Xenogenic Material Research Articles

Comparison of two types of xenogeneic matrices to treat single gingival recessions: A randomized clinical trial.

Xenogeneic matrices (XMs) have been increasingly used for root coverage procedures. This study compared the use of two types of XM (collagen matrix [CM] and xenogeneic acellular dermal matrix [XDM]) associated with the coronally advanced flap technique (CAF) to treat single gingival recessions. Seventy-five patients presenting single RT1 gingival recession were treated by CAF (control group, n=25), CAF+CM (test group 1, n=25), or CAF+XDM (test group 2, n=25) and completed 6-month follow-up. Clinical, patient-centered, and esthetic assessments were performed and intra- and intergroup differences were analyzed. At 6 months, the mean recession reduction for CAF, CAF+CM, and CAF+XDM was 2.4 ± 0.8mm, 2.4 ± 0.9mm and 2.1 ± 0.8mm, respectively (P>0.05). The corresponding mean percentage of root coverage was 78.9% ± 26.2% for CAF, 78.0% ± 28.5% for CAF+CM, and 65.6% ± 26.9% for CAF+XDM (P>0.05). Dentin hypersensitivity and esthetic conditions showed significantly improvements in all groups. Test groups presented significant gains in gingival thickness (GT; CAF+CM: 0.4 ± 0.3mm; CAF+XDM: 0.4 ± 0.2mm) compared to the control group (CAF: 0.0 ± 0.1mm; P<0.05). The CAF, CAF+CM, and CAF+XDM treatments each provided similar results in the treatment of single gingival recessions. The addition of either CM or XDM to CAF increases the GT.

Ex Vivo and In Vivo Analysis of a Novel Porcine Aortic Patch for Vascular Reconstruction.

(1) Background: The aim of the present study was the biocompatibility analysis of a novel xenogeneic vascular graft material (PAP) based on native collagen won from porcine aorta using the subcutaneous implantation model up to 120 days post implantationem. As a control, an already commercially available collagen-based vessel graft (XenoSure®) based on bovine pericardium was used. Another focus was to analyze the (ultra-) structure and the purification effort. (2) Methods: Established methodologies such as the histological material analysis and the conduct of the subcutaneous implantation model in Wistar rats were applied. Moreover, established methods combining histological, immunohistochemical, and histomorphometrical procedures were applied to analyze the tissue reactions to the vessel graft materials, including the induction of pro- and anti-inflammatory macrophages to test the immune response. (3) Results: The results showed that the PAP implants induced a special cellular infiltration and host tissue integration based on its three different parts based on the different layers of the donor tissue. Thereby, these material parts induced a vascularization pattern that branches to all parts of the graft and altogether a balanced immune tissue reaction in contrast to the control material. (4) Conclusions: PAP implants seemed to be advantageous in many aspects: (i) cellular infiltration and host tissue integration, (ii) vascularization pattern that branches to all parts of the graft, and (iii) balanced immune tissue reaction that can result in less scar tissue and enhanced integrative healing patterns. Moreover, the unique trans-implant vascularization can provide unprecedented anti-infection properties that can avoid material-related bacterial infections.

Pulmonary artery augmentation using decellularized equine pericardium (Matrix Patch™): initial single-centre experience.

The aim of this study was to report our initial experience when using Matrix Patch™ a cell-free equine-derived pericardium for the augmentation of branch pulmonary arteries (PAs) in children. Between September 2016 and September 2019, Matrix Patch was used for the augmentation of branch PAs in 96 patients and implanted in 147 separate locations. The median age at implantation was 3.2 years (interquartile range: 0.9-8.4), and 33% of patients were infants. The patch was used mainly in redo surgeries (89.6%). Intra-procedural feasibility and reinterventions were analysed. Primary end points were death or patch-related reoperation/stent implantation. Explanted patches were stained for recellularization/calcification, or to reveal proliferation/inflammation. A total of 81 patients, who received patches in 119 separate locations, were followed within a median of 20 months (interquartile range: 10.2-30.2). Patients with early reoperation/stent implantation were excluded from follow-up. No patch-related death was noted. Survival at last follow-up was 88% (95% CI: 78.8-93.7%). Overall probability of freedom from reoperation/stent implantation per location, 12 and 24 months after initial surgery was 85.8% (95% CI: 76.2-91.7%) and 78.7 (95% CI: 65.9-87.2%), respectively. At 20 months, superficial proliferation with discrete macrophage activity was seen in explants; however, no signs of calcification are observed. The initial experience with the Matrix Patch in PAs showed comparable results to other xenogeneic patch materials. Long-term follow-up data are needed to prove the desired durability of the patch in different locations.

