics and mechanical properties of a bio scaffold obtained from a Micro-CT Scan, using the fused deposition modeling technique

The objective is to determine which biopolymer has the best 3D printing characteristics and mechanical properties for the manufacture of a bioscaffold, using the fused deposition printing technique, with models generated from an STL file obtained from a Micro-CT scan taken from a bovine iliac crest bone structure. Through an experimental exploratory study, three study groups of the analyzed biopolymers were carried out with thirteen printed structures of each one. The first is made of 100% PLA. The second, 90B, we added 1g of diatom extract, and the third, 88C, differs from the previous one in that it also contains 1g of calcium phosphate. The 39 printed structures underwent a visual inspection test, which required the fabrication of a gold standard scaffold in resin, with greater detail and similarity to the scanned bone structure. Finally, the structures were subjected to a compressive force (N) to obtain the modulus of elasticity (MPa) and compressive strength (MPa) of each one of them. A statistically significant difference (p=0.001) was obtained in the printing properties of the biomaterial 88C, compared to 90B and pure PLA and the 88C presented the best 3D printing characteristics. In addition, it also presented the best mechanical properties compared to the other groups of materials. Although the difference between these was not statistically significant (p=0.388), in the structures of the 88C biomaterial, values of compressive strength (8,84692 MPa) and modulus of elasticity (43,23615 MPa) were similar to those of cancellous bone in the jaws could be observed. Because of this result, the 88C biomaterial has the potential to be used in the manufacture of bioscaffolds in tissue engineering.

El objetivo es determinar cuál biopolímero presenta las mejores características de impresión 3D y propiedades mecánicas para la fabricación de un bioandamiaje, utilizando la técnica de impresión por deposición fundida, con modelos generados a partir de un archivo en formato STL que se obtuvo de un Micro-CT Scan de una estructura osea de cresta iliaca bovina. Mediante un estudio exploratorio, se realizaron 3 grupos de estudio con trece estructuras impresas de cada uno. El primero, se compone 100% de PLA. El segundo, 90B, se le agrega 1g de extracto de diatomea, y el tercero, 88C, se diferencia del anterior ya que contiene además, 1g de fosfato de calcio. A las 39 estructuras impresas se les realizó una prueba de inspección visual, por lo que se requirió la confección de un patrón de oro en resina, con mayor detalle y similitud a la estructura ósea escaneada. Finalmente, las estructuras fueron sometidas a una fuerza compresiva (N) para la obtención del módulo de elasticidad (MPa) y de la resistencia compresiva (MPa) de cada una de ellas. Se obtuvo una diferencia estadísticamente significativa (p=0,001) en las propiedades de impresión del biomaterial 88C, con respecto al 90B y al PLA puro, presentando las mejores características de impresión 3D. Además, obtuvo las mejores propiedades mecánicas en comparación con los otros grupos de materiales. Aunque la diferencia entre estos no fue estadísticamente significativa (p=0,388), en las estructuras del biomaterial 88C, se pudieron observar valores de resistencia compresiva (8,84692 MPa) y módulo de elasticidad (43,23615 MPa) que son semejantes a los del hueso esponjoso de los maxilares. A razón de este resultado, el biomaterial 88C cuenta con el potencial para ser utilizado en la fabricación de bioandamiajes en la ingeniería tisular.

Research progress of periodontal tissue regeneration by combined biomaterials of dental derived mesenchymal stem cells / 口腔医学

@#The ultimate treatment goal of periodontitis is the structural and functional regeneration of periodontium. However, existing methods for periodontal regeneration have difficulties in regenerating the hierarchical structure. Therefore, stem cell-based tissue engineering has attracted more and more attention for its advantages of self-renewal and multi-lineage differentiation potential. This review summarized the progress of research on periodontal tissue regeneration by combined biomaterials of dental-derived stem cells. It is pointed out that the application of autologous stem cell transplantation is limited by the donor source, and the subsequent research should focus on the development of multi-phase scaffold materials and the attempt to establish a stem cell bank.

