• The Journal of Advanced Prosthodontics
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• 제14권1호
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• pp.1-11
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• 2022

PURPOSE. The maximum width between the mesial and distal labial transitional line angles, described as "esthetic width" herein, could significantly influence the visual perception of the teeth and smile. This study aimed to conduct biometric research on esthetic width and to explore whether regular distribution exists in the esthetic width of human teeth. MATERIALS AND METHODS. A total of 4,264 maxillary and mandibular anterior teeth were measured using the Geomagic studio software program. The proportions of maxillary to mandibular homonymous teeth and proportions between the adjacent teeth were calculated. Bilateral symmetry and the correlation between the esthetic and mesiodistal widths were both accounted for during the measurement procedures. RESULTS. The mean esthetic widths were 6.773 ± 0.518 mm and 4.329 ± 0.331 mm for maxillary and mandibular central incisors, respectively, 5.451 ± 0.487 mm and 5.008 ± 0.351 mm for maxillary and mandibular lateral incisors, respectively, and 3.340 ± 0.353 mm and 5.958 ± 0.415 mm for maxillary and mandibular canines, respectively. Except for the mandibular canines, no significant difference in esthetic width was found among homonymous teeth from the same jaw. A high linear correlation was found between the esthetic and mesiodistal widths of the same tooth, except for the maxillary canines. Esthetic width proportions among different tooth categories showed some regular patterns, which were similar to those of the mesiodistal width. CONCLUSION. Esthetic width is regularly distributed among the teeth in the Chinese population. This could provide an important reference for anterior dental restorations and dimension recovery in esthetic reconstruction of anterior teeth.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제36권5호
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• pp.207-213
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• 2014

Fractures of the mandible occur with a greater frequency in the elderly. This study reports three cases of edentulous atrophic mandible fracture in elderly patients treated with open reduction technique. Three patients who presented with edentulous atrophic mandible fractures underwent surgical management using open reduction and internal fixation. After treatment, clinical evaluations and postoperative complications were examined with postoperative x-ray. Patients were followed with clinical and radiographic examinations. In the postoperative clinical evaluation, two male patients healed well, but one female patient complained of pain and swelling. In radiographic examinations, no union delay or lack of fusion was observed in the edentulous area. Open reduction technique is a viable treatment option for the edentulous atrophic mandible fractures in geriatric patients.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권4호
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• pp.351-358
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• 2010

A 31-year-old woman with hemifacial microsomia presented to the Department of Oral and Maxillofacial Surgery, Seoul National University Dental Hospital. The patient was previously treated with distraction osteogenesis device to elongate right maxilla and mandibular ramus. But, the result was not satisfactory, to correct residual facial asymmetry due to hemifacial microsomia we planned costochondral graft for reconstruction of ramus and condyle, Le Fort I osteotomy and sagittal split ramus osteotomy for facial asymmetry. The right mandibular condyle and ramus was reconstructed with right eleventh costochondral graft via submandibular approach. Using costochondral graft and orthognathic surgery the facial asymmetry in hemifacial microsomia patient was corrected. 1-stage treatment consists of costochondral graft and orthognathic surgery can achieve function and esthetics at the same time, is timesaving to both patient and surgeon.

• 한국방사선학회논문지
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• 제7권4호
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• pp.301-305
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• 2013

Cone Beam CT 데이터를 3차원 컴퓨터 프로그램을 이용하여 기존의 파노라마 영상과 재구성된 파노라마 영상을 재현해서 악궁형태에 따른 치아의 왜곡을 분석하고자 하였다. Cone Beam CT의 횡단면 영상과 재구성 파노라마에서 측정된 치아의 직경은 전치부에서 구치부로 갈수록 큰 변화없이 일치되는 것을 알 수 있었다. 하지만 파노라마는 전치부에서 약간의 왜곡이 보이다가 구치부로 갈수록 왜곡이 더 심한 것을 알 수 있었다. 환자 개개인의 악궁에 맞게 재구성된 파노라마가 일반적으로 사용되는 파노라마 촬영보다 왜곡이 더 감소한다는 것을 알 수 있었다. 또한 파노라마는 전치부에서 구치부로 갈수록 왜곡이 더 심해지는 것을 알 수 있었는데, 이 또한 재구성된 파노라마 영상에서는 왜곡이 감소한다는 것을 알 수 있었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권2호
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• pp.269-278
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• 1996

