• The Journal of Advanced Prosthodontics
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• v.4 no.3
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• pp.170-173
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• 2012

Correct occlusal relationships are part of the successful prosthetic treatment for edentulous patients. Fabrication of complete dentures comprises of clinical and laboratory procedures that should be executed accurately for achieving success with fabricated dentures. Errors occurring during the clinical and laboratory procedures of a denture may subsequently lead to the occlusal errors in the final prosthesis. These occlusal errors can be corrected in two ways: i) in patient's mouth ii) by recording new centric relation and remounting dentures on an articulator. The latter method is more feasible because the mobility of denture base on the mucosa in oral cavity does not permit the identification of premature contacts in centric occlusion and tooth guided eccentric excursions. This article describes a modest and effective clinical chair-side remount procedure using customized mounting platforms.

• Maxillofacial Plastic and Reconstructive Surgery
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• v.33 no.2
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• pp.128-136
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• 2011

Purpose: Errors in orthognathic model surgery occur during the planning, measuring and/or moving of the models. However, there has been little effort to find ways to reduce these errors. In this study, we introduce a new orthognathic model surgery technique (Yonsei method) which adopts the tooth point as the reference and the occlusal index as a moving vehicle for the model. Methods: The technique consists mainly of: 1) measuring the three-dimensional lengths of model points, 2) fabricating and moving the occlusal index and 3) verifying the movement. Then we compared the accuracy of the Yonsei method to conventional methods, with special reference made to influencing factors. Results: Errors for the Yonsei method with the occlusal index were reduced to the range of 0.61~1.04 mm in three-dimension, providing a more accurate model surgery technique than conventional methods which have errors ranging from 0.77~3.11 mm. Conclusion: It provided us a more accurate model surgery technique based on the reference points onto the teeth and the use of occlusal index.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.29 no.4
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• pp.239-244
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• 2003

The common errors in preoperative treatment plan for the orthognathic surgery can be occurred during cast impression, cast mounting procedure with face-bow transfer, surgical stent fabrication, and so on. One of the most common errors exists during mounting process of the model on the articulator. Accurate mounting of dental casts to articulator should be achieved by transferring the 3-dimensional spatial relationship of the maxillary arch to an articulator. A face-bow is used for transfer this relationship to articulator, usually by relating the face-bow to a plane of reference of maxillary cast. The purpose of this study is evaluation of the accuracy of face-bow transferring of maxillary model to the articulator. The maxillary casts of thirty patients for orthognathic surgery were mounted on articulator with an face-bow instrument. The relationship of occlusal plane angle to Frankfort horizontal plane relations were compared the cephalogram with the cast-mounted articulator. As a result of this study, the significant difference between the maxillary occlusal planes angle in the cephalogram and articulator were found. The results were followed, 1. The mean occlusal plane angle in cast-mounted articulator was $13.5^{\circ}\;(SD{\pm}5.4)$. 2. The mean occlusal plane angle in cephalogram was $10.4^{\circ}\;(SD{\pm}4.3)$. 3. The mean difference of occlusal plane angle between cast-mounted articulator and cephalogram was $3.3^{\circ}\;(SD{\pm}4.6)$. According to the result, we should suggest that the occlusal plane angle to Frankfort plane in cast-mounted articulator is more steeper than that of cephalogram. And then, maxillofacial surgeon should try to get a more predictable result by suggesting the proper correction method and mounting the cast accurately.

• Imaging Science in Dentistry
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• v.43 no.3
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• pp.191-196
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• 2013

Purpose: This study assessed the accuracy of linear and angular measurements on panoramic radiographs taken at different positions in vitro. Materials and Methods: Two acrylic models were fabricated from a cast with normal occlusion. Straight and $75^{\circ}$ mesially and lingually angulated pins were placed, and standardized panoramic radiographs were taken at standard position, at an $8^{\circ}$ downward tilt of the occlusal plane compared to the standard position, at an $8^{\circ}$ upward tilt of the anterior occlusal plane, and at a $10^{\circ}$ downward tilt of the right and left sides of the model. On the radiographs, the length of the pins above (crown) and below (root) the occlusal plane, total pin length, crown-to-root ratio, and angulation of pins relative to the occlusal plane were calculated. The data were subjected to repeated measures ANOVA and LSD multiple comparisons tests. Results: Significant differences were noted between the radiographic measurements and true values in different positions on both models with linear (P<0.001) and those with angulated pins (P<0.005). No statistically significant differences were observed between the angular measurements and baselines of the natural head posture at different positions for the linear and angulated pins. Conclusion: Angular measurements on panoramic radiographs were sufficiently accurate and changes in the position of the occlusal plane equal to or less than $10^{\circ}$ had no significant effect on them. Some variations could exist in the pin positioning (head positioning), and they were tolerable while taking panoramic radiographs. Linear measurements showed the least errors in the standard position and $8^{\circ}$ upward tilt of the anterior part of the occlusal plane compared to other positions.