Application of biomaterial model in breast minimally invasive surgery training / 中华医学教育探索杂志

Objective:To explore the application value of biomaterial breast model combined with traditional clinical teaching methods in the training of minimally invasive breast surgery.Methods:A total of 50 physicians who studied at the Thyroid and Breast Surgery Department of The First Affiliated Hospital of Air Force Medical University from March to December 2021 were selected as the research subjects and divided into the experimental group and the control group. The training time was one week, with three modules, namely, the study of Doppler ultrasound system and ultrasound theory, the study of the operating system for minimally invasive breast surgery, and the clinical observation and practice of minimally invasive breast surgery. Additionally, physicians in the experimental group practiced the surgical skills by using the biological material breast model. After the training, the assessment of breast minimally invasive surgery was performed, and the differences of minimally invasive operation and subjective evaluation of the two groups of physicians were analyzed. SPSS 22.0 was used to conduct independent-samples t-test and Chi-square test. Results:The time spent on breast mass localization, rotary cutter localization and residual rates of breast mass in the experimental group were (4.12±1.05) min, (12.12±2.61) min and 40%, respectively, and the corresponding results of the control group were (6.68±1.97) min, (15.32±2.89) min and 72%, which showed statistically significant differences between the two groups ( P<0.05). At the same time, the physicians in the experimental group were better than the control group in terms of self-evaluation of operational proficiency and clinical operation confidence. Conclusion:Compared with the traditional teaching method, the biomaterially simulated breast model combined with traditional teaching has significant advantages. It is an efficient teaching aid in the training and teaching of breast minimally invasive surgery, and plays an important role in the training of breast surgeons.

An injectable signal-amplifying device elicits a specific immune response against malignant glioblastoma

Despite exciting achievements with some malignancies, immunotherapy for hypoimmunogenic cancers, especially glioblastoma (GBM), remains a formidable clinical challenge. Poor immunogenicity and deficient immune infiltrates are two major limitations to an effective cancer-specific immune response. Herein, we propose that an injectable signal-amplifying nanocomposite/hydrogel system consisting of granulocyte-macrophage colony-stimulating factor and imiquimod-loaded antigen-capturing nanoparticles can simultaneously amplify the chemotactic signal of antigen-presenting cells and the "danger" signal of GBM. We demonstrated the feasibility of this strategy in two scenarios of GBM. In the first scenario, we showed that this simultaneous amplification system, in conjunction with local chemotherapy, enhanced both the immunogenicity and immune infiltrates in a recurrent GBM model; thus, ultimately making a cold GBM hot and suppressing postoperative relapse. Encouraged by excellent efficacy, we further exploited this signal-amplifying system to improve the efficiency of vaccine lysate in the treatment of refractory multiple GBM, a disease with limited clinical treatment options. In general, this biomaterial-based immune signal amplification system represents a unique approach to restore GBM-specific immunity and may provide a beneficial preliminary treatment for other clinically refractory malignancies.

Application of soft tissue augmentation in labial contour aesthetics of anterior dental implants / 口腔疾病防治

@#After tooth extraction, labial contour collapses due to inevitable physiologic bone remodeling. To achieve optimal outcomes for pink esthetic treatment at anterior implant sites, bone or soft tissue augmentation has been advocated to maintain or reconstruct the labial tissue contour. When choosing soft tissue augmentation for esthetic restoration, it is necessary to strictly grasp the indications for surgery. Soft tissue augmentation to maintain or reconstruct the labial tissue contour could be considered in patients with healthy soft tissue and no bone defects or only mild horizontal bone defects. In immediate, early and late implant placement, the timing of soft tissue augmentation may vary. In immediate implantation, the labial bone plate is intact, so it is highly recommended to simultaneously manage soft tissue during implant placement. However, patients may have large bone defects with early or late implant placement. The risk of augmenting bone and soft tissue simultaneously is likely too high, and bone augmentation surgery is often performed at the first stage while soft tissue augmentation surgery is performed at the second stage. Therefore, soft tissue surgery is often carried out simultaneously with abutment connection. Currently, soft tissue augmentation is achieved mostly with adjacent autologous soft tissue grafts, such as free gingival grafts, subepithelial connective tissue grafts or pedicle palatal flaps, which are often accompanied by a second surgical area. The replacement of autogenous soft tissue grafting with new biological materials will become an inevitable trend. In this article, we analyze and summarize the indications, timing and different methods of soft tissue augmentation to maintain and reconstruct the labial contour.

