• Journal of the korean academy of Pediatric Dentistry
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• v.49 no.1
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• pp.57-64
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• 2022

Additional dentition images are needed because the dentitions are distorted in cone-beam computed tomography (CBCT) due to streak artifacts and non-uniformity of the x-ray beam. The purpose of this study is to evaluate the feasibility of improving the dentition image of CBCT scan with intraoral scanner instead of plaster models. Maxilla images from plaster models, two intraoral scanners, and CBCT of 20 patients aged 12 to 18 were used in this study. With one of the intraoral scanners, the full arch was scanned by three segments and combined into a complete full arch. Virtual skull-dentition hybrid images from intraoral scanners were superimposed with the images from plaster models to evaluate the coordinate value difference and distance at reference points. The results showed that the coordinate value difference and distance were smallest with segmented intraoral scan, which showed only 2 ㎛ distance. Intraoral scan may provide good dentition images for virtual skull-dentition images.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.3
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• pp.619-624
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• 2024

Scaling is one of the most basic dental gum treatments and involves removing tartar that has hardened on teeth. However, inexperienced and unprofessional removal of tartar may damage the gums, resulting in excessive bleeding or damage to the teeth. For this reason, scaling must be done delicately according to the gum structure of various people, and sufficient practice must be provided. Related departments at the university are conducting scaling exercises. However, from the perspective of students who have not had sufficient practice, selecting subjects and conducting practice is not easy, and practice subjects may also avoid participating in practice due to discomfort and anxiety. Accordingly, in this study, we designed and implemented a virtual reality practice system using VR to create a virtual patient rather than an actual subject and implement various gum shapes step by step to enable repetitive practice and various scaling experiences.

• Journal of Dental Anesthesia and Pain Medicine
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• v.24 no.3
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• pp.195-204
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• 2024

Background: Distraction is a technique used to divert a patient's attention from unpleasant procedures. This study aimed to evaluate the effectiveness of kaleidoscopy, virtual reality, and video games in reducing anxiety and pain during invasive dental procedures in children. Methods: Sixty-six children aged 6 to 9 years were randomly assigned to three groups during local anesthesia administration: Group 1 (kaleidoscope), Group 2 (virtual reality), and Group 3 (mobile video games). The anxiety of the children was evaluated using physiological measures (heart rate) at three different time points: before, during, and after the procedure. The Raghavendra, Madhuri, and Sujata pictorial scale was used as a subjective measure before and after the procedure. Subjective measures of pain were assessed using the Wong-Baker Faces Pain Scale. The data were statistically analyzed using the Kruskal-Wallis and Wilcoxon signed-rank tests. Results: In the intergroup comparison, there were no statistically significant differences in the physiological measures of anxiety scores between the three groups before, during, and after distraction. Raghavendra, Madhuri, and Sujata pictorial scale scores were assessed before and after distraction, but no statistically significant differences were observed. Among the three groups, the children in Group 2 showed a significant reduction in pain scores. Conclusion: Compared with kaleidoscopes and video games, virtual reality is a promising distraction technique for reducing dental fear, anxiety, and pain during local anesthesia administration in children.

• Journal of Korea Multimedia Society
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• v.14 no.12
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• pp.1517-1527
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• 2011

This paper presents a motion capture based rehabilitation training system for a lower-limb paretic patient. The system evaluates the rehabilitation status of the patient by using the bend posture of the knees and the weight balance of the body. The posture of both legs is captured with a single camera using the planar mirror. The weight distribution is obtained by the Wii Balance Board. Self-occlusion problem in the tracking of the legs is resolved by using k-nearest neighbor based clustering with body symmetry and local-linearity of the posture data. To do this, we present data normalization and its symmetric property in the normalized vector space.

• Journal of the Korean Society of Radiology
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• v.10 no.1
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• pp.39-44
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• 2016

This study is fulfilled to evaluate the exposure dose nearby a patient during the brachytherapy of the prostate cancer treatment and to minimize the radiation exposure by evaluating the exposure dose of the person near the relevant implanted patient, technicians and gardians. The experiment method is used on the study is MCNPX that is stood on the basis monte-carlo method and implant the source to MIRD-type phantom in $^{192}Ir$, $^{125}I$, and $^{103}Pd$ in virtual space. For dose evaluations according to distance, the radiation dose on the patient near the corresponding implanted patient is evaluated by each distance of 30, 50, 100, 200 cm to anterior from the implanted patient. As a result, $^{192}Ir$ showed a higher dose than $^{125}I$ and $^{103}Pd$ in every distance.

• The Journal of Information Technology
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• v.5 no.4
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• pp.45-55
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• 2002

Virtual Reality(VR) is a new technology which makes humans communicate with computer. It allows the user to see, hear, feel and interact in a three-dimensional virtual world created graphically. In this paper, we introduced VR into psychotherapy area and developed VR system for the exposure therapy of acrophobia. Acrophobia is an abnormal fear of heights. Medications or cognitive-behavior methods have been mainly used as a treatment. Lately the virtual reality technology has been applied to that kind of anxiety disorders. A virtual environment provides patient with stimuli which arouses phobia, and exposing to that environment makes him having ability to over come the fear. In this study, the elevator stimulator that composed with a position sensor, head mount display, and audio system, is suggested. To illustrate the physiological difference between a person who has a feel of phobia and without phobia, heart rate was measured during experiment. And also measured a person's HR after the virtual reality training. In this study, we demonstrated the subjective effectiveness of virtual reality psychotherapy through the clinical experiment.

