• Journal of Periodontal and Implant Science
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• 제46권5호
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• pp.303-319
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• 2016

Purpose: The purpose of this animal study was to perform a 3-dimensional micro-computed tomography (micro-CT) analysis in order to investigate the influence of root surface distance to the alveolar bone and the periodontal ligament on periodontal wound healing after a guided tissue regeneration (GTR) procedure. Methods: Three adult Sus scrofa domesticus specimens were used. The study sample included 6 teeth, corresponding to 2 third mandibular incisors from each animal. After coronectomy, a circumferential bone defect was created in each tooth by means of calibrated piezoelectric inserts. The experimental defects had depths of 3 mm, 5 mm, 7 mm, 9 mm, and 11 mm, with a constant width of 2 mm. One tooth with no defect was used as a control. The defects were covered with a bioresorbable membrane and protected with a flap. After 6 months, the animals were euthanised and tissue blocks were harvested and preserved for micro-CT analysis. Results: New alveolar bone was consistently present in all experimental defects. Signs of root resorption were observed in all samples, with the extent of resorption directly correlated to the vertical extent of the defect; the medial third of the root was the most commonly affected area. Signs of ankylosis were recorded in the defects that were 3 mm and 7 mm in depth. Density and other indicators of bone quality decreased with increasing defect depth. Conclusions: After a GTR procedure, the periodontal ligament and the alveolar bone appeared to compete in periodontal wound healing. Moreover, the observed decrease in bone quality indicators suggests that intrabony defects beyond a critical size cannot be regenerated. This finding may be relevant for the clinical application of periodontal regeneration, since it implies that GTR has a dimensional limit.

• Journal of Periodontal and Implant Science
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• 제26권2호
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• pp.334-349
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• 1996

Regeneration of the periodontal tissue destroyed by periodontal disease is one of the final goals of periodontal therapy. In the past few years, periodontists have used various alloplastic grafting materials in an attempt to regenerate bone lost from periodontal disease. These materials have used widely because they have shown to be nontoxic, biologically compatible with surrounding host tissue and chemically similar to bone. The purpose of this study was to investigate the effect of Porous Resorbable Calcium Carbonate and Porous Replamineform Hydroxyapatite on the regeneration of the alveolar bone and the healing of roots transplanted into the periodontally diseased extraction sockets of dogs. The experimental chronic periodontitis was induced by elastic ligatures on the 2nd and 3rd mandibular premolars of 2 adult dogs for 8weeks after surgically creating periodontal defect. The extracted root were split in half along the long-axis, and the extend of plaque exposure was marked on the root surfaces with burs. The roots were inserted in extraction sockets with Porous Resorbable Calcium Carbonate(PRCC) in left side and with Porous Replaminefrom Hydroxyapatite(PRH) in right side. The flaps were sutured to cover the sockets completely. The animals were sacrificed after 12 weeks of healing, and the specimens were examined histologically. The results were as follows: 1. No inflammatory reactions were observed in either groups. 2. Hoot resorption was observed in both groups while the general outline of the roots were maintained. 3. PRCC was almost completely resorbed and replaced with new bone, while R.H.A. was not resorbed & remained encased in newly-formed C-T and alveolar bone. 4. PRH was encapsulated with alveolar bone which has been deposited from apical & lateral area of the sockets, while the coronal portion of the sockets were filled with C-T. 5. In both groups, the resorbed portions of the roots were replaced with new bone. These results suggest that either PRCC or PRH may not interfere with bone formation or healing in extraction sockets, and in some degree, retard the root resorption. Because the roots maintained in anatomy, we think that graft materials prevent the root resorption.

• 대한치과교정학회지
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• 제46권6호
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• pp.379-385
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• 2016

Objective: Forced eruption has been proposed for the reconstruction of deficient bone and soft tissue. The aim of this study was to examine the changes in the alveolar ridge width and the vertical levels of the interproximal bone and papilla following forced eruption. Methods: Patients whose hopeless maxillary anterior teeth were expected to undergo severe bone resorption and soft tissue recession upon extraction were recruited. In addition, patients whose maxillary anterior teeth required forced eruption for restoration due to tooth fracture or dental caries were included. Before and after forced eruption, the interproximal bone height was measured by radiographic analysis, and changes in the alveolar ridge width and the interproximal papilla height were measured with an acrylic stent. Results: This prospective study demonstrated that the levels of the interproximal alveolar bone and papilla were significantly increased by 1.36 mm and 1.09 mm, respectively, in the vertical direction. However, the alveolar ridge width was significantly reduced by an average of 0.67 mm in the buccolingual direction. The changes in the level of the interproximal alveolar bone and papilla were positively correlated. Conclusions: Although the levels of the interproximal bone and papilla were significantly increased, the alveolar ridge width was significantly decreased following forced eruption. There was a modest positive and significant correlation between the changes in the height of the interproximal alveolar bone and the papilla. Based on our findings, modification of vertical forced eruption should be considered when augmentation of the alveolar ridge width is required.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제30권3호
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• pp.276-282
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• 2008

