• Journal of Biomedical Engineering Research
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• v.20 no.2
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• pp.221-230
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• 1999

A new technique for the preparation of porous polyurethane vascular prostheses was investigated. Synthetic vascular grafts with porous wall have been widely proposed, claiming that strength, suture retention, kink resistance, and other handling properties are improved over those with nonporous solid wall. Related to these facts, the control of pores and compliance match have been very important and interesting issues. Two kinds of polymer sheets were compared. One was the porous PU-sheet made at room temerature by the solvent/non-solvent exchange. And the other was the porous PU-sheet fabricated by thermal phase transition and solvent/non-solvent exchange in the thermal controlled bath. According to the result of the above experiments, polyurethane solution was injected into a mold designed for U-type graft. After freezing at low temperature, solvent was dissolved out with alcohol at < $0^{\circ}C$ and water at room temperature to form porous vessels. The average pore size and pore occupation were easily changed by changing polyurethane concentration and freezing rate. This technique can give a proper pore size for tissue ingrowth, and suitable compliances for matching with arteries and veins. In addition, the fabrication of more complicated shaped vessels such as the U-type vascular grafts is easily controlled by using a mold. This method might give a desired compliact graft for artificial implantaion with the commercially available medical polymers.

• Journal of Periodontal and Implant Science
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• v.31 no.4
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• pp.737-747
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• 2001

Regeneration of Periodontium with PRP does not only improve regeneration rate and density of bone but have a possibility to estimate faster healing process for soft tissue. And also, synthetic bone and xenogenic bone graft are effective on regeneration of periodontium. The purpose of this study is to evaluate the effectiveness of synthetic bone ($Biogran^{(R)}$) and xenogenic bone ($BBP^{(R)}$) grafts with the PRP technique on regeneration of periodontium. 52 Generally healthy Pt. who had pocket depth 5mm at any of 6 surfaces of the teeth were in the study at Dept. of Perio. in Dankook Dental Hospital. Open Flap was treated for 18 infra-bony pockets as control group, $Biogran^{(R)}$ with PRP was inserted for 25 infrabony pockets as first test group, and $BBP^{(R)}$ with PRP was inserted for 22 infrabony pockets as 2nd test group. Then evaluation was made after 3 and 6 months 1. 6 months after surgery, each difference of average probing pocket depth was $2.61{\pm}0.23$ for control, $3.40{\pm}0.30$ for 1st test, and $3.45{\pm}0.37$ for 2nd test group. 2. 6 months after surgery, each difference of clinical probing attachment level was $1.39{\pm}0.12$ for control, $2.88{\pm}0,24$ for 1st, and $2.86{\pm}0,27$ for 2nd test group. 3. 6 months after surgery, each difference of Maximal probing attachment level was $1.11{\pm}0.16$ for control, $3.28{\pm}0.30$ for 1st, and $3.27{\pm}0.35$ for 2nd test group. 4. There were significant differences for clinical change of each three group which were between average probing pocket depth and clinical attachment level of 3,6 months and minimal and maximal attachment level after 6 months 5. There were significant differences for average probing pocket depth which were only at control group and 2nd test group between 1 and 6months. For clinical attachment level and minimal and maximal proving attachment level, there was a significant difference after 6month of surgery. 6. There was no significant difference between two test groups for average probing depth, clinical attachment level, and minima1 and maximal probing attachment level. As the result, PRP with bone graft is very effective for regeneration of periodontium and there is no difference between xenogenic bone and synthetic bone.

• Journal of Periodontal and Implant Science
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• v.38 no.2
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• pp.237-246
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• 2008

