• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제29권6호
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• pp.379-391
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• 2003

The present study was undertaken to evaluate bone regenerative capacity around titanium screw implants placed in irradiated rat's tibiae. At one week after single 15-Gy dose irradiation, miniaturized titanium screw implants were inserted into anterior aspect of the upper tibia of rats weighing 200-250g. Seventy rats were involved: 35 rats were control and 35 rats radiation group. The rats were killed at different intervals as 1, 2, 3, 4, 6, 8, 12 weeks after implantation for histologic observation, histomorphometric analysis and immunohistochemical study with fibronectin and CD34 antibody. 1. Histologically, various stages of bone maturation and ossification can be seen at 4 weeks and regenerated bone close to edges demonstrates more advanced calcification, and network of new bone are well formed at 12 weeks in non-irradiated group. In contrast, active bone formation with increased contact of newly formed bone to implant surface was noted at 4 weeks and a significant amount of new bone formation and bone-implant contact is oberved at 12 weeks in irradiated group. 2. Histomorphometrical analysis confirmed these histologic findings. A significant difference in implant-bone contact and bone density was measured between the control and radiation group. Mean MBD was 62.2% in control group and 27.5% in radiation group, mean MBIC was 86.6% in control group and 47.7% in radiation group, and mean TBIC was 87.3% in control group and 45.6% in radiation group at 12 weeks after implantation. 3. In immunohistochemical study with fibronectin and CD34, radiation reduced hematopoietic progenitor cells severely and disturbed differentiation of osteoblast in bone marrow. The results of this study revealed bone healing capacity around implant after radiation therapy was severely impaired and irradiation reduces the capacity for osseointegration of titanium implants. Many factors including radiation dose, period between radiation and implantation, bone quality, time elapse between first and second surgery, type of prosthetics and hyperbaric oxygen therapy must be considered carefully in postradiation implantation.

• 구강회복응용과학지
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• 제26권2호
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• pp.205-220
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• 2010

본 연구에서는 임플란트 디자인이 주입회전력과 주변 응력에 미치는 영향을 알아보고자 삼차원 유한 요소 분석을 이용하여 유효 응력과 모멘트 그리고 축력을 측정, 비교 조사하였다. 나사형 임플란트 매식체의 디자인을 4종의 평행형과 7종의 근첨형으로 구분하였고 하악골 소구치 부위에 식립한 것으로 가정하여 유한 요소 모델을 제작하였다. 각각의 임플란트가 식립될 때 주변부에 발생하는 응력을 분석하였으며 그 결과 근첨형 임플란트가 평행형 임플란트에 비해 높은 식립 회전력을 보여 초기 고정력이 우수할 것으로 예상되었으나 응력 분산 측면에 있어서는 효율성이 낮은 양상을 나타내었다. 근첨형 임플란트에 비해 평행형 임플란트가 나사산의 높이에 따른 영향을 크게 받는 것으로 나타났으며 근첨형 임플란트는 임플란트 몸체의 경사도가 증가함에 따라 높은 응력이 발생되는 것이 관찰되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권1호
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• pp.1-14
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• 2000

The purpose of this study was to evaluate the efficacy of adding autogenous bone to the toothash-plaster mixture in the healing process of bone. Full-thickness round osseous defects with the diameter of 20mm were made at the calvarial bone of adult dogs (n=19) bilaterally, which were thought to be critical size defect. The right defects were repaired with the toothash-plaster mixture plus autogenous bone (compressed volume 0.3cc) and the left defects with only toothash-plaster mixture. At 2-, 4-, 8-, 12- and 20- week after implantation, dogs were sacrificed and evaluated the osseous healing of bony defects clinically, radiographically, and microscopically. The results were as follows; 1. At the clinical observation, the wound healed very well without any problem except severe swelling in the early period after operation. Slight depression was recognized at the both sides when the portions of cranial defect were palpated. 2. There were statistically significant differences between toothash-plaster mixture groups and autogenous bone added groups at the same period, and among the groups in the bone density of the digital radiograms (P<0.001). There was a tendency that bone density was increasing with time. 3. In light microscopic examination, new bone formation was more active in the autogenous bone added groups than toothash-plaster mixture groups at the early period after implantation but there is little difference at 20-week after implantation. 4. In fluorescent microscopic examination, the fluorescent band could be observed at the area of active bone formation and the band was more distinct in the autogenous bone added groups then toothash-plaster mixture groups. 5. In transmitted electron microscopic examination, organelles such as rER, Golgi complex and secretory granule and osteoblast were observed. In summary higher volume ratio of autogenous bone is needed to improve the bone healing in that there is little difference between toothash-plaster mixture group and autogenous bone added group at the 20-week after implantation in spite of new bone formation was more active in the autogenous bone added groups than toothash-plaster mixture groups at the early period after operation.

