• The korean journal of orthodontics
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• v.25 no.4
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• pp.433-445
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• 1995

Tooth movement, the phenomena and mechanisms of which are still controversial, can be considered as part of the result of the inflammatory processes. The purpose of this study was to examine the activity of macrophage and T-cell, playing important roles in the immune reaction, in the periodontal ligament of dog, in which experimental tooth movement was performed. Six one and half year-old dogs, a control and 5 experimentals, were studied. Light force (50-75g) was applied by placing open-coil spring between left mandibular premolars ; heavy force (250-300g), between right mandibular premolars. Experimental dogs were sacrificed at 12 hours, 1, 3, 7 and 14 days since force application, respectively. And the histologic and the immunohistochemical evaluation on the obtained tissue were performed, using $\alpha$-1-antichymotrypsin and CD3 antibodies. The results were as follows : 1. There were more inflammatory cell infiltrations in heavy force group than in light force group until 3 days. But from 7 dsays on, no difference was not observed between groups ; Such an infiltration was more evident at pressure side than at tension side. 2. Osteoclastic activity at pressure side began to be seen in 12 hours, increasing until 7 days. After then it decreased ; Such an activity was more evident in heavy force group than in light force group. 3. Tearing of periodontal ligament and vascular dilatation at tension side began to be seen in 12 hours, increasing until 3 days. After then it decreased ; Such an observation was more evident in heavy force group than in light force group, but there was no difference between groups in 14 days. 4. $\alpha$-1-antichymotrypsin expression in control group was positive, mainly in sulcular epithelium, but negative in periodontal membrane, pulp, bone cells. 5. $\alpha$-1-antichymotrypsin expression in experimental group was more positive in pressure side than in tension side ; The expression was a little more positive in cervical area of tooth until 3 days, but after 7days, it was more positive in apical area. 6. $\alpha$-1-antichymotrypsin expression in light force group began to be observed in 12 hours and reached to the greatest level in 7 days, after which it decreased ; In heavy force group, it was the greatest in 3 days, after which it decreased. 3 Expression in the periodontium was almost negative.

• Restorative Dentistry and Endodontics
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• v.37 no.3
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• pp.136-141
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• 2012

Objectives: The maintenance of the healthy periodontal ligament cells of the root surface of donor tooth and intimate surface contact between the donor tooth and the recipient bone are the key factors for successful tooth transplantation. In order to achieve these purposes, a duplicated donor tooth model can be utilized to reduce the extra-oral time using the computer-aided rapid prototyping (CARP) technique. Materials and Methods: Briefly, a three-dimensional digital imaging and communication in medicine (DICOM) image with the real dimensions of the donor tooth was obtained from a computed tomography (CT), and a life-sized resin tooth model was fabricated. Dimensional errors between real tooth, 3D CT image model and CARP model were calculated. And extra-oral time was recorded during the autotransplantation of the teeth. Results: The average extra-oral time was 7 min 25 sec with the range of immediate to 25 min in cases which extra-oral root canal treatments were not performed while it was 9 min 15 sec when extra-oral root canal treatments were performed. The average radiographic distance between the root surface and the alveolar bone was 1.17 mm and 1.35 mm at mesial cervix and apex; they were 0.98 mm and 1.26 mm at the distal cervix and apex. When the dimensional errors between real tooth, 3D CT image model and CARP model were measured in cadavers, the average of absolute error was 0.291 mm between real teeth and CARP model. Conclusions: These data indicate that CARP may be of value in minimizing the extra-oral time and the gap between the donor tooth and the recipient alveolar bone in tooth transplantation.

