• The Journal of Korean Academy of Prosthodontics
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• v.47 no.4
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• pp.435-444
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• 2009

Statement of problem: The clinical use of electric and electomagnetic fields for fracture healing applications began in the early 1970s. Since then, several technologies have been developed and shown to promote healing of fractures. Developments of these devices have been aided in recent years by basic research and several well controlled clinical trials not only in the medical field but in dentistry. Purpose: The purpose of this study was to compare alveolar bone reduction following immediate implantation using implants onto which magnets were attached in fresh extracted sockets. Material and methods: Four mongrel dogs were involved. Full buccal and lingual mucoperiosteal flaps were elevated and third and fourth premolars of the mandible were removed. Implants with magnets and implants without magnets were installed in the fresh extracted sockets and after 3 months of healing the animals were sacrificed. The mandibles were dissected and each implant sites were sampled and processed for histological examination. Results: The marginal gaps that were present between the implant and walls of the sockets at the implantation stage disappeared in both groups as a result of bone fill and resorption of the bone crest. The buccal bone crests were located apical of its lingual counterparts. At the 12 week interval the mean of marginal bone resorption in the control group was significantly higher than that of the magnet group. The majority of specimens in magnet group presented early bone formation and less resorption of the buccal marginal bone compared to the control group. Conclusion: Within the limitations of this study, it could be concluded that implants with magnets attached in the early stages of implantation may provide more favorable conditions for early bone formation and reduce resorption and remodeling of marginal bone.

• The korean journal of orthodontics
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• v.30 no.1 s.78
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• pp.9-17
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• 2000

This study was performed to compare and analyze the mode of tooth movement according to the timing of orthodontic force application alter extraction. The upper right and left third incisors were carefully extracted at three-week interval in lout adult dogs. Both canines were used as an anchorage for the bodily movement of the upper second incisors. Orthodontic forte of 100 gm was simultaneously applied at one week after extraction on one side and four weeks after extraction on the other side using NiTi closed coil spring. While orthodontic force was applied for twelve weeks, the amount of tooth movement was measured at every second week with digital calipers. The animals were sacrificed at twelve weeks and histologic examination was executed to reveal any difference between both sides. The results were obtained as follows. 1. The tooth movement was likely to be faster in lout-week side 4han one-week side for the first two weeks while faster in one-week side during next two weeks 2. The rate of tooth movement was fastest during four to six weeks period, then decreased gradually. 3. The total amount of tooth movement was likely to be larger in one-week side compared to four-week side. 4. Any damage to tooth and periodontal tissue could not be seen in the histologic section of one-week side. These results suggest that earlier application of orthodontic force is better than later after extraction In terms of the rate of tooth movement.

• The korean journal of orthodontics
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• v.27 no.5 s.64
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• pp.825-837
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• 1997

The purpose of this study was to evaluate the effect of splinting methods on the rearrangement of periodontal fibers after experimental tooth movement. Orthodontic force was applied by placing closed coil spring between upper third incisor and canine in seven dogs, weighing 20 kg or more. After 3 weeks of force application, 0.0215 inch multistrand wire and polyethylene ribbon were bonded to each side, as a flexible and rigid splinting respectively in 6 experimental animals. The remaining one served as a control. Each two animals were sacrificed at 4, 8 and 12 weeks after splinting respectively and prepared histologically for hematoxylin-eosin and Masson's trichrome staining. The results of this study were obtained as follows: 1. After tooth movement, periodontal space was narrowed and periodontal titers were thick on pressure side while elongated fibers were observed on tension side. 2. After 4 weeks of retention, the rearrangement of periodontal fibers was observed in the flexible splinting group, but not in the rigid splinting group. 3. After 8 weeks of retention, the rearrangement of periodontal titers was observed in both groups, but the difference could not be detected between two groups. 4. During the retention period, the rearrangement of periodontal fibers was faster in tension side than in pressure side. These results show that the rearrangement of periodontal fibers is also obtained by rigid splinting after tooth movement. It is suggested that the rigid splinting by polyethylene ribbon can be used as a way of postorthodontic retention.

• Journal of Periodontal and Implant Science
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• v.29 no.2
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• pp.289-297
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• 1999

