Functionalized Asymmetric Poly (Lactic Acid)/Gelatin Composite Membrane for Guided Periodontal Tissue Regeneration

Aim: Periodontitis is caused by chronic gingival inflammation and affects a large population in the world. Although guided tissue regeneration (GTR) therapy has been proven to be an effective treatment, the deficiency in the symmetrical design of all the GTR membrane in the market leaves large space for improvement. Therefore, we designed a novel asymmetrical bi-layer PLA/gelatin composite membrane for treating periodontitis. Methods: The PLA side was fabricated by electrospinning with metronidazole (MNA) pre-mixed with the PLA solution. The gelatin side containing bioglass (BG) 45S5 was fabricated with freeze-drying process and cross-linked with PLA membrane. The bio-compatibility of the membrane was evaluated in vitro using NIH3T3 cells. The releasing of MNA was measured by spectrophotometer. The bioactivity of the membrane was evaluated by hydroxyapatite (HA) deposit and determined by FTIR spectrometer. The ionic concentration of Ca2+ and was measured by ICPOES. The expression of the osteogenesis makers was determined by qRT-PCR. Results: The bi-layer PLA/gelatin composite membrane is biocompatible and bioactive. The releasing of MNA can rapidly reach the anti-bacterial effective concentration. Interestingly, the incorporation of MNA modulated the degradation rate of PLA scaffold to meet the requirement of tissue regeneration. Meanwhile, the embedding of the BG powder in the gelatin porous layer provided a favorable Ca2+ and ion environment for the regeneration of the alveolar bone tissue. Conclusions: Taken together, this bi-layer GTR membrane is closer to the physiological structure of the periodontal. The addition of MNA and BG makes it more powerful in treating periodontitis. Moreover, this research provides an example of biomimetic design in fabricating biomaterial for clinical applications.

Research progress of strontium in promoting periodontal tissue regeneration

Periodontal disease is a chronic infectious disease of the oral cavity.Its main clinical features are periodontal pocket formation and alveolar bone resorption.Scholars'research hotspot is to achieve periodontal tissue regeneration in patients.Studies have found that strontium has certain potential in promoting periodontal tissue regeneration.In recent years,scholars have been conducting research on strontium and periodontal tissue regeneration,with a view to opening a new path for periodontal disease treatment.This article reviews the research status of strontium and periodontal tissue regeneration.The review results show that strontium can induce the proliferation and differentiation of PDLSCs and promote the regeneration of lost bone tissue;it can inhibit osteoclast activity and induce osteoclast apoptosis through a variety of signaling pathways,thereby inhibiting bone resorption;Promote bone formation;Strontium also has the function of promoting early angiogenesis and suppressing immune inflammatory response.Because the current research on strontium and periodontal tissue regeneration is only focused on in vivo and in vitro experiments,there is no relevant clinical trial to apply strontium to periodontal tissue regeneration.Therefore,if strontium is used to promote periodontal tissue regeneration to achieve the treatment of periodontal disease,further research is needed.

Local icariin application enhanced periodontal tissue regeneration and relieved local inflammation in a minipig model of periodontitis

Periodontitis is an inflammatory autoimmune disease. Treatment should alleviate inflammation, regulate the immune reaction and promote periodontal tissue regeneration. Icariin is the main active ingredient of Epimedii Folium, and it is a promising compound for the enhancement of mesenchymal stem cell function, promotion of bone formation, inhibition of bone resorption, alleviation of inflammation and regulation of immunity. The study investigated the effect of icariin on periodontal tissue regeneration in a minipig model of periodontitis. The minipig model of periodontitis was established. Icariin was injected locally. The periodontal clinical assessment index, a computed tomography(CT) scan, histopathology and enzyme-linked immune sorbent assay(ELISA)were used to evaluate the effects of icariin. Quantitative analysis results 12 weeks post-injection demonstrated that probing depth,gingival recession, attachment loss and alveolar bone regeneration values were(3.72 ± 1.18) mm vs.(6.56 ± 1.47) mm,(1.67 ± 0.59)mm vs.(2.38 ± 0.61) mm,(5.56 ± 1.29) mm vs.(8.61 ± 1.72) mm, and(25.65 ± 5.13) mm3 vs.(9.48 ± 1.78) mm3 in the icariin group and0.9% NaCl group, respectively. The clinical assessment, CT scan, and histopathology results demonstrated significant enhancement of periodontal tissue regeneration in the icariin group compared to the 0.9% NaCl group. The ELISA results suggested that the concentration of interleukin-1 beta(IL-1β) in the icariin group was downregulated compared to the 0.9% NaCl group, which indicates that local injection of icariin relieved local inflammation in a minipig model of periodontitis. Local injection of icariin promoted periodontal tissue regeneration and exerted anti-inflammatory and immunomodulatory function. These results support the application of icariin for the clinical treatment of periodontitis.

