• The korean journal of orthodontics
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• v.35 no.4 s.111
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• pp.320-329
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• 2005

The three-dimensional (3D) changes of bone, soft tissue and the ratio of soft tissue to bony movement was investigated in 8 skeletal Class III patients treated by mandibular setback surgery. CT scans of each patient at pre- and post-operative states were taken. Each scan was segmented by a threshold value and registered to a universal three-dimensional coordinate system, consisting of an FH plane, a mid-sagittal plane, and a coronal plane defined by PNS. In the study, the grid parallel to the coronal plane was proposed for the comparison of the changes. The bone or soft tissue was intersected by the projected line from each point on the gird. The coordinate values of intersected point were measured and compared between the pre- and post-operative models. The facial surface changes after setback surgery occurred not only in the mandible, but also in the mouth corner region. The soft tissue changes of the mandibular area were measured relatively by the proportional ratios to the bone changes. The ratios at the mid-sagittal plane were $77\~102\%(p<0.05)$. The ratios at all other sagittal planes had similar patterns to the mid-sagittal plane, but with decreased values. And, the changes in the maxillary region were calculated as a ratio, relative to the movement of a point representing a mandibular movement. When B point was used as a representative point, the ratios were $14\~29\%$, and when Pog was used, the ratios were $17\~37\%(9<0.05)$. In case of the 83rd point of the grid, the ratios were $11\~22\%(p<0.05)$.

• Korean Journal of Head & Neck Oncology
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• v.22 no.1
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• pp.29-32
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• 2006

Background: The location of parotid gland tumors can influence the duration and the difficulty of the operation. If the information about tumor location was available preoperatively, it would allow accurate operative planning and counseling of patients in terms of the length of the operation and the potential morbidity. Methods: This study was based on a retrospective review of 100 patients with parotid gland tumors underwent parotidectomy from January 2000 to October 2005 at Yong-Dong Severance Hospital. Based on computed tomographic(CT) scan findings, 4 landmarks such as facial nerve(FN) line, Utrecht(U) line, Conn's are(CA), and retromandibular vein (RV) were drawn on the scans in same plane. The location of tumors were determined by the landmarks and confirmed by the operative findings. The accuracy of each landmarks was evaluated. To find out the accuracies according to tumor size, the tumors were divided into 2 groups; less than 2 cm and larger than 2 cm in diameter. Results: U line was the most accurate(94%), sensitive(89.3%) and specific(97.7%) in predicting tumor location of the parotid gland. However, in small tumors less than 2cm, FN line (p=0.022) and RV criteria (p=0.028) were more reliable in accuracy. Conclusion: CA, FN line, U line, and RV are all useful landmarks in preoperative prediction for the location of parotid gland tumors. However, U line was the most accurate, but we must consider that proper landmark should be used in prediction according to the size of tumor because the accuracy of landmark may change.

• Journal of the Korean Society of Radiology
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• v.13 no.7
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• pp.955-960
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• 2019

The Computed tomography (CT) scan can have high radiation in a few tests, and this risk is significant given that it is often repeated in one patient. In children, the incidence of radiation-induced cancer is reported because organs are growing, are more sensitive to radiation. 3D printing has recently been studied to be applied to various applications as a research field for 3D printing applications, research on fabrication of radiation shields and materials has been conducted. The purpose of the 3D printer is to replace the existing panel-type shields and to make customized designs according to the shape of the human body. Therefore, research on 3D information processing to be input to the 3D printer is also necessary. In this study, 3D data of the human body surface, which is the preliminary step of the manufacture of patient-specific eye shield using stereo vision depth map technology, was studied. This study aims to increase the possibility of three-dimensional output. As a result of experimenting with this method, which is relatively simple compared with other methods of 3D information processing, the minimum coordinates for 3D information are extracted. The results of this study provided the advantages and limitations of stereo images using natural light and will be the basic data for the manufacture of eye shields in the future.

• The Journal of Korean Academy of Prosthodontics
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• v.36 no.6
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• pp.900-913
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• 1998

Despite of technical difficulties, the combination of occlusal projection and densitometric digital analysis may ultimately provide a means of detection of subtle bone loss at the facial and lingual side of dental implant (Oblique occlusal view is more useful for $ITI^{(R)}$ dental implant due to its contour of shoulder as like tulip flower). In this study, conventional periapical projections of x-ray beam had shown more high sensitivity to detect the bony defects than oblique occlusal projections in alveolar crest obscured by dental implants or not, even if the difference was not statistically significant. Unlike conventional periapical projections. occusal projections combined with densitometric digital analysis technique may provide a means for detection of subtle bone change at the all around of implants without obscuring effect by implant itself. Although the results from this in vitro study were performed under limited circumstances, these results might afford more possibility and versatile modality of diagnosis options to clinician in the implant practice.

