Graphene Oxide/Chitosan/Hydroxyapatite Composite Membranes Enhance Osteoblast Adhesion and Guided Bone Regeneration.

Two-dimensional materials provide a secluded space for bone formation and preserve the growth of surrounding tissues, thus playing a crucial role in guided bone regeneration (GBR). Graphene oxide (GO) has been widely employed in GBR due to its good mechanical and hydrophilic properties. A single GO membrane, however, does not provide a friendly environment for osteogenic cell adhesion. With their adjustable mechanical properties and excellent biocompatibility, composite membranes can simulate the multicomponent structure of an extracellular matrix for cell adhesion. To obtain two-dimensional membranes with appropriate mechanical strength and sufficient biocompatibility, GO-based composite membranes simultaneously containing chitosan (CS) and hydroxyapatite (HAP) were first prepared using one-step vacuum filtration and a biomimetic mineralization method. CS and HAP improved the mechanical strength and surface hydrophilicity of the membranes. In addition, moderate addition of HAP enhanced the adhesion, differentiation, and mineralization of osteoblasts. The prepared composite membranes were then implanted into a calvarial defect model to evaluate their osteogenic induction effects in vivo. Microcomputed tomography observation and histological analysis indicate that GO/CS/HAP composite membranes can accelerate bone regeneration without the contribution of endogenous cytokines. GO/CS/HAP composite membranes with unique biomimetic porous structures, superior mechanical properties, and excellent bone regeneration capacity are potential materials for application in GBR.

Evaluation of nanohydroxyapaptite (nano-HA) coated epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes.

Collagen is the main component of extracellular matrix (ECM) with desirable biological activities and low antigenicity. Collagen materials have been widely utilized in guided bone regeneration (GBR) surgery due to its abilities to maintain space for hard tissue growth. However, pure collagen lacks optimal mechanical properties. In our previous study, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, with better biological activities and enhanced mechanical properties, may promote osteoblast proliferation, but their effect on osteoblast differentiation is not very significant. Nanohydroxyapatite (nano-HA) is the main component of mineral bone, which possesses exceptional bioactivity properties including good biocompatibility, high osteoconductivity and osteoinductivity, non-immunogenicity and non-inflammatory behavior. Herein, by analyzing the physical and chemical properties as well as the effects on promoting bone regeneration, we have attempted to present a novel EGCG-modified collagen membrane with nano-HA coating, and have found evidence that the novel collagen membrane may promote bone regeneration with a better surface morphology, without destroying collagen backbone. To evaluate the surface morphologies, chemical and mechanical properties of pure collagen membranes, epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes, nano-HA coated collagen membranes, nano-HA coated EGCG-collagen membranes, (ii) to evaluate the bone regeneration promoted by theses membranes. In the present study, collagen membranes were divided into 4 groups: (1) untreated collagen membranes (2) EGCG cross-linked collagen membranes (3) nano-HA modified collagen membranes (4) nano-HA modified EGCG-collagen membranes. Scanning electron microscope (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to evaluate surface morphologies and chemical properties, respectively. Mechanical properties were determined by differential scanning calorimeter (DSC) and elastic modulus (EM) measurements. Then in 12 rats, 4 types of membranes were randomly applied to cover the rat calvarial defects. The animals were sacrificed at 8weeks. Histologic analyses were performed using Hematoxylin-eosin (H&E) staining and Masson's Trichrome stains. For statistical analysis, analysis of variance (ANOVA) followed by Tukey's multiple comparison tests was applied. HA nanoparticles were fairly well distributed nanoparticles among the collagen fibers on the nano-HA-modified EGCG-collagen membranes, with smoother surface. Moreover, collagen membranes with modifications all maintained their collagen backbone and the mechanical properties were enhanced by EGCG and nano-HA treatments. In addition, EGCG cross-linked collagen membranes with nano-HA coatings promoted bone regeneration. Nano-HA modified EGCG-collagen membranes can be utilized as a barrier membrane to enhance the bone regeneration in GBR surgeries.

Application of PEG and EGCG modified collagen-base membrane to promote osteoblasts proliferation.

Collagen membranes possess ideal biological properties and can be served as a barrier for supporting infiltration and proliferation of osteoblasts in guided bone regeneration (GBR). However, pure collagen lacks desirable mechanical properties and also leads to inflammation, resulting in progressive bone resorption. In our previous study, EGCG cross-linked collagen membranes exhibit better mechanical properties and anti-inflammatory effect. However, higher concentration of EGCG may not improve cell viability. Herein, we present an enhanced EGCG cross-linked collagen membranes with surface modification of PEG to improve cell viability and cell adhesion, considering the better biocompatibility of PEG. Scanning electron microscope images showed that PEG-EGCG-collagen membrane exhibited smoother surface fiber aggregates. Fourier transform infrared spectroscopy demonstrated that the structure characteristics were maintained after addition of EGCG and PEG. Cell viability was significantly increased after modification of PEG, as determined by the Cell Counting Kit-8 (CCK-8) and live/dead assay. Better shapes of cytoskeleton were observed in immunostaining images. Additionally, enzyme-linked immunosorbent assay showed PEG-EGCG-collagen membrane significantly decreased the level of inflammatory factors secreted by MG63 cells. Collectively, with respect to all the aspects including intact structure, cell viability promotion and mediation of pro-inflammatory cytokine secretion, our results indicate that PEG-EGCG-collagen membrane might be used in GBR applications.