Evaluating the Benefits of Platelet Rich-Fibrin in Periodontal Regeneration: A Literature Review

Introduction: Platelet Rich-Fibrin (PRF) is a biological matrix derived from a patient’s own blood, rich in growth factors and platelets. Its use in various periodontal and non-periodontal procedures is gaining recognition due to its potential in promoting tissue regeneration. The purpose of this review was to evaluate the benefits of using PRF in intra-bony defect regeneration, guided-bone regeneration, and sinus floor elevation. Methods: The study searched PubMed for manuscripts published between 2017 and 2022 to better understand the clinical and radiological effects of PRF. The manuscripts were divided into the following sections: intra-bony defect regeneration, guided-bone regeneration, and sinus floor elevation. Results: In intra-bony defects, PRF improved clinical and radiological parameters when compared with OFD alone, with a significant difference in wound healing at 7 days. In GBR, a CBCT evaluation shows no statistical difference between the PRF-autogenous bone complex group and the bovine bone-collagen membrane complex regarding volume change of the augmented bone with a 16% rate of bone loss following a 6-month healing period. Also, a slight increase in bone thickness has been seen when liquid PRF is used. In sinus floor elevation, results revealed no differences in graft volume between PRF group and control group at any of the evaluated time points. Although higher implant stability immediately postoperatively, higher new bone formation, the lesser amount of residual graft and earlier implant placement. Conclusion: Platelet Rich-Fibrin is widely accepted for use in periodontal surgery and dentistry due to its minimally invasive nature and low risk of adverse effects, with positive results in tissue regeneration. There is evidence that PRF leads to improved and faster healing, as well as cost-effective regenerative procedures compared to other treatments.

Possible mechanism of 15D-PGJ2 in promoting periodontal tissue regeneration in patients with mandibular defects

Objective:To explore the main physiological mechanism of 15d-PGJ2 promoting periodontal tissue regeneration in patients with jaw defects caused by periodontal disease.Methods:From February 2016 to July 2019,a controlled study was conducted on 73 healthy residents(healthy group)and 73 patients(case group)with periodontal disease combined with jaw defects in Changsha medical university.T test was used to compare the growth factors of gingival crevicular fluid between the two groups.Peripheral blood cells;Cement-specific protein;Peripheral blood enzyme;Statistical differences in bone metabolites.The t test method compared the content of each index before and after treatment(15d-PGJ2 was treated at a dose of 200 mu/kg for 14 days).The method of factor analysis explores the internal correlation of each index.Result:RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were higher in the case group than in the healthy group.In the case group,RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were lower than those in the healthy group.The differences between the groups were statistically significant(P<0.05).Compared with before treatment,IL-1β,IL-17,Bfgf,YKL-40,BMP-2,ICTP,PICP,CTX were significantly decreased after treatment.RANKL,ICAM-1,TGF-β1,Th17,Treg,PDLSCs,SOST,CAP,HMGB1,CTSK,5-LOX,COX-2,NTX were significantly increased.The differences were statistically significant(P<0.05).Factor analysis shows that four common factors can be extracted from 21 indicators,and the cumulative contribution rate is 96.993%.Conclusions:The treatment of 15d-PGJ2 in patients with periodontal disease with maxillary defects can significantly affect the expression of multiple characteristic indicators,which may involve four mechanisms:dysregulation of cell differentiation or migration,local inflammation or immune imbalance,destruction of alveolar bone microstructure,load or stimulation,and remodeling.The specific pathway related to this is still to be further explored.