To overcome the limitations of conventional microsurgical tissue transfer, experimental creation of various neo-flaps using the vessel implantation technique has been reported. We have performed some experiments of fabrication of neo-osseous flap with local vessels and iliac bone slabs to know that the flap vascularity and neo-angiogenesis are achieved enough to microtransfer. As a next step of our previous experiments, the flap viability and the histologic change between the recipient bone and neo-oseous flap was assessed after microsurgical transplantation. The flap was created on the rabbit femoral region(n=25) using femoral vessel and the iliac bone segments($2.5{\times}1.5cm$ in size). Three weeks after neovascularization, the newly formed flap was harvested and microtransferred to the mandibular defect. As a control, contralateral mandibular defect was created and reconstructed with conventional free iliac bone graft. Scintigrams of experimental group performed 3 days after microtransfer showed hot uptake, while that of control poor uptake. Histologic and vital stain labeling study revealed good bone viability and vascularity of neo-osseous flap. In conclusion, prefabricated neo-osseous flap of our model could be transferred to the recipient site with retaining the flap viability and showed advantages over the conventional bone graft in that it was living bone graft.

• 한국정보전자통신기술학회논문지
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• 제8권5호
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• pp.359-366
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• 2015

카이로프래틱 치료에서 측두하악관절(TMJ)는 인체의 균형을 유지하는데 중요한 역할을 하는 관절로서 구강내 교정장치를 통해 인체의 균형을 교정할 수 있게 된다. 현재 이러한 구강내 교정장치의 효과를 스테레오비전을 이용하여 정량적으로 평가할 수 있는 측정 장치가 없었기 때문에 본 연구에서는 이를 측정 할 수 있는 시스템을 개발하였다. 이 시스템은 스테레오 비전과 적외선 조명, 적외선 통과 필터 등으로 구성되어 있으며, 광학식 마커를 피험자의 주요 부위에 부착하여야 한다. 마커의 부착위치는 얼굴의 주요 랜드 마커 중 구강내 교정장치의 착용으로 인해 변화가 나타날 수 있는 8개의 부위를 선택하였다. 개발된 시스템을 이용하여 11명의 피험자를 대상으로 교정장치 착용 전/후 마커의 변화량을 측정하였을 때, 피험자의 얼굴에 부착된 마커의 위치 변화가 정량적으로 측정되었다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제27권5호
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• pp.415-423
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• 2005

Distraction osteogenesis (DO) is frequently used technique in reconstruction of bony defects resulted from tumor resection, congenital deformity, and trauma in the maxillofacial region. Although the histologic and ultrastructural changes associated with distraction osteogenesis have been extensively described, the exact changing of the surrounding tissues, such as nerve tissues, were still unclear. This study observed the histological changes and the expression of nerve growth factor (NGF) in the inferior alveolar nerve (IAN) after distraction osteogenesis. Unilateral mandibular distraction (0.5 mm twice per day for 10 days) was performed in eight mongrel dogs. Two animals were sacrificed at 7, 14, 28 and 56 days after completion of distraction, respectively. The distracted IAN and contralateral control nerve were harvested and processed for histological and innunohistochemical examinations. The signs of acute nerve injuries, such as demyelination and partial discontinuation of nerver fiber, were observed in the distracted IAN on 7 and 14 days after distraction. The initial remyelination and regeneration of distracted IAN were showed at 14 days after completion of distraction. At 56 days later, the histologic features of distracted IAN was similar to those of the normal control IAN. The expression of NGF was significantly increased in most distracted nerve tissues on 7, 14 and 28 days after distraction. On 56 days after distraction, the expression of NGF returned to the normal level. This study suggested that the acute IAN injury caused by mandibular distraction were mostly recovered during consolidation period. The NGF was seemed to be induced from Schwann cell and damaged nerve tissues, and it may have important roles in the initial healing of damaged nerves.