최근 생약 추출물의 항균, 항염효과에 관한 관심이 증대되고 있으며 이를 이용한 치주질환의 예방 및 억제효과에 관한 연구들이진행되고 있다. 이 연구의 목적은 시험관 실험을 통하여 이미 밝혀진 후박 및 대조추출물의 치주질환 원인 균에 대한 항균, 항염효과를 성견에서 인위적으로 치주질환을 일으킨 후 실험 약제의 경구투여를 통하여 질환의 진행에 미치는 영향을 알아보는 것이다. 실험동물은 생후 18개월된 비글견 6마리를 이용하였다. 상악은 제2,3 소구치 및 제4소구치에 하악은 제2, 3, 4 소구치 및 제1 대구치를 실험대상 치아로 하였으며 교정용 철사와 봉합사를 이용하여 치경부주위에 결찰하여 인위적 치주질환을 일으켰다. 염증 유발 8주 후에 결찰을 풀고 실험동물을 아무 것도 투여하지 않은 군(음성대조군, 3마리), 후박 및 대조 추출혼합물 투여군(실험군, 3마리)으로 나누었다. 실험 시작 (-8주), 약제 투여 시작(0주), 투여 후 2, 4, 6, 8주째에 치태지수, 치은지수, Florida Probe를 이용한 치주낭깊이 및 치은열구액 등의 임상지수를 측정하였다. 염증유발 8주동안에 치태지수, 치은지수, 치주낭깊이, 치은열구액은 급속히 증가하였다. 결찰은 제거하고, 약제를 투여한 이후 실험군에서 치은지수, 치주낭깊이, 치은열구액은 가장 높은 값을 나타내고 있었다. 실험군에서는 8주가 될때까지 임상지수 수치가 낮아지고 있었으며, 8주째에는 대부분의 지수에서 음성대조군과 유의성 있는 차이를 보이고 있었다. 양성대조군에서 비해서 실험군은 대부분의 경우에 임상지수가 나이지고 있었지만 6주 또는 8주째의 치은지수, 치주낭깊이 중 일부만을 제외하고는 유의성 있는 차이를 보이지는 않았다. 이 연구결과 후박 및 대조 추출혼합물이 in vitro뿐만 아니라 in vivo 상태에서도 치주염의 치료 및 골재생의 효과가 있음을 알 수 있었으며, 이와 같은 동물실험의 결과를 바탕으로 임상시험을 거쳐 향후 사람에게 유용한 치주염치료제로 개발, 사용될 수 있을 것으로 여겨진다.

• The korean journal of orthodontics
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• v.28 no.3 s.68
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• pp.431-440
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• 1998

While periodontal disease results in the extrusion of upper incisors with interdental spacing in adult patient, the intrusive movement should be executed for the rehabilitation in terms of esthetics and function. The present study was peformed to investigate the periodontal response following orthodontic intrusion of teeth with infrabony pocket. Bone defect and periodontal disease were produced adjacent to the both maxillary second lateral incisors in four adult dogs. Four weeks later, a flap operation was performed to eliminate inflammation and a reference notch was made on the root surface at the level of bottom of each defect. Two weeks after periodontal surgery, 4 weeks of intrusion and subsequent another 4 weeks of retention was executed on the right side of incisors while left incisors served as the control. Through the histologic analysis, following results were obtained. 1. Histologic section of control side showed the reduction of pocket depth after flap operation. However, the status of long junctional epithelium was observed while new connective tissue attachment occurred in a small area adjacent newly formed cementum 2. Epithelial attachment was less around the intruded incisor while new connective tissue attachment was much more compared to the control side. 3. Plenty of cells were observed in the connective tissue around the reference notch of the intruded incisor and the degree of the new cementum formation was higher in the intruded incisor than the control. The results of the present study suggested that an orthodontic intrusion of periodontally involved and extruded incisors could be carried out with a desirable periodontal response, provided that inflammation is under control.

• Journal of Periodontal and Implant Science
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• v.24 no.1
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• pp.26-38
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• 1994

The purpose of this study was to evaluate the effects of citric acid and fibrin on the regeneration of periodontal tissues using 4 normal canines of five dogs. Mucoperiosteal flap was raised and experimental defects were made at the buccal root surfaces about $4{\times}6mm$ in length. The denuded root surfaces were covered using coronally repositioning technique after root planing alone at left lower canine, root planing plus fibrin at rigth lower canine, root planing plus citric acid at left upper canine or root planning plus citric acid and fibrin at right upper canine. All of the specimens were tangentially cut(about $3-5{\mu}m$)and available for histologic analysis 1, 3, 7, 14 and 21 days after operations. The results were as follows : At one' day after operations, the amounts of fibrin were similarly higher in the group I, II and III than control group and at 3 days after operations, the apical migrations of the long junctional epithelium were prominent in the control group and group I. At 7 days after operations, the fibrin meshworks of each group were partly changed to the collagen fibers and characteristics of the fibers were almost collagenous rather than fibrinous at 14 days after operations and at 21 days after operations, the orientation of collagen fibers were partly normal in group II and group III, but not in control group and group I. Root resorptions were visible in group II and group III at 14 days after operations and more significant in group II than group III at 21 days.

• Journal of Veterinary Clinics
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• v.22 no.3
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• pp.190-193
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• 2005

The concentration of tartrate resistant acid phosphatase (TRAP) in synovial fluid of normal stifle joint was investigated in order to establish a baseline data to distinguish between healthy joint and joint with injury of cranial cruciate ligament (CCL). Twenty three mixed-breed healthy dogs free from joint diseases (fourteen adult and nine young) were used in this study. The dogs were sedated and synovial fluid was collected from the femoropatellar compartment of stifle joints by direct arthrocentesis. The concentration of TRAP in synovial fluid was determined using the method of Lang. The concentration of TRAP were $0.083{\pm}0.039$ IU/ml in adult dogs, $0.064{\pm}0.023$ IU/ml in young dogs, $0.075{\pm}0.028$ IU/ml in large dogs (>22 kg), $0.076{\pm}0.046$ IU/ml in small dogs (<22 kg), $0.085{\pm}0.036$ IU/ml in neutered dogs and $0.056{\pm}0.022$ IU/ml in intact dogs. The concentration of TRAP in the neutered dogs was significantly (p<0.05) higher than the intact dogs. This data can be used baseline data for a comparison with joint with injury of cranial cruciate ligament.

