• 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.

• Imaging Science in Dentistry
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• 제49권4호
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• pp.265-272
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• 2019

Purpose: To compare the diagnostic accuracy of cone-beam computed tomography (CBCT) with that of parallel(PPA) and oblique projected periapical(OPA) radiography for the detection of different types of peri-implant bone defects. Materials and Methods: Forty implants inserted into bovine rib blocks were used. Thirty had standardized bone defects(10 each of angular, fenestration, and dehiscence defects), and 10 were defect-free controls. CBCT, PPA, and OPA images of the samples were acquired. The images were evaluated twice by each of 2 blinded observers regarding the presence or absence and the type of the defects. The area under the receiver operating characteristic curve (AUC), sensitivity, and specificity were determined for each radiographic technique. The 3 modalities were compared using the Fisher exact and chi-square tests, with P<0.05 considered as statistical significance. Results: High inter-examiner reliability was observed for the 3 techniques. Angular defects were detected with high sensitivity and specificity by all 3 modalities. CBCT and OPA showed similar AUC and sensitivity in the detection of fenestration defects. In the identification of dehiscence defects, CBCT showed the highest sensitivity, followed by OPA and PPA, respectively. CBCT and OPA had a significantly greater ability than PPA to detect fenestration and dehiscence defects(P<0.05). Conclusion: The application of OPA radiography in addition to routine PPA imaging as a radiographic follow-up method for dental implantation greatly enhances the visualization of fenestration and dehiscence defects. CBCT properly depicted all defect types studied, but it involves a relatively high dose of radiation and cost.

• 대한치과보철학회지
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• 제36권5호
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• pp.758-771
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• 1998

Assessment of implant mobility is an important and reliable method to clinically evaluate implant stability. PerioTest is a precise and reproducible device that cam dynamically measure the reaction of damping characteristics of peri-implant tissue. The aim of this study is to evaluate the effects of amount of implant surface area, diameter, type, implantation site, degrees of cortical engagement, and length of time in function on PTVs and to find out the most determining factor on PTVs. The results are as follows 1. 5.0mm diameter implants show significantly lower PTV than that of 3.75mm diameter implants. 2. PTV in the mandible is significantly lower than that of the maxilla 3. In the maxilla, there is no significant difference in PTV during the first year of implant function, but during the second year a significant decrease in PTV is noted. 4. In the mandible, there is a significant decrease in PTV during the first and second year of implant function. 5. Implantation site seems to be the most determining factor on PTV among the influencing factors in this study. In conclusion, the amount of implant surface area, type, degrees of cortical engagement had no significant effect on PTV, but installation site and diameter influenced significantly on PTV

• Journal of Animal Science and Technology
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• 제53권3호
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• pp.203-209
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• 2011

Lysophosphatidic acid (LPA) is a small lipid molecule that plays an important role through LPA receptors (LPARs) in reproductive processes. Our previous study has shown maximal expression of LPAR3 in the uterine endometrium on day (D) 12 of pregnancy in pigs, the period when conceptus secretes various molecules such as estrogen and interleukin-$1{\beta}$ (IL1B) and initiates implantation. We determined that endometrial expression of LPAR3 was increased by conceptus estrogen in the previous study, but the effect of IL1B on LPAR3 expression has not been determined. Thus, in this study we examined whether LPAR3 expression was also affected by IL1B. Endometrial explant cultures from D12 of the estrous cycle showed that levels of endometrial LPAR3 expression did not changed in response to IL1B. We also investigated LPAR3 expression in the uterine endometrium on D12 and D30 of pregnancy from gilts with conceptuses derived from somatic cell nuclear transfer (SCNT). The expression of LPAR3 mRNA was lower in endometria from gilts with conceptuses resulting from SCNT compared with those from gilts with embryos resulting from natural mating on D12 of pregnancy, but it was not different between them on D30 of pregnancy. Our results indicate that estrogen of conceptus origin is responsible for induction of LPAR3 expression during the peri-implantation period and appropriate LPA signaling is impaired in the uterine endometrium with SCNT-derived conceptuses during the implantation period in pigs.