Improvement of Osseointegration by Ultraviolet and/or Simvastatin Treatment on Titanium Implants with or without Bone Graft Materials.

We evaluated and compared ultraviolet (UV) treatment and simvastatin (SIM) immersion effects on the osseointegration of sandblasted, large-grit, acid-etched (SLA) titanium dental implants at two different time points in rabbit tibias, with or without xenogenic bone graft materials. The surface alteration on simvastatin treatment titanium discs was analyzed using an infrared spectrometer. Implants were categorized into four groups according to the surface treatment type. Twelve rabbits received two implants per tibia. A tibial defect model was created using a trephine bur, with implants in contact with the bone surface and bovine bone graft materials for gap filling. The rabbits were sacrificed after 2 or 4 weeks. UV treatment or SIM immersion increased the bone-to-implant contact (BIC) on nongrafted sides, and both increased the BIC and bone area (BA) on grafted sides. The application of both treatments did not result in higher BIC or BA than a single treatment. At two different time points, BIC in the nongrafted sides did not differ significantly among the UV and/or SIM treated groups, whereas BA differed significantly. UV or SIM treatment of SLA titanium implants accelerates osseointegration in tibias with or without xenogenic bone graft materials. The combination of both treatments did not show synergy.

Increasing the Thickness of the Collagen Xenogeneic Matrix Prevents Early Matrix Degradation and Improves the Proliferation, Adhesion, and Viability of Human Gingival Fibroblasts and Mesenchymal Stem Cells.

Using autogenous grafts in mucogingival surgeries is related to postoperative morbidity and limited tissue availability, and thus xenogeneic matrices are increasingly used. This in vitro study evaluated the influence of xenogeneic collagen matrix thickness on cell adhesion, morphology, viability, proliferation, and matrix degradation. Matrices were divided into three groups: SLC: single layer of Lumina Coat, as commercially available (2-mm thickness); DLC: double layer of SLC (Lumina Coat); and MG: single layer of Mucograft, as commercially available (4-mm thickness). SEM was used to evaluate the matrix surface topographies. To evaluate the cell viability, proliferation, adhesion, and morphology, human gingival fibroblasts (HGF) and stem cells from human exfoliated deciduous teeth (SHED) were used. Cell viability was evaluated through MTS colorimetric method evaluating HGF and SHED on days 1, 3, and 7. Cell proliferation was assessed by PicoGreen assay, evaluating HGF and SHED on days 3 and 7. Sample degradation was evaluated on days 1, 3, 7, 14, 21, 28, and 35. All groups were biocompatible for HGF and SHED, showing viabilities > 70% on days 1, 3, and 7. DCL promoted HGF viabilities similar to MG (P = .2828) and the highest SHED viability (P < .0001) on day 1. DLC also demonstrated HGF and SHED proliferations higher than the positive control (MG; P < .05) on day 7. SLC was completely degraded on day 14, while DLC and MG presented 48.41% and 20.52% of their initial mass, respectively, on day 35. Increasing the matrix thickness improved HGF and SHED viability and proliferation and prevented early matrix degradation. DLC demonstrated better results than SLC and MG concerning matrix degradation and HGF and SHED viability and proliferation.

Impact of Porcine Pancreas Decellularization Conditions on the Quality of Obtained dECM.