Progress in Application of Heparin Coating in Blood Contact Medical Devices / 中国医疗器械杂志

Blood compatibility is the main restriction of blood-contacting medical devices in clinical application, especially long-term blood-contacting medical devices will stimulate the immune defense mechanism of the host, resulting in thrombosis. Heparin anticoagulant coating links heparin molecules to the surface of medical device product materials, improves the compatibility between the material surface interface and the body, and reduces the host immune defense reactions. This study reviews the structure and biological properties of heparin, the market application status of heparin-coated medical products, the insufficiency and improvement of heparin coating, which can provide a reference for the application research of blood contact medical devices.

Progress on the cell therapy strategy of mesenchymal stem cells / 口腔疾病防治

@#Cell therapy based on mesenchymal stem cells (MSCs) has been a hot research topic in recent years, including the traditional cell therapy strategy based on living cells and the new cell-free therapy strategy based on soluble proteins or bioactive molecules such as extracellular vesicles (EVs). At present, MSC-induced cells have mature functions and specific structures, and insitu transplantation combined with biomaterials or organic technology has greatly improved the settlement rate and function. On the other hand, as the large-scale culture technique and EVs separation technique evolve, it is possible to obtain a large number of pure EVs, and EVs are gradually becoming a hot spot of current research. An increasing number of studies have shown that the therapeutic effect of MSCs not only occurs by implantation and differentiation but also manifests as the paracrine effect of MSCs. In this review, we discuss the emerging outcomes of cell therapies and acellular therapies to alleviate these pathological conditions.

Functional biomaterials for comprehensive periodontitis therapy

Periodontitis is an inflammatory disease caused by bacterial infection directly, and the dysregulation of host immune-inflammatory response finally destroys periodontal tissues. Current treatment strategies for periodontitis mainly involve mechanical scaling/root planing (SRP), surgical procedures, and systemic or localized delivery of antimicrobial agents. However, SRP or surgical treatment alone has unsatisfactory long-term effects and is easy to relapse. In addition, the existing drugs for local periodontal therapy do not stay in the periodontal pocket long enough and have difficulties in maintaining a steady, effective concentration to obtain a therapeutic effect, and continuous administration always causes drug resistance. Many recent studies have shown that adding bio-functional materials and drug delivery systems upregulates the therapeutic effectiveness of periodontitis. This review focuses on the role of biomaterials in periodontitis treatment and presents an overview of antibacterial therapy, host modulatory therapy, periodontal regeneration, and multifunctional regulation of periodontitis therapy. Biomaterials provide advanced approaches for periodontal therapy, and it is foreseeable that further understanding and applications of biomaterials will promote the development of periodontal therapy.

Research progress on medical devices of polyhydroxyalkanoate in orthopedics / 中国修复重建外科杂志

OBJECTIVE@#To review the research progress of natural biomaterial polyhydroxyalkanoate (PHA) in orthopedics.@*METHODS@#The literature concerning PHA devices for bone defects, bone repair, and bone neoplasms, respectively, in recent years was extensively consulted. The three aspects of the advantages of PHA in bone repair, the preparation of PHA medical devices for bone repair and their application in orthopedics were discussed.@*RESULTS@#Due to excellent biodegradability, biocompatibility, and potential osteoinduction, PHA is a kind of good bone repair material. In addition to the traditional PHA medical implants, the use of electrostatic spinning and three-dimensional printing can be designed to various functional PHA medical devices, in order to meet the orthopedic clinical demands, including the bone regeneration, minimally invasive bone tissue repair by injection, antibacterial bone repair, auxiliary establishment of three-dimensional bone tumor model, directed osteogenic differentiation of stem cells, etc.@*CONCLUSION@#At present, PHA is a hotspot of biomaterials for translational medicine in orthopedics. Although they have not completely applied in the clinic, the advantages of repair in bone defects have been gradually reflected in tissue engineering, showing an application prospect in orthopedics.