• The Journal of Korean Academy of Prosthodontics
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• v.52 no.3
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• pp.246-251
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• 2014

In case of prosthesis fabrication by CAD/CAM, location, area and contour of occlusal contacts can be adjusted so more functional occlusion can be acquired. Also, errors in a manufacturing process is reduced compared to cast metal prostheses and porcelain fused metal prostheses fabricated by conventional methods such as casting and porcelain build up. Therefore, prostheses by CAD/CAM show superior occlusion accuracy. Recently, virtual articulator function has been introduced to CAD/CAM system, which reproduces mandibular movement against maxilla. Thus, it is possible to consider occlusal interference in anterior/lateral movement as well as closing movement. There have been many studies on the marginal and internal fit of prostheses using zirconia but the occlusal fit of zirconia crown fabricated by CAD/CAM has not been researched as much. In this case report, 7 zirconia crowns were designed and fabricated by CAD/CAM for total 5 patients. The models of zirconia crowns before and after occlusal adjustment during intraoral try-in were scanned for occlusal contacts, which were compared to evaluate accuracy of prostheses and understand patterns of occlusal adjustment. Most of the occlusal adjustments were done on functional cusps and slopes of zirconia crown, and the magnitude of occlusal adjustment ranged from $15{\mu}m$ to $60{\mu}m$. In the zirconia crown fabricated with CAD/CAM systems, the occlusal adjustment is a necessary procedure, so additional procedures will be needed for compensating reduced mechanical properties.

• Journal of Dental Rehabilitation and Applied Science
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• v.38 no.3
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• pp.178-188
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• 2022

Interim immediate denture is fabricated to minimize the period of edentulousness after removal of the patient's remaining teeth and before delivery of final prosthesis. In the case of using the CAD/CAM system, there is an advantage in that the manufacturing process in the clinic and laboratory can be simplified by overcoming some of the limitations of manufacturing interim immediate dentures in the traditional way. However, there are also disadvantages in that errors occur in the process of transmitting information about the patient's intermaxillary relationship to the digital network of the laboratory, resulting in unstable occlusal relationships or non-esthetic prostheses. To overcome this problem, using the simple and accurate POP BOW system's occlusal plane digital transfer method, it was possible to fabricate an esthetic and functional 3D printed interim immediate denture after removal of the remaining upper and lower anterior teeth.

• Journal of Technologic Dentistry
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• v.35 no.3
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• pp.231-242
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• 2013

Purpose: The study is to discover the relationship between malocclusion, which is known to cause temporomandibular disorder, and temporomandibular disorder and is aimed at college students who have retained their natural teeth. Methods: The study was aimed at 500 college students at two colleges located in Gyeongsangbuk-do and Daegu metropolitan city and survey research was conducted in order to discover any relationship between malocclusion and temporomandibular disorder. After excluding copies with insincere answers or errors out of the 500 copies of the questionnaire, the study used a total of 435 copies (87%) for research and analysis. Results: Females showed a prevalence of temporomandibular joint clicking and temporomandibular joint pain, and students who had crowding showed a high prevalence of temporomandibular joint pain, temporomandibular joint clicking, and trismus. Students whose occlusal condition was not good demonstrated a high prevalence of temporomandibular joint pain, temporomandibular joint clicking, and trismus. Students who had maxillary protrusion showed a prevalence of temporomandibular joint clicking and trimus, whereas students who had mandibular protrusion showed a high prevalence of temporomandibular joint clicking. Conclusion: Students whose dental condition was crowding and students whose occlusal condition was not good exhibited a high prevalence of three types of symptoms of temporomandibular disorder. Meanwhile student who had maxillary protrusion showed a high prevalence of temporomandibular joint clicking and trismus, while students who had mandibular protrusion showed a prevalence of temporomandibular joint clicking.

• 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.

• Journal of the Korean Academy of Esthetic Dentistry
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• v.26 no.1
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• pp.24-38
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• 2017

Prosthetics procedures in dental clinics 1) Tooth preparation 2) Temporary restoration 3) Post and core 4) Impression 5) Cementation of final prosthesis The final step in the prosthodontic procedure is the fitting of the final prosthesis to the patient's abutment with an exact fit and occlusal relationship. By the way, this final prosthesis is not made in the clinic but is made in the dental lab and comes to the clinic with some time difference. In the clinic, the only medium to deliver the patient's oral information to the dental laboratory is the impression. However, many errors occur in this process. Dentists and dental technicians should try to identify the cause and make an accurate prosthesis to reduce this error.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.402-407
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• 2010

Introduction: The planning of implant surgery is an important factor for the implant prosthesis. Stereolithographic (SLA) surgical stents based on a computer simulation are quite helpful for clinicians to perform the surgery as planned. Although many clinical and technical trials have been performed for computed tomography (CT)-guided implant stents to improve the surgical procedures and prosthetic treatment, there are still many problems to solve. We developed a system of a surgical guide based on 3 dimensional (3D) CT for implant therapy and achieved satisfactory results in the terms of planning and operation. Materials and Methods: Fifteen patients were selected and 30 implant fixtures were installed. The preoperative CT data for surgical planning were prepared after obtaining informed consent. Surgical planning was performed using the simulation program, Ondemend3D In2Guide. The stents were fabricated based on the simulation data containing information of the residual bone, the location of the nerve, and the expected design of the prostheses. After surgery with these customized stents, the accuracy and reproducibility of implant surgery were evaluated based on the computer simulation. The data of postoperative CT were used to confirm this system using the image fusion technique and compare the implant fixtures between the planned and implanted. Results: The mean error was 1.18 (${\pm}0.73$) mm at the occlusal center, 1.23 (${\pm}0.67$) mm at the apical center, and the axis error between the two fixtures was $3.25^{\circ}C$ (${\pm}3.00$). These stents showed superior accuracy in maxilla cases. The lateral side error at the apical center was significantly different from the error at the occlusal center but there were no significant differences between the premolars, 1st molars and 2nd molars. Conclusion: SLA surgical stents based on a computer simulation have the satisfactory accuracy and are expected to be useful for accurate planning and surgery if some errors can be improved.