• Journal of Chest Surgery
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• 제29권5호
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• pp.554-558
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• 1996

대동맥 협부 발육부전, 동맥관 개존, 대동맥기시 우폐동맥을 동반한 원위 대동맥폐동맥 중격결손을 가진 생후 50일된 여아에서 동맥관 결찰,대동맥 협부 발육부전 부위의 절제와 대동맥의 단단문합,우폐동맥과 주폐동맥의 직접 연결과자가심낭편을이용한대동맥폐동맥 중격결손의 봉합을 포함한 일차 완전 교정술을 인공 체외 순환과 완전 순환 정지하에 시행하여 좋은 수술 결과를 얻었다.

• 대한생식의학회:학술대회논문집
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• 대한불임학회 1999년도 제38차 추계 학술대회
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• pp.39-39
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• 1999

• Journal of Periodontal and Implant Science
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• 제52권2호
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• pp.170-180
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• 2022

Purpose: This study was conducted to assess the effect of hard and/or soft tissue grafting on immediate implants in a preclinical model. Methods: In 5 mongrel dogs, the distal roots of P2 and P3 were extracted from the maxilla (4 sites in each animal), and immediate implant placement was performed. Each site was randomly assigned to 1 of the following 4 groups: i) gap filling with guided bone regeneration (the GBR group), ii) subepithelial connective tissue grafting (the SCTG group), iii) GBR and SCTG (the GBR/SCTG group), and iv) no further treatment (control). Non-submerged healing was provided for 4 months. Histological and histomorphometric analyses were performed. Results: Peri-implant tissue height and thickness favored the SCTG group (height of periimplant mucosa: 1.14 mm; tissue thickness at the implant shoulder and ±1 mm from the shoulder: 1.14 mm, 0.78 mm, and 1.57 mm, respectively; median value) over the other groups. Bone grafting was not effective at the level of the implant shoulder and on the coronal level of the shoulder. In addition, simultaneous soft and hard tissue augmentation (the GBR/SCTG group) led to a less favorable tissue contour compared to GBR or SCTG alone (height of periimplant mucosa: 3.06 mm; thickness of peri-implant mucosa at the implant shoulder and ±1 mm from the shoulder: 0.72 mm, 0.3 mm, and 1.09 mm, respectively). Conclusion: SCTG tended to have positive effects on the thickness and height of the periimplant mucosa in immediate implant placement. However, simultaneous soft and hard tissue augmentation might not allow a satisfactory tissue contour in cases where the relationship between implant position and neighboring bone housing is unfavorable.

• 한국가축번식학회지
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• 제18권2호
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• pp.141-150
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• 1994

전자현미경에 의해 자궁부착 전후의 돼지 수정란의 형태형성 및 분화에 따른 배발생 과정을 검토하였다. 돼지 초기배는 자궁이주후 균일하게 자궁에 배분되기전 약 2~3일간은 자궁각의 proximal portion에 존재하며, 임신 4일째에 할구와 할구의 경계를 상실하는 tight한 gap junction을 가진 상실배로 발달한다. 배반포를 형성하는 시기에 estradiol 17$\beta$는 compact한 상실배를 cavitated blastocyst로 발달을 촉진시키면서, steroid hormone이 이후의 배발생을 지배한다. Hatching의 시기는 교배후 6~7일경 zona pellucida을 둘러사고 있는 glycoprotein의 thinning과 lysis에 의해 이루워지는데, hatching 과정은 embryo의 세포수와 무관하였으며, 이때의 embryo의 직경은 0.5~1.0mm인 것을 본 실험에서 확인하였다. 12일경부터는 embryo는 prostaglandins, IGF-binding protein, retinol binding protein, plasminogen activator등의 단백질이 풍부해 이들 인자가 elongation 개시 후보로 고려될 수 있었다. 또한 이 시기의 embryo는 embryonic disc로 발달시 progesterone과 estrogen을 estradiol 17$\beta$로 전활할 수 있으며, 이러한 변화와 함께 spherical stage로부터 tubular 혹은 filamentous form으로 변형되었다. Estrogen이 임신을 통해 prostagladins의 분비를 uterine lumen에 지시하는지는 알 수 없으나 13일 경을 전후해 conceptus estrogen이 uterine arterial blood flow, uterine vasular permeability을 증가시키는 것으로 나타났으며, 자궁에서 protein과 calcium, PGF2$\alpha$, plasminogen inhibitor를 증가시키는 것으로 나타났다. 이 시기의 자궁 변화와 함께 embryo의 attachment는 trophoblast와 uterine membrane사이의 느슨한 결합에 의해 개시되었으며, 18일경 uterine과 trophoblastic microvili의 interdigitation에 의해 완성된다. 이 시기에 conceptus attachment를 위해 필요한 uterine microvili에서의 glycocalyx의 형성과 endometrial epithelium의 erosion을 야기하기 위해 plasminogen activator을 분비하였으며, 반면 자궁에서 plasminogen 역할을 하는 것은 estrogen이며, blastocyst cell 표면의 lectin binding이 attachment에 중요한 역할을 한다. 이상과 같은 일련의 과정을 거친 초기배는 성공적인 임신으로 유도된다고 본다. 따라서, 본 연구는 이상과 같이 착상을 전후한 시기의 배를 전자현미경에 의해 형태형성의 변화를 특히 착상을 전후해 배 취사율이 높은 시기를 대상으로 분석하였다. 이 분석 시기중 성공적인 착상성공율은 56%(71/126)였다.