Antimicrobial Activity of Minocycline-Loaded Genipin-Crosslinked Nano-Fibrous Chitosan Mats for Guided Tissue Regeneration

Antimicrobial delivery has been advocated for guided tissue regeneration (GTR) or guided bone regeneration (GBR) therapies involving patients with aggressive or unresolved periodontitis/peri-implantitis. Electrospun chitosan membranes demonstrate several advantages over traditional GTR barrier membranes because they stimulate healing, mimic the topology of the extracellular matrix, and allow for diffusion of nutrients and wastes into/out of the graft site, and were shown to stimulate bone formation in a rabbit calvarial criticalsize defect model. Previously, we have shown improvements in mechanical properties and degradation kinetics by crosslinking electrospun membranes with 5 mM or 10 mM genipin. We have also demonstrated the ability of elecrospun chitosan membranes to inhibit lippopolysaccharide (LPS)-induced monocyte activation. In this study, minocycline was incorporated into the chitosan membrane by passive absorption at 5 or 10 mg/mL. The minocycline-loaded membranes and control membranes (carrier only) were tested against Porphyromonas gingivalis (P. gingivalis) by repeated zone of inhibition (ZOI) measurements. Testing showed that uncrosslinked and genipin-crosslinked membranes have similar capacity to absorb aqueous solutions (swelling ratio 1.7 - 2.2). Minocycline loading resulted in bacterial inhibition for up to 8 days from crosslinked membranes (with 11 mm initial ZOI) whereas uncrosslinked membranes loaded with minocycline only inhibited bacteria for 4 days (with 8 mm initial ZOI). These in vitro results suggest that genipin-crosslinked electrospun chitosan membranes loaded with minocycline may be able to reduce early bacterial contamination of GTR graft sites.

Evaluation of periodontal healing in class II furcation defects following guided tissue regeneration with two different types of poly lactic acid membranes

Background Guided tissue regeneration procedures provide predictable reconstruction of periodontal tissues in the treatment of furcation involvements in animals and huamns. This study was to compare long-term effectiveness of two different types of polylactic acid (PLA) membranes on periodontal regeneration in surgically created class II furcation defects in dogs.Methods Full thickness mucoperiosteal flap was raised on the buccal aspects of the experimental teeth and class II furcation defects having 5 mm vertical dimensions were created on mandibular premolar III and IV on each quadrant. The exposed root surfaces were thoroughly planed and PLA membranes were placed over the experimental defects on both sites. One site received liquid polymer membrane (LPM), and resorbable periodontal mesh (RPM) membranes were applied to the other site. The animals were sacrificed at 7 months after surgery and the specimens were processed for histological evaluation.Results The average length of new attachment formed on the treated roots in both groups ranged from 3. 02 mm to 4. 5 mm. Complete bone filling was observed at the furcation sites. No statistically significant differences were found between two membranes in any of the parameters (P>0. 05).Conclusion This study demonstrates favorable regenerative outcomes by the use of two different types of PLA membranes that could be used as alternatives for guided tissue regeneration (GTR).

A novel porcine acellular dermal matrix scaffold used in periodontal regeneration

Regeneration of periodontal tissue is the most promising method for restoring periodontal structures.To find a suitable bioactive three- dimensional scaffold promoting cell proliferation and differentiation is critical in periodontal tissue engineering.The objective of this study was to evaluate the biocompatibility of a novel porcine acellular dermal matrix as periodontal tissue scaffolds both in vitro and in vivo.The scaffolds in this study were purified porcine acellular dermal matrix(PADM) and hydroxyapatite-treated PADM(HA-PADM). The biodegradation patterns of the scaffolds were evaluated in vitro.The biocompatibility of the scaffolds in vivo was assessed by implanting them into the sacrospinal muscle of 20 New Zealand white rabbits.The hPDL cells were cultured with PADM or HA-PADM scaffolds for 3,7,14,21 and 28 days.Cell viability assay,scanning electron microscopy(SEM),hematoxylin and eosin(H&E) staining, immunohistochemistry and confocal microscopy were used to evaluate the biocompatibility of the scaffolds.In vitro,both PADM and HA-PADM scaffolds displayed appropriate biodegradation pattern,and also,demonstrated favorable tissue compatibility without tissue necrosis,fibrosis and other abnormal response.The absorbance readings of the WST-1 assay were increased with the time course, suggesting the cell proliferation in the scaffolds.The hPDL cells attaching,spreading and morphology on the surface of the scaffold were visualized by SEM,H&E staining,immnuohjstochemistry and confocal microscopy,demonstrated that hPDL cells were able to grow into the HA-PADM scaffolds and the amount of cells were growing up in the course of time.This study proved that HA-PADM scaffold had good biocompatibility in animals in vivo and appropriate biodegrading characteristics in vitro.The hPDL cells were able to proliferate and migrate into the scaffold.These observations may suggest that HA-PADM scaffold is a potential cell carrier for periodontal tissue regeneration.