Due to the limited number of organ donors, 3D printing of organs is a promising technique. Tissue engineering is increasingly using xenogeneic material for this purpose. This study was aimed at assessing the safety of decellularized porcine pancreas, together with the analysis of the risk of an undesirable immune response. We tested eight variants of the decellularization process. We determined the following impacts: rinsing agents (PBS/NH3·H2O), temperature conditions (4 °C/24 °C), and the grinding method of native material (ground/cut). To assess the quality of the extracellular matrix after the completed decellularization process, analyses of the following were performed: DNA concentration, fat content, microscopic evaluation, proteolysis, material cytotoxicity, and most importantly, the Triton X-100 content. Our analyses showed that we obtained a product with an extremely low detergent content with negligible residual DNA content. The obtained results confirmed the performed histological and immuno-fluorescence staining. Moreover, the TEM microscopic analysis proved that the correct collagen structure was preserved after the decellularization process. Based on the obtained results, we chose the most favorable variant in terms of quality and biology. The method we chose is an effective and safe method that gives a chance for the development of transplant and regenerative medicine.

Polydioxanone-Based Membranes for Bone Regeneration.

Resorbable synthetic and natural polymer-based membranes have been extensively studied for guided tissue regeneration. Alloplastic biomaterials are often used for tissue regeneration due to their lower immunoreactivity when compared with allogeneic and xenogeneic materials. Plenum® Guide is a synthetic membrane material based on polydioxanone (PDO), whose surface morphology closely mimics the extracellular matrix. In this study, Plenum® Guide was compared with collagen membranes as a barrier material for bone-tissue regeneration in terms of acute and subchronic systemic toxicity. Moreover, characterizations such as morphology, thermal analysis (Tm = 107.35 °C and crystallinity degree = 52.86 ± 2.97 %, final product), swelling (thickness: 0.25 mm ≅ 436% and 0.5 mm ≅ 425% within 24 h), and mechanical tests (E = 30.1 ± 6.25 MPa; σ = 3.92 ± 0.28 MPa; ε = 287.96 ± 34.68%, final product) were performed. The in vivo results revealed that the PDO membranes induced a slightly higher quantity of newly formed bone tissue than the control group (score: treated group = 15, control group = 13) without detectable systemic toxicity (clinical signs and evaluation of the membranes after necropsy did not result in differences between groups, i.e., non-reaction -> tissue-reaction index = 1.3), showing that these synthetic membranes have the essential characteristics for an effective tissue regeneration. Human adipose-derived stem cells (hASCs) were seeded on PDO membranes; results demonstrated efficient cell migration, adhesion, spread, and proliferation, such that there was a slightly better hASC osteogenic differentiation on PDO than on collagen membranes. Hence, Plenum® Guide membranes are a safe and efficient alternative for resorbable membranes for tissue regeneration.

Xenogeneic materials for the surgical treatment of aortic infections.