• 한국임상수의학회지
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• 제20권2호
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• pp.207-211
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• 2003

This investigation aimed to determine the relative merit of osseointegration in immediate and delayed implantation in the dog mandible using radiography and bone scintigraphy. five adult mongrel dogs with a mean weight of 8.5 kg were used in this investigation. During the entire study period. all dogs were fed with a soft commercial diet and water ad libitum to minimize functional loading of the implant. Twenty titanium alloy systems 4 mm in diameter and 10 mm in length blasted with calcium phosphate were prepared for insertion. The second and third left mandibular premolars in each dog were extracted for the delayed implant insertion. Twelve weeks later, the second and third right mandibular premolars were extracted for the immediate implant insertion. Before the delayed and immediate implantation procedures and 0, 4, 8, and 12 weeks after the insertions, radiography and bone scintigraphy were conducted. Bone scans were obtained using a large field of view gamma camera equipped with a collimator about 3 hours after intravenous injection of Tc-99m-MDP to the dogs. All the dogs were evaluated weekly for inflammation, necrosis, and other of the bone or sort tissue. Significant macroscopic lesions were not detected. Radioisotope scintigraphy with Tc-99m-MDP hat proved to be a reliable method for measuring increased bone activity at specific skeleton tissue sites. In conclusion, osseointegration in peri-implant bone did not differ significantly between the immediate and delayed implant procedures during the experimental period. The immediate implant may be an alternative treatment of implant insertion in animals.

• Journal of Periodontal and Implant Science
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• 제41권5호
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• pp.253-258
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• 2011

Purpose: Immediate implantation presents challenges regarding site healing, osseointegration, and obtaining complete soft-tissue coverage of the extraction socket, especially in the posterior area. This last issue is addressed herein using the double-membrane (collagen membrane+high-density polytetrafluoroethylene [dPTFE] membrane) technique in two clinical cases of posterior immediate implant placement. Methods: An implant was placed immediately after atraumatically extracting the maxillary posterior tooth. The gap between the coronal portion of the fixture and the adjacent bony walls was filled with allograft material. In addition, a collagen membrane (lower) and dPTFE membrane (upper) were placed in a layer-by-layer manner to enable the closure of the extraction socket without a primary flap closure, thus facilitating the preservation of keratinized mucosa. The upper dPTFE membrane was left exposed for 4 weeks, after which the membrane was gently removed using forceps without flap elevation. Results: There was considerable plaque deposition on the outer surface of the dPTFE membrane but not on the inner surface. Moreover, scanning electron microscopy of the removed membrane revealed only a small amount of bacteria on the inner surface of the membrane. The peri-implant tissue was favorable both clinically and radiographically after a conventional dental-implant healing period. Conclusions: Secondary closure of the extraction socket and immediate guided bone regeneration using the double-membrane technique may produce a good clinical outcome after immediate placement of a dental implant in the posterior area.