• Journal of Periodontal and Implant Science
• /
• 제24권1호
• /
• pp.64-86
• /
• 1994

The authors have transplanted periodontally involved roots which had been root planed into healthy and periodontally involved extraction sockets, and studied the root resorption patterns as well as its effect on new bone formation and wound healing. Alveolar bone around mandibular premolars of 6 adult dogs has been surgically removed, followed by ligation of orthodontic elastic wires for 8 weeks inducing chronic periodontal disease. After removing the crown portions, roots were extracted, and notches were made on the root surfaces discriminating healthy and periodontally involved areas using burs. Controls and experimental groups were divided as follows. Control I : Transplantation of periodontally involved root into healthy extraction sockets. Control II : Transplantation of periodontally involved root into diseased extraction sockets. Experimental group I : Transplantation of root planed roots into healthy extraction sockets. Experimental group II : Transplantation of root planed roots into diseased extraction sockets. Extraction sockets were sutured after transplantations, completely submerging the roots. Healing progress was histologically observed at 2nd, 8th, 12th, and 20th weeks, and the results were as follows ; 1. No inflammation or infection within the extraction sockets had been observed in all groups throughout the experimental period. 2. Reversal lines were observed at week 2 in all groups, clearly discriminating socket walls and new bone, and numerous blood vessels were observed in the new bone trabeculae. 3. Experimental groups showed markedly less root resorption compared to the controls at week 2, but as time progressed, severe resorptions were present in all groups. 4. Localized areas of new bone ankylosis were observed, and the rest of the areas showed collagen fiber insertion with new bone formation at its periphery. 5. No clear differences were found in healing and alveolar bone regeneration between healthy and diseased extraction sockets. 6. The amount of root resorption and ankylosis had increased up to week 8 and 12, showing ankylosis of new bone and the roots. However, no further increase in ankylosis was observed at week 20. 7. Most of the cementum on healthy roots was directly ankylosed to new bone at week, 2, and were gradually resorbed and replaced by new bone thereafter. These results appear to indicate that root planing may inhibit early root resorption of transplanted roots, but gradual replacement by alveolar bone and collagen fibers eventually occur. Condition of the roots or presence of disease in extraction sockets do not appear to make marked differences in alveolar bone regeneration process.

• Journal of Periodontal and Implant Science
• /
• 제27권3호
• /
• pp.603-619
• /
• 1997

레이저를 이용한 연조직 수술은 출혈이 없어 시야를 좋게 하고 시술시간이 단축되며, 술후 종창이 최소화 되고, 통증이 감소화 최소화된 반흔 형성, 그리고 레이저가 조사되는 일부 부위의 멸균효과등이 장점이 있어 최근에 의학분야 및 치의학분야에서 많이 사용되는 추세에 있다. 이에 본 연구에서는 $CO_2$레이저를 이용한 백서의 치은절제술시의 치유과정과 레이저 출력을 달리 하였을때의 치유과정을 관찰하기 위해, 백서의 상악전치의 치은조직에서 치은절제술 효과를 얻을 수 있는 최소 출력인 4watts를 이용한 부위를 대조군으로, 6watts를 이용한 부위를 실험군으로 하여, 술후 2일, 3일, 1주, 3주후에 각각 실험동물을 희생시켜 치유결과를 조직학적으로 비교 관찰하여 다음과 같은 결과를 얻었다. 대조군과 실험군 모두에서 2일째에서만 작은 크기의 혈병이 관찰되었고, 그 이후에서는 관찰되지 않았다. 2. 염증세포 침윤지역 크기는 대조군과 실험군 모두에게 2일째 가장 컸으며, 그 크기는 시간이 경과될수록 줄어들어 2주째는 거의 소실되었으며, 실험군의 경우 대조군에 비해 2,3째까지 크기가 더 컸으나, 1주째부터는 크기의 차이가 관찰되지 않았다. 3. 육아조직은 대조군, 실험군 모두 시간의 경과에 따라 점점 성숙되어, 2주째부터는 거의 정상 치은 결합조직으로 대체되는 소견을 보였고, 3주째에서는 완전한 치유양상을 보였다. 실험군의 경우 대조군보다 3일째까지는 그 크기가 더 컸으나 1주째부터는 크기의 차이가 없다. 4. 대조군과 실험군 모두에게 치은의 상피화하는 2일째에서 시작되는 소견을 보였고, 1주부터 상피돌기와 부분적인 접합상피의 재생이 관찰되었으며, 2주째부터는 구강열구상피의 각화가 시작되어 3주째에는 각화의 완성이 관찰되었다.

