• Imaging Science in Dentistry
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• v.40 no.2
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• pp.59-62
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• 2010

Purpose : To investigate and compare the prevalence, size, and location of maxillary sinus septa on panoramic and cone beam computed tomography (CBCT) images. Materials and Methods : Two hundred patients who had taken both panoramic and CBCT images were included. The location of maxillary sinus septa on the panoramic radiographs were recorded and confirmed on the CBCT images. Also the size of septa was measured on the reformatted CBCT images. Results : The prevalence of the patients who had maxillary sinus septa was 51.0% and they showed 179 septa totally. Among them 51.0% of the patients had one septum, 32.4% two septa, 13.7% three, and 2.9% four. The measured heights of the septa were $4.37{\pm}2.87\;mm$, $3.51{\pm}2.47\;mm$, and $3.04{\pm}2.37\;mm$ in the medial, middle, and lateral areas, respectively. It was revealed that 1.0% was located at canine region, 18.0% at first premolar, 25.0% at second premolar, 22.7% at first molar, 19.8% at second molar, and 14.0% at third molar region. Among 213 septa depicted by the panoramic radiographs, only 69.0% were confirmed at the CBCT images. Conclusion : Since various heights and courses of the septa can develop in all parts of the maxillary sinus, adequate assessment of the inner aspect of the maxillary sinus is essential to avoid complications during sinus augmentation procedures. CBCT scanning is the preferred radiographic method for detecting the presence of sinus septa.

• Imaging Science in Dentistry
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• v.52 no.4
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• pp.429-434
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• 2022

Supernumerary teeth that are present in the molar region may be evident based on crowding and impaction, but most cases are asymptomatic and discovered as incidental findings during routine radiological examinations. This article reports the case of a 29-year-old woman who presented with a severe feeling of pressure in the region of the maxillary third molars that had been increasing in intensity for weeks. A clinical examination revealed crowding of the maxillary anterior teeth despite the completion of orthodontic treatment and an erupted third molar with localized gingivitis in the second quadrant. A radiographic examination revealed bilateral supernumerary maxillary fourth and fifth molars, so cone-beam computed tomography was performed to locate the supernumerary teeth precisely for a preoperative diagnosis and comprehensive treatment planning. This report presents the radiological and surgical case management of a rare case of bilateral supernumerary molars and reviews the literature regarding epidemiology and treatment options.

• The Journal of the Korean dental association
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• v.16 no.11 s.114
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• pp.857-860
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• 1978

An instance of dentigerous cyst, 6×2.5×1.5cm, occurred in posterior region of the right mandible, originated from 3rd molar, involved the 2nd premolar, 1st and 2nd molar in a 38-year-old man was observed and surgical enucleation followed by careful excision of all cyst wall was successfully carried out, recovery and healing were rapid and uncomplicated.

• The Journal of the Korean dental association
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• v.13 no.4
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• pp.329-334
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• 1975

In 190 dental casts of Korean adults, 78 males and 112 females, the author measured cuspal distances beween the lingual cusps of the samed named teeth. And following conclusions were obtained : 1. In maxillary dental arch, the smallest measurement was revealed in the interpremolar distance in both sexes. 2. In mandibular dental arch, the intercanine distance was the smallest, and then measurements were increased in molar region. 3. In both sexes the intermolar distance was smaller than the central incisor to first molar distance.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.33 no.3
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• pp.110-115
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• 2023

During the Hg₂Br₂ physical vapor transport process, with increasing the partial pressure of component B, P_B from 40 Torr to 200 Torr, a unicellular convective flow structures move from the crystal growth region to the center region in the vapor phase. The boundary layer flow is dominant for P_B = 40 Torr, and the core region flow is dominant for P_B = 200 Torr. The flow in the vapor phase shows a three-dimensional convective flow structure with a single cell (unicellular) for P_B = 40 Torr and 200 Torr, exhibits an asymmetrical flow with respect to the x, y central axis under the horizontally oriented configuration with an aspect ratio (length-to-width) of 3 and linear conducting walls. The critical temperature difference between the source and crystal region is about 30 K. The total molar flux of Hg₂Br₂ increases with the temperature difference until the total molar flux reaches the critical value. At the critical total molar flux, the total molar flux abruptly decreases.

• Journal of Periodontal and Implant Science
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• v.25 no.1
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• pp.14-23
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• 1995

Cyclosporin A is a powerful immunosuppressive agent commonly used for patients receiving organ transplants. Like phenytoin and the calcium channel blockers, the drug is associated with gingival overgrowth. The purpose of this study was to compare the correlation with gingival overgrowth score and clinical indices(i.e, : plaque index, papillary bleeding index, probing depth) and correlation with gingival overgrowth score and microorganism distribution in use of phase contrast microscope. After renal tranplant, taking cyclosporin A 40 patients participating in this investigation. Post - transplatation cyclosporin medication period was average $17.53{\pm}15.75$ months. In previous study reported that gingival overgrowth is an adverse side - effects seen in about 25-81% of patient taking cyclosporin A. The results were as follows : 1. Gingival overgrowth prevalence in taking cyclosporin A patients was 77.5%. Prevalence rate of region was anterior region(26 teeth, 55.3%), molar region(14 teeth, 29.8%), premolar region(7 teeth, 14.8%) in turns. Gingival overgrowth score by Angelopoulos & Goaz method was molar region($1.56{\pm}0.81$), anterior region($1.52{\pm}0.75$), premolar region($1.14{\pm}0.90$) in turns. 2. Medication period was not correlation with gingival overgrowth score. 3. Clinical indices and gingival overgrowth score were as follows. 1) Plaque index and gingival overgrowth score was significantly correlated(p