Demineralized human dentin matrix for alveolar ridge preservation using a volumetric and histologic analyses in rats

Abstract The aim of this study was to evaluate a Demineralized Human Dentine Matrix (DHDM) as viable biomaterial for alveolar ridge preservation in a rat model. Wistar rats were submitted to the extraction of maxillary first molars bilaterally. Sockets were filled with biomaterials and divided into 4 experimental groups (n=5): blood clot, autogenous bone, bovine-derived xenograft (BDX) and DHDM. Animals were sacrificed at 7, 14 e 28 days. Microtomography (uCT) volumetric evaluation and qualitative histological analyses were performed. Results obtained through the uCT showed similar values between the DHDM and the other experimental groups. The histological evaluation demonstrated DHDM with an unspecific inflammatory process and bone neoformation with slow reabsorption of the material. This result indicates that DHDM implanted in rat sockets is biocompatible and reduces the alveolar ridge volume loss after tooth extraction.

Resumo O objetivo deste estudo foi avaliar a Matriz Dentinária Humana Desmineralizada (MDHD) como biomaterial viável para preservação do rebordo alveolar, no modelo em rato. Ratos Wistar foram submetidos à exodontias dos primeiros molares superiores bilateralmente. Os alvéolos foram preenchidos com biomateriais e divididos em 4 grupos experimentais (n=5): coágulo sanguíneo, osso autógeno, osso xenógeno de origem bovina e MDHD. Os animais foram sacrificados aos 7, 14 e 28 dias. Foram realizadas avaliações volumétricas por microtomografia (uCT) e análises histológicas qualitativas. Os resultados obtidos por meio do uCT mostraram valores semelhantes entre o MDHD e os demais grupos experimentais. A avaliação histológica demonstrou MDHD com processo inflamatório inespecífico e neoformação óssea com lenta reabsorção do material. Esse resultado indica que a MDHD implantada em alvéolo de rato é biocompatível e reduz a perda de volume do rebordo alveolar após extração dentária.

Research progress of natural biomaterials for construction of tissue engineering cornea / 国际眼科杂志(Guoji Yanke Zazhi)

@#Vision loss can occur when the cornea loses transparency or changes shape. The most effective treatment to restore vision is to use full or partial layers of donor cornea for corneal transplantation. However, there is a severe shortage of donor corneas worldwide, with more than 98.5% of patients with corneal blindness waiting for donor corneas. In addition, there exist some problems such as the possibility of infection, allotransplantation immunologic rejection, and other problems after corneal transplantation. Therefore, tissue-engineering corneas have been widely studied over the years as a viable alternative to donor corneas, with different materials and methods. And in nearly ten years, the research has had breakthrough progress. The ultimate goal of the research is to construct a full or partial tissue-engineering graft with good transparency, biocompatibility, and appropriate mechanical strength to repair, regenerate, or replace diseased corneas. This review discusses the research progress and existing problems about the most frequently studied natural biomaterials in recent years. These biomaterials include amniotic membrane, acellular cornea, collagen, and silk. In addition to the future research directions, other challenges related to the biomaterials discussed in this field are illustrated.