GUIDED TISSUE REGENERATION AROUND DENTAL IMPLANTS IN IMMEDIATE EXTRACTION SOCKETS:COMPARISON OF RESORBABLE ANDNONRESORBABLE MEMBRANES

This study was per formed to compare the efficacy of guided tissue regeneration (GTR) around dentalimplants immediately placed into extraction sockets by resorbable of nonresorbable membranes. Mandibular. P2, P3, and P4 of four aduIt beagle dogs were extracted bilaterally, and buccal standard defects were cre-ated and measured. Eighteen commercially pure titanium Steri-Oss implant fixtures were placed into thefresh extraction sockets. Four implants were untreated controls, four implants received polytetrafluoro-ethylene (e-PTFE, Gore-Tex) membranes, five implants received collagen membranes (ParaGuide), andfive implants received polyglactin 910 mesh (Vicryl). After l4 weeks, clinical measurements were takenand the dogs were sacrificed and all specimens retrieved for histologic and histomorphometric evaluation.The average gain in bone height was 2. 1mm for untreated control sites, 3. 3mm for Gore-Tex sites,3. 8mm for collagen sites, and 1. 3mm for polyglactin 910 sites. The greatest gain in bone height and volume was seen for two sites that received Gore-Tex membranes and remained covered for the entire evalua-tion interval. The results of this study indicate that Gore-Tex and collagen membrane preduced gdri re-sults for GTR around Implants immediately placed into extraction sockets. Since collagen membrane doesnot cause obvious infection and does not need the surgical reentry for membrane removal, it can be a validalternative to Gore-Tex membrane to improve bone regeneration around dental implants, while polyglactin910 mesh seems not suitable to be used as GTR membrane in immediate implantation for its hIgh infectionrate.

Exposure to Hyaluronan and Radon-Containing Water during the Treatment of Periodontal Pockets

Hyaluronic acid (HA) preparations have emerged as pivotal components in contemporary dentistry, gaining widespread recognition for their multifaceted roles in various biological functions. Extensive literature underscores the significance of HA in maintaining tissue water balance, fostering cell proliferation, promoting rapid cell migration, influencing cell differentiation during organism development, and facilitating tissue regeneration. Notably, HA’s interactions with cell surface receptors contribute to the viscosity of synovial fluid, activate the immune system, and enhance cartilage elasticity. Beyond these established functions, HA has also been investigated for its potential involvement in determining and studying the hormetic effects of radon water, adding a novel dimension to its applications in dental research. A thorough exploration of existing studies reveals a nuanced understanding of how HA interventions impact the outcomes of dental procedures. The comprehensive scope of these investigations allows for a more accurate assessment of the potential effectiveness of specific interventions and provides valuable insights into post-procedural prognoses for individual patients. This synthesis of literature serves as the foundation for elucidating the intricate interplay between HA, radon exposure, and their relevance in modern dental practices.

Periodontal-orthodontic interdisciplinary management of a“periodontally hopeless”maxillary central incisor with severe mobility:A case report and review of literature

BACKGROUND Treating periodontally hopeless teeth with advanced bone resorption and severe tooth mobility is a great challenge for both orthodontists and periodontists.Biofilm-induced periodontal inflammation and occlusal trauma-related inflammation may synergistically aggravate tooth mobility.This case report illustrates that even periodontally hopeless teeth can be saved and have long-term stability with comprehensive periodontal treatment to control periodontal inflammation and promote periodontal bone regeneration and intricate orthodontic mechanical control to correct cross bite and occlusal trauma.CASE SUMMARY A 27-year-old female patient whose chief complaint was severe tooth mobility and discomfort of the maxillary incisor was diagnosed with severe aggressive periodontitis by clinical and radiographic examinations.To reduce tooth mobility and establish stable occlusion,we combined orthodontic treatment with periodontal therapy to preserve the tooth.Orthodontic treatment was performed after basic periodontal therapy and periodontal surgery.The loosened upper right central incisor was successfully retained,and the periodontal tissue remained stable during follow-up.CONCLUSION Teeth with severe mobility and bone loss can be saved through interdisciplinary treatment when periodontal inflammation is strictly controlled.

