• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.23 no.1
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• pp.95-100
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• 1993

The author observed a case of osteogenic sarcoma in a 11-year-old female with complaint of painful swelling on face in right side. The observed results were as follows: 1. Large hematoma was obsered, and patient complanited painfull swelling on c/c site. 2. Predisposing factor of osteogenic sarcoma was not clear, but patient had history of extraction before patient visiting infirmary of our dental collage. 3. Serologic findings were not specific, and serum alkaline level was normal. 4. Radiographic findings were as follows: ① Diffuse faint radiopacity in the lesion ② Bony destruction and increased radiopaciy in right antrum ③ Displacement of multiple teeth on involved area(i. e ;＃12, 15. 55, 16, 17, 18), ④, Increased periodontal space in singel tooth(＃13) ⑤Destruction of bony crypt on involved teeth(＃13, 14, 15, 17, 18) ⑥ Loss of lamina dura of three teeth in involved area(＃11, 12, 16) 5. Computed tomographic findings were as follows: ① Large calcific and hetergenous component mass in the Rt. maxillary sinus, and this mass extending to Rt. maxilla, alveolar bone, ethmoid sinus. ②, Soft tissue bulging into Rt. side nasal cavity and oral cavity. ③ Bone destruction of maxillary sinus wall and Rt. alveolar bone.

• Journal of the Korea Society of Computer and Information
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• v.13 no.6
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• pp.107-115
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• 2008

Face feature detection plays an important role in application such as automatic speechreading, human computer interface, face recognition, and face image database management. We proposed a automatic speechreading feature detection algorithm for color image using color information. Face feature pixels is represented for various value because of the luminance and chrominance in various color space. Face features are detected by amplifying, reducing the value and make a comparison between the represented image. The eye and nose position, inner boundary of lips and the outer line of the tooth is detected and show very encouraging result.

• Journal of Korean Dental Science
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• v.3 no.2
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• pp.40-49
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• 2010

Dental clinicians often encounter cases wherein the patient's lost molar area was neglected and left untreated for an extended period of time, thereby causing the extrusion of opposite molars and occlusal disharmony as well as occlusion in the anterior teeth and consequently resulting in anterior displacement in the area. Clinicians normally carry out prosthetic treatment via occlusal plane lifting when such becomes absolutely necessary due to the lack of sufficient space needed for prosthetic therapy aimed at proper anterior and lateral induction. In this case report, we examined occlusal disharmony and VDO loss in a patient who had lost his molars and had not received prosthetic treatment for an extended period of time. We treated the maxillary area with dental implant prosthetics and Kennedy Class I RPD and the mandibular area with residual natural tooth-based implant placement and dental implant prosthetics. The patient reported treatment outcomes that were deemed satisfactory both functionally and aesthetically.

• Journal of Korean Academy of Oral and Maxillofacial Radiology
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• v.15 no.1
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• pp.41-49
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• 1985

The purpose of this study was to evaluate the initial and postoperative radiographic features of the endodontic treated teeth. The author examined the radiographs which comprise 114 teeth with 155 canals of 64 persons. The following factors were considered; Age, sex, tooth location, number of root canals, postoperative periods, initial diagnosis, and radiographic findings, postoperative radiographic findings. The apical levels of the root fillings were 76.8% to apex, 19.0% underfilling, 3.9% overfilling. The following results were obtained. 1. Of the 93 teeth which revealed initial periapical rarefaction, 66 teeth (71.0%) had showed complete bone healing, 19 teeth (20.4%) decreased rarefaction, 6 teeth (6.5%) no change, 2 teeth (2.2%) increased rarefaction after 20.0 months mean healing time. 2. 21 teeth which had no initial periapical rarefaction showed no occurrence of new periapical rarefaction. 3. Of the 66 teeth completely healed, 53 teeth (80.3%) had showed reappearance of lamina dura, 64 teeth (97.0%) reappearance of periodontal ligament space after 23.4 months mean healing time.

• Journal of the Korean institute of surface engineering
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• v.40 no.4
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• pp.197-202
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• 2007

Fit of the restoration and its cementation procedure is crucial to both its short and long term prognosis. Marginal fit is affected by many variables during the fabrication process. These variables, being intrinsic properties of the materials or the clinical technique used, can cause changes in the size and shape of the definitive restoration. Even if all variables are controlled carefully, the seating of a restoration can still be affected due to insufficient space for the luting agent. The use of die spacer can reduce the elevation of a cast restoration of a prepared tooth, decreased seating time, improve the outflow of excess cement, and lower the seating forces. The purpose of this study was to evaluate the marginal fidelity according to die spacer application times and measurement site. Casting alloys were prepared and fabricated using non-precious metal at $950^{\circ}C$. Specimens are divided into four groups: I(die spacer painted casting for wax pattern), II(die spacer non painted casting for wax pattern). The specimens were cut and polished for marginal gap observation. The marginal gap was observed using scanning electron microscopy (SEM).