• Journal of Periodontal and Implant Science
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• 제36권1호
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• pp.167-177
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• 2006

연구배경 임플란트에 관한 전통적인 연구들은 주로 임플란트 매식체와 골조직간의 결합에 중점을 두어왔다. 최근 임플란트의 심미적 관점에 대한 관심이 높아지면서 임플란트 주위 연조직의 재건 및 유지에 대한 연구들이 많이 이루어지고 있다. 이번 연구는 임플란트 주위 연조직이 임플란트 지대주의 모양에 따라 어떻게 반응하는지 알아보고자 한다. 연구방법 및 재료 2 마리의 성견을 대상으로, 먼저 하악의 모든 소구치를 발치하고, 3개월의 치유 기간 후에 각 4분악에 실험에 사용된 3개의 다른 모양의 지대주를 가진 임플란트를 식립하였다: (1) 위로 벌어진 모양의 지대주 (2) 안쪽으로 오목하게 좁아진 지대주 (3) 평행한 모양의 지대주. 식립 순서는 무작위로 하였으며, 3개월 후 실험동물을 희생하고 조직 표본을 얻었다. 조직 표본은 광학 현미경을 통해 관찰하고, 상피, 결합조직, 전체 연조직의 수직적 거리를 측정하여 비교하였다. 연구 결과 이번 연구에서 임플란트 주위의 연조직을 측정한 결과, 접합 상피는 1.21 ${\pm}$ 0.47 mm, 결합조직은 1.16 ${\pm}$ 0.39 mm, 전체 연조직 두께는 2.37 ${\pm}$ 0.47 mm로 이전의 연구들과 비슷한 결과를 보였다. 지대주 주위의 연조직 중 결합조직이 많은 부위에서는 여러 주행 방향의 교원 섬유들이 관찰되었다. 그 중에서 결합조직이 차단막으로써의 역할을 할 수 있도록 하는 원형으로 주행하는 교원 섬유들이 모든 지대주 모양에서 관찰되었다. 특히 오목하게 좁아진 모양을 가진 지대주에서는 오목하게 파인 부분으로 많은 원형으로 주행하는 교원 섬유들이 관찰되었다. 오목한 모양의 지대주는 다른 모양의 지대주에 비해서 측면 방향의 연조직 두께가 두꺼웠다. 특히 위로 벌어진 모양의 지대주에 비해서 두꺼운 연조직을 확보할 수 있었으며, 내부에 많은 결합조직 교원 섬유들을 관찰할 수 있었다. 결론 이번 연구에서 오목한 모양의 지대주가 연조직을 두껍게 유지하고, 많은 원형으로 주행하는 교원 섬유들을 확보할 수 있었다. 이를 통해 오목한 여태의 지대주가 연조직 유지에 더 유리하고, 따라서 심미적인 부위에서 연조직의 퇴축을 예방하는데 더 유리하다고 할 수 있다.

• Journal of Periodontal and Implant Science
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• 제23권3호
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• pp.400-410
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• 1993