PREPARATION OF CHITOSAN/HYDROXYAPATITE GUIDED MEMBRANE USED FOR PERIODONTAL TISSUE REGENERATION

In an effort to develop biomaterials to meet guided tissue regeneration （GTR） standards for periodontal tissue recovery, a homogeneous and transparent chitosan （CS）/hydroxyapatite （HA） membrane with potential applications as GTR barrier in periodontal therapy has been prepared via in situ compositing. The membrane has been designed to have a smoothrough asymmetric structure that meets the demand for GTR. Component and morphology of the membrane are characterized by XRD and SEM. It can be indicated that HA was in situ synthesized uniformly in the CS membrane. Mechanical experiments of the membranes with various HA contents show that their tensile strengths are adequate for periodontal therapy. Biological properties of the membrane have been performed by cell toxicity assays, hemolysis tests and animal experiments. Results indicate that the membrane has good biocompatibility and inductive effect for cell growth. Therefore this membrane can be potentially applied as GTR barrier membrane for periodontal tissue regeneration.

Dimethyloxallyl glycine/nanosilicates-loaded osteogenic/angiogenic difunctional fibrous structure for functional periodontal tissue regeneration

The coupled process of osteogenesis-angiogenesis plays a crucial role in periodontal tissue regeneration.Although various cytokines or chemokines have been widely applied in periodontal in situ tissue engineering,most of them are macromolecular proteins with the drawbacks of short effective half-life,poor stability and high cost,which constrain their clinical translation.Our study aimed to develop a difunctional structure for periodontal tissue regeneration by incorporating an angiogenic small molecule,dimethyloxalylglycine(DMOG),and an osteoinductive inorganic nanomaterial,nanosilicate(nSi)into poly(lactic-co-glycolic acid)(PLGA)fibers by electrospinning.The physiochemical properties of DMOG/nSi-PLGA fibrous membranes were characterized.Thereafter,the effect of DMOG/nSi-PLGA membranes on periodontal tissue regeneration was evaluated by detecting osteogenic and angiogenic differentiation potential of periodontal ligament stem cells(PDLSCs)in vitro.Additionally,the fibrous membranes were transplanted into rat periodontal defects,and tissue regeneration was assessed with histological evaluation,micro-computed tomography(micro-CT),and immunohistochemical analysis.DMOG/nSi-PLGA membranes possessed preferable mechanical property and biocompatibility.PDLSCs seeded on the DMOG/nSi-PLGA membranes showed up-regulated expression of osteogenic and angiogenic markers,higher alkaline phosphatase(ALP)activity,and more tube formation in comparison with single application.Further,in vivo study showed that the DMOG/nSi-PLGA membranes promoted recruitment of CD90+/CD34stromal cells,induced angiogenesis and osteogenesis,and regenerated cementum-ligament-bone complex in periodontal defects.Consequently,the combination of DMOG and nSi exerted admirable effects on periodontal tissue regeneration.DMOG/nSi-PLGA fibrous membranes could enhance and orchestrate osteogenesis-angiogenesis,and may have the potential to be translated as an effective scaffold in periodontal tissue engineering.

L-cysteine-modified chiral gold nanoparticles promote periodontal tissue regeneration

Gold nanoparticles(AuNPs)with surface-anchored molecules present tremendous potential in tissue regeneration.However,little is known about chiral-modified AuNPs.In this study,we successfully prepared L/D-cysteine-anchored AuNPs(L/D-Cys-AuNPs)and studied the effects of chiral-modified AuNPs on osteogenic differentiation and autophagy of human periodontal ligament cells(hPDLCs)and periodontal tissue regeneration.In vitro,more L-Cys-AuNPs than D-Cys-AuNPs tend to internalize in hPDLCs.L-Cys-AuNPs also significantly increased the expression of alkaline phosphatase,collagen type 1,osteocalcin,runt-related transcription factor 2,and microtubule-associated protein light chain 3 II and decreased the expression of sequestosome 1 in hPDLCs compared to the expression levels in the hPDLCs treated by D-Cys-AuNPs.In vivo tests in a rat periodontal-defect model showed that L-Cys-AuNPs had the greatest effect on periodontal-tissue regeneration.The activation of autophagy in L-Cys-AuNP-treated hPDLCs may be responsible for the cell differentiation and tissue regeneration.Therefore,compared to D-Cys-AuNPs,L-Cys-AuNPs show a better performance in cellular internalization,regulation of autophagy,cell osteogenic differentiation,and periodontal tissue regeneration.This demonstrates the immense potential of L-Cys-AuNPs for periodontal regeneration and provides a new insight into chirally modified bioactive nanomaterials.

