식립 보조도구를 이용한 3D 치아 임플란트 시술 시뮬레이션

박형욱(Hyung-Wook Park),김명수(Myong-Soo Kim),박형준(Hyungjun Park) (사)한국CDE학회 2011 한국CDE학회 논문집 Vol.16 No.3

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™. 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™. 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.

식립 보조도구를 이용한 3D 치아 임플란트 시술 시뮬레이션

박형욱(Hyung-Wook Park),김명수(Myong-Soo Kim),박형준(Hyungjun Park) (사)한국CDE학회 2012 한국 CAD/CAM 학회 학술발표회 논문집 Vol.2012 No.2

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 MimicsTM. 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 SimplantTM. 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.

노인유사체험이 치위생학 전공 대학생의 노인에 대한 태도에 미치는 영향

김선주 ( Sun Ju Kim ) 한국치위생과학회 2012 치위생과학회지 Vol.12 No.6

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 태도 변화를 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. The purpose of this study was to examine whether senior simulation would bring any positive change to the attitude of dental hygiene students toward the elderly. The experimental group consisted of 58 dental hygiene students at a college. The experimental procedure was to do activities for 40 minutes wearing aging simulation suit. Self administered questionnaires were used to ask the attitude toward the elderly after senior simulation. The data were analyzed with SPSS program. General and aging related characteristics of subjects were analyzed through descriptive statistics. To testify the differences of the attitude after senior simulation, paired t-test was used. An experiment was conducted from May 27 to June 14, 2012, and the findings of the study were as follows: 1. There wasn`t any perfect positive change in the overall attitude of the students toward elderly people after senior simulation, but their attitude got a little more positive whereas they took a neutral attitude in the past; 2. The students who had ever lived with elderly people under the same roof and who had ever received education related to the elderly underwent a more positive change in their attitude toward the elderly; 3. To what extent senior simulation was helpful for the understanding of the elderly was checked, and the majority replied that it was very useful or useful for the understanding of their physical aspects. The findings of the study confirmed that senior simulation didn`t change the overall attitude of the students toward the elderly in a positive way yet brought about some positive changes in part. Therefore senior simulation is expected to be one of significant educational programs that could encourage students to have a better physical understanding of the elderly, to take a more positive attitude to them and to provide them with quality dental service.

Mixed-reality simulation for orthognathic surgery

Fushima, Kenji,Kobayashi, Masaru Korean Association of Maxillofacial Plastic and Re 2016 Maxillofacial Plastic Reconstructive Surgery Vol.38 No.-

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.

Development of a prototype simulator for dental education

김미엘,심재훈,에인,김명주,박영석,권호범,박재흥 대한치과보철학회 2023 대한치과보철학회지 Vol.61 No.4

Purpose. The purpose of the study was to fabricate a prototype robotic simulator for dental education, to test whether it could simulate mandibular movements, and to assess the possibility of the stimulator responding to stimuli during dental practice. Materials and methods. A virtual simulator model was developed based on segmentation of the hard tissues using cone-beam computed tomography (CBCT) data. The simulator frame was 3D printed using polylactic acid (PLA) material, and dentiforms and silicone face skin were also inserted. Servo actuators were used to control the movements of the simulator, and the simulator’s response to dental stimuli was created by pressure and water level sensors. A water level test was performed to determine the specific threshold of the water level sensor. The mandibular movements and mandibular range of motion of the simulator were tested through computer simulation and the actual model. Results. The prototype robotic simulator consisted of an operational unit, an upper body with an electric device, a head with a temporomandibular joint (TMJ) and dentiforms. The TMJ of the simulator was capable of driving two degrees of freedom, implementing rotational and translational movements. In the water level test, the specific threshold of the water level sensor was 10.35 ml. The mandibular range of motion of the simulator was 50 mm in both computer simulation and the actual model. Conclusion. Although further advancements are still required to improve its efficiency and stability, the upper-body prototype simulator has the potential to be useful in dental practice education.

Effects of auditory feedback and task difficulty on the cognitive load and virtual presence in a virtual reality dental simulation

Byunggee Kim,Eunbyul Yang,Namki Choi,Seonmi Kim,Jeeheon Ryu 대한치과의사협회 2020 대한치과의사협회지 Vol.58 No.11

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.

An Efficient Virtual Teeth Modeling for Dental Training System

Kim, Lae-Hyun,Park, Se-Hyung Society for Computational Design and Engineering 2008 International Journal of CAD/CAM Vol.8 No.1

This paper describes an implementation of virtual teeth modeling for a haptic dental simulation. The system allows dental students to practice dental procedures with realistic tactual feelings. The system requires fast and stable haptic rendering and volume modeling techniques working on the virtual tooth. In our implementation, a volumetric implicit surface is used for intuitive shape modification without topological constraints and haptic rendering. The volumetric implicit surface is generated from input geometric model by using a closest point transformation algorithm. And for visual rendering, we apply an adaptive polygonization method to convert volumetric teeth model to geometric model. We improve our previous system using new octree design to save memory requirement while increase the performance and visual quality.

