• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.127-138
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• 2004

Background: Crestal bone loss known as saucerization is a frequently observed phenomenon. Recent studies have shown that implants with micothreaded crest module reduced the force concentration in the crestal region thus resulting in no or reduced crestal bone loss. This study presents a clinical, histologic, and histometric evaluation of implants with microthreaded crest module and SLA surface. Methods: The implants were placed in the mandible of 5 beagle dogs weighing 10-15kg. Four premolars were bilaterally extracted 8 weeks prior to implant placement. Mucoperiosteal flap was elevated and drilling with increasing diameter was performed under saline irrigation. After countersinking 2 implants were placed in each side resulting in 4 implants per dog. Healing period of 8 weeks was allowed before sacrificing the animals. Histologic preparation was performed for histologic and histometric analysis. Bone to implant contact as well as percentage of bone area inside threads were measured. T-test was used for statistical analysis with pvalue p<0.05. Results: 1. Healing was uneventful without any cover screw exposure. New bone formation around the implants was observed without any inflammatory infiltration. 2. Bone to implant contact in the microthread and thread were 43.90 ${\pm}$ 20.30 %, and 53.19 ${\pm}$ 20.97 % respectively. The overall bone to implant contact was 48.54 ${\pm}$ 20.95 %. 3. Percentage of bone area inside threads were 54.43 ${\pm}$ 10.39 %, and 38.44 ${\pm}$ 16.44 % for the microthread and thread respectively. There was statistically significant difference(p<0.05). The overall percentage of bone area inside threads was 46.67 ${\pm}$ 15.68 %.

• Journal of Periodontal and Implant Science
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• 제47권3호
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• pp.143-153
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• 2017

Purpose: The aim of the present exploratory study was to evaluate extraction socket healing at sites with a history of periodontal and endodontic pathology. Methods: The mandibular 4th premolar teeth in 5 adult beagle dogs served as experimental units. Periodontal and endodontic lesions were induced in 1 premolar site in each animal using wire ligatures and pulpal exposure over 3 months (diseased sites). The contralateral premolar sites served as healthy controls. The mandibular 4th premolar teeth were then extracted with minimal trauma, followed by careful wound debridement. The animals were sacrificed at days 1, 7, 30, 60, and 90 post-extraction for analysis, and the healing patterns at the healthy and diseased extraction sites were compared using radiography, scanning electron microscopy, histology, and histometry. Results: During the first 7 days of healing, a significant presence of inflammatory granulation tissue was noted at the diseased sites (day 1), along with a slightly accelerated rate of fibrin clot resolution on day 7. On day 30, the diseased extraction sites showed a greater percentage of persistent fibrous connective tissue, and an absence of bone marrow formation. In contrast, healthy sites showed initial signs of bone marrow formation on day 30, and subsequently a significantly greater proportion of mature bone marrow formation on both days 60 and 90. Radiographs exhibited sclerotic changes adjoining apical endodontic lesions, with scanning electron microscopy showing collapsed Volkmann canals protruding from these regions in the diseased sites. Furthermore, periodontal ligament fibers exhibited a parallel orientation to the alveolar walls of the diseased sites, in contrast to a perpendicular arrangement in the healthy sites. Conclusions: Within the limitations of this study, it appears that a history of periodontal and endodontic pathology may critically affect bone formation and maturation, leading to delayed and compromised extraction socket healing.

• Journal of Periodontal and Implant Science
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• 제27권1호
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• pp.61-78
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• 1997

PDGF-BB has been recognized as a highly potential growth factor for guided tissue regeneration in periodontal defect. This study carried out histologic and histometric evaluation of $200ng/cm^2$ PDGF-BB loaded bioresorbable membrane made from polyglycolic and polylactic acid. It was tested for its biocompatibility, ability to prevent epithelial downgrowth and amount of periodontal regeneration. Without membrane and PDGF-BB unloaded bioresorbable membrane were used as control. Healthy six beagle dogs were used. Each dog was anesthetized and buccal flaps were reflected in the mandibular and maxillary premolar areas. Buccal alveolar bone between the mesiobuccal and distobuccal line angles was surgically removed on the lower 2nd and 4th premolar in mandible, 2nd premolar in maxilla, to a level 4mm apical to the cementoenamel junction with creating a Class II buccal furcation defect for available space. Care was taken not to remove the root cementum layer and rubber impression materials were placed over each surgically created defect. Flaps were repositioned and sutured. Reconstructive surgery was performed 1 month after defect preparation. PDGF-BB loaded membranes and controls were randomly placed on maxillary 2nd premolars and mandibular 2nd and 4th premolars. Plaque control regimen was instituted with daily brushing with a 0.1% chlorhexidine digluconate during experimental periods. The animals were sacrificed 2 and 5 weeks after surgery and undecalcified specimens were prepared for histologic evaluation. The degree of coronal regrowth of new bone, new cementum and the amonut of new bone areas formed on the defected area of the PDGF-BB loaded membrnae turned superior to without membrane and drug unloaded membrane. Experimental membrane could prevent the epithelial downgrowth irrespective of drug loaded or not and showed good biocompatiblity, These results implicated that PDGF-BB loaded bioresorbable membrane could be highly useful tool for guided tissue regeneration of periodontal defects.