BackgroundThe surgical treatment of aortic infections (AIs) is challenging. In situ aortic reconstructions represent nowadays the favored therapy for fit patients and xenogeneic materials are used increasingly. The aim of this study was to present our experience with xenogeneic reconstructions for AI using self-made bovine pericardium tubes and/or the biosynthetic Omniflow® II graft.MethodsThis retrospective single-center study included all patients undergoing xenogeneic aortic and aortoiliac reconstructions from December 2015 to June 2020. Patient comorbidities, symptoms, procedural characteristics, types of pathogens and postoperative outcomes were analyzed.ResultsTwenty-eight patients [23 male (82%), median age 68 (range, 28–84) years] were included. Ten patients (36%) had native AIs and 18 (64%) had graft infections, including 3 (11%) aortoesophageal and 2 (7%) aortoduodenal fistulas (ADF). Twenty-four patients (86%) were symptomatic, the most common symptoms being contained aortic rupture (n=8) and sepsis (n=4). The surgical procedures were infra- and juxtarenal aortic repairs (n=11, 39% and n=7, 25%), thoracoabdominal aortic repairs (type IV: n=1, 4%; type V: n=3, 11%), descending thoracic aortic repairs (n=4, 14%) and 2 reconstructions (7%) involving the ascending aorta/aortic arch. Most were urgent (n=10, 43%) or emergent operations (n=11, 35%). Identification of pathogen(s), mostly Gram-positive bacteria, was possible in 25 patients (89%). Twelve patients (43%) had polymicrobial infections and 6 (21%) infections with multi-resistant bacteria. In-hospital mortality was 32% (n=9) due to acute cardiac failure (1/9), endocarditis (1/9), bleeding (3/9) and sepsis (4/9). The most frequent complications were transient need for dialysis (n=12, 43%) and persisting sepsis (n=11, 39%). Two early occlusions of Omniflow® II grafts were observed (7%). Median follow-up (FU), during which 2 patients died of non-aortic causes, was 14 months (95% CI: 9–19 months). Freedom from reoperation was 100%, there was no evidence for reinfection during FU.ConclusionsXenogeneic orthotopic reconstructions for AI can be performed at all aortic levels. Combining bovine pericardium and the Omniflow® II graft can be useful for reconstructing the branched aortic segments and both materials show appropriate early to midterm outcomes. Nonetheless, AIs are serious conditions associated with relevant morbidity/mortality rates, even in a specialized center.

Evaluation of the effectiveness of xenogenic material at the site of the osteoplastic procedure on the alveolar ridge of the jaw in case of exposure of the dPTFE membrane

Various types of techniques increase the volume of the atrophied alveolar ridge are used as bone blocks, ridge splitting, osteoperiostal flap, etc. However, one of the most promising methods to date is the GBR method. The use of bone-substituting materials and isolating membranes gives a reliable and predictable result in dental implantology. Recent studies using the dPTFE (dense polytetrafluoroethylene ) membrane have shown a positive result at the site of regeneration even if the membrane itself is exposed in repaired period. With this type of complication the membrane is removed at a period of 4–6 weeks and replaced with a collagen membrane with subsequent approximation of the edges of the flap by sutures (24, 25). This article shows the possibility of regenerating the bone graft from sole xenogenic material using dPTFE membrane in case wound dehiscence in repaired period but without using the collagen membrane coating step after removing dPTFE and it healing by secondary tension.

Xenografts in Periodontal Regeneration: A Viable Alternative

Periodontal disease is categorized by the destruction of periodontal tissues. Over the years, there have beenseveral clinical techniques and material options that have been investigated for periodontal defect repair orregeneration. The development of improved biomaterials for periodontal tissue engineering has significantlyupgraded the available treatment options and their clinical results. Bone replacement graft materials, barriermembranes, various growth factors and combination of these have been used. Autografts have been used asthe bone graft material of choice since many years. But this type of grafts has many limitations to its use.In order to overcome its drawbacks, xenografts may be used as a viable alternative. Xenografts also knownas heterologous graft tissues, is obtained from different species, and has been used in various differentperiodontal procedures. The characteristic properties of xenografts and the benefits of using it has made thistype of graft to emerge as an appropriate choice for periodontal regeneration. The objective of this articleis to a review xenograft as a bone replacement graft material to be used in periodontal therapy. The source,mode of bone regeneration and the respective advantages and disadvantages of xenogenic materials havebeen discussed in detail.

Possible Implications for Improved Osteogenesis? The Combination of Platelet-Rich Fibrin With Different Bone Substitute Materials.