Dental implants have been widely used in the treatment of esthetic and functional problems of the mouth due to alveolar bone loss, after tooth extraction. The success of implantation strongly depends on osseointegration. For osseointegration, implant material, methodology, and design have been investigated. For materials, two popular materials at present are titanium and hydroxyapatite. For methods, immediate implantation is being used recently. The purpose of this study is to evaluate osseointegration between the unthreaded cylindrical TPS implant and the HA-coated implant by a histomorphometric analysis. For this analysis, experimental periodontits was induced on the 3, 4 premolars of adult dogs by the ligation of orthodontic threads. Thereafter, each tooth was extracted. TPS. Implants and HA-coated implants were immediately inserted in the extraction socket. In control group, TPS implants were immediately inserted, and In experimental group, HA implants were immediately inserted. The dogs were sacrificed after 12 weeks, then the specimens were prepared for LM and histomorphometric analysis. The conclusion of this study is as follows l. In both control and experimental group, no inflammatory cells were observed. 2. The results of the histomorphometric analysis showed that the total osseointegration was 48.5% in control group, and 68.8% in expermental group. The experimental group was higher than the control group, and the difference was not statistically significant (p<0.05). 3. The results of the histomorphometric analysis showed that the osseointegration in the hole was 40.6% in control group, and 70.2% in experimental group. The experimental group was higher than the control group, and the difference was statistically significant (p<0.05). In both control and experinental group, no inflammatory cells were observed. 4. The results of the histomorphometric analysis showed that the osseointegration in the lower part was 52.1% in control group, and 73.3% in experimental group. The experimental group was higher than the control group, and the difference was statistically significant (p<0.05). 5. In experimental group, the bone to HA interface seemed to be mixed of bone and HA. We could not distinguish HA from the bone. The HA coating was detached from the titanium surface.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제22권3호
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• pp.274-287
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• 2000

The use of dental implants has increased tremendously in recent years and is expected to increase even more in the future. The successful outcome of any implant procedure is surely dependent on interrelationship of the various components of an equation that includes biocompatibility of implant material, macroscopic and microscopic nature of the implant surface, the status of implant bed, surgical technique, undisturbed healing phase and subsequent prosthetic design and long-term loading phase. The purpose of this study was to clarify the effects of adrenalectomy on the osseointegration of pure titanium implants. Seventy rats, 11 weeks of age, were divided into two groups : an adrenalectomized group and a control group. Titanium screw implant(diameter, 2.0mm; length, 3.5mm) was placed into left tibia of 70 rats, 35 in control group and 35 in the experimental group. The rats were sacrificed at different time interval (1, 2, 3, 4, 6, 8, and 12 weeks after implantation) for histopathologic observation, histomorphometric analysis and immunohistochemistry with fibronectin and CD44 antibody. The results obtained from this study were as follows: 1. Histopathogically, findings, newly formed bone was seen at 3 weeks control group and became lamellar bone at 12 weeks. At 6 weeks, lipocytes were observed in bone marrow space. Thickness of regenerated trabecular bone increased till 6 weeks after then, that decreased gradually. 2. By histomorphometric analysis, marrow bone density and contact ratio of marrow bone to implant decreased significantly from 8 to 12 weeks in experimental group compared to control group and also total bone to implant contact ratio decreased significantly from 4 to 12 weeks in experimental group compared to control group. 3. Fibronectin immunoreactivity was very strong at 3 and 4 weeks control group. And after that reduced gradually. But it was continuously strong from 1 to 12 weeks experimental group. 4. CD44 immunoreactivity was very strong in the newly formed osteoblasts at 3 and 4 weeks control group. But it reacted minimally later. However, it reacted continuously strong from 3 to 12 weeks experimental group. From these results, bone to implant contact ratio decreased gradually from 4 weeks in adrenalectomized group compared to control group. CD44 and fibronectin immunoreactivities were strong at all times in adrenalectomized rats. Therefore, it could be stated that immature bone remained continuously for a long time and not readily proceeded into mature status.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권1호
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• pp.135-143
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• 1996

이 연구의 목적은 성견의 발치와에 식립된 implants에 새로운 골 형성을 유도할 목적으로 사용한 흡수성막의 골유도재생술을 평가하고자 하였다. 성견의 제 3소구치를 발거하고 cylindrial HA-coated implants를 식립하였다. 실험군에는 흡수성막인 $GUIDOR^{(R)}$ 를 덮어 보호를 하고, 대조군은 막으로 보호하지 않았다. 성견은 1, 2, 4개월에 차례로 희생하였으며, 치유과정 및 골형성 정도의 평가를 위해 임상적, 방사선학적, 그리고 조직학적 관찰을 통한 다음과 같은 결론을 얻었다. 1. 치유리간 동안에 실험군의 흡수성막의 안정성과 조직의 만족할 만한 치유능력을 볼 수 있었다. 2. 술후 4개월 정도에서 막이 완전한 흡수를 볼 수 있었다. 3. 미숙골이 정상적인 충판의 성숙골로 바뀌는데 약 4개월의 시간이 필요하였다. 4. 대조군에 비하여 실험군에서 더 많은 골형성을 관찰할 수 있었다. 5. 흡수성막이 implant 매식에 유용하게 이용될 수 있으리라 평가한다.

