• Journal of Periodontal and Implant Science
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• v.28 no.2
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• pp.263-273
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• 1998

For histologic observation of the regenerated bone following guided tissue regeneration (GTR) using ePTFE membranes with calcium carbonate implant and autogenous bone graft, biopsies were collected from 2 patients during 5-year-postoperative surgical reentry. In both combined cases with guided tissue regeneration in conjunction with calcium carbonate implant and autogenous bone graft, significant bone fill and gain in probing attachment level was observed. In histologic examination, specimen in GTR case with calcium carbonate grafting was composed of a dense bone containing vascular channel with lamellar structure and viable bone cells in lacunae, however considerable calcium carbonate particles remained unresorbed and isolated from regenerated bone by the dense cellular and fibrous connective tissue. No formative cells could be seen in contact with remained calcium carbonate particles. In GTR case with autogenous bone grafting, specimen show was composed of a dense lamellar bone containing vascular channel, which showed normal alveolar bone architectures. The present observation indicate that guided tissue regeneration in conjunction with grafting, especially autogenous bone graft, has highly osteogenic potential, however resorbable calcium carbonate granules were not completely resorbed at 5 year postimplantation.

• Journal of Periodontal and Implant Science
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• v.33 no.4
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• pp.673-691
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• 2003

The current interest in periodontal tissue regeneration has lead to research in bone graft, root surface treatments, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. Several studies have shown that a strong correlation between platelet-rich plasma and the stimulation of remodeling and remineralization of grafted bone exists, resulting in a possible increase of 15-30% in the density of bone trabeculae. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and a bone xenograft used in conjunction with a non-resorbable guided-tissue membrane, e-PTFE, compared to a control group with regards to bone regeneration at the implant fixture site. Implant fixtures were inserted and graft materials placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2 , 4, and 8 weeks after implant fixture insertion. The results of the experiment are as follows: 1. The rate of osseointegration to the fixture threads was found to be greater in the first experimental group compared to the control group. 2. The histopathological findings of the second experimental group showed rapid resorption of BBP with subsequent new bone formation replacing the resorbed BBP. 3. The second experimental group showed new bone formation in the area adjacent to the fixture threads beginning two weeks after fixture implantation, with continued bone remodeling in the areas mesial and distal to the fixture. 4. Significant new bone formation and bone remodeling was observed in both experimental groups near the implant fixture sites. 5. The rate of osseointegration at the fixture threads was greater in the second experimental group compared to the first group, and the formation of new bone and trabeculae around the fixture site occurred after the fourth week in the second experimental group. The results of the experiment suggest that a greater degree of new bone formation and osseointegration can occur at the implant fixture site by utilizing platelet-rich plasma and bone xenografts, and that these effects can be accelerated and enhanced by concurrent use of a non-resorbable guided tissue membrane.

• Archives of Plastic Surgery
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• v.36 no.4
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• pp.380-384
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• 2009

Purpose: Autologous vessels remain the gold standard for vascular grafts in microanastomoses. However, they are sometimes unavailable and have a limited long - term patency. Synthetic vessels have high success rates in large - diameter reconstructions but failed when used as small - diameter grafts due to graft occlusion. It has been proved that endothelial cell seeding improves prosthesis performance and long - term patency. Among polyurethane, PET and ePTFE, polyurethane has the best affinity to endothelial cells and mechanical properties closest to human vessels. We examined the ability of endothelial cells to attach to a polyurethane graft manufactured by the electrospinning method. Methods: Endothelial cells, which were cultured from porcine internal jugular veins, were attached to polyurethane grafts with an internal diameter of 3 mm. The same cells were attached to allogeneic decellularized porcine internal carotid artery grafts as controls. Both of the 10 mm - long grafts were exposed to endothelial cells in a well for 1 hour. Each well contained $2{\times}10^5$ endothelial cells. The graft materials were rotated through 90 degrees every 15 minutes in order to minimize the effect of gravity. The extent of cell attachment was examined with the MTT assay. Results: The MTT assay showed good incorporation of endothelial cells into both grafts. For the evaluation of affinity, the number of attached cells was counted at 10 fields of microscopic examination with ${\times}40$ magnification. Endothelial cells adhered more to polyurethane grafts (mean, $127.4{\pm}6.2cells$) compared to porcine artery grafts (mean $45.8{\pm}5.1cells$)(p<0.05,Mann - Whitney test). Conclusion: In this study, we attached porcine endothelial cells to polyurethane grafts, manufactured by electrospinning. The grafts exhibited a better affinity to endothelial cells than allogeneic decellularized porcine internal carotid artery grafts. It is suggested that the time required for endothelial cells to attach to decellulized artery grafts may be longer than that which is required for attachment to polyurethane grafts.

