• Imaging Science in Dentistry
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• v.45 no.2
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• pp.95-101
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• 2015

Purpose: This study used cone-beam computed tomography (CBCT) to characterize mandibular molar root and canal morphology and its variability in Belgian and Chilean population samples. Materials and Methods: We analyzed the CBCT images of 515 mandibular molars (257 from Belgium and 258 from Chile). Molars meeting the inclusion criteria were analyzed to determine (1) the number of roots; (2) the root canal configuration; (3) the presence of a curved canal in the cross-sectional image of the distal root in the mandibular first molar and (4) the presence of a C-shaped canal in the second mandibular molar. A descriptive analysis was performed. The association between national origin and the presence of a curved or C-shaped canal was evaluated using the chi-squared test. Results: The most common configurations in the mesial root of both molars were type V and type III. In the distal root, type I canal configuration was the most common. Curvature in the cross-sectional image was found in 25% of the distal canals of the mandibular first molars in the Belgian population, compared to 11% in the Chilean population. The prevalence of C-shaped canals was 10% or less in both populations. Conclusion: In cases of unclear or complex root and canal morphology in the mandibular molars, CBCT imaging might assist endodontic specialists in making an accurate diagnosis and in treatment planning.

• Journal of the korean academy of Pediatric Dentistry
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• v.47 no.2
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• pp.219-227
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• 2020

Tooth eruption involves a complex developmental process of tooth migration from the dental follicular origin to the final occlusion position in the oral cavity via the alveolar process. Disturbance of tooth eruption can occur at any point in a series of eruption stages; however, horizontal impaction of the mandibular first molar and primary retention of the primary mandibular second molar are rarely observed simultaneously. This study describes the treatment for two cases of horizontally impacted first molar with primary retention of primary molar. The primary retention of the primary mandibular second molar was extracted, and orthodontic traction was applied to the horizontally impacted primary mandibular first molar. Subsequently, displacement of the premolar tooth bud was improved and space regaining for eruption was achieved, guiding to normal eruption of the first molar.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.1
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• pp.49-54
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• 2011

A case of Behcet's syndrome found in a 22 years old male was is reported along with the histological and immunohistochemical studiesfindings. He The patient had had received prolonged medical therapy of anti-inflammatory agents for the conjunctival ulcer, genital ulcer, oral ulcer, and intestinal ulcers since the first onset of the Behcet's syndrome about approximately 7 years agoearlier. Recently, he felt the athickening of both corners of his lip causing that caused mouth opening difficultydifficulties. A plastic rReconstructive surgery was performed to enlarge the size of the oral orifice by multiple Z-plasty incisions, and finallywhich resulted in proper enlargement of the circumferential length of the lip. During the operation, a scar-like thick fibrous tissue was obtained and examined pathologically. In theThe microscopic observation the revealed the submucosal lesion was to be diffusely fibrosed with the a distribution of sclerotic collagen bundles. Particularly, sSeveral foci of collagen degeneration were found observed in the deep connective tissue, and the degenerating collagen bundles were gradually lost their fibrillar appearance. In the immunohistochemical observations, the foci of collagen degeneration was were strongly positive for IgK, but almost negative for TNF${\alpha}$ lysozyme, and MMP-3. Taken together, it was presumed that tThe submucosal fibrosis was presumed to have firstly presented in this study was probablybeeninduced by the prolonged anti-inflammatory therapy, which may inhibit the removal of sclerosed collagen bundles by the cell-mediated immunity and proteolytic digestion of macrophages, and that it was secondarily aggravated by the deposition of immunoglobulins derived from an autoimmune origin. Therefore, even after the successful plastic surgery of the lip to ameliorate the mouth opening difficulty, the recurrent submucosal fibrosis of lip should be carefully managed in the follow-up treatment.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.180-184
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• 2011

The mucocele is a mucus extravasation cyst arising from the salivary gland. Although it is a common?lesion of the minor salivary gland, it is uncommon when it originated from the submandibular gland. The ranula is a form of mucocele which specifically occurs in the floor of the mouth and the sublingual gland is generally accepted as the origin of ranula. They can be classified into two types based on extent: simple ranula are confined to the sublingual space and plunging ranula extend into the adjacent space. It is difficult to differentiate the submandibular gland mucocele from the plunging ranula because both of them can occupy the submandibular space. A 37-year old male visited our clinic with the chief complaint of left facial swelling. The patient's history revealed that he had suffered from a cystic lesion on the left side of the floor of the mouth 10 months previously. He supposed the cystic lesion had come from trauma at other dental clinics. Using CT and MRI, we diagnosed a simple ranula on the sublingual space and a submandibular gland mucocele. We then excised the mucocele with the submandibular gland by an extraoral approach and the sublingual gland by an intraoral approach under general anesthesia. We report a rare case of an enormous submandibular gland mucocele which extended into the pterygoid plate and parapharyngeal space with good surgical results.

• Radiation Oncology Journal
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• v.12 no.3
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• pp.315-321
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• 1994

Ameloblastoma is a rare epithelial tumor of the jaw, comprising approximately $1\%$ of all tumors and cysts of odontogenic origin. The tumor has been the subject of much controversy and cliscussion. Amelobiastoma is slow growing, locally invasive, and has a high rate of total recurrence, but rarely metastasizes. This neoplasm has been considered radioresistant, so it has been treated with surgery primarily except some cases. Recently it is suggested that ameloblastoma is radiosensitive, so radiation therapy (RT) would be used in addition to or, in certain cases, in place of surgery. We report these two cases which were referred to the Department of Therapeutic Radiology for deciding tile need of postoperative RT, because amelobiastoma is rare and has been known tot be radioresistant. Postoperative RT was given to one of these two Patients.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.3
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• pp.297-309
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• 2010

The objective of the present study was to perform a fracture analysis on fractured implant fixture after use in vivo and make clear the cause & mechanisms of failure. In case of fatigue fracture, the fractured surface represents fatigue striation. Fatigue striation indicate the progression of the crack front under cyclic loading, are characteristic of stage 2 crack growth. The site of crack initiation and stage 1 crack growth were not easily identified in any of the failure, presumably because of the complex microstructural features of the polycrystalline sample. In case of fractured by overload, dimpled or cleavage surface were observed. Using the interpretation of characteristic markings(ratchet mark, fatigue striation, dimple, cleavage et al) in fracture surfaces, failure events containing the crack origin, crack propagation, material deficiency could be understand.

