• Macromolecular Research
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• v.12 no.4
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• pp.367-373
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• 2004

We have developed a rigorous heat treatment method to improve the biocompatibility of chitosan as a tissue-engineered scaffold. The chitosan scaffold was prepared by the controlled freezing and lyophilizing method using dilute acetic acid and then it was heat-treated at 110$^{\circ}C$ in vacuo for 1-3 days. To explore changes in the physicochemical properties of the heat-treated scaffold, we analyzed the degree of deacetylation by colloid titration with poly(vinyl potassium sulfate) and the structural changes were analyzed by scanning electron microscopy, Fourier transform infrared (FT-IR) spectroscopy, wide-angle X-ray diffractometry (WAXD), and lysozyme susceptibility. The degree of deacetylation of chitosan scaffolds decreased significantly from 85 to 30% as the heat treatment time increased. FT-IR spectroscopic and WAXD data indicated the formation of amide bonds between the amino groups of chitosan and acetic acids carbonyl group, and of interchain hydrogen bonding between the carbonyl groups in the C-6 residues of chitosan and the N-acetyl groups. Our rigorous heat treatment method causes the scaffold to become more susceptible to lysozyme treatment. We performed further examinations of the changes in the biocompatibility of the chitosan scaffold after rigorous heat treatment by measuring the initial cell binding capacity and cell growth rate. Human dermal fibroblasts (HDFs) adhere and spread more effectively to the heat-treated chitosan than to the untreated sample. When the cell growth of the HDFs on the film or the scaffold was analyzed by an MTT assay, we found that rigorous heat treatment stimulated cell growth by 1.5∼1.95-fold relative to that of the untreated chitosan. We conclude that the rigorous dry heat treatment process increases the biocompatibility of the chitosan scaffold by decreasing the degree of deacetylation and by increasing cell attachment and growth.

• Journal of Periodontal and Implant Science
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• v.32 no.1
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• pp.161-172
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• 2002

The present study evaluated the effects of guided tissue regeneration using xenograft material(deproteinated bovine bone powder), with and without biodegradable membrane in beagle dogs. Contralateral fenestration defects (6 ${\times}$ 4mm) were created 4 mm apical to the buccal alveolar crest of maxillary premolar teeth in 5 beagle dogs. Deproteinated bovine bone powders were implanted into fenestration defect and one randomly covered biodegradable membrane (experimental group). Biodegradable membrane was used to provide GTR. Tissue blocks including defects with soft tissues which were harvested following four & eight weeks healing interval, prepared for histo-phathologic analysis. The results of this study were as follows. 1. In control group, at 4 weeks after surgery, new bony trabecular contacted with interstitial tissue and osteocytes like cell were arranged in new bony trabecule. Bony lamellation was not observed. 2. In control gruop, at 8 weeks after surgery, scar-like interstitial tissue was filled defect and bony trabecule form lamellation. New bony trabecular was contacted with interstitial tissue but defect was not filled yet. 3. In experimental group, at 4 weeks after surgery, new bony trabecular partially recovered around damaged bone. But new bony trabecular was observed as irregularity and lower density. 4. In experimental group, at 8 weeks after surgery, lamella bone trabecular developed around bone cavity and damaged tissue was replaced with dense interstitial tissue. In conclusion, new bone formation regenerated more in experimental than control groups and there was seen observe more regular bony trabecular in experimental than control groups at 4 weeks after surgery. In control group, at 8 weeks after surgery, the defects was filled with scar-like interstitial tissue but, in experimental group, the defects was connected with new bone. Therefore xenograft material had osteoconduction but could not fill the defects. We thought that the effective regeneration of periodontal tissue, could be achieved using GTR with biodegradable membrane.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.4
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• pp.407-417
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• 2013

The one of peri-implant soft tissue problems seen during the maintenance phase of implant therapy is an inadequate zone of keratinized tissue. Keratinized tissue plays a major role around teeth and dental implants, helping in maintaining and facilitating oral hygiene. A free gingival graft (FGG) is chosen to correct the soft tissue defects and provide optimal peri-implant health in order to increase the long-term prognosis of the implant reconstruction. However, the patient treated with FGG has pain and discomfort on donor site such as palate. It is also technically demanding, time consuming, and the color match of the tissue is often less than ideal. An apically positioned flap (APF) is selected for increasing the keratinized tissue simply while or after the second stage implant surgery. This case report shows successfully increasing the width of peri-implant kenratinized tissue through APF procedure on small site of dental implant instead of FGG.

