• Imaging Science in Dentistry
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• 제45권1호
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• pp.7-13
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• 2015

Purpose: We have developed a new method of segmenting the areas of absorbable implants and bone using region-based segmentation of micro-computed tomography (micro-CT) images, which allowed us to quantify volumetric bone-implant contact (VBIC) and volumetric absorption (VA). Materials and Methods: The simple threshold technique generally used in micro-CT analysis cannot be used to segment the areas of absorbable implants and bone. Instead, a region-based segmentation method, a region-labeling method, and subsequent morphological operations were successively applied to micro-CT images. The three-dimensional VBIC and VA of the absorbable implant were then calculated over the entire volume of the implant. Two-dimensional (2D) bone-implant contact (BIC) and bone area (BA) were also measured based on the conventional histomorphometric method. Results: VA and VBIC increased significantly with as the healing period increased (p<0.05). VBIC values were significantly correlated with VA values (p<0.05) and with 2D BIC values (p<0.05). Conclusion: It is possible to quantify VBIC and VA for absorbable implants using micro-CT analysis using a region-based segmentation method.

• 치과방사선
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• 제21권1호
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• pp.137-143
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• 1991

In the study of the focal trough of panoramic radiograph using Panoura Eight-S (the Yoshida company), a series of 63 X-ray films were taken with the 8-19 metal pins placed in the holes of the plastic model plate and evaluated by 4 observers. The author analized the focal trough defined by the sharpness criteria and calculated dimension of focal trough in the horizontal plane. The results were as follows; 1. Focal trough was not continued in the anterior region within a very high degree of sharpness. 2. With optional sharpness, the width of anterior and posterior focal trough was approximately l3㎜ and 60㎜ respectively. 3. The focal trough was narrow in the anterior region and was flared laterally with symmetry in posterior region. 4. Sharp image began to show at the position of 18㎜ posteriorly from the most anterior position of chin rest.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제40권
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• pp.32.1-32.8
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• 2018

Background: The free vascularized fibula flap presents many advantages such as sufficient length of the bony segment, good vascularization, better quality of the bone, and a long vascular pedicle, but it is also associated with some disadvantages with regard to prosthetic rehabilitation because of its limited height. Improvement in bone height is necessary for ideal dental implant treatment of reconstructed mandibles. Case presentation: For two squamous cell carcinoma patients, mandibular bone reconstruction was performed secondarily with the peroneal flap after tumor resection. Since the bone height was insufficient at the time of implant treatment, occlusion reconstruction by dental implant was performed after vertical distraction osteogenesis. Conclusions: Vertical distraction osteogenesis is a suitable treatment option for alveolar ridge deficiency resulting from fibula transplantation for mandibular reconstruction following tumor surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제32권6호
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• pp.582-587
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• 2010

Pilomatricoma or calcifying epithelioma is a benign tumor of hair follicle origin. Pilomatricoma presents a slowly enlarged and asymptomatic mass that located dermal or subdermal area. It showed mostly on face and upper limb and head and neck represents 50% of all case. And it developed almostly in the first 2 decade of life. Histologically, encapsulated mass composed of solid small basophilic cells and eosinophilic ghost cells. Surgical excision is the treatment choice and rarely recurs. The purpose of this article is to represent of pilomatricoma on subauricular region that treated with mass excision and local transpositional flap. Althrough the presurgical diagnosis of pilomatricoma may be difficult, clinicians must keep in mind the differential of head and neck masses that located subdermal layers.

• Imaging Science in Dentistry
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• 제48권4호
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• pp.295-300
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• 2018

This report presents a clinical case of trauma due to assault with a knife, and describes the importance of using the correct imaging modality in cases of facial penetrating trauma involving the superficial and deep anatomical planes. Penetrating wounds in the maxillofacial region are rare and poorly reported, but can result in serious complications that are difficult to resolve and may compromise the patient's quality of life, especially when large blood vessels or other vital structures are involved. Thus, it is essential to determine the extent of the affected blood vessels and the proximity of the retained object to the anatomical structures. In this case, digital subtraction angiography was the imaging modality chosen. The use of appropriate imaging examinations allows a proper map of the surgical field, reducing the chances of vascular damage during the surgical procedure.

• The Journal of Advanced Prosthodontics
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• 제8권3호
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• pp.229-234
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• 2016

PURPOSE. The purpose of this study was to investigate the demographic patterns of maxillofacial prosthetic treatment to identify the characteristics and geographic distribution of patients with maxillofacial prosthetics in the capital region of Korea. MATERIALS AND METHODS. This retrospective analytical multicenter study was performed by chart reviews. This study included patients who visited the department of prosthodontics at four university dental hospitals for maxillofacial prosthetic rehabilitation. Patients with facial and congenital defects or with insufficient medical data were excluded. The patients were classified into three categories based on the location of the defect. Patients' sex, age, and residential area were analyzed. Pearson's chi-square test with a significance level of 0.05 was used to analyze the variables. RESULTS. Among 540 patients with maxillofacial prosthetics, there were 284 (52.59%) male patients and 256 (47.41%) female patients. The number of the patients varied greatly by hospital. Most patients were older than 70, and the most common defect was a hard palate defect. Chi-square analysis did not identify any significant differences in sex, age, and distance to hospital for any defect group (P>.05). CONCLUSION. The results of this study indicated that there was imbalance in the distribution of patients with maxillofacial prosthetic among the hospitals in the capital region of Korea. Considerations on specialists and insurance policies for the improvement of maxillofacial prosthetics in Korea are required.