구내 촬영용 엑스선 장치의 관전류에 따른 영상 평가

김아연,조병두,이승재 한국방사선학회 2023 한국방사선학회 논문지 Vol.17 No.4

The radiation dose received by the patient varies according to the tube current and time used during dental intraoral imaging. A large amount of tube current is required for image quality, but the radiation dose to the patient increases accordingly. Therefore, in this study, the optimal amount of tube current that can reduce the radiation dose received by the patient while securing the image quality was calculated through the evaluation of the image quality according to the tube current used during intraoral imaging through simulation. The average tube current, time, and tube voltage presented in the Guidelines for Diagnostic Reference Level for intraoral radiography were used as basic imaging conditions, and images were obtained when only the tube current was changed, and then the optimal tube current was compared and analyzed with the basic image quantity was calculated. Images were obtained by changing the tube current to 0.1, 0.5, 1, 2, 3, 4 and 5 mA under the basic conditions of 63 kV, 6 mA, and 0.29 s. The obtained image was evaluated for structural similarity index with the image taken under the condition of 6 mA using the ICY program. As a result, even under the condition of 0.5 mA tube current, the index of structural similarity with the image of 6 mA was evaluated to be high. Based on these results, it is considered that the radiation dose given to the patient can be greatly reduced if imaging is performed at 0.5 mA instead of 6 mA during dental intraoral imaging.

기하모델-볼륨모델간 실시간 변환을 이용한 기하모델 변형방법

유병찬,한상원,신병석 한국차세대컴퓨팅학회 2023 한국차세대컴퓨팅학회 논문지 Vol.19 No.1

With the development of virtual reality technology, various types of education/training simulations are being developed. An important technique in these simulations is to deform the object by an external force. Here, we will discuss how to process the deformation of a part of a solid object in real time. In this paper, we propose a geometric model transformation technique using two-step voxelization and adaptive remeshing. First, the target mesh is voxelized at high resolution and the generated volume data is compressed. If a part of the model is cut or polished by an external force, the corresponding voxel is modified by reflecting it in the converted volume data instead of directly applying it to the mesh. Then, the mesh is extracted again through the marching cube algorithm and the surface is smoothed through Laplacian smoothing. Existing marching cube algorithms and Laplacian smoothing algorithms have slow processing speeds, so real-time transformation processing is difficult. To solve this problem, real-time mesh creation was made possible by applying remeshing only to the deformed part instead of remeshing the entire mesh. In order to confirm the effectiveness of this method, it was confirmed that it is possible to shave part of the teeth by applying this method to dental surgery simulation. 가상현실 기술의 발전에 따라 다양한 종류의 교육/훈련 시뮬레이션들이 개발되고 있다. 이러한 시뮬레이션에서 중요한 기술은 외력에 의해 대상물체를 변형하는 것이다. 여기서는 단단한 물체의 일부가 깎이는 변형을 실시간에 처리할 수 있는 방법을 다루고자 한다. 이 논문에서는 2단계 복셀화(voxelization)와 적응형 리메싱(remeshing)을 이용한 기하모델 변형 기법을 제안한다. 먼저 대상 메쉬를 고해상도로 복셀화하고 생성된 볼륨 데이터를 압축한다. 외력에 의해 모델의 일부가 절단되거나 연마되면 이것을 직접 메쉬에 적용하는 대신 변환된 볼륨 데이터에 반영하여 해당 복셀(voxel)을 수정한다. 이후 Marching Cubes 알고리즘을 통하여 메쉬를 다시 추출하고 라플라시안 스무딩(Laplacian smoothing)을 통해 표면을 부드럽게 한다. 기존 Marching Cubes 알고리즘 및 라플라시안 스무딩 알고리즘은 처리속도가 느리기 때문에 실시간 변형처리가 어렵다. 이를 해결하기 위해 전체 메쉬에 대해 리메싱하는 것이 아니라 변형된 부분에 대해서만 리메싱을 적용함으로써 실시간 메쉬 생성이 가능하도록 했다. 이 방법의 유효성을 확인하기 위해 치과 수술 시뮬레이션에 이 방법을 적용하여 치아의 일부를 깎아내는 시술이 가능함을 확인하였다.

Validity on the Study Models of Dental Simulation Training: Focus on the Dental Arch and Occlusal Curvature

Hee-Kyung Lee,Shin-Eun Nam 대한예방치과학회 2018 International Journal of Clinical Preventive Denti Vol.14 No.3

Objective: The purpose of this study was to evaluate the validity of the study models involved in the simulation training for dental technology using 3-dimensional virtual models. Methods: The study models and dental models from 25 young adult Korean were scanned as a virtual dental model with a 3-dimensional scanner (Scanner S600; Zirkonzahn). The dental arch form (arch width, arch length), buccolingual cusp inclination, and the radius of Monson’s sphere were measured on prepared virtual models using RapidForm2004 (INUS Technology Inc.). Wilcoxon signed-rank test was performed to verify the validity of the study models participating in the dental technique training using 3-dimensional virtual models (=0.05). Results: Arch width (intercanine width/intermolar width) and arch length (incisor to intercanine/incisor to intermolar) were smaller in both upper and lower study models than those of adult Korean models in general (p<0.05). In maxilla, buccolingual cusp inclinations of right and left side of premolars and molar were larger (2.21°-5.20°) in adult Korean models except for the first molar (p<0.05), which was the opposite in mandible (2.98°-9.20°) (p<0.05). The radii of Monson’ sphere was 104.92 mm in the study models and 121.85±47.11 mm in adult Korean models. There was no statistically significant difference between the two groups (p>0.05). Conclusion: In the study models involved in the simulation training, dental arch was smaller. Buccolingual cusp inclination was more inclined for upper and less inclined for lower than 25 subjects. This finding could be used as a meaningful reference for further studies focusing on validity on dental technique trainings for study models.