Bone substitute materials (BSM) are widely used in oral regeneration, but sufficient angiogenesis is crucial for osteogenesis. The combination of BSM with autologous thrombocyte concentrations such as platelet-rich fibrin (PRF) may represent a clinical approach to overcome this limitation. This study analyzes the early influence on osteoblast (HOB) in vitro. Here, four different BSM (allogeneic, alloplastic, and two of xenogeneic origin) were combined with PRF. After the incubation with osteoblasts for 24 h, cell viability, migration, and proliferation were assessed. Next, marker of proliferation, migration, and differentiation were evaluated on gene and protein levels in comparison to the native BSM and osteoblast alone. Addition of PRF increased viability for both the xenogeneic BSM (p = 0.0008, p = 0.032, respectively) in comparison to HOB and vs. native BSM (p = 0.008), and led to a tendency for increased cell proliferation and migration for all BSM (each p > 0.05). On gene basis, allogeneic and alloplastic BSM displayed a significantly increased RUNX2 expression (each p = 0.050). Expression of alkaline phosphatase for alloplastic (p = 0.050) and collagen-1 for xenogeneic BSM (p = 0.05) were significantly increased in combination with PRF. In addition, bone morphogenic protein was expressed significantly higher when xenogeneic material was combined with PRF in comparison to HOB alone (each p = 0.05). In summary, the combination of PRF with different BSM increases initial viability and may influence early proliferation and migration potential of osteoblast via RUNX2, alkaline phosphatase, collagen, and BMP2 especially in combination with alloplastic and xenogeneic BSM. Biofunctionalization of BSM using PRF might improve osteogenesis and extend the range of indications.

RNU (Foxn1RNU-Nude) Rats Demonstrate an Improved Ability to Regenerate Muscle in a Volumetric Muscle Injury Compared to Sprague Dawley Rats

Products developed for skeletal muscle regeneration frequently incorporate allogeneic and xenogeneic materials to elicit a regenerative response to heal skeletal muscle wounds. To avoid graft rejection in preclinical studies, immunodeficient rodents are used. Whether the immunodeficiency alters the host response to the material in skeletal muscle has not been studied. In this study, we hypothesized that an allogeneic acellular skeletal muscle grafts implanted in an immunodeficient rat (RNU, Foxn1-deficient) would exhibit better new muscle fiber formation compared to grafts implanted in immunocompetent Sprague Dawley (SD) rats. Decellularized SD skeletal muscle matrix (DMM) was implanted in the gastrocnemius (N = 8 rats/group). 56 days after surgery, animal gait was examined and animals were euthanized. Muscle force was assessed and fiber number as well as immune cell infiltrate was measured by histomorphometry and immunohistochemistry. Animal gait and percent recovery of muscle force were unchanged in both groups, but newly regenerated muscle fibers increased in RNU rats. Macrophage staining for CD68 was higher in RNU rats than in SD rats. These data show differences in muscle regeneration between animal models using the same biomaterial treatment, but these differences could not be ascribed to the immune response. Overall, our data provide awareness that more studies are needed to understand how host responses to biomaterials differ based on the animal model used.

Does Platelet-Rich Fibrin Enhance the Early Angiogenetic Potential of Different Bone Substitute Materials? An In Vitro and In Vivo Analysis.

The impaired angiogenic potential of bone substitute materials (BSMs) may limit regenerative processes. Therefore, changes in the angiogenetic properties of different BSMs in combination with platelet-rich fibrin (PRF) in comparison to PRF alone, as well as to native BSMs, were analyzed in vitro and in vivo to evaluate possible clinical application. In vitro, four BSMs of different origins (allogeneic, alloplastic, and xenogeneic) were biofunctionalized with PRF and compared to PRF in terms of platelet interaction and growth factor release (vascular endothelial growth factor (VEGF), tissue growth factor ß (TGFß) and platelet-derived growth factor (PDGF)) after 15 min. To visualize initial cell–cell interactions, SEM was performed. In vivo, all BSMs (±PRF) were analyzed after 24 h for new-formed vessels using a chorioallantoic membrane (CAM) assay. Especially for alloplastic BSMs, the addition of PRF led to a significant consumption of platelets (p = 0.05). PDGF expression significantly decreased in comparison to PRF alone (all BSMs: p < 0.013). SEM showed the close spatial relation of each BSM and PRF. In vivo, PRF had a significant positive pro-angiogenic influence in combination with alloplastic (p = 0.007) and xenogeneic materials (p = 0.015) in comparison to the native BSMs. For bio-activated xenogeneic BSMs, the branching points were also significantly increased (p = 0.005). Finally, vessel formation was increased for BSMs and PRF in comparison to the native control (allogeneic: p = 0.046; alloplastic: p = 0.046; and xenogeneic: p = 0.050). An early enhancement of angiogenetic properties was demonstrated when combining BSMs with PRF in vitro and led to upregulated vessel formation in vivo. Thus, the use of BSMs in combination with PRF may trigger bony regeneration in clinical approaches.