Objective: This is to report the efficacy of the sandwich technique for bone augmentation in a moderate atrophic posterior mandible through clinical and histological results in two cases. Subjects and Method: Two patients selected had moderate bone resorption in left lower edentulous area. Sandwich osteotomy using the piezosurgery was performed and the osteomized alveolar segments were elevated by 6mm in each two patients. The interpositional mineral allograft materials were inserted in the atrophic posterior mandibles. After four months healing period, bone biopsies in the grafted areas and placement of dental implants were performed. In both cases, panoramic views were taken preoperatively to measure the alveolar bone height for diagnosis, to monitor patient healing, and to evaluate bone healing and bone gain. Results: Sufficient vertical bone height was gained by using the sandwich technique and implants were placed successfully. In radiological evaluation, there was minimal resorption of bone height after the second operation and in histomorphometric evaluation, they showed favorable new bone formation without inflammation in the grafted areas. Conclusion: The sandwich technique can be an effective choice for augmenting vertical bone height in the atrophic mandible. More of cases and long term follow-up are needed to evaluate bone resorption and implant prognosis.

• 대한치과보철학회지
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• 제36권1호
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• pp.150-165
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• 1998

For the purpose of evaluating the effect of both direct retainer design and bony absorption degree around abutment of indirect retainer on the supporting tissue of abutment of indirect retainer, dislodging force was transmitted to unilateral distal extension RPD bases. Analysis of stress distributed within the supporting tissue around abutment of indirect retainer was carried out. Using three-dimensional photoelastic stress analysis method and the conclusion is a follows. 1. According to the extent of force which the direct retainer of the most distal abutment tooth, the amount of force transmitted to the abutment tooth of indirect retainer was small. 2. Of all the cases, Mandibular first premolar which was used abutment tooth of indirect retainer, buccal, mesial and distal sides represented compression stress and lingual side represented tensile stress. 3. The more bone resorption of abutment tooth of indirect retainer, the more distortion of buccal and distal side of abutment tooth was existed and the extent of compression stress which was existed and distal side to abutment tooth was large. 4. When the alveolar bone around the abutment with indircet retainer is normal. The amount of force transmitted on abutment with indirect retainer was small in the order of Akers clasp, RPA clasp, RPI clasp. 5. When the alveolar bone around the abutment with indirect retainer has been absorbed 20% and 30%, the amount of force transmitted on abutment with indirect retainer was small in the order of RPA calsp, RPI clasp, Akers clasp. 6. When denture is displaced, shape of the direct retainer reciprocating abutment affect much the function of indirect retainer.

• 대한치과교정학회지
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• 제44권6호
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• pp.320-329
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• 2014

Objective: To investigate the involvement of ephrinB2 in periodontal tissue remodeling in compression areas during orthodontic tooth movement and the effects of compressive force on EphB4 and ephrinB2 expression in osteoblasts and osteoclasts. Methods: A rat model of experimental tooth movement was established to examine the histological changes and the localization of ephrinB2 in compressed periodontal tissues during experimental tooth movement. RAW264.7 cells and ST2 cells, used as precursor cells of osteoclasts and osteoblasts, respectively, were subjected to compressive force in vitro. The gene expression of EphB4 and ephrinB2, as well as bone-associated factors including Runx2, Sp7, NFATc1, and calcitonin receptor, were examined by quantitative real-time polymerase chain reaction (PCR). Results: Histological examination of the compression areas of alveolar bone from experimental rats showed that osteoclastogenic activities were promoted while osteogenic activities were inhibited. Immunohistochemistry revealed that ephrinB2 was strongly expressed in osteoclasts in these areas. Quantitative real-time PCR showed that mRNA levels of NFATc1, calcitonin receptor, and ephrinB2 were increased significantly in compressed RAW264.7 cells, and the expression of ephrinB2, EphB4, Sp7, and Runx2 was decreased significantly in compressed ST2 cells. Conclusions: Our results indicate that compressive force can regulate EphB4 and ephrinB2 expression in osteoblasts and osteoclasts, which might contribute to alveolar bone resorption in compression areas during orthodontic tooth movement.