• 대한치과교정학회지
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• 제53권2호
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• pp.77-88
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• 2023

Objective: To develop a method for generating three-dimensional (3D) digital models of the periodontal ligament (PDL) using 3D cone-beam computed tomography (CBCT) reconstruction and to evaluate the accuracy and agreement of the 3D PDL models in the measurement of periodontal bone loss. Methods: CBCT data collected from four patients with skeletal Class III malocclusion prior to periodontal surgery were reconstructed at three voxel sizes (0.2 mm, 0.25 mm, and 0.3 mm), and 3D tooth and alveolar bone models were generated to obtain digital PDL models for the maxillary and mandibular anterior teeth. Linear measurements of the alveolar bone crest obtained during periodontal surgery were compared with the digital measurements for assessment of the accuracy of the digital models. The agreement and reliability of the digital PDL models were analyzed using intra- and interexaminer correlation coefficients and Bland-Altman plots. Results: Digital models of the maxillary and mandibular anterior teeth, PDL, and alveolar bone of the four patients were successfully established. Relative to the intraoperative measurements, linear measurements obtained from the 3D digital models were accurate, and there were no significant differences among different voxel sizes at different sites. High diagnostic coincidence rates were found for the maxillary anterior teeth. The digital models showed high intra- and interexaminer agreement. Conclusions: Digital PDL models generated by 3D CBCT reconstruction can provide accurate and useful information regarding the alveolar crest morphology and facilitate reproducible measurements. This could assist clinicians in the evaluation of periodontal prognosis and establishment of an appropriate orthodontic treatment plan.

• Imaging Science in Dentistry
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• 제32권3호
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• pp.153-157
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• 2002

Purpose : This study was performed to determine the proper reference line for taking axial computed tomograms from which the good cross-sectional views can be reformatted by multiplanar reconstruction. Methods : Three dry mandibles with implanted gutta percha cones in the extracted socket were scanned axially according to 6 reference lines of 2 mandibular positions with computed tomogram Hitachi W550. The accuracy of measurements of the lengths of implanted gutta perch a cones in the each cross-sectional view reformatted from axial computed tomogram by multiplanar reconstruction was evaluated. Results: The difference between the measurements and the real length of implant was smallest in the bucco-lingual views reformatted from the axial views scanned according to the reference line of group V-a. The smaller the angle difference between reference line and occlusal line was, the smaller the difference between the measurements in the bucco-lingual views reformatted from axial views and the real length of implant. The majority of measured widths of implants in the bucco-lingually reformatted views were larger than the actual values. Conclusions : When the mandible is inclined within the limitation of gantry angle and scanned with the reference line coincident with occlusal plane, the bucco-lingual view can be reformatted without deformation of images from the axially scanned images.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제18권3호
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• pp.339-347
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• 1996

하악골 재건을 위한 여러 골이식 방법중 유리혈관화 견갑골은 다른 방법에 비해 여러 가지장점을 갖고 있다. 저자는 독일 Wuerzburg 대학에서 연수중 다수의 하악골 복합결손환자를혈관화 견갑골판을 이용 재건하여 우수한 결과를 얻는 것을 경험하였다. 견갑골 피판은 혈관분포를 보존하면서 여러 군데의 쐐기형 부분절골술에 의해 쉽게 하악골 외형에 따라 형성할 수 있었으며, 대부분의 증례에서 혈관경의 길이는 충분하였고, 수혜부의 조건에 따라 견갑골판 단독으로 또는 피부판을 포함하여 채취되었으며, 공여부의 유병율은 거의 없이 우수한 심미적 기능적 결과를 얻을 수 있었다. 결론적으로 이 유리골관은 다양한 피판의 유용성과 하악골의 3차원적인 재건 그리고 적은 유병율을 가지고 있어, 연조직을 포함한 하악골 복합결손부 재건에 매우 적합하리라 사료된다.