Novel chitosan-based bone substitute. A summary of in vitro and in vivo evaluation

Backgorund: Composite bone substitute materials have been raising more interest as an alternative for autologous transplants and pure xenogenic materials in oral surgery for last few years. These not immunogenic and completely resorbable biomaterials may become the basis for complete and predictable guided bone regeneration. In the majority of cases the deciding factor is ease of application of the material by a surgeon.

Інвагінація зуба третього типу. Діагностика та комплексне лікування

Object: researching the combination of endodontic and surgical treatment of a tooth with developing dens invaginatus pathology. Materials and methods. X-ray diagnostics were performed with the Veraview X800 Morita. Irrigation with sodium hypochlorite solution 5.25 % with additional ultrasound treatmentabd 17 % EDTA solution were used for drug treatment of invagination and the main channel. The root canal and invagination, due to a non-standard structure, were handled by VDW hand tools combined with the Aurum BLUE (Meta Biomed) machine tool. Constant obturation was performed by the method of vertical compaction «Siller-AN plus». During the surgical stage, Langer (Hu-Friedy) periodontal curettes, CL 8 (Hu-Friedy) curettage spoon, 141-004-31W Oval Spoon Excavator (Hu-Friedy) were used; access to the focus was formed using a piezo surgical spherical nozzle (CE 1, Piezotome Solo (Satelec, Akteon). 4583 Kohler needle holder was used for suturing, suture material – polypropylene 5.0. The bone defect was filled with xenogenic material BIO GEN cancellous size 2/3 mm, 2.0 (Biotek), the barrier membrane – BIOCOLLAGEN (Biotek), the periodontal defect was filled with BIO GEN mix (Biotek). Key words: dens invaginatus, tooth in tooth, endodontic treatment, bone augmentation, apical surgery.

The Effects of Smoking Cigarettes on Immediate Dental Implant Stability—A Prospective Case Series Study

Background: Smoking tobacco significantly affects the biology of periodontal tissues and contributes to the increased risk of peri-implant diseases. The aim of the study was to investigate whether smoking cigarettes affects the primary and secondary stability of maxillary dental implants, inserted into fresh sockets immediately after extraction. Methods: The study was conducted on 164 patients between the ages of 27–71 years old. 67 individuals smoked more than 20 cigarettes daily and 97 were non-smokers. 190 immediate implants were inserted in the maxilla. Immediate implantations were performed with simultaneous augmentation of the socket with xenogenic bone grafting material. In the posterior region, implants were inserted into the palatal alveolus. The stability of the implants was measured using Insertion Torque Value (ITV) and two types of devices: Periotest (PT) and Osstell (ISQ). Marginal bone loss was evaluated on cone beam computed tomography scans. Results: In an aesthetic area, the PT values at 6 months post-implantation were higher for smokers than non-smokers (p &lt; 0.05), respectively. The ISQ values were significantly lower in smokers compared to non-smokers at 6 months post-implantation (p = 0.0226), respectively. In the posterior region PT values were higher in smokers both on the day of implantation (p = 0.0179), 6 months after surgery (p = 0.0003) as well as 24 months after surgery (p &lt; 0.0001), as compared to non-smokers, respectively. Smokers revealed lower ISQ values than non-smokers (p = 0.0047) on the day of implantation, as well as 6 months after implantation (p = 0.0002), respectively. There were no significant differences in marginal bone loss after 18 months of loading between smokers and non-smokers in the aesthetic, as well as posterior regions (p &gt; 0.05). ITV measurements were lower in smokers than non-smokers in the aesthetic (16.3 vs. 17.5 Ncm) and posterior area (16.8 vs. 17.9 Ncm). Conclusions: This study indicate that smoking cigarettes has a negative effect on the stability of immediate implants in the maxilla. Primary stability of immediate implants may be lower in the posterior area of the maxilla in smokers when compared to non-smokers, which may eliminate smokers from immediate implants in this region. Secondary stability of immediate implants may be lower in both the aesthetic and posterior areas in smokers compared to non-smokers, which may encourage the postponement of final crowns delivery at 6 months post op and the extension of the occlusaly temporary crowns use in some smoker cases.