• Journal of Periodontal and Implant Science
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• v.34 no.3
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• pp.509-522
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• 2004

This study was performed to compare the clinical effectiveness of two regenerative techniques for class II furcation involvements in human: a combination of bone grafts with PRP vs. GTR with bone grafts. The e-PTFE group was treated with non-absorbable membrane and bone grafts, the PRP group was treated with PRP and bone grafts Pocket depth, clinical attachment level, and gingival recession were measured at baseline and postoperative 6 months. Vertical and horizontal furcation depth were measured by re-entry surgeries at 6 months post-treatment Both groups were statistically analyzed by Wilcoxon signed Ranks Test & Mann-whitney Test using SPSS program (5% significance level). The results were as follows: 1. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was decreased significantly at 6 months than at baseline. (p<0.05) 2. The change of gingival recession in both groups was increased significantly at 6 months than at baseline. (p<0.05) 3. The change of alveolar crest absorption in both groups was increased at 6 months than at baseline but there were no statistically significant differences. 4. The change of pocket depth, clinical attachment level, vertical furcation depth and horizontal furcation depth in both groups was increased significantly at 6 months, but there were no statistically or clinically significant differences with both groups. 5. The change of gingival recession and alveolar crest absorption in both groups was increased at 6 months, but there were no statistically or clinically significant differences with both groups. In conclusion, the use of bone graft with PRP or GTR technique improved clinical index of the soft and hard tissue in mandibular class II furcation involvement but there were no statistically or clinically significant differences between bone graft with PRP and GTR technique.

• Journal of Periodontal and Implant Science
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• v.35 no.3
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• pp.687-702
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• 2005

The purpose of this study is to examine the effect of non-resorbable membrane such as e-PTFE which was used with DFDB in bone regeneration on dehiscence defect in peri-implant area. Amomg the patients, who have recieved an implant surgery at the department of Periodontics in Dan Kook University Dental Hospital, 12 patients showed implant exposure due to the dehiscence defect and 15 implants of these 22 patients were the target of the treatment. Periodontists randomly applied $Gore-Tex^{(R)}$ to the patients and treated them with antibiotics for five days both preoperatively and postoperatively. Reentry period was 26 weeks on average in maxilla and 14 weeks on average in mandible. The results were as follows : 1. Dehiscence bone defect frequently appeared in premolar in mandible and anterior teeth in maxilla respectively. 2. Among 15 cases, 1 membrane exposure was observed and in this case, regenerated area was decreased. 3. In non-resorbable membrane, bone surface area $9.25{\pm}4.84$ preoperatively and significantly increased to $11.48{\pm}7.52$ postoperatively(0.05). 4. The increase of bone surface area in non-resorbable membrane was $2.23{\pm}3.38$. 5. As a result of histopathological finding, DFDB surrounded by new bone formation and lamellate bone, resorption of DFDB and bone mineralization was found. Also, fibrosis of connective tissue beneath the membrane was found. This study shows that the surgical method using DFDB and non-resorbable membrane on dehiscence defect in peri-implant area is effective in bone regeneration.

• Journal of Chest Surgery
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• v.30 no.4
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• pp.378-382
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• 1997