Purpose: If bone grafts and guided tissue regeneration are effective individually in treating osseous defects, then the questionis, what would happen when they are combined. Bone grafts using Calcium Carbonate(Biocoral) and Guided Tissue Regeneration using Calcium Sulfate(CALMATRIX) will maximize their advantages and show the best clinical results in intrabony defects. This study was to compare the effects of a combination of CS and CC with control treated only with modified widman flap in a periodontal repair of intrabony defects. Materials and Methods: 30 patients with chronic periodontitis were used in this study. 10 patients were treated with a combination of CS and CC as the experimental group II and another 10 patients were treated with CC as the experimental group I, and the remaining 10 patients, the control group were treated only with modified widman flap. Clinical parameters including probing depth, gingival recession, bone probing depth and loss of attachment were recorded 6 months later. Results: The probing depth changes were $3.30{\pm}1.34\;mm$ in the control group, $4.2{\pm}1.55\;mm$ in the experimental group I(CC) and $5.00{\pm}1.33\;mm$ in the experimental group II(CS+CC). They all showed a significant decrease 6 months after surgery(p<0.01). There was a significant difference(p<0.05) between the control and experimental group. However there were no significant difference(p<0.05) between the experimental group I and II. The gingival recession changes w $-1.30{\pm}1.25\;mm$ in the control group, This is a significant difference(p<0.01). However, there was a $-0.50{\pm}0.53\;mm$ change in the experimental group I(CC) and $-0.60{\pm}0.97\;mm$ in the experimental group II(CS+CC). In addition, in terms of gingival recession, there was a no significance difference(p<0.05) among the groups. The clinical attachment level changes were $2.00{\pm}1.33\;mm$ in the control group, $3.60{\pm}1.58\;mm$ in the experimental group I(CC) and $4.40{\pm}1.17\;mm$ in the experimental group II(CS+CC). They all showed a significant decrease 6 months after surgery(p<0.01). There was a significant difference(p<0.05) between the control and experimental group. However there was a no significance difference(p<0.05) between the experimental group I and II. The bone probing depth changes were $0.60{\pm}0.52\;mm$ in the control group, $3.20{\pm}1.48\;mm$ in the experimental group I(CC) and $4.60{\pm}1.43\;mm$ in the experimental group II(CS+CC). All of them showed a significant decrease 6 months after surgery(p<0.01), there was a significance difference(p<0.05) among the groups. Conclusion: Treatment using a combination of CS and CC have a potential to improve periodontal parameters in intrabony defects and More efficient clinical results can be expected in intrabony defects less than 2 walls grafted with CS and CC.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.83-91
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• 2008

The goal of reconstruction following ablative therapy for intraoral cancer is the restoration of form and function to permit a return to activities of daily life. Traditional reconstruction includes split thickness skin grafts, myocutaneous flaps and, more recently, various free flaps. Free flaps provide higher level of functional recovery relative to that seen with other techniques but require the complexity of the technique and microvascular anastomosis and thus, extended surgical time and occasionally a second team for harvesting. The platysma myocutaneous cervical flap is a possible alternative for intraoral reconstruction. It is thin and pliable like the tissue provided by the radial forearm free flap. It can be harvested with enough tissue to close most head and neck ablative defects. There is virtually no donor site morbidity involved. This study evaluated 7 patients affected by intraoral squamous cell carcinoma (SCC). All patients underwent the resection of intraoral SCC with neck dissection and subsequent intraoral reconstruction with the superiorly based platysma myocutaneous cervical flap. Flap-related complications occurred in 3 patients. Adjuvant radiation therapy was performed in 3 patients. Average follow-up was 24.1 months after surgery, with a range of 8 to 42 months. All patients presented self assessment of discomfort associated with intraoral recipient sites and cervical donor sites. However, the neck function measured by two-inclinometer technique was within the normal range during relatively long term follow-up period. Our study concluded that superiorly based platysma myocutaneous cervical flap is good alternative to free flaps, especially for relatively smaller defects and for the defects appropriate for the rotation arc of the flap.

• Journal of Chest Surgery
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• v.20 no.3
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• pp.451-457
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• 1987

Reoperations following cardiac surgery have an increased risk of the danger of damaging the heart, great vessels or extracardiac grafts because of adhesions to the sternum. We experimentally evaluated 3 different methods for pericardial closure. A standardized procedure for induction of pericardial adhesions was carried out in 30 rabbits. For closure of pericardium, animals were divided into 3 groups, 10 animals respectively: Croup 1 [simple pericardial closure]The pericardium was primarily resuture; Group 2 [Core-Tex surgical membrane as a pericardial substitute]- A Gore-Tex surgical membrane was interposed between the sternum and the heart; and Group 3 [pericardial tension releasing technique]-Three longitudinal overlapping incisions were made on the right side of the pericardium while the midline incison was sutured. Animals were put to death 4 weeks postoperatively and the pericardial space was examined for pericardial adhesions and epicardial reactions. The extent of adhesions and reactions were graded as: I-none; II-minimal; III-moderate; and IV-severe. Histologic studies of the pericardium, the pericardial substitute and the epicardium were also performed. The results were as follows: 1. In group 1 [simple pericardial closure], the degree of pericardial adhesions were grade I in 1 animal, grade II in 2, grade III in 4 and grade IV in 3. Epicardial reactions were grade I in 1 animal, grade II in 3, grade III in 5 and grade IV in 1. Histologic examination revealed thick fibrous tissue that obliterated the pericardial space in 7 animals. 2. In group 2 [Gore-Tex surgical membrane as a pericardial substitute], the degree of pericardial adhesions were grade I in 3 animals, grade II in 3, grade III in 2 and grade IV in 2. The degree of epicardial reactions were grade II in 1 animal, grade III in 5 and grade IV in 4. Histologic studies revealed a thin layer of dense fibrous tissue which covered the Gore-Tex surgical membrane and thick loose fibrous tissue on the epicardium just beneath the substitute. 3. In group 3 [pericardial tension releasing technique], the degree of pericardial adhesions were grade I in 3 animals, grade II in 4, grade III in 2 and grade IV in 1. The degree of epicardial reactions were grade 1 in 4 animals, grade II in 4 and grade III in 2. Severe epicardial reactions were not observed in this group. Histologic examination showed normal epicardium in 4 animals and the epicardium of the other 6 animals only revealed very thin fibrous layer compared to group I and group II. Pericardial adhesions more than grade III were 70% in group 1, 40% in group 2 and 30% in group 3. Pericardial adhesions were reduced in group 2 and group 3 compared to group 1, but statistically not significant. Epicardial reactions more than grade III were 60% in group 1, 90% in group 2 and 20% in group 3. Epicardial reactions were significantly reduced in group 3 compared to group 2. Author`s modified pericardial releasing technique provides marked augment of pericardial surface area and facilitates tension-free pericardial closure. Furthermore, pericardial adhesion and epicardial reaction will be reduced with the pericardial tension releasing technique.

