• 대한치과의사협회지
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• 제58권11호
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• pp.670-682
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• 2020

This research examined the difference in cognitive load and the virtual presence depending on auditory feedback and task difficulty in haptic-based dental simulation. In the field of dental education, practice-centered training using handpiece has been crucial because a practitioner's psychomotor experience has a significant impact on the mastery of treatment skills. For the novice, it is necessary to reduce errors in dental treatment to enhancing skill acquisition in the haptic practice. In the training process, the force-feedback is crucial to elaborate subtle movement to guide what to do and how it should be hard or soft. However, It is not easy to add force-feedback to generate kinetic experience training. As an alternative method, we examined that auditory feedback can help learners' skill training. In this study, we analyzed how the presence/absence of auditory feedback at the different levels of task difficulty impacts learners' psychological demand and virtual presence in the virtual reality simulation. For this study, 29 dental college students participated in a dental simulation. The participants were grouped into two conditions that are with and without auditory feedback. Additionally, two consecutive tooth preparation tasks with different levels of difficulty were used in the simulation. The auditory feedback condition gives alarms to a learner when he treats a non-targeted tooth with a virtual handpiece. The user's cognitive load and virtual presence were measured to examine the effects of auditory feedback. The results revealed that the main effect was found in cognitive loads. Also, a significant interaction effect was shown in the virtual presence. We discussed the effective design methods for the virtual reality-based dental simulation through the result of this study.

• 한국CDE학회논문집
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• 제16권3호
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• pp.216-226
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• 2011

Surgeon dentists usually rely on their experiential judgments from patients' oral plaster casts and medical images to determine the positional and directional information of implant fixtures and to perform drilling tasks during dental implant surgical operations. This approach, however, may cause some errors and deteriorate the quality of dental implants. Computer-aided methods have been introduced as supportive tools to alleviate the shortcomings of the conventional approach. In this paper, we present an approach of 3D dental implant simulation which can provide the realistic and immersive experience of dental implant information. The dental implant information is primarily composed of several kinds of 3D mesh models obtained as follows. Firstly, we construct 3D mesh models of jawbones, teeth and nerve curves from the patient's dental images using software $Mimics^{TM}$. Secondly, we construct 3D mesh models of gingival regions from the patient's oral impression using a reverse engineering technique. Thirdly, we select suitable types of implant fixtures from fixture database and determine the positions and directions of the fixtures by using the 3D mesh models and the dental images with software $Simplant^{TM}$. Fourthly, from the geometric and/or directional information of the jawbones, the gingival regions, the teeth and the fixtures, we construct the 3D models of surgical guide stents which are crucial to perform the drilling operations with ease and accuracy. In the application phase, the dental implant information is combined with the tangible interface device to accomplish 3D dental implant simulation. The user can see and touch the 3D models related with dental implant surgery. Furthermore, the user can experience drilling paths to make holes where fixtures are implanted. A preliminary user study shows that the presented approach can be used to provide dental students with good educational contents. With future work, we expect that it can be utilized for clinical studies of dental implant surgery.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.13.1-13.12
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• 2016

Background: Mandibular motion tracking system (ManMoS) has been developed for orthognathic surgery. This article aimed to introduce the ManMoS and to examine the accuracy of this system. Methods: Skeletal and dental models are reconstructed in a virtual space from the DICOM data of three-dimensional computed tomography (3D-CT) recording and the STL data of 3D scanning, respectively. The ManMoS uniquely integrates the virtual dento-skeletal model with the real motion of the dental cast mounted on the simulator, using the reference splint. Positional change of the dental cast is tracked by using the 3D motion tracking equipment and reflects on the jaw position of the virtual model in real time, generating the mixed-reality surgical simulation. ManMoS was applied for two clinical cases having a facial asymmetry. In order to assess the accuracy of the ManMoS, the positional change of the lower dental arch was compared between the virtual and real models. Results: With the measurement data of the real lower dental cast as a reference, measurement error for the whole simulation system was less than 0.32 mm. In ManMoS, the skeletal and dental asymmetries were adequately diagnosed in three dimensions. Jaw repositioning was simulated with priority given to the skeletal correction rather than the occlusal correction. In two cases, facial asymmetry was successfully improved while a normal occlusal relationship was reconstructed. Positional change measured in the virtual model did not differ significantly from that in the real model. Conclusions: It was suggested that the accuracy of the ManMoS was good enough for a clinical use. This surgical simulation system appears to meet clinical demands well and is an important facilitator of communication between orthodontists and surgeons.