• Imaging Science in Dentistry
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• v.51 no.3
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• pp.307-311
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• 2021

Purpose: An oroantral communication (OAC) is an abnormal space between the maxillary sinus and oral cavity. The causes, complications, treatment, and radiographic features of OAC in 2-dimensional and 3-dimensional imaging modalities are discussed. Materials and Methods: This pictorial review presents a broad spectrum of imaging findings of OAC. Representative radiographs depicting OAC were chosen from our database. PubMed was used to conduct a comprehensive literature search of OAC. Results: Characteristic features of OAC include discontinuity of the maxillary sinus floor, thickening of the maxillary sinus mucosa, or a combination of both. Two-dimensional imaging modalities are the method of choice for identifying discontinuities in the maxillary sinus floor. However, 3-dimensional imaging modalities are also essential for determining the status of soft tissue in the maxillary sinus. Conclusion: The integration of 2-dimensional and 3-dimensional imaging modalities is crucial for the correct diagnosis and comprehensive treatment of OAC. However, the diagnosis of OAC must be confirmed clinically to prevent unnecessary mental and financial burdens to patients.

• Journal of the Korean Society of Laryngology, Phoniatrics and Logopedics
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• v.33 no.2
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• pp.83-88
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• 2022

Hunminjeongeum had 17 initial consonant letters. Among them, five consonant letters, those are ㄱ (牙音, molar sound letter), ㄴ (舌音, lingual sound letter), ㅁ(脣音, labial sound letter), ㅅ (齒音, dental sound letter), ㅇ (喉音, guttural sound letter), were served as chief consonants. There was no argument that consonant letters were made by symbolizing the shape of vocal organs during phonation of them. It could be phoniatrically explained that all of five chief consonants were morphologically symbolized from left lateral view of vocal tract during articulation. Although 'ㄱ' was known as molar sound, it was not modeled the shape of molar tooth but modeled the shape of tongue at molar teeth bearing area. The same principle applies to 'ㅅ', and it was represented the shape of upper surface of anterior tongue instead of incisor teeth. 'ㄴ' was a lingual sound and directly shaped the shape of tongue. 'ㄷ' was made by addition of a stroke 'ㅡ' meaning hard palate above 'ㄴ'. 'ㅁ' was represented the shape of lateral view of anterior mouth. 'ㅇ' was looked like shaping left lateral view of laryngopharyngeal space.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.48 no.1
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• pp.63-67
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• 2022

Controversies exist regarding the need for prophylactic extraction of mandibular third molars in patients who plan to undergo orthognathic surgery. An 18-year-old male patient was diagnosed with mandibular prognathism and maxillary retrognathism with mild facial asymmetry. He had a severely damaged mandibular first molar and a horizontally impacted third molar. After extraction of the first molar, the second molar was protracted into the first molar space, and the third molar erupted into the posterior line of occlusion. The orthognathic surgery involved clockwise rotation of the maxillomandibular complex as well as angle shaving and chin border trimming. Patients who are missing or have damaged mandibular molars should be monitored for eruption of third molars to replace the missing posterior tooth regardless of the timing of orthognathic surgery.

• The korean journal of orthodontics
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• v.34 no.1 s.102
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• pp.1-11
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• 2004