• Journal of Periodontal and Implant Science
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• 제45권3호
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• pp.120-126
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• 2015

Purpose: With the significance of stable adhesion of alveolar bone and peri-implant soft tissue on the surface of titanium for successful dental implantation procedure, the purpose of this study was to apply microgrooves on the titanium surface and investigate their effects on peri-implant cells and tissues. Methods: Three types of commercially pure titanium discs were prepared; machined-surface discs (A), sandblasted, large-grit, acid-etched (SLA)-treated discs (B), SLA and microgroove-formed discs (C). After surface topography of the discs was examined by confocal laser scanning electron microscopy, water contact angle and surface energy were measured. Human gingival fibroblasts (hGFs) and murine osteoblastic cells (MC3T3-E1) were seeded onto the titanium discs for immunofluorescence assay of adhesion proteins. Commercially pure titanium implants with microgrooves on the coronal microthreads design were inserted into the edentulous mandible of beagle dogs. After 2 weeks and 6 weeks of implant insertion, the animal subjects were euthanized to confirm peri-implant tissue healing pattern in histologic specimens. Results: Group C presented the lowest water contact angle ($62.89{\pm}5.66{\theta}$), highest surface energy ($45{\pm}1.2mN/m$), and highest surface roughness ($Ra=22.351{\pm}2.766{\mu}m$). The expression of adhesion molecules of hGFs and MC3T30E1 cells was prominent in group C. Titanium implants with microgrooves on the coronal portion showed firm adhesion to peri-implant soft tissue. Conclusions: Microgrooves on the titanium surface promoted the adhesion of gingival fibroblasts and osteoblastic cells, as well as favorable peri-implant soft tissue sealing.

• 한국임상수의학회지
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• 제25권5호
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• pp.359-362
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• 2008

본 연구는 개 빈맥에 대한 내관 (PC06) 및 심수 (BLl5)자침의 효과를 입증하고자 실시하였다. 총 18두의 비글견을 대조군 (6두), PC06 군 (6두) 및 BL15 군 (6두)로 각각 나누었다. 빈맥은 glycopyrrolate를 근육주사하여 유발하였다. 대조군은 아무런 처치를 하지 않았으나, 실험군은 glycopyrrolate 투여와 동시에 각각 PC06 및 BL15에 20분간 유침하였으며, R-R 간격의 변화 및 호흡수의 변화를 측정하였다. PC06군과 BL15군에서의 R-R 간격은 대조군에 비하여 유의성 있는 증가를 나타내었으며, BL15군의 R-R 간격은 PC06군에 비하여 유의성 있는 증가를 나타내었다. PC06군의 호흡수는 대조군과 비슷한 경향을 나타냈으나 BL15군은 대조군 및 PC06군에 비하여 유의성 있는 감소를 나타내었다. 결과적으로, PC06 및 BL15의 자침은 개 빈맥의 회복에 도움이 되며, BL15가 PC06보다 효과적인 것으로 판단된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권6호
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• pp.485-493
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• 2007