• Journal of Periodontal and Implant Science
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• v.36 no.1
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• pp.239-251
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• 2006

결합조직이식을 이용한 치근피개 술식에 많은 관심이 집중되고 있다. 최근에는 acellular dermal matrix가 자가 결합조직 이식편의 대체물로써 소개되었다. 본 실험의 목적은 치근피개를 위해 acellular dermal matrix을 사용시, 그 임상 효과 빚 조직 치유 양상을 평가하고, 이를 자가 결합조직 이삭시의 결과와 비교하기 위함이다. 3마리의 성견에 인위적인 치은 퇴축부 형성을 위해서, 상악 좌우견치의 협측에서 각화치은을 모두 제거하고, 법랑백악경계부로부터 12mm 정도 치조골을 삭제한 후에 판막을 봉합하였다. 그 후 35일을 치유 기간으로 부여하였다. 총 6 부위의 결손부가 실험에 포함되었고, 각각 3 부위씩이 대조군과 실험군으로 분류되었다. 실험군에서는 acellular dermal matrix 이식과 치관측 변위 판막을 시행하였고, 대조군에서는 치은 퇴축부위에 자가 결합조직 이식과 치관측 변위 판막을 시행하였다. 치주낭 깊이, 임상적 부착 수준, 치은 퇴축 높이, 각화조직 높이 등을 인위적 결손부 형성전, 치은 피개술 시행 직전, 피개술 시행후 4주 경과시에 각각 측정하였다. 술후 4주시에, 상악 좌우 견치 부위에서 시편을 얻어 조직학적으로 관찰하고 Wilcoxon signed rank test 와 Mann-Whitney U test으로 통계처리하였다. 임상결과 관찰시, 대조군과 실험군 모두에서, 술전과 비교시 치은 퇴축 감소와 각화조직의 증가, 임상 부착수준의 개선이 나타났다.(p ( 0.05) 평균 치근 피개율은 실험군에서 61.33(5.67%(n=3), 대조군에서 55.67(5.67%(n=3) 이었고, 대조군과 실험군에서 임상결과에서는 통계학적으로 유의성 있는 차이는 없었다.(p ( 0.05). 조직학상으로는, 두 군 모두에서 이식편이 수여부에 잘 융화되어 있었고 비슷한 치유 양상을 보였다. 이상의 실험결과에 의하면, Acellular dermal matrix은 치근피개술 시행시에 결합조직 이식편의 대용품으로 사용할 수 있고 비슷한 피개 결과를 얻을수 있었다.

• Journal of the korean academy of Pediatric Dentistry
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• v.46 no.3
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• pp.255-264
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• 2019

Endodontic treatment of primary molars is a great challenge to the dentists because of their complex morphology. However, there have been limited controlled in vivo studies about filling materials for primary teeth. Hence, the aim of this study is to evaluate and compare histologic responses of different calcium hydroxide canal filling materials that are used in daily clinical practice. Pulpectomies were performed in 132 teeth of the dogs. The root canals were randomly filled with either $Vitapex^{(R)}$ (n = 44), $Metapex^{(R)}$ (n = 44), or $Metapaste^{(R)}$ (n = 44). After 4 or 13 weeks, respectively after operation, the dogs were sacrificed, and teeth were processed for histologic examinations. Inflammatory reaction was evaluated and scored in a blind manner. The Fisher's exact test and Kruskal-Wallis test were used to compare the tested groups. In 4-week-group, all inflammatory responses were in normal range except for fibrosis. In 13-week-group, increased response to various inflammation reaction was shown compared to the 4-week-group. However, there were no statically significant differences between the tested groups in all inflammatory reaction. Overall, there were no significant differences among three materials in responses of apical tissues and all of them showed favorable tissue responses.

• The Journal of the Korean dental association
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• v.22 no.5 s.180
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• pp.439-446
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• 1984

The purpose of this study was observe the effects of excessive occlusal force on gingival fibroblasts and collagen fibers of dog. The experiment was performed in 5 dogs. 1 dog was used as control and 4 dogs as experimental group. In experimental group, high Sun Platinum casting metal crowns with 2.0mm thick were placed artificially onto the upper right third premolars to create the traumatic occlusion. After 3, 7, 15, 30 experimental days, the specimens were examined under electron microscope. The following results were observed: 1. In 3, 7, 15 day groups, swelling of the mitochondria in the fibroblast was observed. 2. In 7, 14, day groups, dilation of the endoplasmicreticulum in the fibroblast was observed. 3. There were no remarkable changes in the nucleus of the fibroblasts and collagen fibers. 4. In 30 day group, the changes of the mitochondria and the ER in the fibroblast were recovered to have the similar appearance with that of the control group.