Development of Films, Based on Oxidized Ipomea Batatas Starch, with Protein Encapsulation / Desarrollo de Películas, Basadas en Almidón Oxidado de Ipomea Batatas, con Encapsulación de Proteínas

ABSTRACT Dialdehyde starches (DAS) have been used as biomaterials due to their biocompatibility and biodegradability; nonetheless, sweet potato (Ipomea batatas L.) starch has not been researched. Films based on sweet potato DAS, mixed with native starch (NS), poly-vinyl alcohol (PVA) and glycerin have been developed with protein encapsulation, using central composite design (CCD) and response surface methodology (RSM). Input variables were oxidation degree, NS concentration and polymeric mixture volume, while output variables were film's thickness, equilibrium swelling and BSA (Bovine serum albumin) release. DAS was obtained through hydrogen peroxide (H2O2) oxidation, and the oxidation degree is referred to as H2O2 concentration. Films presented rough surfaces, and formulations containing 10% H2O2 DAS presented micropores. Water uptake was greater with higher DAS content. Film thickness depended on the volume of the polymeric suspension and influenced swelling capacity. According to RSM, the optimal formulation was DAS with 5% H2O2 and 35% NS. These results demonstrate that oxidized sweet potato starch has potential for protein encapsulation and delivery.

RESUMEN Almidones dialdehído (DAS) se han utilizado como biomateriales por su biocompatibilidad y biodegradabilidad; sin embargo, el almidón de camote (Ipomea batatas L.) no ha sido investigado. Se han desarrollado películas de DAS de camote, con almidón nativo (NS), alcohol polivinílico (PVA) y glicerina con encapsulación de proteínas, utilizando un diseño central compuesto (CCD) y metodología de superficie de respuesta (RSM). Las variables de entrada fueron: grado de oxidación, concentración de NS y volumen de la mezcla polimérica, mientras que las variables de salida fueron: espesor de la película, hinchamiento y liberación de BSA (Albúmina de Suero Bovino) en equilibrio. DAS se obtuvo mediante oxidación con peróxido de hidrógeno (H2O2), y el grado de oxidación se define como concentración de H2O2. Las películas presentaron superficies rugosas y las formulaciones con 10% H2O2 DAS presentaron microporos. La absorción de agua fue mayor con mayor contenido de DAS. El espesor de la película dependió del volumen de la mezcla polimérica e influyó en la capacidad de hinchamiento. Según RSM, la formulación óptima fue DAS con 5% H2O2 y 35% NS. Estos resultados demuestran que el almidón de camote oxidado tiene potencial para aplicaciones en la encapsulación y liberación de proteínas.

Uso da túnica vaginal canina conservada em glicerina a 98% como curativo biológico no tratamento de feridas cutâneas produzidas em ratos Wistar / Use of canine vaginal tunic preserved in 98% glycerin as biological curative in the treatment of skin produced in wound Wistar rats

Na procura por material alternativo no tratamento de feridas cutâneas, buscou-se com este estudo avaliar o comportamento da túnica vaginal canina conservada em glicerina a 98% como curativo biológico no tratamento de feridas cutâneas provocadas experimentalmente em ratos. Foram utilizados 16 ratos Wistar, nos quais foram induzidas experimentalmente duas lesões cutâneas na região dorsal, sendo uma cranial e a outra caudal. Uma ferida serviu de controle, a qual não recebeu tratamento, a outra recebeu a túnica vaginal recobrindo toda extensão da lesão. A seleção de qual das feridas, cranial ou caudal, iria receber a membrana foi feita de forma aleatória. Os animais foram distribuídos em quatro grupos de igual número para análises clínicas, macroscópicas e histológicas decorridos três, sete, 14 e 21 dias de pós-operatório. Na avaliação clínica e macroscópica pode-se observar que o processo de reparação teve evolução semelhante tanto no grupo controle quanto no grupo membrana. Na análise histopatológica foi constatada grande quantidade de infiltrado inflamatório nos períodos iniciais, no entanto, decorridos 21 dias, a epiderme já se encontrava reparada, e em todos os momentos foi observada maior presença de tecido conjuntivo no grupo membrana, sugerindo maior precocidade na cicatrização. Deste modo, concluiu-se que a túnica vaginal canina pode ser utilizada como nova alternativa no tratamento de feridas cutâneas.

