• 구강회복응용과학지
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• 제22권2호
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• pp.173-180
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• 2006

Objectives The aim of this study is to compare the quality of root canal preparation completed using MFile-$System^{(R)}$ instrument ( Komet, Gebr.Brsaseler, Germany) and conventional stainless steel file in the canals of Maxillary molar teeth that had a canal curvature between $25^{\circ}$ or more Materials & Methods Buccal canals of 24 first and second maxillary molar teeth, extracted for periodontal and prosthetic reasons were used. Tissue fragments and calcified debris were removed from teeth by scaling and the teeth were stored in 10% formalin solution for 24 hour. Then, teeth were stored in saline until used. To be included the roots had to have completed formed apices and angle of curvature ranging between $25^{\circ}$ or more according to the criteria described by Schneider(1971). Palatal and Second mesiobuccal canals were not included. Teeth were embedded into transparent acrylic. The teeth were randomly divided into two experimental groups. All teeth were scanned by Dental CT (PSR9000N, Asahi, Japan) to determine the root canal shape before instrumentation. Image slices were prepared from the apical end point to the pulp chamber. The first two sections were 2 mm from the apical end of root and 2 mm below the orifice. Further section was recorded, dividing the distance between the sections of apical and coronal levels into two equal lengths. 12 teeth were instrumented using stainless steel fileand another 12 teeth were instrumented using MFile-$System^{(R)}$. Following the completion of the instrumentation, the teeth were again scanned and compared with the cross sectional images taken prior to canal preparation. Amount of transportation and centering ability was assessed. Student's t-test was used for statistical analysis. Result Less transportation occurred with MFile-$System^{(R)}$ rotary instrumentation than stainless steel instrument. MFile-$System^{(R)}$ had better centering ability than stainless steel instrument. Conclusion MFile-$System^{(R)}$ rotary instrumentation transported canals less and had good centering ability.

• Journal of Periodontal and Implant Science
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• 제34권4호
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• pp.733-746
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• 2004

Bisphosphonates는 파골세포에 의한 골흡수를 방지하는 물질로 알려져 있으며 임상에서 널리 쓰이고 있다. 그 중 Alendronate는 Aminobisphosphonates의 한 종류로 non-aminobisphosphonates인 etidronate보다 100-1000배 더 강한 효과를 보이는 것으로 알려져 있다. 본 실험의 목적은 백서두개골 결손부의 골재생을 실험모델로 하여 alendronate의 국소투여 효과를 알아보는 것으로 액체의 흡수성과 골전도성이 우수한 것으로 알려진 collagen membrane을 사용하여 결손부 양측에 alendronate와 physiologic saline을 각각 적용하여 1주, 2주, 4주의 조직학적 치유양상, 파골세포활성도, 경도를 평가하였다. 조직학적 치유양상은 1주째 collagen membrane에 의한 염증성 침윤이 나타났으며 2주째부터 골성회복이 관찰되었고 4주째 완전한 골성회복을 보여 각주별 실험군, 대조군 공히 유사한 양상을 보였고 실험에 사용한 $200{\mu}g$의 용량은 조직학적으로 관찰할만한 골재생의 향상을 위해서는 부족한 용량으로 사료되는 바이다. TRAP(+) cell은 1주째 대조군에 비해 실험군에서 유의하게 적은 수를 보였으며(p<0.01) 2주와 4주째는 유의한 차이를 나타내지 않았고 경도측정에서는 2주째 대조군에 비해 실험군에서 유의하게 높은 경도를 보였으며 4주째 유의한 차이를 나타내지 않았다(p<0.05). 이상의 실험에서 alendronate는 골조직 치유과정의 초기에 파골세포의 활성도와 경도에 다소 영향을 미친 것으로 사료되며 향후 골조직 재생을 위한 임상적용에 응용을 위해서는 치유과정을 더욱 향상시킬 수 있는 추가적인 연구가 필요하리라 사료된다.

• Journal of Periodontal and Implant Science
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• 제34권1호
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• pp.71-81
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• 2004