• Restorative Dentistry and Endodontics
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• v.27 no.6
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• pp.600-611
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• 2002

본 연구의 목적은 클로로필린이 치주인대 세포 생활력에 미치는 영향을 평가하는데 있다. 치주인대 세포는 건강한 사람에서 발치한 소구치의 치주인대 조직으로부터 채취하여 배양하였다. 비교 기준을 설정하기 위하여, HBSS 내에서 $37^{\ circ}C$로 보관한 치주인대 세포수의 50%가 생존하는데 소요되는 시간을 MTT 분석법에 의해 측정하였다. 그 결과는 6시간이었다. HBSS에 클로로필린 10, 100, 500 nM이 각각 첨가된 3군의 실험 보존액과 F-medium, ViaSpan, Likorol 등 모두 6군의 실험 보존액을 96-well plate에 접종한 후, 치주인대 세포를 동일한 수로 분주하였다. 이를 6시간동안 보관한 후, 각 실험군 보존액에서의 세포 생활력을 MTT 분석법으로 측정하였다 또한, HBSS와 F-medium 및 클로로필린 500 nM이 첨가된 HBSS군의 세포들에 대해 유식세포 계측을 시행하여 각각의 세포주기를 분석하였다. 실험 결과, 클로로필린 500 nM이 첨가된 HBSS에서 보관한 세포들이 가장 높은 생활력을 나타내었으며, 클로로필린이 첨가되지 않은 HBSS에 비해서 유의하게 양호한 세포 생활력 유지 능력을 보였다. 클로로필린으로 처치한 세포들은 클로로필린의 농도가 커짐에 따라 세포 생활력이 증가하는 양상을 나타내었다. 유식세포 계측 결과, HBSS와 F-medium 및 클로로필린 500 nM이 첨가된 HBSS에서 보관한 세포의 77~80%가 G0-G1 단계의 세포 주기로 측정되어, 대부분의 세포들이 안정된 세포 대사 상태를 보이는 것으로 나타났다. 결론적으로, 클로로필린 처치는 치주인대 세포의 생활력 유지에 도움이 되는 것으로 사료된다.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.475-490
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• 2005

본 실험은 흡연이 치주인대세포의 기능에 미치는 영향을 알아보기 위해 담배 부산물 중 하나인 니코틴이 지주인대세포의 부착과 성장 및 세포의 가역성에 미치는 영향을 관찰하였다. 니코틴이 치주인대세포의 부착에 미치는 영향을 관찰하기 위하여 치주인대세포에 니코틴을 투여한 후 1, 3, 6, 12, 24시간째 trypan blue 염색 후 부착된 세포수의 측정과 H&E stain후 형태학적 관찰을 하였고 니코틴이 치주인대세포의 성장에 미치는 영향을 관찰하기 위하여 치주인대세포에 니코틴을 투여한 후 1, 4, 7, 11, 14일째 trypan blue 염색 후 증식된 세포수의 측정과 H&E stain후 형태학적 관찰을 하였다. 또 니코틴의 세포독성효과의 가역성 평가를 위하여 니코틴을 투여하고 1, 4, 7, 11일째 니코틴이 없는 새로운 배지로 갈아주어 2일 더 배양한 후 trypan blue로 염색하여 세포수를 측정, 비교하였고 H&E 염색 후 형태학적 관찰을 하였다. 실험결과 니코틴 농도가 증가함에 따라 치주인대세포의 부착율은 감소되었고 24시간 배양 후 2mg/ml, 0.5mg/ml, 0.1mg/ml니코틴 투여군에서 통계학적으로 유의성 있는 부착억제가 관찰되었고(P<0.01) 형태학적 관찰결과 2mg/ml, 0.5mg/ml 니코틴 투여군에서는 대조해서 관찰되는 세포질의 확장이 관찰되지 않았다. 니코틴이 치주인대세포의 증식에 미치는 효과를 살펴본 결과 2mg/ml, 0.5mg/ml, 0.1mg/ml 니코틴 투여군에서 증식억제가 관찰되었고(P<0.01) 0.005mg/ml이하의 니코틴 투여군에서는 아무런 변화도 관찰되지 않았다. 14일 배양 후 형태학적 관찰결과 0.1mg/ml 니코틴 투여군에서 세포질내 공포를 관찰할 수 있었고 2mg/ml, 0.5mg/ml 니코틴 투여군에서는 세포의 괴사가 나타났다. 니코틴의 세포독성효과의 가역성평가결과 2mg/ml이상의 니코틴은 세포에 비가역적인 손상을 일으키며 0.5mg/ml, 0.1mg/ml 니코틴에 의한 세포독성은 초기에는 가역적이나 장기간 세포에 노출시키면 비가역적인 손상을 야기하는 것으로 나타났다.(P<0.05) 본 실험결과 담배의 구성성분 중 니코틴은 농도 의존적으로 치주인대세포의 부착과 증식에 영향을 주었고 니코틴의 치주인대세포에 대한 독성효과는 농도가 증가할수록, 시간이 지닐수록 비가역적으로 나타났다. 따라서 흡연은 치주조직재생에 영향을 미칠 것으로 생각되며 흡연의 기간과 정도가 치주질환의 심도 및 치주치료 후 불량한 치유반응과 관계가 있을 것으로 사료된다.