• 대한치과보철학회지
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• 제58권2호
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• pp.145-152
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• 2020

심미와 기능이 조화를 이루는 총의치 제작을 위해서는 상하악 관계를 정확히 기록하는 것이 필수적이다. 고딕아치 묘기법은 하악의 운동을 시각적으로 보여주며, 정확하고 반복재현성 있는 중심위를 확립하는데 유용하다. 또한, 고도의 치조제 흡수를 갖는 환자에서는 총의치의 적절한 유지 및 안정을 얻기가 어려운데, 이런 경우 환자의 생리적인 동작으로 변연을 형성하여 의치상연 주위가 가동점막으로 봉쇄되도록 하는 폐구 인상법이 유용할 수 있다. 본 증례에서는 우측 하악과두골절 병력과 고도의 하악 치조제 흡수를 보이는 환자에서 폐구인상법과 고딕아치 묘기법을 이용한 총의치로 수복하였고 만족할 만한 결과를 얻어 보고하는 바이다.

• 대한치과보철학회지
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• 제54권2호
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• pp.152-159
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• 2016

상악무치악 환자에서 임플란트를 이용한 고정성 보철 수복 치료는 전통적인 가철성 의치에 비해 안정성과 유지력이 개선되어 저작, 발음 등의 기능적인 면과 환자의 심리적 안정성 및 만족도에서 이점을 갖는다. 본 증례에서 환자는 치주질환에 이환된 국소의치의 지대치를 모두 발거한 상악무치악 상태로, 7개의 임플란트를 식립하여 임플란트 지지 고정성 보철물로 수복하였다. 잔존 치조골의 흡수가 심한 전치부 골 결손부위에는 적절한 상순 지지를 얻기 위해 부피가 큰 지르코니아 하부구조물을 제작하였고, 치경부에 분홍색 도재를 축성하여 치은 연조직의 색조 및 외형을 재현하였다. 치료 후 9개월간의 임상 관찰에서 환자는 심미적, 기능적으로 만족하였고, 보철물은 합병증 없이 안정적으로 유지되었기에 이에 보고하고자 한다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제29권5호
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• pp.444-450
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• 2007

In general, labiolingual or buccolingual widths of residual alveolar bone are insufficient in edentulous area, because of alveolar resorption. Horizontal augmentation is bone graft procedure with a view to reinforcing horizontally insufficient bone quantity for installation of implants. The standard method is taking appropriate amount of block bone from intraoral or extraoral autogenous bone, and solid fixation with screws or mini-plate on labial or buccal side of residual alveolar bone. The purpose of this study is to discuss clinical usefulness of horizontal augmentation with autogenous block bone by observation and analysis of course of 41 implants installed to 12 patients by horizontal augmentation in Seoul National University Bundang Hospital from July, 2002 to December, 2005. The mean age of patients is 52.7, from 19 to 70, and the number of men and women is each 2 and 10. Block bone was taken from symphysis, body, ramus of mandible or iliac bone. And 6 types of implants were installed simultaneously or not, the diameters of implants are from 3.3 to 5.5mm, the lengths are from 8 to 15mm. The operator added artificial bone grafting material and optionally covered with membrane. The mean periods of observation after operation and final prosthetics were 28.6 and 17.0 months. As a result, 40 among 41 implants survived, the survival rate was 97.6%. Average 0.9mm crestal resorption was observed at final point of time by periapical view of each patients. Major complication related to the procedure was numbness in 7 patients.

• 대한소아치과학회지
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• 제32권3호
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• pp.403-408
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• 2005

치아유착은 치근의 상아질 또는 백악질이 치조골과 융합된 것으로 치아의 맹출이상을 야기하여 치조골 성장의 장애를 일으킨다. 본 6세 여아는 유구치의 유착과 영구 소구치의 결손을 주소로 본과에 의뢰되었으며 특이할 만한 의과적, 치과적 병력은 없었다. 구강 검진 소견상 상, 하악의 좌, 우측 유구치에서 저위교합이 관찰되었으며, 다수의 치아우식증이 존재하였다. 방사선 사진 검사 소견상 상악의 좌, 우측 영구 견치와 계승 소구치의 결손, 상악 유구치의 치근흡수와 하악 유구치의 치주인대공간의 소실 및 미약한 치근흡수가 관찰되었다. 계승 영구치의 결손을 동반한 유구치 유착시 치료목표는 적절한 치조골 성장과 유치의 유지이며, 유착의 발현 시기와 치근의 흡수 정도에 따라 관찰, 수복 또는 발치 등의 치료를 고려할 수 있다. 유착치아의 발치는 인접 치조골 성장에 문제가 없고 인접치의 경사가 일어나지 않도록 최대성장점(growth spurt)을 고려하여 그 시기를 결정해야 한다.