• The korean journal of orthodontics
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• v.26 no.6
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• pp.691-703
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• 1996

Three-dimensional finite element model was made from adult skull to find desirable direction of retraction force to treat skeletal class II malocclusion. The retraction force of 400g was applied to the first molar. The direction of the force application was $23^{\circ}$ downward, parallel, $23^{\circ}$ upward and $45^{\circ}$ upward to the occlusal plane. The stress distribution and the displacement within the maxilla were analyzed by three-dimensional finite element method. The findings obtained were as follows: 1. Maxillary first molar was displaced posteriorly and inferiorly in $23^{\circ}$ downward, parallel, $23^{\circ}$ upward retraction but it was displaced posteriorly and superiorly in $45^{\circ}$ upward retraction. 2. ANS, A point and prosthion were moved posteriorly and inferiorly and pterygomaxillary fissure was moved posteriorly and superiorly. Clockwise rotation of maxilla occurred when retraction force was applied. 3. The degree of clockwise rotation of maxilla was greatest when the force was applied $23^{\circ}$ upward to the occlusal plane and was least when the force was applied $23^{\circ}$ downward to the occlusal plane. 4. Large tensile stress appeared in maxillary first molar and alveolar bone and the infraorbital region of maxilla when the force was applied $23^{\circ}$ downward to the occlusal plane. Tensile stress was smaller as the direction of force move upward. 5. Large compressive stress was appeared in maxillary first molar and infraorbital region in $45^{\circ}$ upward case and large compressive stress occurred in the posterior part of maxilla as the retraction force was upward.

• Journal of Periodontal and Implant Science
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• v.35 no.2
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• pp.371-381
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• 2005

The masticatory function of tooth is maintained by the periodontal health, and periodontal health is also maintained by the masticatory function. Bite forces are withstanded by the PDL, and this thought to be through the viscoelastic theory. Mobility test and Bite force test are used to evaluate the viscoelastic theory of the PDL. In this study, the bite force test was used. In the same conditions of quantity of the supporting tissue, the maximum bite force according to the quality of the supporting tissue was evaluated. The study was conducted on 40 patients with moderate adult periodontitis, who were indications to the modified widman flap treatment. The maximum bite force in the premolar and molar regions were tested before treatment, 3weeks and 4 weeks after treatment. and the results were as follows. 1. In the premolar region, 3 weeks and 4 weeks after treatment showed higher maximum bite force than before treatment. And in the molar region the maximum bite force decreased 3 weeks after treatment, but increased after 4 weeks, compared to before treatment. 2. In the 1st premolar, there were only significant difference between before and 3 weeks after treatment, and between and 4 weeks after treatment. 3. In the 2nd premolar, there were only significant difference between before and 3 weeks after treatment, and between and 4 weeks after treatment. 4. In the 1st molar, there were no significant difference between before, 3 weeks after treatment, 4 weeks after treatment. 5. In the 2nd molar, there were no significant difference between before, 3 weeks after treatment, 4 weeks after treatment. From the results above, it shows that there were improvements in the maximum bite force through specific periodontal treatments, and thus it can be considered in clinical situations, that selection of the prosthodontic material, decisions of extraction, evaluation of the prognosis after periodontal treatment is a helpful method.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.17 no.1
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• pp.209-222
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• 1987

The author invested the gonial angle, the angle of mandibular and mental canal to the lower border of the mandible, and a relationship of the position of the mandibular canal to the root apex of the posterior teeth and the cortical plate of the lower of the mandible. The materials consisted of 458 pantomograms in male and female aged 11-40 and divided into 5 groups at 5 year intervals and subdivided into 3 groups by gonial angle. The results were as follows; 1. The gonial angle decreased with age, but slight increase occurred over 26-30 years. 2. The average angle of the mandibular canal to the lower border of the mandible was 151.6° and did not correlate with age. 3. The average angle of the mental canal to the lower border of the mandible was 36.9° and didn't correlate with age. 4. The angles of mandibular and mental canal to the lower border of the mandible correlated with gonial angle. 5. The distance from the root apex of the posterior teeth to the upper wall of the mandibular canal was most short at the region of the distal root of the mandibular second molar and increased with age at the region of the mandibular second molar. 6. The distance from the lower wall of the mandibular canal to the cortical plate of the lower border of the mandible was most short at the region of the mesial root of the mandibular first molar and didn't correlate with age.

• The Journal of the Korean dental association
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• v.18 no.2 s.131
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• pp.103-108
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• 1980

The occurrence of odontogenic epithelium in the well of a dentigerous cyst is a well known entity. This epithelium usually remains inactive and does not have clinical significance. However, these small inactive islands of epithelium may be stimulated, resulting in an ameloblastoma. Therefore correct diagnosis and proper treatment are very important. A 15 year-old boy came to the outpatient clinic on August 13, 1979. The Chief complaint was pain, difficulty in mouth opening and swelling of the right mandible of 1 month's durations. With the X-ray filming, it was revealed that dentigerous cyst had been originated from the third molar, occurred in posterior region of the right mandible involving the 1st and the and molar and the portion just beneath the sigmoid notch area. Pus discharged from the gingival sulcus distal to the 2nd molar and it was sure that the cyst had been infected. Enucleation performed with careful excision of all cyst wall was successfully carried out, and recovery and heading were rapid and uncomplicated.