• International Journal of Oral Biology
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• v.40 no.4
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• pp.175-182
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• 2015

Previous studies suggested that myelinated axons innervating rat molar pulps undergo morphological changes in their peripheral course. However, little information is available on the morphological feature of the parent axons at the site of origin. We therefore investigated the size of the myelinated parent axons and their morphological features at the proximal sensory root of the trigeminal ganglion by horseradish peroxidase (HRP) injection into rat upper molar pulps and subsequent light and electron microscopy. A total of 248 HRP-labeled myelinated axons investigated were highly variable in the size. Fiber area, fiber diameter, axon area (axoplasm area), axon diameter (axoplasm diameter), and myelin thickness were $11.32{\pm}8.36{\mu}m^2(0.80{\sim}53.17{\mu}m^2)$, $3.99{\pm}1.53{\mu}m(1.08{\sim}9.26{\mu}m)$, $8.70{\pm}6.30{\mu}m^2(0.70{\sim}41.83{\mu}m^2)$, $3.13{\pm}1.13{\mu}m(0.94{\sim}7.20{\mu}m)$ and $0.43{\pm}0.23{\mu}m(0.07{\sim}1.06{\mu}m)$, respectively. The g-ratio (axon diameter / fiber diameter) of the labeled axons was $0.79{\pm}0.05$ (0.61~0.91). Axon diameter was highly correlated with myelin thickness (correlation coefficients, r=0.83) but little correlated with g-ratio (r=-0.33) of individual myelinated parent axons. These results indicate that myelin thickness of the myelinated parent axons innervating rat molar pulps increase with increasing axon diameter, thus maintaining a constant g-ratio.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.32 no.6
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• pp.598-602
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• 2006

The lipoma is the neoplasm of mesenchymal origin. Although most lipomas occur on the trunk and the proximal portion of the extremities, lipomas of the oral and maxillofacial regions are relatively rare, approximately 13% of all cases. Lipomas have been found in all age, but usually found between 40 and 60 years of age. Clinically the lipoma is a painless, slowly growing, nearly always benign soft mass. The treatment of choice is a surgical excision, and the recurrence is rare. But the infiltrating lipoma originated from muscle has high recurrence rate. It has ill-defined border and little or no evidence of encapsulation. Histologically there is a consistent infiltration with dissociation of the surrounding muscle fiber. The infiltrating lipoma should be excised with surrounding normal muscle and tissue to prevent the recurrence. This case was a 57-year-old female with a painless swelling of the right cervical and parotid areas which was diagnosed as large infiltrating lipoma by clinical examination and radiographic findings. The patient was treated by surgical excision and showed good functional and esthetic results. Histologically the tumor was diagnosed as infiltrating lipoma with no evidence of malignancy.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.162-168
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• 2007

Oral and maxillofacial infection is the oldest and most common disease in human history. The infection ranges from the low-grade infection that only requires minimal treatment to the high-grade and life-threatening fascial space infection. In this study, the data on oral and maxillofacial infections were analyzed to aid in the diagnosis and treatment, and to predict the prognosis. This report was based on data from 831 patients with oral and maxillofacial infection (394 males and 437 females) who were hospitalized in the Department of Oral and Maxillofacial surgery of Chosun University Dental Hospital from January 1998 to May 2005. The ratio of males to females was 0.9:1. By age, patients between 60 and 70 years old were the greatest in number (17.1%), while only 5.9% of the patients were between 10 and 20 years old. The most common cause of infection was odontogenic origin (84.4%), followed by post-extraction infection (6.2%), unknown (5.9%), and trauma (3.5%). The most common fascial space involved was the buccal space (39.4%), followed by the canine (20.6%), submandibular (15.9%), pterygomandibular (9.5%), submental (7.6%) and sublingual (2.8%) space. The number of the involved fascial space was one (75.2%), two (19.8%), or more than three (5.0%). In terms of the treatment duration, the hospitalization period of 6 to 10 days was the greatest in number (49.9%). All patients had uneventful recovery without major complication. There are statistically significant correlations between age and treatment period, and the involved space and treatment period, but no correlations between the variables of sex and treatment.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.4
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• pp.623-629
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• 1999

The definition of fascial spaces are latent spaces between fascial planes. If infections which spread from dental origin to soft tissue are mild, they are restricted by fascial planes. But, when infections are severe, fascial spaces are often used as a natural pathway which spread to the deep cervical region. If they are not treated at early stage, they may result in the fatal complications as followings; airway obstruction, septicemia, cerebral abscess, and thrombophlebitis etc. The early treatment of fascial space abscess is very important for young children. These case reports present the successful result of fascial space abscess treatment through intracanal drainage without surgical excision. It is proven that the treatment through intracanal drainage has some benefits to the surgical excision, which are as follows: 1) It is economic to the patients or their parents avoiding admission. 2) The treatment procedure is more simple. 3) Childrens can avoid the fearful environment.