• The Korean Journal of Zoology
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• v.4 no.1
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• pp.7-12
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• 1961

1) Respiratory metabolism patterns and its enzyme systems in the gill tissue of the fresh water mussels, Cristaria plicata were investigated through the examination on the effects of respiratory enzyme inhibitors, (KCN, NAF) and succinoxidase assay, while studying the effects of neutral salts (NaCL, KCL, CaCl2) and pH on oxygen consumption of the gill tissue. 2) In the limited concentration of KCL (0.3mM) and NaCl (0.4mM) solutions, oxygen consumption of the intact gill tissue was accelerated, but in CaCl2(0.5mM) solution, it showed no significant effect. The oxygen consumption was gradually decreased at the above concentrations of these limitations. The optimum pH for the respiration of the gill was 7.3. 3)Cyanide in 10-8M solution inhibited 88.8% of the respiration of the intact gill tissue. Methylene blue accelerated the respiration of the noral gill tissue, and slightly but significantly reversed the cyaniide poisoned respiration. 4)Oxygen consumption of the gill homogenate was apparently increased by the mixed addition of succinate, cytochrome c and activators (AlCl3 and CaCl2). This results suggested that succinoxidase system acts on the respiratory pattern of the gil tissue. 5) It was able to recognize that the enolase, which acts on the anaerobic glycolytic system, participated in the tissue respiration of the gill for NaF in 5$\times$10-2 M solution inhibited 55.5% of the respiration of the same intact tissue.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.27 no.6
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• pp.523-527
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• 2005

Allograft donations are commonly found to be contaminated. The most of tissue banks has promoted the use of ionizing radiation for the sterilization of biological tissues. The potential for transmission of human infectious diseases and contamination of microorganism has created serious concern for the continued clinical use of hard and soft-tissue allografts. Tissue banks have employed 15-25kGy for sterilization of hard and tendon allografts, which, according to the national standards, approaches the level at which the tissue quality is adversely affected for transplantation. The donations of allogeneic tissues to the Korea Tissue Bank over a 2-year period were reviewed, and the incidence and bacteriology of contamination were detailed. Clinical outcomes were determined for donors who had positive cultures at the time of retrieval and during the processing and they were compared with those of post sterilization. After exposure of the frozen block bone to 25kGy and the processed tissues to 15kGy of gamma irradiation, the authors were able to demonstrate complete inactivation of the bacteria. The aim of this study was to obtain the effects of gamma irradiation and the irradiation dose according to the type of tissue, through conventional microbiologic test without on influence of biocompatibility in allografts. The contamination rate after the final irradiation sterilization is 0% in the processed allografts. This may be due to the fact that the gamma radiation and processing steps are effective to control contamination.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.28 no.2
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• pp.74-85
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• 2019

The aesthetic restoration of dental implants in the anterior maxilla is a challenge for clinicians because it requires proper harmony in three following conditions; reconstruction of hard tissue, soft tissue, and aesthetic prosthesis. A newer technique, VIP-CT (Vacularized Interpositional Periosteal Connective Tissue) graft has been introduced as an alternative to these technique which allows the clinicians perform large volume soft tissue augmentation in esthetic sites with a single procedure. The advantages of the VIP-CT graft technique are that it allows the reconstruction of large soft tissue deficiency, with little constriction postoperatively. Furthermore, it facilitates improved hard tissue augmentation due to the additional blood supply and improved bone healing by mesenchymal cells. Moreover, this technique reduces patient discomfort and treatment time. This clinical report describes the procedure of bone augmentation during immediate implantation in facial dehiscence defect, especially Vascularized Interpositional Periosteal Connective Tissue(VIP-CT) graft for aesthetic anterior soft tissue.