• 한국병원경영학회지
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• 제16권4호
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• pp.161-182
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• 2011

In today's competitive dental markets, it is of paramount importance to improve service quality and at the same time to use scarce resource efficiently. In this study, we present appointment policies and scheduling rules for private dental clinics to reduce the waiting time of patients and to increase the revenue by utilizing resource more effectively. This study validates the proposed appointment policies and scheduling rules based on simulation models. We show that the bottleneck-based appointment policy is the most effective among appointment policies, followed by the multiple-block appointment one. The shortest processing time among scheduling rules contributes most to the performance of the appointment system.

• 치위생과학회지
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• 제12권6호
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• pp.652-659
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• 2012

본 연구는 치위생학 전공 대학생을 대상으로 노인유사체험이 노인에 대한 태도를 긍정적으로 변화시킬 수 있는지 여부를 확인하고자 2012년 5월 27일부터 6월 14일까지 1개 대학교에 재학 중인 치위생학과 학생 58명을 대상으로 실험을 실시하여 다음과 같은 결과를 얻었다. 1. 노인유사체험 후 노인에 대한 전반적인 태도는 긍정적인 방향으로 완전히 전환되지는 않았으나 중립적인 태도에서 좀 더 긍정적인 태도로 변화하였다. 2. 노인과 동거경험이 있거나 노인관련 교육을 받은 경험이 있는 경우 노인유사체험 후 노인에 대해 긍정적인 태도변화를 보였다. 3. 노인유사체험이 노화를 이해하는데 도움이 된 정도를 확인한 결과, 노화의 신체적 측면에 대해 대다수가 매우 도움이 되었거나 도움이 된다고 응답하였다. 이러한 결과를 통해 노인유사체험이 노인에 대한 전반적인 태도를 긍정적으로 변화시키지는 못하였지만 부분적인 항목에서 긍정적인 변화를 이끌어 냄을 확인할 수 있었다. 따라서 노인유사체험은 노화에 대한 신체적인 이해도를 높여 노인에 대한 태도를 보다 긍정적으로 형성하고, 더 나아가 노인에 대한 양질의 구강진료서비스를 제공할 수 있도록 유도하는 의미있는 교육프로그램이 될 것이라 생각된다.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.4.1-4.6
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• 2016

Background: Most cases of facial asymmetry involve yaw deformity, and determination of the yaw correction level is very difficult. Methods: We use three-dimensional soft tissue simulation to determine the yaw correction level. This three-dimensional simulation is based on the addition of cephalometric prediction to gradual yaw correction. Optimal yaw correction is determined visually, and an intermediate splint is fabricated with computer-aided design and computer-aided manufacturing. Application of positioning devices and the performance of horseshoe osteotomy are advisable. Results: With this procedure, accurate repositioning of jaws was confirmed and patients obtained fairly good facial contour. Conclusions: This procedure is a promising method for a widespread, predictable treatment of facial asymmetry.