• 치과방사선
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• 제28권1호
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• pp.245-259
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• 1998

Cellular transforming genes have been identified in a number of different tumor cell lines and tumor types. A significant number of these oncogenes belong to the ras gene family. The ras gene family consists of three closely related genes:H-ras, K-ras and N-ras which code for a related 21 kDa protein. Mutations in codon 12, 13 and 61 of one of the three ras genes convert these genes into acute oncogenes. The presence of H-ras gene mutations has important prognostic implications in various tumors. Each genomic DNA was isolated from tumors induced by implantation with DMBA, or by treatment with DMBA -implantation/irradiation. When genome DNA was transfected into NIH 3T3 cells and investigated by two-step PCR-RFLP, the fOllowing results were concluded: 1. Transformation foci developed in two groups when the genome DNA of two experimental groups were transfected into NIH 3T3 cells. 2. Transformation efficiency was 0.01-0.02 foci/㎍DNA in the experimental group with the DMBA-implantation, 0.01-0.03 foci/㎍lgDNA in the experimental group with the DMBA-implantation/irradiation according to results of transfection assay. 3. When the point mutation of H-ras gene was investigated by a two-step PCR-RFLP, there was 13.9％ (5/36) in the experimental group with the DMBA implantation, 15.4 ％ (6/39) in the experimental group with the DMBA -implantation/irradiation. 4. The point mutation in codon 12 and 61 of H-ras was 5.6％(2/36) and 8.3％(3/36) in the experimental group with the DMBA implantation. 5. The point mutation in codon 12 and 61 of H-ras gene was 7.7％(3/39) in the experimental group with the DMBA -implantation/irradiation.

• Journal of Periodontal and Implant Science
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• 제30권1호
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• pp.1-11
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• 2000

Although various analgesics have been administrated for postoperative pain control, postoperative pain has not been adequately controlled . The purpose of this study was to evaluate the effects and patient's satisfaction of $Myprodol^{(R)}$(combination analgesics with codeine, ibuprofen, paracetamol) compared to Acetamionphen and placebo drug after periodontal surgery and dental implant surgery. We studied 98 cases of outpatients which were composed of 67 cases of flap operation(which separated to 3 groups: Placebo group(n=25), $Myprodol^{(R)}$ group(n=22), Acetaminophen group(n=20)) and 21 cases of dental implant surgery(which separated to 3 groups : Placebo group(n=10), $Myprodol^{(R)}$ group(n=12), Acetaminophen group(n=9)). We evaluated the postoperative pain(Pain 1), Pain after first drug administraion(Pain 2), the degrees of pain reduction(pain 3), patient's satisfaction for drug, and side-effects. We obtained following results; 1. In Pain 1, making a comparison among groups, there was no significant difference in both cases of flap operation-group and dental implant surgery-group 2. In Pain 2, establishing a comparison among groups, there was no significant difference in flap operation-group, but significant difference was seen between placebo group and $Myprodol^{(R)}$ group in cases of dental implant surgery group(P<0.05). 3. In Pain 3, making a comparison among groups, $Myprodol^{(R)}$ group showed significant differences compared to placebo group and Acetaminophen group in both cases of flap operation group and dental implant surgery group(P<0.05). 4. In patient's satisfactory score, making a comparison among groups, there were significant differences between placebo group and $Myprodol^{(R)}$ group in cases of flap operation group and between $Myprodol^{(R)}$ group and Acetaminophen group in cases of dental implant surgery group(P<0.05). 5. Making a comparison in side-dffect, no significant differrence was seen. Our conclusion is that $Myprodol^{(R)}$ is a effective oral analgesics to the patients who underwent periodontal surgery or implant surgery for it's synergism among three dugs.

• Journal of Periodontal and Implant Science
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• 제35권2호
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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.