Animal models for testing biomaterials in periodontal regeneration

Periodontitis is a prevalent oral disease. It can cause tooth loss and has a significant impact on patients’ quality of life. While existing treatments can only slow the progression of periodontitis, they are unable to achieve complete regeneration and functional reconstruction of periodontal tissues. As a result, regenerative therapies based on biomaterials have become a focal point of research in the field of periodontology. Despite numerous studies reporting the superiority of new materials in periodontal regeneration, limited progress has been made in translating these findings into clinical practice. This may be due to the lack of appropriate animal models to simulate the tissue defects caused by human periodontitis. This review aims to provide an overview of established animal models for periodontal regeneration, examine their advantages and limitations, and outline the steps for model construction. The objective is to determine the most relevant animal models for periodontal regeneration based on the hypothesis and expected outcomes.

Application of Induced Pluripotent Stem Cells Derived from Human Periodontal Ligament Cells in Bone Regeneration

The purpose of this study was to primarily culture human periodontal ligament cells(hPDLCs)and to reprogram hPDLCs with exogenous genes via a lentivirus-mediated transfection system.Then induced pluripotent stem cells derived from h PDLCs(hPDLC-iPSCs)were identified.Alizarin red staining was used to observe the formation of mineralized nodules and real-time Polymerase Chain Reaction(PCR)was used to detect the expression of osteogenic genes.For the in vivo experiment,nude mouse skull defect models were established and cell sheets were made to repair the bone defect.The reprogrammed cells were positive for alkaline phosphatase(ALP)staining and embryonic stem cells(ESCs)-specific proteins,and could form teratomas.After osteogenic induction,alizarin red staining showed that the number of mineralized nodules in the h PDLC-i PSCs group was more and the osteogenic related factors ALP,osteocalcin(OCN),Col-I and Runx2 were also expressed higher in hPDLC-iPSCs.The hPDLC-iPSC cell sheets were all successfully made.Histological analysis showed that the h PDLC-i PSC cell sheet got new bone formation.These results demonstrated that hPDLC-iPSCs were successfully generated from human periodontal ligament fibroblasts and hPDLC-iPSC cell sheets provided new options for bone tissue engineering.

Application of dental stem cells in three-dimensional tissue regeneration

Dental stem cells can differentiate into different types of cells.Dental pulp stem cells,stem cells from human exfoliated deciduous teeth,periodontal ligament stem cells,stem cells from apical papilla,and dental follicle progenitor cells are five different types of dental stem cells that have been identified during different stages of tooth development.The availability of dental stem cells from discarded or removed teeth makes them promising candidates for tissue engineering.In recent years,three-dimensional(3D)tissue scaffolds have been used to reconstruct and restore different anatomical defects.With rapid advances in 3D tissue engineering,dental stem cells have been used in the regeneration of 3D engineered tissue.This review presents an overview of different types of dental stem cells used in 3D tissue regeneration,which are currently the most common type of stem cells used to treat human tissue conditions.

Effect of concentrated growth factor combined with guided bone regeneration on cell proliferation and bone resorption in patients with severe periodontitis

Objective: To study the effect of concentrated growth factor (CGF) combined with guided bone regeneration on cell proliferation and bone resorption in patients with severe periodontitis. Methods: Patients with severe periodontitis who were treated in Stomatology Department of Shenmu Hospital between May 2014 and February 2017 were selected as the research subjects and randomly divided into two groups, surgery + CGF group received concentrated growth factor combined with guided bone regeneration, and pure surgery group received guided bone regeneration. The contents of inflammatory response, cell proliferation and bone resorption markers in gingival crevicular fluid were determined 1 week after treatment. Results: 1 week after treatment, HMGB1, ICAM1, E-selectin, Smac, FasL, Caspase-8, Caspase-9, Caspase-3, RANKL and NTX contents in gingival crevicular fluid of surgery + CGF group were significantly lower than those of pure surgery group while PD-L1, hBD-3, Wnt3a, BGP and OPG contents were significantly higher than those of pure surgery group. Conclusion:Concentrated growth factor combined with guided bone regeneration for severe periodontitis can inhibit inflammatory response, apoptosis and bone resorption, which is beneficial to the reconstruction of periodontal tissue.