Predicting the arch length discrepancy by simply comparing the available arch perimeter with tooth materials is merely a 2-dimensional analysis of the teeth movement. However, the real teeth movement takes place 3-dimensionally and is affected by various factors such as, the arch fen the curve of Spee and the axis of the incisors. The purpose of this study is to clarify the relationship between the decrease in the arch perimeter and the horizontal positional change of the incisors after extraction of the 1st bicuspids, for more analytic evaluation of the arch length discrepancy at pre-treatment model analysis stage. In addition to that to evaluate the effect of the curve of Spee, teeth axis to the basal plane, and the incisional crowding to the treatment outcome. All patients were treated at the department of orthodontics, dental hospital, Yonsei university. Inclusion criteria for patients selection were as follows. $\cdot$ Angle classification I malocclusion with bialveolar protrusion $\cdot$ Extraction of 4 1st bicuspids $\cdot$ No tooth anomaly or prosthesis $\cdot$ No abnormal attrition $\cdot$ No ectopically erupted teeth $\cdot$ Angle classification I canine and molar relationship $\cdot$ Less than 3mm of crowding Model analysis of the above patients was performed and the following conclusions were obtained. 1. When the intercanine distance was maintained, the available space for the distal movement of the mandibular incisors after the extraction of the 4 1st bicuspids was larger than the space provided by the extraction of the 4 1st bicuspids. However the difference was less than 1mm. The more tapered the anterior arch form, the larger the difference. 2. Compared to the situation in which the intercanine distance was maintained, when the intercanine distance was expanded to meet the width of the Posterior teeth, the incisors could move about 3mm more distally. 3. The positional difference of the incisal tip was insignificant whether the central incisors were moved by tipping or bodily movement. 4. When the anterior crowding was solved without changing the intercanine distance, the larger the anterior arch length was, the more the anterior movement of the incisors. 5. When the curve of Spee was levelled, the increase in the arch perimeter was less than half of the deepest curve of Spee.

• Restorative Dentistry and Endodontics
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• v.22 no.1
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• pp.1-33
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• 1997

The objective of this study was to analyze the in vitro and in vivo corrosion products of low and high copper amalgams. The four different types of amalgam alloy used in this study were Fine cut, Caulk spherical, Dispersalloy, and Tytin. After each amalgam alloy and Hg were triturated according to the directions of the manufacturer by means of the mechanical amalgamator(Amalgam mixer. Shinhung Co. Korea), the triturated mass was inserted into a cylindrical metal mold which was 12mm in diameter and 10mm in height. The mass was condensed by 150Kg/cm compressive force. The specimen was removed from the mold and aged at room temperature for about seven days. The standard surface preparation was routinely carried out by emery paper polishing under running water. In vitro amalgam specimens were potentiostatically polarized ten times in a normal saline solution at $37^{\circ}C$(potentiostat : HA-301. Hukuto Denko Corp. Japan). Each specimen was subjected to anodic polarization scan within the potential range -1700mV to+400mV(SCE). After corrosion tests, anodic polarization curves and corrosion potentials were obtained. The amount of component elements dissolved from amalgams into solution was measured three times by ICP AES(Inductive Coupled Plasma Atomic Emission Spectrometry: Plasma 40. Perkim Elmer Co. U.S.A.). The four different types of amalgam were filled in occlusal and buccal class I cavities of four human 3rd molars. After about five years the restorations were carefully removed after tooth extraction to preserve the structural details including the deteriorated margins. The occlusal surface, amalgam-tooth interface and the fractured surface of in vivo amalgam corrosion products were analyzed. In vivo and in vitro amalgam specimens were examined and analyzed metallographically by SEM(Scanning Electron Microscope: JSM 840. Jeol Co. Japan) and EDAX(Energy Dispersive Micro X-ray Analyser: JSM 840. Jeol Co. Japan). 1. The following results are obtained from in vitro corrosion tests. 1) Corrosion potentials of all amalgams became more noble after ten times passing through the in vitro corrosion test compared to first time. 2) After times through the test, released Cu concentration in saline solution was almost equal but highest in Fine cut. Ag and Hg ion concentration was highest in Caulk spherical and Sn was highest in Dispersalloy. 3) Analyses of surface corrosion products in vitro reveal the following results. a)The corroded surface of Caulk spherical has Na-Sn-Cl containing clusters of $5{\mu}m$ needle-like crystals and oval shapes of Sn-Cl phase, polyhedral Sn oxide phase. b)In Fine cut, there appeared to be a large Sn containing phase, surrounded by many Cu-Sn phases of $1{\mu}m$ granular shapes. c)Dispersalloy was covered by a thick reticular layer which contained Zn-Cl phase. d)In Tytin, a very thin, corroded layer had formed with irregularly growing Sn-Cl phases that looked like a stack of plates. 2. The following results are obtained by an analysis of in vivo amalgam corrosion products. 1) Occlusal surfaces of all amalgams were covered by thick amorphous layers containing Ca-P elements which were abraded by occlusal force. 2) In tooth-amalgam interface, Ca-P containing products were examined in all amalgams but were most clearly seen in low copper amalgams. 3) Sn oxide appeared as a polyhedral shape in internal space in Caulk spherical and Fine cut. 4) Apical pyramidal shaped Sn oxide and curved plate-like Sn-Cl phases resulted in Dispersalloy. 5) In Tytin, Sn oxide and Sn hydroxide were not seen but polyhedral Ag-Hg phase crystal appeared in internal space which assumed a ${\beta}_l$ phase.