Introduction: Although several types of calcium-phosphate coumpound have been frequently applied to osseous defects at maxillofacial area for many years, there is a controversy about its efficiency on bone conductivity comprared to xenograft bone substitute. Alloplastic carbonapatite has been introduced to improve disadvantages of hydroxyapatite and to mimic natural bone containing carbon elements. However, a preclinical study about its efficiency of osteoconductivity has not been reported. This study was performed to evaluate the early osteoconductive potential of synthetic carbonapatite with multiple pores relative to anorganic bovine xenograft. Materials and methods: Total 5 beagle dogs were used for maxillary augmentation model. The control (anorganic bovine xenograft) and experimental groups (synthetic carbonapatite) were randomly distributed in the mouth split design. After bone graft, all animals were sacrificed 4 weeks after surgery. Histological specimens with Masson Trichrome staining were made and histomorphometrically analysed with image analyser. The statistical analysis was performed using paired t-test. Results: In both groups, all animals had no complications. The experimental group showed relatively much new bone formation around and along the bone substitutes, whereas it was clearly reduced in the control group. The ratios of new bone area to total area, to material area and to the residual area excluding materials were higher in the experimental group ($0.13{\pm}0.03,\;0.40{\pm}0.13,\;0.20{\pm}0.06$ respectively) than in the control group ($0.01{\pm}0.01,\;0.03{\pm}0.02,\;0.03{\pm}0.03$, respectively). And the differences between both groups were statistically significant (p<0.001, <0.01, <0.01, respectively), while the ratio of material area to total area in two groups was not significant. Conclusion: Carbonapatite showed a high osteoconductivity in the early stage of bone healing compared to bovine derived anorganic bone substitute. This study suggests that this bone materials can be applied as a reliable bone substitute in the clinical treatment.

• 대한치과교정학회지
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• 제38권1호
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• pp.5-12
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• 2008

교정용 미니스크류의 원추 형태가 식립 후 시기별 안정성에 미치는 영향을 알아보기 위해, 시기별 제거 토오크 및 동요도와 조직시편분석을 시행하였다. 성견 6마리의 하악 협측골에 원통형과 원추형 교정용 미니스크류 (Biomaterials Korea, Seoul, Korea) 48개를 식립하고, 식립 시 식립 토오크와 동요도를 측정하고 3주, 12주 동안 교정력을 부여한 후, 제거 시 제거 토오크와 동요도를 측정하였다. 식립 토오크는 원통형 미니스크류에서 13.6 Ncm, 원추형 미니스크류에서 22.3 Ncm 로 원추형 미니스크류에서 높은 식립 토오크가 측정되었다 (p < 0.001). 식립 3주째 제거 토오크는 원통형 미니스크류에서 5.7 Ncm, 원추형 미니스크류에서 9.1 Ncm 로 유의한 차이가 관찰되었다 (p < 0.05). 식립 12주째 원추형 미니스크류의 제거 토오크는 3.6 Ncm 로 유의하게 감소하여 (p < 0.05) 원통형 미니 스크류의 4.2 Ncm 와 유의한 차이를 보이지 않았다. 이상의 결과로 미니스크류의 원추 구조는 식립 토오크를 유의하게 증가시켜 식립 후 3주간 안정성에 도움이 되었으나, 12주 후 안정성에 있어서는 원통형 미니스크류와 유사하였음을 시사한다.

• 대한치과교정학회지
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• 제40권3호
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• pp.167-175
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• 2010

Periotest$^{(R)}$는 보철용 임플랜트 식립 3 - 4개월 후 골유착 정도를 평가하기 위해 사용되는 동요도 측정 기기로 교정용 미니임플랜트 안정성 평가에 적용가능성이 높다. 본 연구는 교정용 미니임플랜트의 안정성 평가를 위해 Periotest$^{(R)}$의 유효성을 검증하고자 하였다. 성견 다섯 마리의 상악, 하악 협측골에 교정용 미니임플랜트를 식립하고, 식립 시 식립토오크와 동요도를 측정하고 12주 동안 교정력을 부여한 후, 제거 시 제거 토오크와 동요도를 측정하였다. 동요도 (Periotest$^{(R)}$ value, PTV) 측정은 재현성을 위해 동일 부위에 2회 측정하였다. PTV와 다른 변수와의 상관성 분석을 위해 모든 실험견은 CT 촬영 후 식립 부위의 골밀도와 피질골 두께를 계측하였다. 동요도 측정에 대한 재현성은 0.96의 상관계수를 나타내 매우 높았으며 (p < 0.001) 골밀도와 피질골 두께에 있어 하악골 협측치조골이 상악골에 비해 유의하게 컸다 (p < 0.05). 12주 동안 PTV 값은 -3.2에서 4.8의 범위를 나타내며 모든 임플랜트는 임상적으로 안정적이었다. 식립 시 PTV 값은 하악에서 식립 토오크(-0.51), 골밀도(-0.48), 피질골 두께(-0.42)와 상관성이 있었으나 (p < 0.05), 상악에서는 상관성이 없었다. 제거 시 PTV 값은 하악에서 제거 토오크(-0.66)와 상관성이 있었으며(p < 0.05), 상악에서는 상관성이 없었다. 이상의 결과는 Periotest$^{(R)}$를 이용하여 교정용 미니임플랜트의 안정성을 간접적으로 평가할 수 있으나 골밀도가 높고 피질골이 두꺼운 부위에서 제한적으로 응용할 수 있음을 시사한다.