• The korean journal of orthodontics
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• v.36 no.4
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• pp.242-250
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• 2006

Objective: Periodontal ligament fibroblasts have an ectomesenchymal origin and are thought to play a crucial role for not only homeostasis of periodontal tissues but also bone remodeling, wound healing and regeneration of tissues. Recently, it has been reported that UNC-50 is not expressed in gingival fibroblasts but in PDL fibroblasts. The purpose of this study was to examine the expression of UNC-50 and osteocalcin in the periodontium after application of intermittent force. Methods: Twelve rats had 40 grams of mesially-directed force applied at the upper molar for 1 hour/day. Four rats were sacrificed at 1, 3 and 5 days. Immunohistochemical localization of UNC-50 and osteocalcin antibody was carried out. The results showed apposition of new cellular cementum and a slight increase in periodontal space at the tension side. Results: Strong UNC-50 expression was observed in the differentiating cementoblasts close to PDL fibroblasts in the tension side whereas it was barely expressed at the compression side. Expression was strong at day 3, and decreased at day 5. Osteocalcin immunoreactivity expression was strong in differentiating cementoblasts at the tension side. Conclusion: It can be suggested that UNC-50 is related to the differentiation of cementoblasts, and may be responsible for the molecular event in PDL cells under mechanical stress.

• Restorative Dentistry and Endodontics
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• v.27 no.4
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• pp.355-362
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• 2002

One fifth dilution of formocresol is usually used for pulpotomy of the primary teeth and emergency pulpotomy of the permanent teeth. However the use of formaldehyde has been subjected to criticism because it may be absorbed into the blood stream and become distributed systemically, it nay also alter the pulp tissue rendering it immunologically active, and have carcinogenic potential. Recently Depulpin$^{\circledR}$(VoCo., Germany) gains popularity as a devitalizing agent during root canal therapy in spite of high concentration of 49 % paraformaldehyde because it facilitate devitalization of pulp and make root canal therapy easier But there have been not enough publications about the reaction of pulp and periapical tissue caused by Depulpin. This study was performed to evaluate the histological changes in pulp and periapical tissue of rats after pulpotomy using formocresol and Depulpin and to elucidate the toxic effects of these agents. Thirty six Sprague-Dawley rats were anesthetized by intraperitoneal injection of ketamine Maxillary first molar teeth were used for pulpotomy with formocresol and Depulpin. Rats were sacrificed after 2 days, 4 days, 1 week, 2 weeks, 3 weeks and 4 weeks respectively. Specimens were histologically observed by light microscope changes in pulp and periapical tissue. The obtained results were as follows. 1. Formocresol group A zone of fixed tissue. in which odontoblasts could clearly be defined, was present directly underneath the pulpotomy dressing in almost all teeth of this group. This was followed by an area of necrotic tissue which resembled dried out fibrous tissue with no cellular detail except some pyknotic nuclei. In the specimens of after 2 days, 4 days, 1 week, 2 weeks in which vital tissue was present, it was separated from the fibrous area by a zone of inflammation. In the specimens of after 3 weeks and after 4 weeks, inflammatory infiltrate was in the periodontal ligament adjacent to the apical foramina of the teeth. 2. Depulpin$^{\circledR}$ group The area of necrotic tissue which had no cells and fibers, was present adjacent to the dressing. This was followed by dried out fibrous tissue with no cellular details except some pyknotic nuclei, A short stump of vital pulp with odontoblasts was present at the end of the canal after 2 days. Inflammatory infiltrate was in the periodontal ligament after 4 days and after 1week. Severe root resolution and necrosis of periapical tissue opposite the root resorption site were defined after 2 weeks and after 3 weeks. Periapical lesion which consist of necrotic tissue surrounded by a fibrous connective wall, was found after 4 weeks. The results indicated that Depulpin can cause more adverse reaction to the dental pulp and periapical tissue than formocresol, and further studies are needed for its clinical use with safety.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.198-206
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• 2015