• Advances in pediatric surgery
• /
• 제3권2호
• /
• pp.98-107
• /
• 1997

To determine whether bile juice exclusion can prevent the mucosal damage, and Insulin-like growth factor-I can promote mucosal regeneration in ischemia-reperfusion injury of the bowel, 39 weanling rats with 10 cm of Thiry-Vella loop were studied. Animal groups were; Control, BL(common bile duct ligation), IGF{insulin-like growth factor-I(IGF-I) infusion} and IGF-BL(combined treatment). IGF-I(1.5 mg/kg/day) was continuously delivered through a subcutaneously implanted miniosmotic pump. After 15 minutes of superior mesenteric artery clamping, a tissue specimen(P) was taken after 30 minutes of reperfusion. Intestinal continuity was restored to allow oral feeding. A specimen of main tract(M) and another of the Thiry-Vella loop(T) were collected for histomorphometry after 48 hours of reperfusion and free feeding. Villus size ratio(VSR), crypt depth(CD), crypt-depth/villus-height ratio(CVR) and injury score(IS) were measured in 15 consecutive villi. The postoperative mortalities of bile duct ligation groups(BL and IGF-BL) were higher than those of other groups. In control group, VSR of M was lower(P<0.05) than P or T, but not in the other groups. VSR of M in control was lower than those in other groups. CD of T in control, IGF and IGF-BL group were higher than those of M. CD of M and T showed gradual increments from control, IGF and IGF-BL group, respectively. CVR of M and T in IGF group were higher than those in control. CVR in IGF-BL group, T was higher than M, and M was higher than P. About IS, M of BL($20.1{\pm}2.5$) and IGF-BL($20.9{\pm}3.3$) groups were significantly lower than that of control($32.4{\pm}2.5$). These results suggest that the exclusion of bile juice reduces the severity of the reperfusion injury of the mucosa, by inability to activate pancreatic enzymes and IGF-I stimulates mucosal regeneration in injured bowel, and the effect is potentiated by bile juice exclusion.

• KIEAE Journal
• /
• 제12권4호
• /
• pp.59-69
• /
• 2012

In order to create humanitarian living environment with sustainable ecological environment, urban regeneration project has been implemented recently seeking diverse methods for residents'participation stressing the process of communication with the residents changing from the existing one way planning by limited number of experts. Particularly, it is essential to develop systematic tools to promote the voluntary and positive participation of the residents because residents have to perform as the master of urban streetscape design project that requires sophisticated knowledge and experience and also because the residents have to function as sustainable maintainers and managers of their streetscape. This study intends to identify the organizational structure and major contents of design guideline as a tool to support the voluntary and positive participation of the residents in streetscape maintenance. For this purpose based on the structural system and characteristics of Chicago streetscape design guideline that was developed as tool for residents' participation, efforts were made to set up framework of design guideline for sustainable streetscape project with the users' participation with their overall understanding and trust. In detail, the author studied the resident participatory process for sustainable maintenance and management in a long term landscape project and the principle and theories of design planning for streetscape that supports the utilizing behaviors of the users, and how this information should be linked and organized to form the structure and contents of design guideline. As a tool supporting residents' participation and helping the residents perform the responsible function as sustainable maintainers and managers of their streetscape through social maturity with ontological sense of masters of their local community as they experience the gradual processes of their streetscape maintenance project, streetscape design guideline has its meaning in the efforts that tried to achieve deep participation of the residents through researches converging the two academic sectors of urban architecture and social psychology.

• Journal of Periodontal and Implant Science
• /
• 제29권2호
• /
• pp.355-373
• /
• 1999

Many researches have been reported that collagen as cellular stroma, matrix of grafting materials, mediator of agents for the purpose of promoting healing process invivo, but the responses in vivo were seen various. The goal of this experiment is to assess the effect of collagen on bony healing, through histological evaluation of implanted collagen on the calvarial defect in rats. 2-month-old Sprague-Dawley, 24 rats were used and 12 rats assigned to each group of control and test. Defect of 5mm in diameter was made on the calvarial bone with trephine bur. Following thorough saline rinse, defect of control group was left in empty and that of experimental group was filled with fibrillar collagen($COLLATAPE^{(R)}$, COLLA-TEC. INC. U.S.A.) soaked in saline. 3 rats in each group were sacrificed at 3, 7, 14, 21 days after operation respectively, and the tissue blocks were prepared for light microscope with H-E for evaluation of overall healing, with TRAP(tartrate resistant acid phosphatase) for evaluation of osteoclastic activity and with immunohistochemical staining for macrophages. The results were as follows : 1. In the control group, inflammatory responses were disappeared at day 14, but, in the experimental group inflammatory infiltrates were reduced at day 21. Thus, the experimental group showed more severe soft tissue inflammation than control group. 2. Both control and experimental group showed slight appositional growth at day 7 and gradual bony growth to 21th day. But, complete bony healing of the defect was not shown. There was no significant difference in bony healing between control and experimental group 3. Specific response of macrophages for implanted collagen was observed at day 14 in the experimental group. In conclusion, although fibrillar collagen caused inflammation of soft tissue during initial healing period, inflammatory responses by fibrillar collagen didn't inhibit bony regeneration and implanted collagen was biodegradaded by macrophages. Thus, we expect that fibrillar collagen can be used for useful mediator of graft materials or growth factors.