• Journal of Periodontal and Implant Science
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• 제30권4호
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• pp.757-779
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• 2000

The aim of our study is to achieve complete periodontal tissue regeneration by the application of BMP and resorbable membrane. Three beagle dogs aged over one and half years and weighed 14 to 16 kg were used in this study. Mandibular 1st, 2nd premolars were extracted bilaterally. Horizontal furcation defects were induced around 3rd, 4th premolars bilaterally. BMP-4 were applied in the right side with resorbable membranes and only resorbable membranes were applied in the left side respectively. Each animal was sacrificed at 2, 4, and 8weeks, after regenerative surgery. Specimens were prepared with Hematoxylin-Eosin stain and Goldner's modified Masson Trichrome stain for light microscopic evaluation. The results were as follows: 1. At 2 weeks after regenerative surgery, downgrowth of junctional epithelium was observed both in the membraneapplied site and BMP-4-and-membrane-applied site. 2. At 4 weeks after regenerative surgery, resorbable membranes were completely resolved, therefore would not prevent downgrowth of junctional epithelium. New bone formation, new cementum formation and Sharpey's fiber were observed in BMP-4-andmembrane-applied site. 3. At 8 weeks after regenerative surgery, downgrowth of junctional epithelium was observed in the membrane-applied site. But, new cementum formation was observed in the same site. The extensive regeneration of new bone, new cementum and remarkable formation of Shapey's fiber were showed in BMP-4-and-membrane-applied site. 4. Resorbable membranes were resolved via the cell-mediated processes. 5. Periodontal tissue regeneration were better achieved in the BMP-4-andmembrane-applied site than in the membrane-applied site. Within the above results, BMP-4 may have the strong capability to form the new bone and resorbable membrane may be able to prevent the bony ankylosis. However, resolution rate of resorbable membrane may not be enough to protect rapid epithelial downgrowth for ideal periodontal regeneration. In conclusion, I suggest BMP-4 may have the strong possibility to be utilized in the clinical periodontal treat-

• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.39-49
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• 2006

1. 목 적 이 연구의 목적은 성견의 하악 골 결손부에 이식한 생체 유래 골 이식재에 대한 치조골의 반응을 알아보는 것이다. 2. 연구방법 및 재료 생후 1년 이상 된 성견 4마리의 하악 제2소구치 및 제 4 소구치를 발거하고 발치와에 금원심 폭경 8mm, 협설 폭경 5mm, 치조정에서의 깊이 6mm인 결손부를 형성하였다. 4주간의 자연 치유 후 판막을 형성하여 결손부의 크기를 확인하였다. 각각의 결손부 크기가 일정하도록 수정한 후 '이식재+차폐막'군에는 OCS-B을 이식하고 Bio-gide을 차단막으로 사용한 후 봉합하고 '이식재군'은 OCS-B 이식 후 차폐막 없이 봉합하였으며 '비이식'군은 아무런 처치없이 일차봉합하였다. 수술 4, 6주에 실험동물을 각각 희생시켜 실험부위를 적출하고 비탈회 연마 표본을 제작하여 골 치유 양성을 조직학적 및 조직계측학적으로 관찰하였다. 3. 연구결과 이식재 비이식군 및 이식군 모돼서 별다른 부작용없이 잘 치유되었다. 세 실험군 모두에서 술후 4주에 비교하여 술 후 6주에서의 결손부 산생골 형성량이 증가하였다. 술후 4주 소견에서 비이식군은 결손부 주변부위에서 골이 생성되어 나오는 양상을 보였으며 이식군은 이식재 주변으로 골침착 시작되는 것을 관찰할 수 있었다. 술후 6주 소견에서 비이식군은 결손부 경계부로부터의 지속적인 골 생성을 관찰할 수 있었으며 이식군은 이식재 주변으로 침착된 골의 양이 많아지고 신생골이 가교를 형성하는 것을 관찰할 수 있었다. 4. 결 론 차폐막 유무와 상관없이 OCS-B는 염증반응을 전혀 일으키지 않았으며 우수한 골 전도성을 보였다. 또한 결손부의 형태를 잘 유지하여 골재생을 위한 공간을 확보할 수 있었다. 이는 OCS-B가 골이식재로서의 필요조건을 갖추었음을 확인한 결과이며 보다 장기적인 관찰에서 OCS-B의 흡수 가능성을 확인하는 것이 필요할 것으로 보인다.