In the search for alternative material in the treatment of cutaneous wounds, this study aimed to evaluate the behavior of canine vaginal tunic conserved in glycerin 98% as a biological dressing in the treatment of cutaneous wounds provoked experimentally in rats. Sixteen animals were used in which two cutaneous lesions were caused in the dorsal region, one cranial and the other caudal. One wound served as a control which did not receive treatment, the other received the vaginal tunic covering all extension of the lesion. The selection of which of the wounds, cranial or caudal, would receive the membrane was made at random. The animals were divided into four groups of equal numbers for clinical, macroscopic, and histological analyzes after three, seven, 14 and 21 postoperative days. In the clinical and macroscopic evaluation, it can be observed that the healing process had similar evolution in both the control group and the membrane group. In the histopathological analysis, a large amount of inflammatory infiltrate was observed in the initial periods; however, after 21 days the epidermis was already healed, and at all times a greater presence of connective tissue was observed in the membrane group, suggesting a greater precocity in healing. Thus, it was concluded that the canine vaginal tunic can be used as a new alternative in the treatment of cutaneous wounds.

Uso da túnica vaginal canina conservada em glicerina a 98% como curativo biológico no tratamento de feridas cutâneas produzidas em ratos Wistar / Use of canine vaginal tunic preserved in 98% glycerin as biological curative in the treatment of skin produced in wound Wistar rats

Na procura por material alternativo no tratamento de feridas cutâneas, buscou-se com este estudo avaliar o comportamento da túnica vaginal canina conservada em glicerina a 98% como curativo biológico no tratamento de feridas cutâneas provocadas experimentalmente em ratos. Foram utilizados 16 ratos Wistar, nos quais foram induzidas experimentalmente duas lesões cutâneas na região dorsal, sendo uma cranial e a outra caudal. Uma ferida serviu de controle, a qual não recebeu tratamento, a outra recebeu a túnica vaginal recobrindo toda extensão da lesão. A seleção de qual das feridas, cranial ou caudal, iria receber a membrana foi feita de forma aleatória. Os animais foram distribuídos em quatro grupos de igual número para análises clínicas, macroscópicas e histológicas decorridos três, sete, 14 e 21 dias de pós-operatório. Na avaliação clínica e macroscópica pode-se observar que o processo de reparação teve evolução semelhante tanto no grupo controle quanto no grupo membrana. Na análise histopatológica foi constatada grande quantidade de infiltrado inflamatório nos períodos iniciais, no entanto, decorridos 21 dias, a epiderme já se encontrava reparada, e em todos os momentos foi observada maior presença de tecido conjuntivo no grupo membrana, sugerindo maior precocidade na cicatrização. Deste modo, concluiu-se que a túnica vaginal canina pode ser utilizada como nova alternativa no tratamento de feridas cutâneas.

In the search for alternative material in the treatment of cutaneous wounds, this study aimed to evaluate the behavior of canine vaginal tunic conserved in glycerin 98% as a biological dressing in the treatment of cutaneous wounds provoked experimentally in rats. Sixteen animals were used in which two cutaneous lesions were caused in the dorsal region, one cranial and the other caudal. One wound served as a control which did not receive treatment, the other received the vaginal tunic covering all extension of the lesion. The selection of which of the wounds, cranial or caudal, would receive the membrane was made at random. The animals were divided into four groups of equal numbers for clinical, macroscopic, and histological analyzes after three, seven, 14 and 21 postoperative days. In the clinical and macroscopic evaluation, it can be observed that the healing process had similar evolution in both the control group and the membrane group. In the histopathological analysis, a large amount of inflammatory infiltrate was observed in the initial periods; however, after 21 days the epidermis was already healed, and at all times a greater presence of connective tissue was observed in the membrane group, suggesting a greater precocity in healing. Thus, it was concluded that the canine vaginal tunic can be used as a new alternative in the treatment of cutaneous wounds.