• Journal of the Institute of Electronics and Information Engineers
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• v.53 no.12
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• pp.169-174
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• 2016

In this study, we evaluated the virtual reality model for dental implant surgery and discussed about the method to make the surgical environment for virtual reality with practical patient data. The anatomical model for patient face was fabricated by facial and oral scan data based on CT data. The simulation scenario was composed step by step fashion with Unity3D. From incision and sinus bone graft procedure which is needed to this patient model to implant installation and bone graft was included in this scenario. We used the HMD and leap motion for immersiveness and feeling of real operation. Twenty training doctor was attended this simulation study, and surveyed their satisfactory results by questionnaire. Implant surgery education program was showed the possibilities of educational tool for dental students and training doctors. Virtual reality for surgical education with HMD and leap motion had advantages, in terms of cheap prcie, easy access.

• Advances in pediatric surgery
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• v.2 no.2
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• pp.119-128
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• 1996

The survey on branchial anomalies was conducted by Korean Association of Pediatric Surgeons. A total of 173 cases were reported, which were managed by 36 members and cooperators during the three years from January 1, 1993 through December 31, 1995. The following results were obtained by retrospective analysis of the 173 cases of branchial anomalies. The presenting symptoms were cervical mass in 101 cases, pit with or without discharge in 71, cervical abscess in 47 and respiratory difficulty in 3. The average age of the patients with cervical abscess was 52 months. Seventy(79%) of 89 patients with branchial anomalies and a cystic mass had their first clinical manifestations by 1 year of age, while 40(51%) of 78 patients with only a branchial cyst had their first clinical manifestation in first year of life. Radiologic studies were carried out in 77 patients (43%). The preferred diagnostic modalities were ultrasonography(47 patients), simple neck radiogram(19) and CT scan(17). Preoperative diagnosis was correctly made in 156(91%) of 173 patients. Seventeen patients were incorrectly diagnosed as thyroglossal duct cyst in 5 patients, cystic hygroma in 4, dermoid cyst in 3, and lymphadenopathy in 3. There were no remarkable difference in sex and laterality of presentation but bilateral lesions were found in 9(5%) patients and unusual locations of the anomalies were the manubrium, left subclavicular area, median cervial area, preauricular and parotid area. There were 78(45%) patients with cyst, 52(30%) patients with sinus, 35(20%) patients with fistula and 8(5%) patient with skin tag. Embryological classification was possible in only 64(37%) patients. The 2nd branchial anomaly was present in 50(78%), the 1st branchial anomaly in 10(18%), and the 3rd or 4th branchial anomaly in 4(6%). Histopathological study of the lining epithelium(N=134) is recorded that 45% were lined with squamous epithelium, 17% with respiratory epithelium, 6% with. squamous and respiratory epithelium, 14% with inflammatory change. Lymphoid tissue was common(62%) in the wall of the lesions. Twelve(7%) of 158 patients had postoperative complications including wound complication, recurrence and facial nerve palsy.

• The Journal of Korean Medicine
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• v.15 no.2 s.28
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• pp.28-39
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• 1994

Clinical studies were made on 79 cases with thalamic hemorrhage diagnosed by computed tomographic scan and only localized on the thalamic area, were admitted to the Kyung San University Taegu Oriental Medical Hospital from August 1990 to March 1994. The age and sex distribution, sites of hematoma, recurrence rate, incidence of hypertension, inducing factor, prodromal syndroms, symptoms and neurologic signs on admission, relationship between the hospital course and many factors affecting the prognosis such as age, side of hematoma, level of consciousness, volume of the hematoma. ventricular hemorrhage were analysed. The results were summarized as follows; 1. The most prevalent age group was above 60 years of age with 50-59 years, 70-79 years, 40-49 years and 80-89 years of age in the order of frequency. Male to female ratio was 1:1.55. 2. The ratio of left hematoma to the right was 1.32:1. The recurrence rate of cerebrovascular accident was 17.7% 3. The incidence of hypertension was 69.6% and inducing factors of thalamic hemorrhage in the order of frequency were physical work(29.1%), drinking or eating(13.9%), walking(12.7%) and rest(12.7%), The prodromal syndroms were numbness of extremities(5.1%), headache(2.5%), fatigue(2.5%), dizziness(1.3%), insomnia(1.3%), but prodromal syndrom was not found in 89.9% of thalamic hemorrhage. 4. The symptoms and neurologic signs on admission in the order of frequency were motor disturbance(98.7%), dysarthria(82.3%), positive Babinski sign(78.5%), headache(69.6%), dizziness(62.0%). hemisensory deficit(48.1%). nausea or vomiting(39.2%), absent or sluggish light reflex(35.4%), changes of consciousness (35.4%), dysphagia (20.3%), voiding difficulty.(13.9%), facial palsy(6.3%), aphasia(3.8%), seizure(38%), 6th N. palsy(3.8%) and small pupil(1.3%). 5. The rate of improvement was found almost equally in the 4th, 5th and 6th decades, but it was shown with dramatic decrease in the over 7th decades. The hospital course had no relationship with the side of hematoma but the level of consciousness had influence upon the prognosis. 6, The small hematoma had better outcome than large in the volume of hematoma under 15cc, but volume of the hematoma had no influence upon the prognosis because the rate of improvement was 75.0% in the volume of hematoma over 15cc. The hospital course had no relationship with ventricular hemorrhage.

