• Maxillofacial Plastic and Reconstructive Surgery
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• v.34 no.6
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• pp.466-472
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• 2012

The loss of mandibular continuity due to trauma, neoplasm, or infection results in major esthetic and biologic compromise. The reconstruction of the mandibular bone defect still poses a challenge to oral and maxillofacial surgeons. There have been a number of variety graft materials. Among them, free block bone graft with rigid fixation has been widely used. However, cases using free block bone grafts may lead to a marked invasion of the donor site, mal-union, and absorption of the block bone. In this respect, particulate cortical bone using a titanium mesh tray can be an effective alternative option in order to achieve a proper bone contour and good oral rehabilitation. We have developed an intraoral approach for the mandibular reconstruction method using a titanium mesh tray with autogenous particulate cortical bone graft.

• The Journal of Korean Academy of Prosthodontics
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• v.45 no.2
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• pp.274-282
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• 2007

Statement of problem: Main consideration was given to the stresses at the site of implant entry into the cortical bone at the alveolar crest. As a suspectible factor affecting the occurrence of stress concentrations, the contact angle between the implant and the alveolar crest bone was addressed. Purpose: The purpose of this study is to evaluate angles between the alveolar crest bone and the implant effect on the implant crestal area induced stresses using a finite element method. Material and methods: Cylindrically shaped, standard size ITI implants entering into alveolar crest with four different contact angles of 0, 15, 30, and 45 deg. with the long axis of the implant were axisymmetrically modelled. Alterations of stresses around the implants were computed and compared at the cervical cortical bone. Results and conclusion: The results demonstrated that regardless of the difference of the implant/alveolar crest bone contact angles, stress concentration occurred at the cervical bone and the angle differences led to insignificant variations in stress level.

• Journal of Korea Multimedia Society
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• v.17 no.3
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• pp.342-352
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• 2014

This paper proposes an automatic segmentation method of cortical bone and trabecular bone and describes an implementation of structural analysis method of trabecular bone in micro-CT images. The proposed segmentation method extract bone region with binarization using a threshold value. Next, it finds adjacent contour lines from outer boundary line into inward direction and sets candidate regions of cortical bone. Next it remove cortical bone region by finding the candidate cortical region of which the average pixel value is maximum. We implemented the method which computes four structural indicators BV/TV, Tb.Th, Tb.Sp, Tb.N by using VTK(Visualization ToolKit) and sphere fitting algorithm. We applied the implemented method to twenty proximal femur of mouses and compared with the manual segmentation method. Experimental result shows that the average error rates between the proposed segmentation method and the manual segmentation method are less than 3% for the four structural indicatiors. This result means that the proposed method can be used instead of the combersome and time consuming manual segmentation method.

• The Journal of the Korean bone and joint tumor society
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• v.5 no.3
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• pp.155-161
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• 1999

This study was performed to document the morphologic relationships between non-ossifying fibroma (NOF) and fibrous cortical defect (FCD), as well as to determine any new diagnostic clues. Eighteen patients with 21 NOFs and 14 patients with 15 FCDs found incidentally on radiography were included. The authors prospectively performed CT, MRI, or both on all subjects. The study included size, location, sclerotic property and contour of the periphery, as well as calcification of the matrix of the lesions and the distance from the lesion to the growth plate. The morphologic characteristics were thoroughly reviewed focusing on the presence of the cortical tract in the lesions. The size of the lesion and the distance from the growth plate were not correlated with the patient' age. The presence of the cortical tract was noted in 18(85.7%) out of 21 NOFs, and 10(66.7%) out of 15 FCDs. The presence of the cortical tract was correlated with the longitudinal length of the lesion and the distance from the growth plate. The presence of the cortical tract may be one of the important characteristics in NOF and FCD, and if the diagnosis of bony lesions is obscure by radiologic finding, its exsitence may be a good indicator of diagnosis for NOF or FCD.

• Proceeding of EDISON Challenge
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• 2016.03a
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• pp.240-245
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• 2016

In this paper, stress contour plots depending on length, load, and diameter of the implant are presented. Depending on the condition and amount of cortical bone, process of implanting can be difficult and stress becomes important. Therefore deciding the right length and diameter of implant is critical. When analyzing stress in the implant, Von-mises yield criterion is often used; however, due to hardship of acquiring the actual material property of surrounding bones, simplified model of a implant was adapted in finite element analysis program of EDISON. The result acquired from EDISON program was then compared with results of different research papers.

• Imaging Science in Dentistry
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• v.51 no.1
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• pp.81-86
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• 2021

Purpose: This study was performed to assess and describe the imaging features of 40 cases of Stafne bone defects (SBDs) on computed tomographic (CT) examinations. Materials and Methods: This study collected data, including age and sex, from 40 patients with SBDs who underwent CT exams. The imaging features of the SBDs were assessed in terms of their location, average size, the relationship of their contour with the cortical plate of the lingual mandible, bone margins, degree of internal density, shape, topographic relationship between the defect and the mandibular edge, the distance from the SBD to the base of the mandible, and the Ariji classification (type I, II, and III). Results: The average age was 57.3 years(range, 28-78 years), and the patients were predominantly male (70%). In all cases (100%), the posterior unilateral lingual SBD variant was observed. Within the Ariji classification, type I was the most common (60%). Among the most frequently observed radiographic characteristics were thick sclerotic bone margin across the entire defect contour, completely hypointense internal content, an oval shape, and continuity with the mandibular base with discontinuity of the mandibular edge. Conclusion: This study showed that posterior SBDs could present with an oval or rounded shape, complete hypodensity, and thick sclerotic margins. Likewise, SBDs could appear almost anywhere, with minor differences from the classic SBD appearance. It is fundamental for dental practitioners to know the imaging features of SBDs, since they are diagnosed primarily based on imaging.