The research progress of bionic scaffolds in ligament tissue engineering / 生物医学工程学杂志

Ligaments are dense fibrous connective tissue that maintains joint stability through bone-to-bone connections. Ligament tears that due to sports injury or tissue aging usually require surgical intervention, and transplanting autologous, allogeneic, or artificial ligaments for reconstruction is the gold standard for treating such diseases in spite of many drawbacks. With the development of materialogy and manufacturing technology, engineered ligament tissue based on bioscaffold is expected to become a new substitute, which can lead to tissue regeneration by simulating the structure, composition, and biomechanical properties of natural tissue. This paper reviewed some recently published

Application and mechanism of nanomedicine in antifungal infection therapy / 药学学报

The threat of fungal diseases is increasingly rigorous. The clinically invasive fungal infections remain a main cause of morbidity and mortality in certain high-risk groups, especially in critical patients or immunocompromised patients. In drug therapy, the problems of off-target toxicity and antifungal drug resistance are still challenging. With the wide application of biomaterials and nanotechnology, more nanomedicine studies have been carried out on antifungal drugs, such as the amphotericin B liposome which greatly reduced the renal toxicity of drugs has been successfully marketed. For the unique physical and chemical properties, the nano-drug delivery system possessed great potential in improving the bioavailability, reducing the side effects of drugs, increasing the stability of drugs, and achieving cells or tissue-specificity through the modification. This review summarized the applications and limitations of antifungal drugs. Some nanomedicines were summarized in discussion oriented around the antifungal therapy, including liposomes, niosomes, lipid nanoparticles, polymer nanoparticles, microemulsion, dendrimers, inorganic nanocarriers. Nanotechnology and nano-drug delivery system provide promising strategies for the research and development of new formulations that can improve antifungal activity and possibly overcome antifungal drug resistance.

Advances in classification and reconstruction of palatal fistula after cleft palate operation / 口腔疾病防治

@#Postoperative fistulae are one of the most significant complications of cleft palate repair. They usually has an adverse effect on patients’ oral hygiene, speech and even mental health. There has been a wide range of rates of fistula occurrence, from 0.8%-60%, with the classification and definition of fistulae differing from one author to the next. In this paper, the definition and classification of palatal fistulae and their reconstruction method are reviewed. At present, there is a lack of a consistent definition of palatal fistulae and a classification that can fully reflect the characteristics of palatal fistula. Adjacent flap is mainly used for repairing small fistulae with an adequate amount of surrounding tissue; anteriorly based dorsal tongue flaps are a safe and reliable method for large fistulae; free flap is beneficial for refractory and complicated palatal fistulae that are difficult to repair by the local and pedicle flap; and different synthetic materials are used in multilayer repair of fistulae; among them, composite polymer membrane is highly biocompatible, promoting cell attachment and proliferation in animal models, but its security in the human body needs further research.

Nanogels as prospective Biomaterial: Radio-induced Synthesis, Characterization, and Biological Assays / Los nanogeles como biomateriales prospectivos: síntesis radioinducida, caracterización y ensayos biológicos

Nowadays, there is a growing interest in biodegradable polymers-based materials due to their diverse application in the biomedical field. Most studied systems involve biocompatible micro and nanodevices, such as liposomes, dendrimer, micelles or polymeric nanogels. The use of Radiation Technology, specifically gamma radiation, to produce micro and nanogels raises the possibility to obtain higher purity products, an important feature for biomedical and pharmaceutical applications. The radio-induced synthesis, characterization, cytotoxicity evaluation, and immunological response of nanogels are described in this study. Nanogel synthesis was performed in the absence of oxygen using aqueous polyvinylpyrrolidone solutions. Crosslinking reactions were carried out at 25 °C in a gamma irradiation chamber with a 60Co source. Nanogels properties were analysed by Scanning Electron Microscopy, Attenuated Total Reflection-Fourier Transform Spectroscopy, Dynamic Light Scattering, and Viscosimetry. The cytotoxicity and immunological response were evaluated by MTT test and analysis of the neutrophil respiratory burst. The results showed that nanogels formation strongly depends on the total absorbed dose. The nanogels have an elliptical shape and their chemical structure is similar to the initial polymer. The nanogels are biocompatible and promote a low-intensity neutrophil activation, similar to the well-characterized biomaterial TiO2, suggesting their potential biomedical uses(AU)