• 대한치과교정학회지
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• 제48권3호
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• pp.189-199
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• 2018

For patients with bimaxillary protrusion, significant retraction and intrusion of the anterior teeth are sometimes essential to improve the facial profile. However, severe root resorption of the maxillary incisors occasionally occurs after treatment because of various factors. For instance, it has been reported that approximation or invasion of the incisive canal by the anterior tooth roots during retraction may cause apical root damage. Thus, determination of the position of the maxillary incisors is key for orthodontic diagnosis and treatment planning in such cases. Cone-beam computed tomography (CBCT) may be useful for simulating the post-treatment position of the maxillary incisors and surrounding structures in order to ensure safe teeth movement. Here, we present a case of Class II malocclusion with bimaxillary protrusion, wherein apical root damage due to treatment was minimized by pretreatment evaluation of the anatomical structures and simulation of the maxillary central incisor movement using CBCT. Considerable retraction and intrusion of the maxillary incisors, which resulted in a significant improvement in the facial profile and smile, were achieved without severe root resorption. Our findings suggest that CBCT-based diagnosis and treatment simulation may facilitate safe and dynamic orthodontic tooth movement, particularly in patients requiring maximum anterior tooth retraction.

• The Journal of Advanced Prosthodontics
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• 제12권6호
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• pp.329-337
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• 2020

PURPOSE. To verify the influence of computer-aided design/computer-aided manufacturing (CAD/CAM) implant-supported prostheses manufactured with cobalt-chromium (Co-Cr) and zirconia (Zr), and whether ceramic application, spark erosion, and simulation of masticatory cycles modify biomechanical parameters (marginal fit, screw-loosening torque, and strain) on the implant-supported system. MATERIALS AND METHODS. Ten full-arch fixed frameworks were manufactured by a CAD/CAM milling system with Co-Cr and Zr (n=5/group). The marginal fit between the abutment and frameworks was measured as stated by single-screw test. Screw-loosening torque evaluated screw stability, and strain analysis was explored on the implant-supported system. All analyses were performed at 3 distinct times: after framework manufacturing; after ceramic application in both materials' frameworks; and after the spark erosion in Co-Cr frameworks. Afterward, stability analysis was re-evaluated after 106 mechanical cycles (2 Hz/150-N) for both materials. Statistical analyses were performed by Kruskal-Wallis and Dunn tests (α=.05). RESULTS. No difference between the two materials was found for marginal fit, screwloosening torque, and strain after framework manufacturing (P>.05). Ceramic application did not affect the variables (P>.05). Spark erosion optimized marginal fit and strain medians for Co-Cr frameworks (P<.05). Screw-loosening torque was significantly reduced by masticatory simulation (P<.05) regardless of the framework materials. CONCLUSION. Co-Cr and Zr frameworks presented similar biomechanical behavior. Ceramic application had no effect on the biomechanical behavior of either material. Spark erosion was an effective technique to improve Co-Cr biomechanical behavior on the implant-supported system. Screw-loosening torque was reduced for both materials after masticatory simulation.

• Journal of International Society for Simulation Surgery
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• 제1권2호
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• pp.90-94
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• 2014

Reconstruction of the mandible after ablative oral cancer surgery requires esthetic and functional rehabilitation. Restoring facial symmetry and dentition need accurate preoperative surgical planning and meticulous surgical technique. Free fibular flap is most useful tools to reconstruct mandible because of its adequate length and height, simultaneous harvest of soft and hard tissues and placing dental implants. In this case report, recurred squamous cell carcinoma in the right mandible had been resected and free fibular flap was utilized for mandible reconstruction using 3D rapid prototype. Simulation surgery before dental implant placement has been performed for esthetic and functional prosthodontics.

• 한국정보통신학회:학술대회논문집
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• 한국해양정보통신학회 2004년도 춘계종합학술대회
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• pp.327-329
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• 2004

치아 매질내에서 전파되는 광신호 해석을 위한 몬테 카를로 수치해석을 National Instrument사의 LabVIEW를 이용하여 개발하였다. 수치해석 결과 치아 조직 내 깊이에 대해 서로 다른 전파 특성을 갖는 두가지 신호를 얻었으며, 검출 신호는 약 60$\mu\textrm{m}$ 이상의 깊이에서 잡음 신호가 특성 신호에 비해 커짐으로 검출이 어려워짐을 알 수 있었다.