• Journal of Dental Rehabilitation and Applied Science
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• v.22 no.1
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• pp.55-74
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• 2006

The external contour of an implant can have significant effects on the load transfer characteristics and may result in different bone failure rates for different implant system. The purpose of this study was to investigate the effects of crest module shape and occlusal load direction on bone failure modes of five commercially available dental implant systems. Five different implant systems with internal connection; ITI (Model 1), Astra (Model 2), Bicon (Model 3), Friadent (Model 4), and Paragon (Model 5), comparable in size, but different in thread profile and cest module shapes, were compared using the finite element method. Conclusively, in the internal connection system of the implant-abutment connection methods, the stress-induced pattern at the supporting bone according to the abutment connection form had differenence among them, and implants with narrowing crestal module cross-sections at the top of the cortical bone created more favorable load transfer characteristics in this region. But it is considered that the future study is necessary about how this difference in the magnitude of the stress have an effect on the practical clinic.

• Archives of Craniofacial Surgery
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• v.21 no.3
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• pp.193-197
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• 2020

Juvenile psammomatoid ossifying fibroma (JPOF) is a rare, benign, fibro-osseous variant of ossifying fibroma. It exhibits short-term rapid growth and has a high recurrence rate. Herein we describe a case of JPOF of the maxilla that was treated via complete excision utilizing an intraoral approach with immediate reconstruction using an iliac bone graft, in conjunction with a comprehensive review of the literature. A 20-year-old man presented with a mass on his right cheek that he reported had been growing over the last 10 months. In that cheek he had noticed fullness and experienced pressure, tenderness, and fluffiness, with no other ophthalmic or dental symptoms. After clinical, radiological, and histological examinations, the diagnosis was confirmed as JPOF. Surgical excision was performed, followed by immediate reconstruction with an autologous iliac cortical and cancellous bone graft harvested from the right iliac crest under general anesthesia. Good cicatrization of the intraoral surgical wounds and right iliac crest were evident. He was monitored for 6 months after the surgery and exhibited appropriate midfacial contour. There were no signs of recurrence or complications.

• Journal of Korean Foot and Ankle Society
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• v.23 no.4
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• pp.183-188
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• 2019

Purpose: Bone contusion is usually treated with conservative therapy for 3 months. Bone contusion around knee and hip joints has been extensively reported on, but there are scant reports on this condition in foot and ankle joints. This study evaluated the nature, characteristics and location of bone contusion around foot and ankle joints to enlighten clinicians on how to better treat this disease entity. Materials and Methods: We classified bone contusion of the 76 patients into three types (102 sites; 47 ankle sprains, 18 traffic accidents, 11 falls) according to the Costa-Paz system with employing magnetic resonance imaging (MRI), and the study then analyzed the common sites and areas of occurrence according to the mechanism of injury and duration of pain after first conducting conservative therapy. Results: Of the 76 patients (102 sites) on the MRI, 43 case (42.2%) for talus, 19 cases for distal tibia, and 12 cases for calcaneus were involved. The classification, according to the Costa-Paz system, was Type I, 51 cases; Type II, 32 cases; and Type III, 19 cases. The duration of pain after conservative treatment was 12.15±2.17 weeks for Type I, 14.5±2.15 weeks for Type II, and 21.0±3.8 weeks for Type III. Conclusion: The most common location of post-traumatic bone contusion around both the foot and ankle is the talus, distal tibia, and calcaneus. The most common type of injury noted on MRI is a diffuse signal with change of the medullary component (Type I), In cases of bone contusion extending to a subjacent articular surface or disruption or depression of the normal contour of the cortical surface (Types II, III), the patients' pain appears to last longer. Thus, it is necessary to consider a longer period of conservative treatment in cases of Types II and III bone contusion because the patients' pain may last longer than 3 months.

• Archives of Craniofacial Surgery
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• v.24 no.2
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• pp.59-65
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• 2023

Background: Fibrous dysplasia (FD) is a localized bone disorder in which fibro-osseous tissue replaces the normal bone structure. Patients with craniofacial FD often present with gradual swelling, deformity, and compromised vision or hearing. We previously introduced "the core extirpation method," a novel surgical technique that is minimally invasive like traditional bone shaving but has longer-lasting effects. This study presents the long-term outcomes of our core extirpation method. Methods: We conducted a retrospective analysis of patients who underwent core extirpation for FD of the zygomaticomaxillary region from 2012 through 2021. Computed tomography (CT) scans were performed 6 to 12 months before the operation, immediately before and after the operation, and during follow-up visits. We performed all operations using the upper gingivobuccal approach, and we extirpated the core of the lesion while preserving the cortical structures of the zygoma and the maxilla to maintain symmetrical facial contour. Results: In 12 patients with lesions in the growth phase, anteroposterior/mediolateral (AP/ML) length discrepancies and the volume increased between preoperative and immediate postoperative CT scans. All patients' immediate postoperative AP/ML discrepancies were stable up to 12-17 months postoperatively. Postoperative volume showed continuous lesion growth; the median volume growth rate was 0.61 cc per month. Conclusion: In this article, we present our experiences managing FD using the minimally invasive core extirpation technique, which entails small expected blood loss and can be performed as day surgery. It provides similar cosmetic outcomes as traditional bone shaving but with longer-lasting results. Although there are some limitations with the study's retrospective nature and small sample size, our 4-year follow-up results show promising results of the core extirpation method in well-indicated patients.