Peri-implantitis could be the result of biomechanical and occlusal overload as well as microbiologic invasion. The dental implant may be more susceptible to dental plaque than the natural tooth, as the predictability of a stable soft tissue attachment complex has not yet been confirmed. With the development of peri-implantitis, the implant surface would be exposed to the oral environment and becomes coated with bacteria. The objective of therapy for this condition is to regain integration of the implant with bone. Since fibroblast adherence to surfaces is impeded by endotoxin, it would seem that decontamination would be desirable to obtain maximum osseointegration. The purpose of this study was to determine whether various chemotherapeutic and mechanical treatments(distilled water, air-powder abrasive, hypersaturated citric acid, tetracycline) can detoxify contaminated titanium implant surface by means of kinetic LAL test. Experimental rough surface titanium disks were fabricated. All of them were divided into two groups(A.a group and P.g group) and each contaminated by A. actinomycetemcomitans and P. gingivalis suspension. Contaminated disks were treated with distilled water, air-powder abrasive, citric acid and tetracycline, and then all disks were placed into LPS-free water for elution. The results were as follows : 1. In A.a group, LPS elute level of all test groups were significantly lower than control group(p<0.05). 2. In A.a group, LPS elute level of test 2, test 3 and test4 groups were significantly lower than that of control group(p<0.05). But, among the test 2, test 3, test4 groups, the significant differences were not detected. 3. In P.g group, LPS elute level of test 2, test 3 and test 4 groups were lower than that of control group(p<0.05). But, among the test groups, the significant differences were not detected. From the result of this study, it would be concluded that air-powder abrasive, hypersaturated citric acid and tetracycline treatments may be effective at reducing endotoxin level on rough titanium implant surfaces, and can be clinically used. But the treatments in peri-implantitis differentially impact osseointegration making one method clinically superior. To gain this knowledges, further molecular biologic and histopathologic studies should be developed.

• Journal of Periodontal and Implant Science
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• 제37권1호
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• pp.65-75
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• 2007

In this study, author examined the effect of the concentration of the inorganic polyphosphate on the process of the bone regeneration by using the 6 weeks old rabbit with the weight of 2.0kg in average. we performed the experiment by using TR-eITFE membrane filled with collagen immersed with 1%, 2%, and 4% of inorganic polyphosphate, respectively, after removing the proper sized cort-ical bones from the calvaria of rabbit. The experimental results were compared with the one of the following four groups: The control group for membrane only, experimental group I for membrane filled with collagen im-mersed with 1% of inorganic polyphosphate, experimental group II for membrane filled with collagen immerse with 2% of inorganic polyphosphate, experimental group III for membrane filled with colla-gen immersed with 4% of inorganic polyphosphate. The fragments of the tissue with membrane were obtained from each group of the sacrificed rab-bits for 4 or 8 weeks sustained after surgery, were then prestained and coated. New bone formation was assessed by histomorphometric and statistical analysis. We may draw the conclusions from these experiments as following: 1. Collagen was an excellent carrier with a minimal inflammatory reaction and sustaining the form. 2. The sample of the 8th week group has shown the best bone regeneration compared with the cases of all groups including the control group. 3. The samples of collagen immersed with 2% and 4% of inorganic polyphosphate have shown more bone regeneration relative to the sample of the 1% inorganic polyphosphate. 4. The new bone regeneration was shown actively in the group for membrane filled with collagen immersed with 4% of inorganic polyphosphate. With above results, it is strongly suggested the use of inorganic polyphosphate with vehicle under TR-eITFE membrane.

• Journal of Periodontal and Implant Science
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• 제37권1호
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• pp.77-89
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• 2007

This study was performed to evaluate the effect of deproteinized bovine bone mineral soaked in inorganic polyphosphate on bone regeneration in the calvaria of rabbit in the procedure of guided bone regeneration with titanium reinforced expanded polytetrafluoroethylene(TR-ePTFE) membrane. The rabbits were divided into four groups. Control group used TR-ePTFE membrane filled with de-proteinized bovine bone mineral, experimental group I used TR-ePTFE membrane and deproteinized bovine bone mineral soaked in 4% inorganic polyphosphate, experimental group II and III used TR-ePTFE membrane and deproteinized bovine bone mineral soaked in 8% or 16% inorganic poly-phosphate respectively. After decortication in the calvaria, GBR procedure was performed on 8 rabbits with only TR-ePTFE membrane or titanium reinforced ePTFE membrane filled with deproteinized bovine bone mineral soaked in inorganic polyphosphate. The animals were sacrificed at 4 weeks, and 8 weeks af-ter the surgery. Non-decalcified specimens were processed for histologic analysis, and new bone for-mation was assessed by histomorphometric as well as statical analysis. 1. Both control group and experirrental group dermnstrated increasing of new bone formation until 8weeks. 2. At 8 weeks, experimental group I and group II showed the significant difference compared to control group in new bone formation. Especially experimental group II showed the most in-creasing of new bone formation. 3. The higher concentration of inorganic polyphosphate filled, the more volume of bone formation pro-moted, but experimental group III did not reveal significant difference compared to contol group. 4. Deproteinized bovine bone mineral did not resorbed at all until 8 weeks. These results suggest that inorganic polyphosphate has a promoting effect on bone regeneration. possibly by enhancing osteoconductivity of the carrier and by increasing osteoinductivity of the defected alveolar bone tissue, but not as we respect.

