• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.13 no.1
• /
• pp.29-73
• /
• 1983

The age related changes in the life cycle of the progenitor cell population of murine oral epithelia was studied. Using radioautographic methods which have been adopted in previous cell cycle studies, the age-related changes of different phases in renewing cells of the palatal, buccal and lingual mucosae were determined. The results confirm published findings on cell cycle changes of epithelia with aging and illustrated further that mitotic phase which has hither to been considered stationary, also changes with aging. The major parts revealed by this study are as follows: 1) The basal progenitor cells in different regions of oral mucosa have different generation times. 2) The basal cell cycle time increases as a function of aging and the region most affected by aging appears to be the epithelium of the cheek. 3) The phases of the cell cycle affected by the process of aging are in increasing order of magnitude: M-, S- and G₁-phase. 4) The age elated change in the number of DNA synthesizing basal progenitor cells occurs at two age periods. Between 1 and 12 months of life it decreases, while from 12 to 20 months it increases.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
• /
• v.24 no.1
• /
• pp.7-21
• /
• 1994

Fifty-two cases of traumatic bone cysts in 50 patients were analysed clinically and radiologically. The obtained results were as follows; 1. Women showed a slightly higher incidence than did men (56% of patients) and the average age proved to be 18.6 years. 2. The majority of the cases were asymptomatic. being detected incidentally. and over the half of the cases occurred in the mandibular symphyseal region. 3. All cases were unilocular and the largest diameter of the lesions varied from 1 to 10㎝, mean 3㎝. 4. Some degree of marginal condensation was present in 28 cases and 23 cases presented pencil-sketch appearance. 5. Many anatomical cortical plates (especially, mandibular inferior cortex and lamina durae) consisted of the margin of the lesions partly. 6. Erosive change of the mandibular inferior cortex was caused by 12 cysts, but cortical expansion only by 3 cysts including 2 cases of buccal expansion. 7. The lesion enveloped the roots of the adjacent teeth in 27 cases and scalloping was present between roots in 17 cases. 8. Lamina dura of the teeth was destroyed by only 1 cyst, and in 1 case root resorption was noticed. But there was no divergence of the roots of teeth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• v.35 no.5
• /
• pp.380-383
• /
• 2009

Osteoma is a slow growing benign osteogenic lesion characterized by proliferation of compact or cancellous bone. Osteomas may be classified as peripheral, central, or extraskeletal. Central osteoma arise from the endosteum, pheripheral osteoma from the periosteum, and extraskeletal soft tissue osteoma within a muscle. Peripheral osteoma of the mandible is uncommon. They manifest as asymptomatic, fixed tumors of bony-hard consistency that may be sessile or pedunculated. Radiographically, a well circumscribed round or oval radiopaque mass is seen. Here, we report a case of a huge solitary peripheral osteoma of the buccal posterior mandible in a 40-year-old woman who was otherwise in good health. The patient visited at the dental clinic because the lesion makes esthetic problem. Treatment was performed by surgical esthetic recontouring and histological examination. The patient remains free of recurrence after surgical esthetic recontouring operation.

• The Journal of Korean Academy of Prosthodontics
• /
• v.40 no.1
• /
• pp.30-41
• /
• 2002

This study was to evaluate the fabrication method and marginal adaptation of the conical inner crown fabricated with CAD/CAM. The informations on abutment teeth were transferred to a computer with a micro contact digitizer, which had a $50{\mu}m$ accuracy on the master die. A conical inner crown was designed on a computer and a real crown was machined based on this design using CAM. The marginal fit of a computer-machined conical inner crown was assessed using electron microscopy Measurement of the marginal gap between the conical inner crown and the abutment was performed on four different locations (mesial, distal, buccal, and lingual surfaces) of the finish line. The evaluation was based on 10 test specimens. The results were as follow. 1 The mean marginal gap between the conical inner crown and abutment tooth was $83.2{\pm}43{\mu}m$, 28.9% of the specimen showed marginal gap over $100{\mu}m$. 2. The fabrication method using CATRS and CAM provided clinically acceptable marginal fitness compared to conventional casting method (P<0.05).

• The Journal of Korean Academy of Prosthodontics
• /
• v.30 no.2
• /
• pp.203-224
• /
• 1992

The purpose of this study was to evaluate the stress distribution developed in supporting structures by distal extension removable partial denture with 4-types of direct retainer. The direct retainers examined were Akers clasp, RPI clasp, RPA clasp and RPL clasp in bilateral & unilateral free end case. 3-dimensional photoelastic stress analysis was used to record the isochromatic fringe patterns and to calculate the compressive stress at measuring points. The results were as follows. 1. In bilateral free end case, RPI clasp exhibited the similar stress distribution on distal and mesial alveolar crest but Akers clasp exhibited higher stress concentration on distal alveolar crest than mesial alveolar crest. 2. In bilateral free end case, RPA clasp and RPL clasp exhibited the similar stress distribution on distal and mesial alveolar crest and RPL clasp exhibited higher stress concentration on buccal alveolar crest than lingual alveolar crest. 3. Akers clasp produced high stress concentration on residual alveolar ridge distally, but RPI clasp, RPA clasp and RPL clasp produced even stress distribution on residual alveolar ridge. 4. Removable partial denture in unilateral free end case exerted higher stress on abutment tooth root apex than bilateral distal extension removable partial denture.