• Journal of Periodontal and Implant Science
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• v.33 no.1
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• pp.91-102
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• 2003

Several effective treatment methods and materials have been developed for the treatment of furcation involvement. Currently, the combination of guided tissue regeneration (GTR) and bone grafts is the most commonly prescribed method of treating furcation involved defects. But because these cases often present with poor accessibility, placement of the membrane may be difficult and consequently, clinically impractical. In this study, the alveolar bone healing patterns of adult beagle dogs presenting with alveolar bone destruction treated by one of two methods - treatment using solely bone allografts (BBP(R)), or treatment using bone allografts (BBP(R)) stabilized by a fibrin adhesive - were comp ared. The effects of the fibrin adhesive on the initial stabilization of the newly formed bone, subsequent regeneration of bone, and the feasibility of the clinical application of the fibrin adhesive were analyzed. The results of the study were as follows: 1. Clinical signs of inflammation at the 4-8 week interval were not observed: but signs of mild inflammation were histologically observed at the 4-week interval. 2. Allografts stabilized by fibrin adhesive showed good bone formation, whereas defects treated with only the allograft material showed incomplete alveolar bone regeneration. 3. Allografts stabilized by fibrin adhesive showed a decrease in the amount old bone with a concurrent increase in the formation of new lamellar bone four weeks post-op, whereas defects treated with only the allograft material showed no new lamellar bone formation at the same interval. 4. In detects treated with only the allograft material, the defective area was filled with connective tissue 8-weeks post-op, whereas fibrin adhesive stabilized allografts showed viable connections between the original bone and the newly formed bone, in addition to neovascularization 8-weeks post-op. The results of this study show that concurrent use of fibrin adhesive materials can stabilize the allograft material and aid in new bone formation Although the stability of fibrin adhesives fall short of the results achievable by GTR membranes, in cases presenting with poor accessibility that contraindicate the use of membranes, fibrin adhesive materials provide a viable and effective alternative to graft stabilization and new bone formation.

• Journal of Periodontal and Implant Science
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• v.37 no.1
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• pp.125-136
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• 2007

Periodontal regenerative therapy and tissue engineering on defects destructed by severe periodontitis need maintaining of space, which provides the environment for cell migration, proliferation and differentiation. Application of bone grafts may offer this environment in periodontal defects. This study evaluated bone graft materials, $MBCP^{(R)}$ and $Algipore^{(R)}$ , in surgically created i-wall periodontal intrabony defects of minipigs by histological analysis. Critical sized($4mm{\times}4mm$), one wall periodontal intrabony defects were surgically produced at the proximal aspect of mandibular premolars in either right and left jaw quadrants in four minipigs. The control group was treated with debridement alone, and experimental group was treated with debridement and $MBCP^{(R)}$ and $Algipore^{(R)}$ application. The healing processes were histologically observed after 8 weeks and the results were as follows. 1. In the control group, limited new bone formation was observed. 2. In MBCP group, more new bone formation was observed compared to other groups. 3. Histologically, dispersed mixture of new bone, biomaterial particles and connective tissue were shown and osteoblasts, osteoclasts and new vessels were present in this area. 4. Defects with Algipore showed limited new bone formation and biomaterial particles capsulated by connective tissue. 5. Histologically, lots of osteoclasts were observed around the biomaterial but relatively small numbers of osteblasts were shown. Within the limitation to this study protocol, $MBCP^{(R)}$ application in 1-wall intrabony defect enhanced new bone formation rather than $Algipore^{(R)}$ application.