• Archives of Pharmacal Research
• /
• 제28권8호
• /
• pp.930-935
• /
• 2005

We have investigated the effects of relatively high concentration of carbachol (CCh), an agonist of muscarinic acetylcholine receptor (mAChR), on cardiac automaticity in mouse heart. Action potentials from automatically beating right atria of mice were measured with conventional microelectrodes. When atria were treated with $100{\mu}M$ CCh, atrial beating was immediately arrested and diastolic membrane potential (DMP) was depolarized. After exposure of the atria to CCh for $\~4 min$, action potentials were regenerated. The regenerated action potentials had lower frequency and shorter duration when compared with the control. When atria were pre-exposed to pirenzepine $(1{\mu}M)$, an $M_1$ mAChR antagonist, there was complete inhibition of CCh-induced depolarization of DMP and regeneration of action potentials. Pre-exposure to AFDX-116 (11 ({2-[(diethylamino)-methyl]-1-piperidyl}acetyl)-5, 11-dihydro-6H-pyridol[2,3-b][1,4] benzodiazepine-6-one base, $1{\mu}M$), an $M_2$ mAChR antagonist, failed to block CCh-induced arrest of the beating. However, prolonged exposure to CCh elicited gradual depolarization of DMP and slight acceleration in beating rate. Our data indicate that high concentration of CCh depolarizes membrane potential and recovers right atrial automaticity via $M_1$ mAChR, providing functional evidence for the role of $M_1$ mAChR in the atrial myocytes.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제11권1호
• /
• pp.130-152
• /
• 1989

The purpose of this study was to observe the effect of intermaxillary fixation on the chondrocytes of the mandibular condyle under the light and the electron microscope. For this study, twenty rabbits were placed in maxillomandibular fixation, and two were used as a control group. The experimental group was subdivided into 3, 7, 14, 21 and 28 day group. After the experimental period of 3, 7, 14, 21 and 28 days, the animals were sacrificed with a vascular perfusion of 2.5% glutaraldehyde. The condylar processes were exenterated, and decalcified in 0.1M EDTA with 2.5% glutaraldehyde solution for two weeks. The specimens were rinsed with phosphate buffer solution and the post-fixation was carried out with 2% osmium tetroxide at $4^{\circ}C$ for two hours. Thereafter the specimens were dehydrated in alcohol series, cleared with propylene oxide and embedded in Epon 812 resin. Thin sections and ultra-thin sections were made, and the cellular structures of the condylar cartilages were observed with light and electron microscope. The results were as follows: 1. In the intermaxillary fixation group, the cartilaginous tissues of mandibular condyles showed a marked decrease in the thickness compared to the control group. 2. A remarkable change was noticed in the proliferating and the hypertrophic zone of the condylar cartilages in the experimental group. 3. An atrophic change of the condylar cartilage was appeared in the 3 day experimental group and degenerative change was observed in the 7 day experimental group, and recovery was seen in thereafter 14 day experimental group. 4. Calcification, degeneration and resorption of condylar cartilage were recognizable, and the cellular zone of the condylar cartilage was appeared indistinctly in 3 day and 7 day experimental group. The chondroblasts, however, were differentiated into chondrocytes and resumed mitosis, and then the cellular zones of the condylar cartilage were reorganized from the 14 day experimental group under the findings of light microscope. 5. Under the findings of electron microscope, atrophic changes and decrease in number of intracellular organelles, degenerative changes of cytoplasm, and pyknosis of nuclei were observed in early stage, however, a gradual regeneration and reorganization of the intracellular organelles were observed from 14 day experimental group.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• 제27권3호
• /
• pp.205-217
• /
• 2005