Peripheral nerve regeneration through nerve conduits evokes differential expression of growth-associated protein-43 in the spinal cord

Growth-associated protein 43 plays a key role in neurite outgrowth through cytoskeleton remodeling.We have previously demonstrated that structural damage of peripheral nerves induces growth-associated protein 43 upregulation to promote growth cone formation.Conversely,the limited regenerative capacity of the central nervous system due to an inhibitory environment prevents major changes in neurite outgrowth and should be presumably associated with low levels of growth-associated protein 43 expression.However,central alterations due to peripheral nerve damage have never been assessed using the growthassociated protein 43 marker.In this study,we used the tubulization technique to repair 1 cm-long nerve gaps in the rat nerve injury/repair model and detected growth-associated protein 43 expression in the peripheral and central nervous systems.First,histological analysis of the regeneration process confirmed an active regeneration process of the nerve gaps through the conduit from 10 days onwards.The growth-associated protein 43 expression profile varied across regions and follow-up times,from a localized expression to an abundant and consistent expression throughout the regeneration tissue,confirming the presence of an active nerve regeneration process.Second,spinal cord changes were also histologically assessed,and no apparent changes in the structural and cellular organization were observed using routine staining methods.Surprisingly,remarkable differences and local changes appeared in growth-associated protein 43 expression at the spinal cord level,in particular at 20 days post-repair and beyond.Growth-associated protein 43 protein was first localized in the gracile fasciculus and was homogeneously distributed in the left posterior cord.These findings differed from the growth-associated protein 43 pattern observed in the healthy control,which did not express growth-associated protein 43 at these levels.Our results revealed a differential expression in growth-associated protein 43 protein not only in the regenerating nerve tissue but also in the spinal cord after peripheral nerve transection.These findings open the possibility of using this marker to monitor changes in the central nervous system after peripheral nerve injury.

Comparison of Different Periodontal Healing of Critical Size Noncontained and Contained Intrabony Defects in Beagles

Background： Regenerative techniques help promote the formation of new attachment and bone filling in periodontal detects. However, the dimensions of intraosseous defects are a key determinant of periodontal regeneration outcomes. In this study, we evaluated the efficacy of use of anorganic bovine bone （ABB） graft in combination with collagen membrane （CM）, to facilitate healing ofnoncontained （1-wall） and contained （3-wall） critical size periodontal defects. Methods： The study began on March 2013, and was completed on May 2014. One-wall （7 mm × 4 mm） and 3-wall （5 mm × 4 mm） intrabony periodontal defects were surgically created bilaterally in the mandibular third premolars and first molars in eight beagles. The defects were treated with ABB in combination with CM （ABB ＋ CM group） or open flap debridement （OFD group）. The animals were euthanized at 8-week postsurgery for histological analysis. Two independent Student＇s t-tests （1-wall [ABB ＋ CM] vs. 1-wall [OFD] and 3-wall [ABB ＋ CM] vs. 3-wall [OFD]） were used to assess between-group differences. Results： The mean new bone height in both 1- and 3-wall intrabony defects in the ABB ＋ CM group was significantly greater than that in the OFD group （1-wall： 4.99± 0.70 mm vs. 3.01 ± 0.37 mm, P 〈 0.05; 3-wall： 3.11±0.59 mm vs. 2.08± 0.24 mm, P 〈 0.05）. The mean new cementum in 1-wall intrabony defects in the ABB ＋ CM group was significantly greater than that in their counterparts in the OFD group （5.08 ±0.68 mm vs. 1.16 ± 0.38 mm; P 〈 0.05）. Likewise, only the 1-wall intrabony defect model showed a significant difference with respect to junctional epithelium between ABB ＋ CM and OFD groups （0.67 ±0.23 mm vs. 1.12 ± 0.28 mm, P 〈 0.05）. Conclusions： One-wall intrabony defects treated with ABB and CM did not show less periodontal regeneration than that in 3-wall intrabony defect. The noncontained l-wall intrabony defect might be a more discriminative defect model for further research into periodontal regeneration.