En la actualidad existe un interés creciente en los materiales biodegradables basados en polímeros, debido a sus diversas aplicaciones en la esfera de la biomedicina. En la mayoría de los sistemas estudiados participan micro- y nanodispositivos biocompatibles, tales como liposomas, dendrímeros, micelas o nanogeles poliméricos. El uso de la tecnología de radiaciones, en particular de radiaciones gamma, para producir micro- y nanogeles, eleva la posibilidad de obtener productos de mayor pureza, un rasgo importante con vistas a su aplicación biomédica y farmacéutica. El estudio describe la síntesis radioinducida, caracterización, evaluación de la citotoxicidad y respuesta inmunológica de los nanogeles. La síntesis de los nanogeles se realizó en ausencia de oxígeno, usando soluciones acuosas de polivinilpirrolidona. Las reacciones de entrecruzamiento se realizaron a 25 ºC en cámara de irradiación gamma con una fuente de 60Co. Las propiedades de los nanogeles se analizaron mediante microscopía electrónica de barrido, espectroscopia por transformada de Fourier total atenuada, dispersión dinámica de luz y viscosimetría. La citotoxicidad y la respuesta inmunológica se evaluaron mediante prueba MTT y análisis del estallido respiratorio de neutrófilos. Los resultados muestran que la formación de nanogeles depende en gran medida de la dosis total absorbida. Los nanogeles tienen forma elíptica y su estructura química es similar a la del polímero inicial. Los nanogeles son biocompatibles y promueven una activación de neutrófilos de baja intensidad similar al bien caracterizado material TiO2, lo que sugiere usos biomédicos potenciales(AU)

Tratamiento regenerativo de lesión interproximal consecuente a fractura del tercio medio en diente permanente joven / Regenerative treatment of interproximal lesion following middle third fracture in a young permanent tooth

Se presenta un caso clínico de fractura radicular del tercio medio, de pieza 2.1 con desplazamiento de los cabos de fractura. Es tratado con un novedoso procedimiento terapéutico, mediante la utilización de un biomaterial de tercera generación osteoconductor, osteogénico y osteoinductor. Se obtiene la reparación del tejido conectivo interproximal y la formación de tejido calcificado (AU)

We present a clinical case of root fracture of the middle third, piece 2.1 with displacement of the fracture ends. It is treated with a novel therapeutic procedure, using a thirdgeneration osteoconductive, osteogenic and osteoinductive biomaterial. Interproximal connective tissue repair and calcified tissue formation are obtained (AU)

Tratamiento de lesiones apicoperirradiculares con un biomaterial de tercera generación (Licon-D) / Treatment of apicoperiradicular lesions with a third-generation biomaterial (Licon-D)

Biomaterial de tercera generación con una tasa de degradabilidad en la zona perirradicular y del foramen apical, con una velocidad similar a la que emplea el organismo para formar tejido calcificado y sellar biológicamente el extremo apical del diente. Mediante el recurso tecnológico de la microencapsulación se produce la liberación lenta y controlada de Ca2+ retenido en la superficie y en el interior de las microesferas de alginato de calcio, sin que se modifique de manera significativa las propiedades reológicas básicas del biomaterial de obturación de conductos, tales como la compresibilidad, plasticidad, extensibilidad, fluidez, viscosidad cinemática, viscosidad de compresión y endurecimiento por trabajo (AU)

Third-generation biomaterial with a degradability rate in the periradicular area and the apical foramen, with a speed similar to that used by the body to form calcified tissue and biologically seal the apical end of the tooth. Through the technological resource of microencapsulation, the slow and controlled release of Ca2+ retained on the surface and inside the calcium alginate microspheres is produced, without significantly modifying the basic rheological properties of the duct sealing biomaterial, such as compressibility, plasticity, extensibility, flowability, kinematic viscosity, compression viscosity, and work hardening (AU)