• Korean Journal of Computational Design and Engineering
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• v.16 no.5
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• pp.315-322
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• 2011

The goal of total knee replacement (TKR) surgery is to replace patient's knee joint with artificial implants in order to restore normal knee joint functions. Since mismatched knee implants often cause a critical balancing problem and short durability, designing a well-fitted implant to a patient's knee joint is essential to improve surgical outcomes. We developed a software system that three-dimensionally (3D) simulates TKR surgery based upon 3D knee models reconstructed from computed tomography (CT) imaging. The main task of the system was to extract precise 3D anatomical parameters of a patient's knee that were directly used to determine a custom fit implant and to virtually perform TKR surgery. The virtual surgery was simulated by amputating a 3D knee model and positioning the determined implant components on the amputated knee. The test result shows that it is applicable to derive surgical parameters, determine individualized implant components, rehearse the whole surgical procedure, and train medical staff or students for actual TKR surgery. The feasibility and verification of the proposed system is described with examples.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.35 no.6
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• pp.381-389
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• 2013

Two patients with partial edentulous maxilla were scheduled to undergo installation of implant fixtures using a tooth-supported surgical template based on computer assisted treatment planning. After 3-dimensional (3D) computed tomographic scanning was transferred to the OnDemand3D (Cybermed Co., Seoul, Korea) software program for virtual planning, fixtures of MK III Groovy RP implant of the Br${\aa}$nemark System (Nobel Biocare AB Co., G$\ddot{o}$teborg, Sweden) was installed using the In2Guide (CyberMed Co., Seoul, Korea) tooth-supported surgical template with a Quick Guide Kit (Osstem Implant Co., Seoul, Korea) system in the posterior maxilla of each patient. Sinus floor elevation with a xenogenic bone graft procedure was also performed simultaneously in one patient. Fixture installations were completed successfully without complications, such as sinus mucosa perforation, bony bleedings, fenestrations, or others. During the last two-year follow-up period after prosthetics delivery, each implant was found to be fine with no other minor complications. The entire procedures are reported and the literatures on use of tooth-supported surgical template was reviewed.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.43 no.4
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• pp.256-261
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• 2017

Objectives: The concept of natural head position (NHP) was first introduced by Broca in 1862, and was described as a person's stable physiologic position "when a man is standing and his visual axis is horizontal." NHP has been used routinely for clinical examination; however, a patient's head position is random during cone-beam computed tomography (CBCT) acquisition. To solve this problem, we developed an accelerometer to record patients' NHP and reproduce them for CBCT images. In this study, we also tested the accuracy and reproducibility of our accelerometer. Materials and Methods: A total of 15 subjects participated in this study. We invented an accelerometer that measured acceleration on three axes and that could record roll and pitch calculations. Recorded roll and pitch data for each NHP were applied to a reoriented virtual image using three-dimensional (3D) imaging software. The data between the 3D models and the clinical photos were statistically analyzed side by side. Paired t-tests were used to statistically analyze the measurements. Results: The average difference in the angles between the clinical photograph and the 3D model was $0.04^{\circ}$ for roll and $0.29^{\circ}$ for pitch. The paired t-tests for the roll data (P=0.781) and the pitch data (P=0.169) showed no significant difference between the clinical photographs and the 3D model (P>0.05). Conclusion: By overcoming the limitations of previous NHP-recording techniques, our new method can accurately record patient NHP in a time-efficient manner. Our method can also accurately transfer the NHP to a 3D virtual model.

• Journal of Dental Anesthesia and Pain Medicine
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• v.20 no.2
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• pp.83-87
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• 2020

Foreign body (FB) ingestion is commonly seen in the ear nose and throat (ENT) field, with different presentations and sequelae. FBs can arrest in the upper aerodigestive tract or continue further down into either the airway tract to the bronchus or the digestive tract to the intestines. The pathway of an FB depends on the size and shape of the FB and how sharp its edges are. Since the 20th century, the use of disposable stainless-steel needles in the oral cavity has proven to be an effective and safe method for performing various intraoral procedures like dental infiltration or a root canal wash. Complications from their use are rare. Generally, dental needle breakages are caused by patients biting the needle, incorrect injection techniques, or inadequate preventative measures. The sudden movement of a patient during a procedure is one of the most common causes of breakage. Occasionally, needles are swallowed during dental procedures such as a root canal. Here, we report a case of a patient that swallowed a broken needle during a dental procedure. A few days later, the patient presented with neck pain, swelling, and a FB sensation. When the patient presented, she claimed that her symptoms had onset after consuming a meal containing duck meat. Initially, the patient was diagnosed as having ingested a duck bone. However, intraoperatively, the FB was discovered to be an injection needle that had migrated from the throat to the neck.