• The Journal of Advanced Prosthodontics
• /
• v.5 no.4
• /
• pp.434-439
• /
• 2013

PURPOSE. The aim of the present study was to evaluate the effects of posts with different morphologies on stress distribution in an endodontically treated mandibular premolar by using finite element models (FEMs). MATERIALS AND METHODS. A mandibular premolar was modeled using the ANSYS software program. Two models were created to represent circular and oval fiber posts in this tooth model. An oblique force of 300 N was applied at an angle of $45^{\circ}$ to the occlusal plane and oriented toward the buccal side. von Mises stress was measured in three regions each for oval and circular fiber posts. RESULTS. FEM analysis showed that the von Mises stress of the circular fiber post (426.81 MPa) was greater than that of the oval fiber post (346.34 MPa). The maximum distribution of von Mises stress was in the luting agent in both groups. Additionally, von Mises stresses accumulated in the coronal third of root dentin, close to the post space in both groups. CONCLUSION. Oval fiber posts are preferable to circular fiber posts in oval-shaped canals given the stress distribution at the postdentin interface.

• Archives of Craniofacial Surgery
• /
• v.9 no.1
• /
• pp.38-40
• /
• 2008

Purpose: Lymphangioma circumscriptum is a rare, congenital benign hamartous malformation, caused by the saccular dilatation of lymph channels lines by normal, single cell, lymphatic endothelia that present as local eruptions of persistent, grouped, translucent vesicles. The lymphangioma circumscriptum lesions may occur on axillary fold shoulder, neck proximal limbs and buccal mucosa. We reported a rare case of lymphangioma circumscriptum on the scalp. Methods: A 15-year-old girl with a $5{\times}3cm$ sized lymphangioma circumscriptum on scalp was examined. It was defined a boundry by ultrasound. And then, a tissue crescent type expander with 120 cc normal saline was inserted on occipital area for a month. After confirmed safety margin of the excised lymphangioma circumscriptum on frozen biopsy and the scalp flap was elevated and covered with empty space. Results: A histopathologic finding revealed that lymphangioma circumscriptum. During 11 months follow up, no relapse was found. Conclusion: We described a rare case of lymphangioma circumscriptum on scalp. By using a tissue expander and excision, we achieved no recurrence and aesthetically satisfactory outcome.

• Archives of Craniofacial Surgery
• /
• v.9 no.2
• /
• pp.51-54
• /
• 2008

Purpose: The choice of open versus closed reduction for mandibular subcondylar fracture is a debatable issue. To evaluate the advantage of open approach to closed method with IMF(intermaxillary fixation), we conducted a retrospective study to compare the outcomes of each method. Methods: From 2002 to 2006, 29 patients with mandibular subcondylar fractures were treated by open or closed reduction. 17 patients were treated by open reduction and 12 patients by closed reduction and IMF. Each group was assessed for duration of mandibular immobilization, incidences of buccal palsy, malocclusion, TMJ(temporomandibular joint) pain, and deviation of the mandible on mouth opening. Results: All cases showed accurate reduction in anatomical position, no significant displacement and no deviation on mouth opening during the follow-up period. IMF period is statistically shorter in open reduction (p<0.05). Differences in incidence of other complications were not significant statistically. Conclusion: As there are significant independent morbidities associated with IMF which requires postoperative rehabilitation, prolonged temporomandibular immobilization should not be overlooked. Some patients with poor compliances will not tolerate IMF in nonsurgical treatment. In the aspect of patient's convenience and early recovery by short IMF period, open reduction would be recommended as a better treatment method.

• The Journal of Korean Academy of Prosthodontics
• /
• v.38 no.1
• /
• pp.59-72
• /
• 2000

This study was performed to investigate the effects of tooth mobility and design of the direct retainer on the stress of supporting tissues in distal extension removable partial denture. Tooth mobility was simulated and four different types of direct retainer such as Alters clasp, I-bar clasp, wrought wire clasp, and Dalbo attachment were designed and stress on the support-ing tissues were measured and analyzed with straingauge method. The following conclusions were drawn from this study. 1. The stress revealed at the lingual side of alveolar bone of the abutment tooth in edentulous area was the largest. 2. The stress at the lingual side of alveolar bone of the abutment tooth in edentulous area was increased according to the increase of tooth mobility in I-bar clasp and Dalbo attachment. 3. The stress at the residual ridge crest was the great in Dalbo attachment on mobility 0, in I-bar clasp on mobility 1, and in wrought wire clasp on mobility 2. 4. There was little changes of stress according to the increase of tooth mobility at buccal and lingual side of the residual ridge crest and around the abutment teeth in dentulous area.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.17 no.4
• /
• pp.407-414
• /
• 1995

The information concerning epithelial dysplasia of the oral cavity has been relatively little published. Of the histolgic grades, most of the cases were classified as moderate and severe category. Their ages ranged from 27 to 78 years(mean 57 years). The developmental incidence by sex was superior in male by ratio of 6 : 1. Epithelial lesions were located in the buccal mucosa, Floor of the mouth, the gingiva and the tongue. It is generally believed with a few exceptions that mild degree of epithelial dysplasia do not indicate any great danger for the patient. But severs dysplasia indicates that there is a very considerable risR of malignant transformation. Surgical excision is the effective method of controlling epithelial dysplasia. The authors investigated 7 cases of epithelial dysplasia histopathologically, 2 patients of them had malignant transformation. We discuss the clinical feature, treatment, prognosis, and histopatholgic analysis with literature reviews.