• Journal of Periodontal and Implant Science
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• v.50 no.1
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• pp.2-13
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• 2020

Purpose: Subepithelial connective tissue grafts (SCTGs) are commonly performed for the treatment of gingival recession due to their high predictability. This study evaluated and histologically compared connective tissue grafts in terms of the presence of epithelial remnants and composition of the tissue types that were present (epithelium, lamina propria, and submucosa). Methods: Ten patients underwent epithelium removal using 2 different techniques: the use of a blade (group B) and through abrasion (group A). Twenty samples were collected and each tissue type was analyzed histologically in terms of its area, thickness, and proportion of the total area of the graft. Results: In 4 samples (40%) from group B (n=10) and 2 samples (20%) from group A (n=10), the presence of an epithelial remnant was observed, but the difference between the groups was not statistically significant (P>0.05). Likewise, no statistically significant differences were observed between the groups regarding the area, mean thickness, or proportion of the total area for any of the tissue types (P>0.05). Conclusions: Histologically, SCTGs did not show statistically significant differences in terms of their tissue composition depending on whether they were separated from the epithelial tissue by abrasion or by using a blade.

• Biotechnology and Bioprocess Engineering:BBE
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• v.3 no.1
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• pp.1-5
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• 1998

One cervical cancer cell line, C9, carrying human papillomavirus type 18 (HPV18) genes that is one of the major etiologic concoviruses for cervical cancer was characterized. This cell line was further characterized for its capacity related to the epithelial cell proliferation, stratification and differentiation in reconstituted artificial epithelial tissue. The in vitro construction of three dimensional artificial cervical opithelial tissue has been engineered using C9 epithelial cancer cells, human foreskin fibroblasts and a matrix made of type I collagen by organotypic culture of epithelial cells. The morphology of paraffin embedded artificial tissue was examined by histochemical staining. The artificial epithelial tissues were well developed having multilayer. However, the tissue morphology was similar to the cervical tissus having displasia induced by HPV infection. The characteristics of the artificial tissues were examined by determinining the expression of specific marker proteins. In the C9 derived artificial tissues, the expression of EGF receptor, as epithelial proliferation marker proteins for stratum basale was observed up to the stratum spinosum. Another epithelial proliferation marker for stratum spinosum, cytokerations 5/6/18, were observed well over the stratum spinosum. For the differentiation markers, the expression of involucrin and filaggrin were observed while the terminal differentiation marker, cytokeratins 10/13 was not detected at all. Therefore the reconstituted artificial epithelial tissues expressed the same types of differentiation marker proteins that are expressed in normal human cervical epithelial tissues but lacked the final differentiation capacity representing characteristics of C9 cell line as a cancer tissue devived cell line. Expression of HPV18 E6 oncoprotein was also observed in this artifical cervical opithelial tissue though the intensity of the staining was weak. Thus this artificial epithelial tissue could be used as a useful model system to examine the relationship between HPV-induced cervical oncogenesis and epithelial cell differentiation.

• Archives of Plastic Surgery
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• v.38 no.4
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• pp.415-420
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• 2011

Purpose: The reconstruction of a soft tissue defect of the heel pad can be challenging. One vital issue is the restoration of the ability of the heel to bear the load of the body weight. Many surgeons prefer to use local flaps or free tissue transfer rather than a skin graft. In this study, we evaluated the criteria for choosing a proper flap for heel pad reconstruction. Methods: In this study, 23 cases of heel pad reconstruction were performed by using the flap technique. The etiologies of the heel defects included pressure sores, trauma, or wide excision of a malignant tumor. During the operation, the location, size and depth of the heel pad defect determined which flap was chosen. When the defect size was relatively small and the defect depth was limited to the subcutaneous layer, a local flap was used. A free flap was selected when the defect was so large and deep that almost entire heel pad had to be replaced. Results: There was only one complication of poor graft acceptance, involving partial flap necrosis. This patient experienced complete recovery after debridement of the necrotic tissue and a split thickness skin graft. None of the other transferred tissues had complications. During the follow-up period, the patients were reported satisfactory with both aesthetic and functional results. Conclusion: The heel pad reconstructive method is determined by the size and soft-tissue requirements of the defect. The proper choice of the donor flap allows to achieve satisfactory surgical outcomes in aesthetic and functional viewpoints with fewer complications.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.422-430
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• 2021

It is very difficult to achieve denture support, stability and retention in single-maxillary complete denture patients with flabby tissue. A 57-year-old male patient was uncomfortable with the existing denture and wanted treatment. The reduction of flabby tissue was confirmed using the treatment denture. Non-pressure impression was obtained using an intraoral scanner during the definitive denture process. This is reported because the resulting denture improved when observing the retention, support and stability of the denture during occlusion.