• Journal of Periodontal and Implant Science
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• 제49권6호
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• pp.382-396
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• 2019

Purpose: The purpose of this study was to elucidate the efficacy and safety of carbonate apatite (CO₃Ap) granules in 2-stage sinus floor augmentation through the radiographic and histomorphometric assessment of bone biopsy specimens. Methods: Two-stage sinus floor augmentation was performed on 13 patients with a total of 17 implants. Radiographic assessment using panoramic radiographs was performed immediately after augmentation and was also performed 2 additional times, at 7±2 months and 18±2 months post-augmentation, respectively. Bone biopsy specimens taken from planned implant placement sites underwent micro-computed tomography, after which histological sections were prepared. Results: Postoperative healing of the sinus floor augmentation was uneventful in all cases. The mean preoperative residual bone height was 3.5±1.3 mm, and this was increased to 13.3±1.7 mm by augmentation with the CO₃Ap granules. The mean height of the augmented site had decreased to 10.7±1.9 mm by 7±2 months after augmentation; however, implants with lengths in the range of 6.5 to 11.5 mm could still be placed. The mean height of the augmented site had decreased to 9.6±1.4 mm by 18±2 months post-augmentation. No implant failure or complications were observed. Few inflammatory cells or foreign body giant cells were observed in the bone biopsy specimens. Although there were individual differences in the amount of new bone detected, new bone was observed to be in direct contact with the CO₃Ap granules in all cases, without an intermediate layer of fibrous tissue. The amounts of bone and residual CO₃Ap were 33.8%±15.1% and 15.3%±11.9%, respectively. Conclusions: In this first demonstration, low-crystalline CO₃Ap granules showed excellent biocompatibility, and bone biopsy showed them to be replaced with bone in humans. CO₃Ap granules are a useful and safe bone substitute for two-stage sinus floor augmentation.

• 대한소아치과학회지
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• 제44권3호
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• pp.289-297
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• 2017

전신적 또는 국소적 요소에 의하여 유치 치근이 병적으로 흡수될 수 있으며 치아 우식증이나 외상 등으로 염증성 치근 흡수가 발생할 수 있다. 유치의 병적 치근 흡수면은 생리적인 치근 흡수와 비교할 때 흡수면의 세포와 흡수와의 형태 등의 흡수 양상이 다르다. 이 연구는 생리적 치근 흡수, 외상, 염증성 치근 흡수면의 형태 및 인접한 세포를 주사전자현미경과 광학현미경으로 관찰하였다. 생리적 치근 흡수면의 흡수소와는 원형과 타원형이고 비교적 작고 균일하였다. 외상으로 인한 치근 흡수면과 염증성 치근 흡수면의 흡수소와는 생리적 치근 흡수면의 흡수소와에 비해 다각형이며 크고 불규칙하였다. 생리적 치근 흡수면과 외상으로 인한 치근 흡수면, 염증성 치근 흡수면에서 다핵거대세포와 단핵세포가 관찰되었으며 염증성 치근 흡수면에서는 간엽세포 및 염증세포가 많이 분포되어 있었다. 생리적 치근 흡수면과 외상으로 인한 치근 흡수면에서는 흡수 표면에 백악질양 조직이 침착되었으나, 염증성 치근 흡수면에서는 관찰되지 않았다.

• Journal of Periodontal and Implant Science
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• 제26권1호
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• pp.216-229
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• 1996

Interferon(IFN) is a sort of glycoproteins that are produced by activated lymphocyte, monocyte and fibroblast. IFN has anti-viral effects, immuno-defensive mechanism and regulating properties to the several kinds of cells that includes affect on the bone formation and resorption. The effect of IFN on the osteoclast & other tissue cells has been studied in a number of researchers with the limited reports on the osteoblast. The purpose of this study was to evaluate the effects of IFN on the osteoblastic function. The MC3T3/El cell(Mouse osteoblast) was incubated in ${\alpha}-minimum$ essential medium containing 10% FBS. To detect the cytotoxic effect of $IFN-{\gamma}$ on osteoblast, the cells were cultured in 96-well plate to which $IFN-{\gamma}$ of various concentrations were added for 2 days. After staining with trypan blue, total cells and living cells were counted under microscope. To determine the activity of alkaline phosphataset(ALP), various concentrations of $IFN-{\gamma}$ were treated to culture medium, and biochemical assay was performed. $IFN-{\gamma}$ and $IFN-{\gamma}$ plus cycloheximide were added to culture medium separately and then ALP activity were determined. To detect the effect of the $IFN-{\gamma}$ on the bone formation of osteoblast, long-term culture was performed, and calcified nodule formation were observed using von Kossa's staining. After the addition of $IFN-{\gamma}$ with various concentrations to the medium, no cytotoxic effect of $IFN-{\gamma}$ was detected at any concentration. The significant increase in ALP activity of osteoblast were found the concentration of $IFN-{\gamma}$ 500-2500U/ml and the culture time of 24-48 hours respectively. The enhancement of ALP activity by $IFN-{\gamma}$ of osteoblast was decreased significantly by the treatment of cycloheximide. After long-term culture of osteoblast, the nodule formation was found to be increased in number and density by the addition of 500 U/ml $IFN-{\gamma}$. These results suggest that $IFN-{\gamma}$ was affected on the bone formation of osteoblast. Forthemore this kind of study or $IFN-{\gamma}$ to osteoblast will be held continuously.