Evaluation of epigallocatechin-3-gallate (EGCG) cross-linked collagen membranes and concerns on osteoblasts.

Collagen membranes have ideal biological and mechanical properties for supporting infiltration and proliferation of osteoblasts and play a vital role in guided bone regeneration (GBR). However, pure collagen can lead to inflammation, resulting in progressive bone resorption. Therefore, a method for regulating the level of inflammatory cytokines at surgical sites is paramount for the healing process. Epigallocatechin-3-gallate (EGCG) is a component extracted from green tea with numerous biological activities including an anti-inflammatory effect. Herein, we present a novel cross-linked collagen membrane containing different concentrations of EGCG (0.0064%, 0.064%, and 0.64%) to regulate the level of inflammatory factors secreted by pre-osteoblast cells; improve cell proliferation; and increase the tensile strength, wettability, and thermal stability of collagen membranes. Scanning electron microscope images show that the surfaces of collagen membranes became smoother and the collagen fiber diameters became larger with EGCG treatment. Measurement of the water contact angle demonstrated that introducing EGCG improved membrane wettability. Fourier transform infrared spectroscopy analyses indicated that the backbone of collagen was intact, and the thermal stability was significant improved in differential scanning calorimetry. The mechanical properties of 0.064% and 0.64% EGCG-treated collagen membranes were 1.5-fold greater than those of the control. The extent of cross-linking was significantly increased, as determined by a 2,4,6-trinitrobenzenesulfonic acid solution assay. The Cell Counting Kit-8 (CCK-8) and live/dead assays revealed that collagen membrane cross-linked by 0.0064% EGCG induced greater cell proliferation than pure collagen membranes. Additionally, real-time polymerase chain reaction and enzyme-linked immunosorbent assay results showed that EGCG significantly affected the production of inflammatory factors secreted by MC3T3-E1 cells. Taken together, our results indicate that treatment of collagen membranes with appropriate concentrations of EGCG has an anti-inflammatory effect and shows promise for GBR applications.

Clinical application of VIP-CT flap with GBR technique in dental implantation of the maxillary anterior region / 安徽医科大学学报

This article presented a series of cases using vascularized interpositional periosteal-connective tissue ( VIP-CT) flap with guide bone regeneration ( GBR) in peri-implant soft and hard tissue reconstuction at the esthet-ic zone of maxillary. Fifteen cases with bone and soft tissue defects underwent VIP-CT flap with GBR in the implant treatment. And the attached gingiva width was evaluated before treatment and six months and eighteen months after the operation. The width of attached gingival of six months and eighteen months after surgery was significantly dif-ferent from the preoperative value (P<0. 05). However, no statistically significant difference could be found at six months and eighteen months postoperative. The application of VIP-CT flap could increase the width of attached gin-giva around implants and the short-term effects were stable and favorable.

Influence of biphasic ß-TCP with and without the use of collagen membranes on bone healing of surgically critical size defects. A radiological, histological, and histomorphometric study.

OBJECTIVES: The aim of this study was to investigate, by means of radiological and histomorphometric analysis, the effect of resorbable collagen membranes on critical size defects (CSD) in rabbit tibiae filled with biphasic calcium phosphate. MATERIALS AND METHODS: Three CSD of 6 mm diameter were created in both tibiae of 20 New Zealand rabbits and divided into three groups according to the filling material: Group A (Ossceram), Group B (Ossceram plus Alveoprotect membrane), and Group C (unfilled control group). Five animals from each group were sacrificed after 15, 30, 45, and 60 days. Anteroposterior and lateral radiographs were taken. Samples were processed for observation under light microscopy. RESULTS: At the end of treatment, radiological analysis found that cortical defect closure was greater in Group B than Group A, and radiopacity was clearly lower and more heterogeneous in the Group A cortical defects than in Group B. There was no cortical defect closure in Group C. Histomorphometric evaluation showed significant differences in newly formed bone and cortical closure in Group B compared with Groups A and C, with the presence of higher density newly formed bone in cortical and medullar zones. There was no cortical defect closure or medullar bone formation in Group C. CONCLUSIONS: Biphasic calcium phosphate functioned well as a scaffolding material allowing mineralized tissue formation. Furthermore, the addiction of absorbable collagen membranes enhanced bone gain compared with non-membrane-treated sites.