• Imaging Science in Dentistry
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• 제48권4호
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• pp.261-268
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• 2018

Purpose: To determine the impact of an image processing technique on diagnostic accuracy of digital panoramic radiographs for the assessment of anatomical structures in paediatric patients with mixed dentition. Materials and Methods: The study consisted of 50 digital panoramic radiographs of children aged from 6 to 12 years, which were later on processed using a dedicated image processing method. A modified clinical image quality evaluation chart was used to evaluate the diagnostic accuracy of anatomical structures in maxillary and mandibular anterior and maxillary premolar region of processed images. Results: A statistically significant difference was observed between pre and post-processed evaluation of anatomical structures(P<0.05) in the maxillary and mandibular anterior region. The anterior region was found to be more accurate in post-processed images. No significant difference was observed in the maxillary premolar region (P>0.05). The Inter-observer and intra-observer reliability of both pre and post processed images were excellent (>0.82) for anterior region and good (>0.63) for premolar region. Conclusion: The application of image processing technique in digital panoramic radiography can be considered a reliable method for improving the quality of anatomical structures in paediatric patients with mixed dentition.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제38권1호
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• pp.55-63
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• 2012

The odontogenic keratocyst (OKC) was originally classified as a developmental cyst, and OKCs were histologically divided into orthokeratotic (O-OKCs) and parakeratotic (P-OKCs) types. Clinical features differ between O-OKCs and P-OKCs with P-OKCs having a tendency to recur after surgical treatment. According to the revised histopathological classification of odontogenic tumors by the World Health Organization (2005), the term keratocystic odontogenic tumor (KCOT) has been adopted to describe P-OKCs. In this retrospective study, we examined 186 KCOTs treated at the Maxillofacial Surgery Department of the Tokyo Medical and Dental University Hospital from 1981 through 2005. The patients ranged in age from 7 to 85 years (mean, 32.7) and consisted of 93 males and 93 females. The most frequently treated areas were the mandibular molar region and ramus. The majority of KCOTs in the maxillary region were treated by enucleation and primary closure. The majority of KCOTs in the mandibular region were enucleated, and the wound was left open. Marginal resection was performed in the 4 patients with large lesions arising in the mandible. In patients who were followed for more than a year, recurrences were observed in 19 of 120 lesions (15.8%). The recurrences were found at the margins of the primary lesion in contact with the roots of the teeth or at the upper margins of the mandibular ramus. Clinicians should consider aggressive treatment for KCOTs because the recurrence rate of P-OKCs is higher than that of other cyst types such as O-OKCs, dentigerous cysts, primordial cysts that were non-keratinized, and slightly keratinized stratified squamous epithelium. Although more aggressive treatment is needed for KCOTs as compared to other cystic lesions, it is difficult to make a precise diagnosis preoperatively on the basis of clinical features and X-ray imaging. Therefore, preoperative biopsy is necessary for selecting the appropriate treatment for patients with cystic lesions.

• Imaging Science in Dentistry
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• 제39권2호
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• pp.99-102
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• 2009

Adenomatoid odontogenic tumor (AOT) is a tumor of odontogenic epithelium with varying degrees of inductive changes in the connective tissue. The common radiographic appearance of AOT is a unilocular radiolucency associated with an unerupted tooth. Detectable radiopacities have been reported in many cases. We present a case of AOT in a 9-year old-female patient. Cystic lesion with numerous, punctuate radiopaque foci was observed on the anterior region of the mandible. These radiopacities were situated mostly on the buccal side of impacted tooth on the multi-planar images of cone beam computed tomograph. Characteristic duct like structures and amyloid like material were observed on histopathologic finding. (Korean J Oral Maxillofac Radiol2009; 39 : 99-102)

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제48권5호
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• pp.315-317
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• 2022

Osseous metaplasia is defined as the formation of lamellar bone inside soft tissue structures where bone normally does not exist. It results from the transformation of non-osseous connective tissue into mature bone. This condition is rare in the oral and maxillofacial region. We report a case of osseous metaplasia of the maxilla, a rare benign tumor in an uncommon region. A 60-year-old male patient visited our clinic complaining of foreign body sensation and asymptomatic swelling on the right palatal side. However, he did not experience pain and reported no local trauma that he could remember. Intra-oral examination revealed an exophytic lesion on the right palatal portion. On computed tomography, there was a round hard-tissue mass approximately 2 cm in diameter on the right palate area. The mass was biopsied and diagnosed as an osseous metaplasia. We review the clinical, radiographic, and histologic features and common causes of osseous metaplasia and report a rare case of osseous metaplasia of the palate.