• Archives of Plastic Surgery
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• v.38 no.2
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• pp.173-181
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• 2011

Purpose: Masseter muscle is an important muscle of mastication. Because it has a great influence on the shape of low facial contour, patients who have masseteric hypertrophy show square-shaped jaw appearance. As aesthetic procedures for the reduction of the masseter muscle volume, radiofrequency ablation or botulinum toxin injection is at the center of attention. Authors studied the anatomical measurement of the thickness and width of masseter muscle and the surface mapping of the maximal thickness point using computed tomography (CT) scan to identify the useful guide for the injection of botulinum toxin in masseteric hypertrophy patients. Methods: We analyzed 2 mm-thickness OMU (ostiomeatal unit) CT of 112 normal people (224 masseter muscles) taken from June 2009 to May 2010. First, we measured the thickness, width and depth of the masseter muscle from the skin surface and analysed each by side, sex and age, respectively. The distribution of the thickness of the muscle and the correlation of thickness and width of the muscle were studied also. Second, we underwent surface mapping of the maximal thickness point using CT analysis by means of checking the vertical and horizontal distance from the angle of the mandible. Results: The average thickness and width of the masseter muscle was 17.73 mm and 40.78 mm in the male patients and were 14.33 mm and 37.42 mm in the female patients. Statistically, both figures of the male patients were larger than those of the female patients. However, the depth of the muscle from the skin surface in female patients (7.37 mm) was larger than that of the male patients (6.15 mm). There were no statistical difference in side or age. The width and thickness of the masseter muscle were in the positive correlation. The location of maximal thickness point of the masseter muscle was 27.77 mm vertically and 27.68 mm horizontally in the male patients, and 25.19 mm vertically and 25.42 mm horizontally in the female patients from the angle of mandible. Conclusion: We were able to present statistical evidence of the diagnosis and treatment of the masseteric hypertrophy regarding the anatomical measurements such as the thickness and width. And the maximal thickness point of the masseter muscle may be a useful guide for the clinical procedures of botulinum toxin injection.

• The Journal of Korean Academy of Prosthodontics
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• v.60 no.2
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• pp.202-210
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• 2022

Recently with the advance in digital dentistry, the fabrication of dentures using computer-aided design and computer-aided manufacturing (CAD-CAM) is on the rise. The denture designed through a CAD software can be produced in a 3-dimensional manufacturing process. This process includes a subtractive processing method such as milling and an additive processing method such as 3D printing and in which it can be applied efficiently in more complex structures. In this case, complete dentures were fabricated using Stereolithography (SLA)-based 3D printing to shorten the production time and interval of visits in patient with physical disabilities due to cerebral infarction. For definitive impression, the existing interim denture was digitally replicated and used as an individual tray. The definitive impression obtained with polyvinyl siloxane impression material was including information about the inclination and length of the maxillary anterior teeth, vertical dimension, and centric relation. In addition, facial scan data with interim denture was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a FDA-approved liquid photocurable resin. The denture showed adequate retention, support, and stability, and results were satisfied functionally and aesthetically.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.1
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• pp.34-41
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• 2022

Recently, digital technology and computer-aided design/computer-aided manufacturing (CAD/CAM) environment have changed the clinician treatment method in the fabrication of dentures. The denture manufacturing method with CAD/CAM technology simplifies the treatment and laboratory process to reduce the occurrence of errors and provides clinical efficiency and convenience. In this case, complete dentures were fabricated using stereolithography (SLA)-based 3D printing in patient with mandibular deviation. Recording base were produced in a digital model obtained with an intraoral scanner, and after recording a jaw relation in the occlusal rim, a definitive impression was obtained with polyvinyl siloxane impression material. In addition, facial scan data with occlusal rim was obtained so that it can be used as a reference in determination of the occlusal plane and in arrangement of artificial teeth during laboratory work. Artificial teeth were arranged through a CAD program, and a gingival festooning was performed. The definitive dentures were printed by SLA-based 3D printer using a Food and Drug Administration (FDA)-approved liquid photocurable resin. The denture showed adequate retention, support and stability, and results were satisfied functionally and aesthetically.