The comparision of the outcomes of guide bone regeneration by calcined bovine bone and Bio-Oss graft material in alveolar ridge preservation after tooth extraction / 实用口腔医学杂志

Objective:To compare the outcomes of guide bone regeneration by calcined bovine bone and Bio-Oss graft material in alveolar ridge preservation after tooth extraction.Methods:280 patients were divided into two groups randomly.Each patient had single tooth extracted.The sockets were filled with calcined bovine bone in 140 patients and Bio-Oss graft in another 140 patients. After shaping,all the sockets were covered with Bio-Gide membrane.Buccal mucoperiosteal flap was released and sutured to close the alveolar sockets.The patients were regularly examined at the 1st,12th and 24th week after surgery.Physical examination and X-ray evaluation were applied to compare the outcomes of the two materials in alveolar ridge preservation.Results:No infection and re-jection occurred.The radiographic results showed the width and height of the alveolar bone were preserved well at the 12th and 24th weeks.No statistically difference was found in the two groups at the 1st and 24th weeks(P>0.05).Conclusion:The two graft ma-terials can effectively preserve alveolar bone after tooth extraction.

Acondicionamiento del lecho óseo implantar mediante regeneración ósea guiada: Reporte de un caso

La regeneración ósea guiada (ROG) actualmente es considerada una terapia de gran importancia en Implantología para promover la regeneración de hueso en defectos óseos maxilares con la finalidad de crear un lecho adecuado para el posicionamiento de implantes. La ROG se basa en el uso de membranas reabsorbibles y no reabsorbibles en combinación con biomateriales de relleno como hueso autólogo, homólogo, heterólogo o materiales aloplásticos con funciones de barrera mecánica, tendientes a excluir de la zona de reparación células epiteliales y conjuntivas, permitiendo la invasión de células osteoprogenitoras. En este artículo se presenta el caso clínico de un paciente al que se le realizó aumento vertical y horizontal de cresta ósea alveolar mediante regeneración ósea guiada en asociación con la colocación de implantes oseointegrados.

Guide Bone Regeneration has been used widely in implantology for enhancing bone healing to optimize implant placements in the maxillary. The GBR is a technique that uses resorbable and non-resorbable membranes in combination with other filling biomaterials as autologous, homologous or heterologous bone graft, or aloplastic materials as mechanic barriers that prohibit the migration of connective and epithelial cells, enabling the osteogenic cells invasion in bone defects. In the present study a clinic case of vertical and horizontal augmentation of alveolar ridge with guided bone regeneration in association with dental implants was reported.

Regeneración osea guiada GBR: revisión de la literatura / Guide bone regeneration GBR: revew of the literature

La regeneración ósea guiada (Guided Bone Regeneration- GBR) actualmente es considerada una terapia de gran importancia en Implantología, para promover la regeneración de hueso en defectos óseos maxilares; la finalidad es crear un lecho adecuado para el posicionamiento de Implantes. La GBR se basa en el uso de membranas reabsorbibles y no reabsorbibles en combinación con biomateriales de relleno como hueso autólogo, homólogo, heterólogo o materiales aloplásticos con funciones de barrera mecánica, tendientes a excluir de la zona de reparación células epiteliales y conjuntivas, permitiendo la invasión de células osteoprogenitoras

Guide Bone Regeneration has been used widely in implantology for enhancing bone healing to optimize implant placements in the maxillary. The GBR is a technique that uses resorbable and non-resorbable membranes in combination with other filling biomaterials as autologous, homologous or heterologous bone graft, or aloplastic materials as mechanic barriers that prohibit the migration of connective and epithelial cells, enabling the osteogenic cells invasion in bone defects

Effect of Enamel Matrix Derivative on Guided Bone Regeneration with Intramarrow Penetration / 대한치주과학회지

The purpose of this study was to investigate effect of enamel matrix derivative on guided bone regeneration with intramarrow penetration in rabbits. Eight adult male rabbits (mean BW 2Kg) were used in this study. Intramarrow penetration defects were surgically created with round carbide bur(HP long #6) on calvaria of rabbits. Defects were assigned to the control group grafted with mixture of the same quantity of demineralized freeze-dried bone allograft and deproteinized bovine bone mineral. Then, guided bone regeneration was carried out using resorbable membrane and suture. Enamel matrix derivative applied to defects was assigned to the test group. And treated as same manners as the control group. At 1, 2, 3 and 8 weeks after the surgery, animals were sacrificed, specimens were obtained and stained with Hematoxylin-Eosin for light microscopic evaluation. The results of this study were as follows: 1. At 1, 2 and 3 weeks, no differences were observed between the control group and the test group in the aspect of bone formation around bone graft. 2. Proliferation of blood capillary was faster in the test group than in the control group. 3. Bone regeneration in intramarrow penetration was faster in the test group than in the control group. 4. At 8 weeks, new osteoid tissue formation around bone graft was more prominent in the test group than in the control group. From the above results, enamel matrix derivative might be considered as the osteopromotion material and effective in the guided bone regeneration with intramarrow penetration.