• Journal of Periodontal and Implant Science
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• v.31 no.2
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• pp.489-499
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• 2001

Bone graft and guided tissue regeneration have been used for the regeneration of periodontal tissue which is the ultimate goal of periodontal treatment. Recently, it was reported that some kind of growth factors were used for regeneration. Platelet rich plasma was researched that it could increase the density of bone and the rate of bone regeneration. For that, 25 patients which have pocket depth more than 5mm at any of 6 surfaces, of healthy patient without any systemic disease were treated. $Biogran^{?}$ Were grafted into 14 infrabony pockets as controls, and $Biogran^{(R)}$ with PRP were inserted into 31 infrabony pockets. And then, follwing evaluations were made at the end of 1, 3 and 6 months. 1. There was no statistical difference between control and experimental group in pocket depth, gingival recession, minimum probing attachment level and maximum probing attachment level at preoperation(p>0.05). 2. Decrease in probing pocket depth were reduced to 3.32mm for experimental group and 2.71mm for control group. The decrease was evident at the end of 1 month, they were 2.97mm and 2.29mm,and it was statistically difference(p<0.05). 3. Gingival recession was increased by 0.55mm in experimental group and 0.50mm in control group, it was evident at the end of 1 month. And it was statistically difference(p<0.05). 4. Minimum probing attachment level was increased by 0.35mm in experimental group and 0.36mm in control group, it was statistically difference(p<0.05). 5. Maximum probing attachment level was decreased by 3.19mm in experimental group and 2.93mm in control group, it was statistically difference(p<0.05). 6. There was no statistical difference between control and experimental group in pocket depth, gingival recession, minimum probing attachment level and maximum probing attachment level(p>0.05). There was statistical difference in decrease of pocket depth between pre-operation and 1 month after post-operation(p<0.05). In conclusion, bone graft using $Biogran^{?}$ and bone graft using $Biogran^{?}$ With platelet rich plasma were both effective in treatment of infrabony pocket, bone graft using $Biogran^{?}$ With platelet rich plasma was more effective in early soft tissue healing.

• Journal of Chest Surgery
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• v.36 no.7
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• pp.504-509
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• 2003

Although arterial grafts are widely used due to the advantage of long-term patency in coronary bypass surgery, greater saphenous vein is still an important additional conduit. It was reported that preservation of the adventitia of vein graft and the adjacent tissues may bring the improved long-term graft patency. The aim of this study is to look for a harvest technique that can reduce vein injury and wound complications. Material and Method: In thirty-four patients that vein grafts were used for coronary bypass surgery, 50 harvest sites were included for the study. In 25 harvest sites in calf below knee (group 1), vein was exposed through a long incision and then clearly dissected from the adjacent tissue. Ten endoscopic vein harvests were performed in the thighs (group 2). Fifteen other vein grafts that were bluntly dissected were harvested from the thighs through three separate incisions (group 3). Result: Vein harvest time was longest in endoscopic harvest group (44.7$\pm$9.8 minutes) and shortest in group 3 (24.2$\pm$5.9 minutes) (p＝0.000). Most avulsion injuries of vein branches happened in the endoscopic group. Sequential grafting numbers per vein were 1.72$\pm$0.98 with thigh vein graft and 1.16$\pm$0.37 with calf vein (p＝0.02). Swelling of foot and/or leg, which was the most common wound complication after vein harvest, was most commonly presented in group 1 (20/25 sites; p＝0.000). Tingling, the most common neurologic complication, was also most prevalent in group 1 (7/25 sites; p＝0.013). The risk factor of the wound complication was vein harvest from calf, and the vein harvest technique was not a risk for wound complication. Conclusion: Vein harvest technique through three separate incisions from thigh presented shorter harvest time and less vein injury and wound complication compared with the endoscopic harvest technique from thigh or the harvest through a long incision from calf.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.20 no.3
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• pp.185-190
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• 1998

Various local flaps and distant flaps including tongue flap, palatal island flap, and buccal flap as well as skin grafts have been used for the reconstruction of oral mucosal defect. In the posterior region of oral cavity and the buccal cheek area, buccal fat pad can be used as a pedicled graft. The buccal fat pad is different from other subcutaneous fat tissue and it is easily accessible. There are many advantages in pedicled buccal fat pad graft for the closure of oral mucosal defect. The procedure is easy, there is no visible scar in the donor site, it is capable of reconstruction of various contour, and it has good viability. We had used buccal fat pad as a pedicled graft for the closure of oral mucosal defect after the excision of tumor and the oroantral fistula. From the results of these cases, we concluded that the use of the buccal fat pad flaps was worth of the consideration for the reconstruction of oral mucosal defect in the regions of the buccal cheek, and posterior oral cavity.