Distraction osteogenesis is a technique of lengthening bone including soft tissue by gradual separation of surgically divided bone surfaces. Although the biomechanical, histological, and ultrastructural changes associated with distraction osteogenesis have been widely described, the molecular mechanisms governing the formation of new bone in distracted bone segments remain largely unclear. However, such information has significant clinical implications because it may enable targeted therapeutic manipulations designed to accelerate osseous regeneration. The purpose of this study was to evaluate the expression of TGF-$\beta$1, IGF-I and bFGF in distraction osteogenesis according to different distraction rates in a rabbit's mandible. When twenty-four adult rabbits underwent open osteotomy between the premolar and mental foramen, an external bilateral distraction device was applied. Latency was allowed for five days before distraction. Three different distraction rates were 0.7 mm/day (A, n=8), 1.4 mm/day (B, n=8) and 2.4 mm/day (C, n=8). The distraction device was activated with the same distraction rhythms of twice a day until 4.9 mm (A & B group) and 8.4 mm (C group) length gains was achieved. The animals were sacrificed at postoperative 3, 7, 14 and 28 days. The bony specimens were stained with H&E for histologic examination, and RT-PCR analysis was done for the identification of the expression of TGF-$\beta$1, IGF-I and bFGF. The results obtained from this study were as follows : The 0.7 mm/day and 1.4 mm/day distraction rate groups were shown to improve regenerative bone formation on radiographic and histologic examination. Also, TGF-$\beta$1, IGF-I and bFGF expression increased in the 0.7 mm/day and 1.4 mm/day distraction rate groups. But the 2.4 mm/day distraction rate group specimen was different with adjacent normal bone and hardly expressed of growth factors. These findings suggest that improved new bone formation in the 0.7 mm/day and 1.4 mm/day distraction rates is associated with enhanced expression of TGF-$\beta$1, IGF-I and bFGF by mechanical tension stress. Additionally, the 0.7 mm/day and 1.4 mm/day distraction rate groups were significantly different from the 2.4 mm/day distraction rate group in the expression of growth factors. According to the above results, it seems possible to apply a distraction rate of up to 1.4 mm/day a day in rabbit's mandible. And further studies are needed to evaluate growth factors of TGF-$\beta$1 and IGF-I, which are excellent in expression.

• 유통과학연구
• /
• 제11권5호
• /
• pp.55-62
• /
• 2013

Purpose - This study aims to determine the problems and limitations of the Commercial Area Activation System, which was created by a special law for promoting traditional markets and shopping districts to revitalize and efficiently manage the central commercial area in different regions. We also suggest different options for its improvement. Research design, data, and methodology - We also look into the problems of which is being promoted as a demonstration project, from the aspects of legal text and guidelines. Results - The current commercial area activation system has several problems. First, the establishment of a comprehensive basic plan on the commercial area activation is not a requirement. Second, the benefit principle should be established to prevent the moral laxity of merchants who serve important roles in the main components of the commercial area activation business when they conduct their business. Third, the current special law constrains the commercial management organization, as under the civil law yields a limitation on finding a profitable business model. Fourth, to efficiently, constructing a system that links the other central government businesses and is needed. into a regional development budget or a budget for funding small businesses that the central government can control, which is effective. Further, we offer some suggestions for medium- and long-term policies. First, an integrated coordination mechanism at the central office level should be installed while setting the basic policy to revitalize the Based on this policy, local governments need a system that exclusively based on the after establishing a comprehensive plan for urban regeneration and getting approval from the integration organization. Second, a system that enables an understanding of the problems with business promotion by monitoring the procedure of supporting projects and regularly assessing business achievements is needed. Third, a plan is needed for resolving conflicts between various interested parties that adopts the commercial area activation system for carrying out a total redevelopment of the commercial area where small shops are densely located. A market maintenance project has been conducted as a means to recover our traditional market, which was economically depressed, and to revive the local economy, but it is mostly conducted in the form of reconstruction or redevelopment and represents the interests of landowners and merchants. Thus, it is most likely to lead to a gradual disappearance of traditional markets. Conclusions - This study looks primarily into the problems that appeared in the legal text or the guidelines regarding the direction of improvement of the commercial area activation business that has been going on as a demonstration project since 2011 and suggests some solutions.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제33권4호
• /
• pp.288-296
• /
• 2007

Distraction osteogenesis(DO) is a technique of lengthning bone including soft tissue by gradual separation of surgically divided bone surfaces. Distraction osteogenesis combination with a compression stimulation(DO-CO) was a new technique by authors to enhance new bone quality and to shorten the consolidation period. The purpose of this study was to compare DO with DO combined with compression force in efficiency by evaluating the expression of TGF-${\beta}1$, osteonectin and BMP-4 on bone regenerate in rabbit mandible. Fourty two rabbits were used for this experiment. On the control group, the distraction was carried out at the rate of 1 mm per day to obtain the amount of 8 mm distraction for 8 days. On the experimental group, the distraction was carried out at the rate of 1 mm per day for 10 days, 3 days-latency period, and then the compression was carried out as counter direction 1 mm per day for 2 days. After 0 day, 5 days, 13 days, 20 days, 27 days, 34 days and 41 days, three rabbits on each group were sacrificed and the distracted portion of mandible were cut and treated for RT-PCR observation. The level of expression of TGF-${\beta}1$ and osteonectin were shown more and longer expression in the experimental group than in the control group. The expression of BMP-4 was maintained with high level during the entire experimental period in both groups. These findings suggested that DO with compression stimulation could be a favorable technique for obtaining a good new bone quality.