• Journal of Periodontal and Implant Science
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• 제27권2호
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• pp.329-346
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• 1997

Dental implants have been developed for enhancement of osseointegration. Biocompatibility, bone affinity and surface characteristics of dental implants are very important factors for osseointegration. The aim of the present study was to determine the cytotoxicity and the bone affinity of titanium phosphide(Ti-P) implant material. The Ti-P surface was obtained by vacuum sintering of titanium within compacted hydroxyapatite powder. The composition and the chemical change of the surface were determined by Auger electron spectroscopy. The in vitro cytotoxicity was evaluated by the viability of the bone cells and macrophages obtained from chicken embryo and rat,s peritonium, respectively. For the comparative evaluation, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 1O.0mm in diameter and 5.0mm in height, were immersed separately in bone cells and macrophages for 10 days. For the evaluation of the in vivo bone affinity, 316L stainless steel, commercially pure titanium and Ti-P materials, prepared in size of 5.0mm in diameter and 10.0mm in length, were implanted after drilling in diameter 5.5mm in femurs of 2 dogs weighing 10Kg more or less. Six weeks after implantation the specimens were prepared for histopathological examination and were observed under light microscope. In comparison of in vitro bone cell viability, Ti-P and commercially pure titanium groups were not significantly different from control group (p>O.1), but 316L stainless steel group was significantly lower than control group(p<0.05). There was no statistical difference in the viability of macrophages between 3 different groups and control group(p>O.l). In comparison of in vivo study, 316L stainless steel and commercially pure titanium showed fibrous encapsulation, but Ti-P showed remarkable new bone formation without any fibrous tissue. The results demonstrate that Ti-P has favorable biocompatibility and bone affinity, and suggest that dental implants with Ti-P surface may enhance osseointegration.

• Journal of Periodontal and Implant Science
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• 제46권6호
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• pp.372-381
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• 2016

Purpose: The aim of this study was to determine the relationship between buccal bone thickness and gingival thickness by means of a noninvasive and relatively accurate digital registration method. Methods: In 20 periodontally healthy subjects, cone-beam computed tomographic images and intraoral scanned files were obtained. Measurements of buccal bone thickness and gingival thickness at the central incisors, lateral incisors, and canines were performed at points 0-5 mm from the alveolar crest on the superimposed images. The Friedman test was used to compare buccal bone and gingival thickness for each depth between the 3 tooth types. Spearman's correlation coefficient was calculated to assess the correlation between buccal bone thickness and gingival thickness. Results: Of the central incisors, 77% of all sites had a buccal thickness of 0.5-1.0 mm, and 23% had a thickness of 1.0-1.5 mm. Of the lateral incisors, 71% of sites demonstrated a buccal bone thickness <1.0 mm, as did 63% of the canine sites. For gingival thickness, the proportion of sites <1.0 mm was 88%, 82%, and 91% for the central incisors, lateral incisors, and canines, respectively. Significant differences were observed in gingival thickness at the alveolar crest level (G0) between the central incisors and canines (P=0.032) and between the central incisors and lateral incisors (P=0.013). At 1 mm inferior to the alveolar crest, a difference was found between the central incisors and canines (P=0.025). The lateral incisors and canines showed a significant difference for buccal bone thickness 5 mm under the alveolar crest (P=0.025). Conclusions: The gingiva and buccal bone of the anterior maxillary teeth were found to be relatively thin (<1 mm) overall. A tendency was found for gingival thickness to increase and bone thickness to decrease toward the root apex. Differences were found between teeth at some positions, although the correlation between buccal bone thickness and soft tissue thickness was generally not significant.