Effect of biologic materials on the outcomes of horizontal alveolar ridge augmentation: A retrospective study.

PurposeThe purpose of this study was to investigate if the addition of biologic agents to a particulate bone graft enhances horizontal ridge augmentation outcomes in terms of bone dimensions, bone density, and successful implant placement.Materials and MethodsA retrospective chart review was done to assess the clinical and radiographic outcomes in 52 horizontal ridge augmentation sites in 43 patients. Information was gathered regarding surgical technique, type of graft material, biologic agents used (PRP or rhPDGF‐BB), method of space maintenance, and achieved alveolar ridge width and bone density changes as quantified on CBCT scans.ResultsThe use of tenting screws, a resorbable membrane, and a combination of particulate allogenic and xenogenic bone graft material provided an average horizontal bone gain of 3.6 mm in the 52 augmented sites. There was no statistically significant difference observed in the amount of horizontal bone gain between sites treated with the addition of biologic agents (n = 21), or with a particulate bone graft alone (n = 31). A marginally statistically significant difference was found in the density of the grafted bone with the addition of biologics (p value = .0653).ConclusionThe addition of biologic agents to the graft materials did not have a significant effect on the amount of horizontal bone gain or successful implant placement; however, it marginally enhanced the bone density of the grafted area.

PECULIARITIES OF REVASCULARIZATION (OR ANGIOGENESIS) OF THE ALVEOLAR AGES USING DIFFERENT BONE-PLASTIC MATERIALS

Secondary anodontia, as a consequence of diseases of the dentoalveolar apparatus is the most common pathology among the population. The results of medical and statistical studies show an increase in the incidence of acquired anodontia in both adults and children.&#x0D; When teeth are lost, bone resorption occurs and this leads to a decrease in the thickness and height of the alveolar processes of the jaws by an average of 25-30%. In addition, there is a loss of bone walls of the dental alveolus, which causes a tissue defect. To eliminate defects and deformations of the walls of the alveolar processes of the jaws, the method of osteosynthesis of autografts in the form of a block of the bone of appropriate volume or controlled bone growth is used.&#x0D; Angiogenesis and blood supply to the cavitary defects of the jaw bones is one of the important indicators of bone graft integration and restoration of the authentic structure of bone tissue at the defect site.&#x0D; However, blood supply recovery depending on the type of graft has not yet been fully elucidated, which is why the study of angiogenesis in limited defects after their replacement by different types of grafts remains relevant.&#x0D; The aim of the research is to study of the features of revascularization of bone regenerates depending on the type of osteoplastic material used.&#x0D; Material and methods of experimental research&#x0D; Experimental studies were performed on 50 male Wistar rats weighing 270-380 g in the vivarium of the State Research Control Institute of Veterinary Drugs and Feed Additives (Lviv).&#x0D; The experimental animals were divided into 5 experimental groups.&#x0D; In groups 2 and 3, we used xenogenic bone-plastic materials:&#x0D; group 1 - healing took place under a blood clot (10 animals);&#x0D; group 2 - Bio-Oss® (Switzerland), a bone mineral of natural origin derived from bovine bone (10 animals);&#x0D; group 3 - Osteoplast-K (Russia), highly purified non-demineralized bone collagen isolated from cancellous bone, which contains sulfated glycosaminoglycans. (10 animals);&#x0D; In groups 4 and 5, we used bone-plastic materials based on calcium phosphate:&#x0D; group 4 - Easy-Graft) (Switzerland), material based on beta-tricalcium phosphate (10 animals);&#x0D; group 5 - Collapan-L (Russia), biocomposite material based on synthetic hydroxyapatite, collagen and antibiotic (lincomycin hydrochloride) (10 animals).&#x0D; The method of bone defect formation in experimental conditions. Under ether anesthesia in aseptic conditions after depilation of the operating field, we made an incision in the dorsal surface of the tibia, created access to the bone surface and formed two defects with a spherical boron (one on each side) according to the topographic and anatomical features of the tibia structure of experimental animals.&#x0D; The formed bone defect on one side was filled with osteoplastic material; on the opposite side, healing took place under a blood clot.&#x0D; It was found that when using osteoplastic materials Bio-Oss® and Osteoplast-K, the most active formation of blood vessels occurred from the 30th to the 60th day of the experiment (from 79.13 ± 2.67% to 81.83 ± 3.68% of vessels caliber 0-20 μm). When using materials Easy-Graft ™ and Collapan-L, the most active formation of vessels was observed from the 60th to the 90th day (from 45.24 ± 3.84% to 90.63 ± 1.63% of vessels of caliber 0-20 μm2). In the control group, where healing took place under a blood clot, the most active vascular formation was observed up to the 14th day (84.28 ± 1.36% of vessels of caliber 0-20 μm2) and up to the 60th day (82.01 ± 1.95%).