To evaulate the effectiveness and risk factors for shunt failure of the Blalock-Taussig shunt in neonates, we analyzed the 21 neonates who were undergone Blalok-Taussig shunt operation at Dong-A University Hospital from December 1991 to Feburary 1996. We evaluated operative mortality, patency of the shunt. and distortion of pulmonary artery. We also determined the risk factors for the shunt failure. Age at operation was from 1 day to 30 days(mean 11.7 days). We ghts were 2.4 to 4.5kg(mean 3.1 kg). The underlying lesions included severe tetralogy of Fallot with pulmonary stenosls or atresia(N=11) and single ventricle varieties with. pulmonary stenosis or atresia(N=10). Prostaglandin El was given in 13 neonates prior to operation. The mean preoperative(prior to prostaglandin El therapy) and postoperative arterial oxygen tension were 30.1 mmHg and 46.3 mmHg respectively(P(0.01). The shunt was performed through a left thoracotomy in 11 patients and through a right thoracotomy In 10. A 5 mm graft was used in 15 patients and a 4 mm graft in 6 patients. The incidence of early shunt occlusion was 9.5%(2 patients). The hospital mortality was 9.5%(2 patients with early shunt occlusion). Univariate analysis revealed that body weight of 2.6 kg or less(p=0.021), pulmonary artery size of 3mm or less(p=0.008), and 4 mm graft (p=0.021) were risk factors predictive of early shunt failure. The patency rate of the shunt in hospital survivors was 100% at mean ollow-up of ll.3 months(There was not death or reoperation related to shunt failure). 10 patients were catheterized during postoperative follow-up. There was no significant distorsion of pulmonary artery. So we concluded that the modified Blalock-Taussig shunt in neonates was excellent in the hospital survivors.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.18 no.2
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• pp.224-235
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• 1996

Early implantation before sufficient ossification has taken place usually results in osseointegartion failure due to reduced bone-fixture interface area. However, various studies have shown successful osseointegration results following immediate implants concurrently with GTR. The clinical trends have been to shorten the patients' edentulous state by immediate implantation, and reduce the alveolar bone resorption. However, it may be difficult to attain the complete soft tissue coverage of the sites, increasing the chance of infection. Furthermore, there may be more studies needed on the clinical behaviors of e-PTFE membranes, various modofications in the membrane materials and bone graft materials. Various animal and clinical studies have been reported on the successful osseointagration following immediate implantation, but the long-term follow-up studies are limited. The present study investigated 16 immediately-implanted implants with GTR therapy with or without calcium carbonate grafting on 11 patients 3 years after installation and 24-30 months after functional loading. Based on the clinical, radiographic and histologic findings, the following results have been attained. 1. Clinically, stability has been shown on all 16 implants throughout the investigated periods. 2. Radiologically, the alveolar bone loss has progressed up to the polished neck portion but not beyond it, suggesting the progressive osseointegration from the GTR therapy. 3. The GTR method used in the present study is easy to use clinically, and may be appied in the regeneration of ossoeous defects around implants and in the immediate implantation. 4. The difficulty in complete tissue coverage may be avoided by delaying the installation for 2 to 3 weeks after the extraction allowing certain degree of soft tissue healing.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.383-399
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• 2005

The successful implantation necessitate tissue regeneration m site of future implant placement, there being severe bone defect. Therapeutic approaches to tissue regeneration in the site have used bone grafts, root surface treatments, barrier membranes, and growth factors, the same way being applied to periodontal tissue regeneration. Great interest in periodontal tissue regeneration has lead to research in bone graft, guided-tissue regeneration, and the administration of growth factors as possible means of regenerating lost periodontal tissue. The blood component separated by centrifuging the blood is the platelet-rich plasma. There are growth factors, PDGF, $TGF{beta}1$, $TGF{beta}2$ and IGF in the platelet-rich plasma. The purpose of this study was to study the histopathological correlation between the use of platelet-rich plasma and the healing of bone defect around implant fixture site. Implant fixtures were inserted and graft materials were placed into the left femur of in the experimental group, while the control group received only implant fixtures. In the first experimental group, platelet-rich plasma and BBP xenograft were placed at the implant fixture site, and the second experimental group had platelet-rich plasma, BBP xenograft, and the e-PTFE membrane placed at the fixture site. The degree of bone regeneration adjacent to the implant fixture was observed and compared histopathologically at 2, 4, and 8 weeks after implant fixture insertion. The results of the experiment were as follows: 1. Bone remodeling in acid etched surface near the implant fixture of all experimental groups was found to be greater than new bone formation. 2. Bone remodeling in acid etched surface distant to the implant fixture of all experimental groups was decreased and new bone formation was not changed. 3. Significant new bone formation in machined surface near the implant fixture of bothl experimental groups was observed in 2 weeks. 4. New bone formation in machined surface distant to the implant fixture of both experimental groups was observed. Bone remodeling was significant in near the implant fixture and not in distant to the implant fixture. The results of the experiment suggested that the change of bone formation around implant. Remodeling in machined surface distant to the implant fixture of both experimental groups, and new bone formation and remodeling near the implant fixture were significant.