Purpose: We aimed to investigate the effect of combined various microgrooves and thermal oxidation on the titanium (Ti) and to evaluate various in vitro responses of human periodontal ligament cells (PLCs). Materials and methods: Grade II titanium disks were fabricated. Microgrooves were applied on titanium discs to have $0/0{{\mu}m}$, $15/3.5{{\mu}m}$, $30/10{{\mu}m}$, and $60/10{{\mu}m}$ of respective width/depth by photolithography. Thermal oxidation was performed on the microgrooves of Ti substrata for 3 h at $700^{\circ}C$ in air. The experiments were divided into 3 groups: control group (ST), thermal oxidation group (ST/TO), and combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO). Surface characterization was performed by field-emission scanning microscopy. Cell adhesion, osteoblastic differentiation, and mineralization were analyzed using the bromodeoxyurdine (BrdU), Alkaline phosphatase (ALP) activity, and extracellular calcium deposition assays, respectively. Statistical analysis was performed using the oneway analysis of variance and Pearson's bivariate correlation analysis (SPSS Version 17.0). Results: In general, the combined microgrooves and thermal oxidation group (Gr15-TO, Gr30-TO, Gr60-TO) showed significantly higher levels compared with the control (ST) or thermal oxidation (ST-TO) groups in the BrdU expression, ALP activity, and extracellular calcium deposition. Gr60-TO group induced highest levels of cell adhesion and osteoblastic differentiation. Conclusion: Within the limitation of this study, we conclude that the Ti surface treatment using combined microgrooves and thermal oxidation is highly effective in inducing the cell adhesion andosteoblastic differentiation. The propose surface is also expected to be effective in inducing rapid and strong osseointegration of Ti oral implants.

• Journal of the korean academy of Pediatric Dentistry
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• v.36 no.4
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• pp.625-630
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• 2009

Root resorption of primary teeth usually occurs as the succeeding permanent teeth erupt, which induces differentiation of the hemopoietic cells into osteoclasts. Their root resorption pattern reflects the eruption path of the succeeding permanent teeth, and eventually the primary teeth shed as their succeeding permanent teeth erupt. Even when a permanent tooth germ is congenitally missing, root resorption of the corresponding primary tooth may still occur due to various factors, such as inflammation, traumatic occlusal force, and weakness of periodontium etc. Such congenital missing of permanent teeth is a commonly observed phenomenon in human be ing, and it often accompanies delayed retention of primary teeth. The etiologic factors for congenital missing in elude not only systemic diseases, but also local factors and human evolution process. In the radiographs of the cases in this report, the primary teeth without succeeding permanent teeth show pathologic root resorption. Root resorption progressed about 1/2~3/4 of the roots, and the surfaces of the resorption area were irregular. Considering high susceptibility of the periodontal ligament of primary teeth to root resorption, pathologic root resorption of primary teeth with delayed retention can be explained by the increased masticatory muscle force and abnormal occlusion developed during the mixed dentition. When the primary teeth without succeeding permanent teeth are lost, decision for space maintenance is required and long-term treatment plan for further prosthetic or orthodontic treatment should be establsihed.