LiQD Cornea: Pro-regeneration collagen mimetics as patches and alternatives to corneal transplantation.

Transplantation with donor corneas is the mainstay for treating corneal blindness, but a severe worldwide shortage necessitates the development of other treatment options. Corneal perforation from infection or inflammation is sealed with cyanoacrylate glue. However, the resulting cytotoxicity requires transplantation. LiQD Cornea is an alternative to conventional corneal transplantation and sealants. It is a cell-free, liquid hydrogel matrix for corneal regeneration, comprising short collagen-like peptides conjugated with polyethylene glycol and mixed with fibrinogen to promote adhesion within tissue defects. Gelation occurs spontaneously at body temperature within 5 min. Light exposure is not required-particularly advantageous because patients with corneal inflammation are typically photophobic. The self-assembling, fully defined, synthetic collagen analog is much less costly than human recombinant collagen and reduces the risk of immune rejection associated with xenogeneic materials. In situ gelation potentially allows for clinical application in outpatient clinics instead of operating theaters, maximizing practicality, and minimizing health care costs.

Composition of spherules and lower mantle minerals, isotopic and geochemical characteristics of zircon from volcaniclastic facies of the Mriya lamproite pipe

The article presents the results of studying the rocks of the pyroclastic facies of the Mriya lamproite pipe, located on the Priazovsky block of the Ukrainian shield. In them the rock's mineral composition includes a complex of exotic mineral particles formed under extreme reduction mantle conditions: silicate spherules, particles of native metals and intermetallic alloys, oxygen-free minerals such as diamond, qusongite (WC), and osbornite (TiN). The aim of the research is to establish the genesis of volcaniclastic rocks and to develop ideas of the highly deoxidized mantle mineral association (HRMMA), as well as to conduct an isotopic and geochemical study of zircon. As a result, groups of minerals from different sources are identified in the heavy fraction: HRMMA can be attributed to the juvenile magmatic component of volcaniclastic rocks; a group of minerals and xenoliths that can be interpreted as xenogenic random material associated with mantle nodules destruction (hornblendite, olivinite and dunite xenoliths), intrusive lamproites (tremolite-hornblende) and crystalline basement rocks (zircon, hornblende, epidote, and granitic xenoliths). The studied volcaniclastic rocks can be defined as intrusive pyroclastic facies (tuffisites) formed after the lamproites intrusion. Obviously, the HRMMA components formed under extreme reducing conditions at high temperatures, which are characteristic of the transition core-mantle zone. Thus, we believe that the formation of primary metal-silicate HRMMA melts is associated with the transition zone D".