• Korean Journal of Computational Design and Engineering
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• v.16 no.3
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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.

• Journal of Technologic Dentistry
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• v.24 no.1
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• pp.127-138
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• 2002

There are some cases that dental prosthesis does not operate as properly as expected in oral mouth. The reasons are such as a distortion of the mandibular, a fault of impression taking system or an extrusion of remaining teeth. One of dental prostheses to consider in the situations is the attachment which connects segment bridge. Active discussions are managed on theoretical side of this field but few on clinical side of it, which must be considered first. Accordingly I'd like to suggest a theoretical background for connect attachment of fixed segmented bridge. 1. As a bridge gets longer, burden on dental ligament is increased and the hardness of a bridge is lessened. 2. The flexibility of a bridge increases in ratio to 3 multiplication of the length and decreases in ratio to 3 multiplication of the width of occlusal surface and base of pontic. 3. Precision rest is needed to cope with the shake of teeth and the difference of axis direction among abutments. 4. Female part of the precision rest should be on middle abutment distal and male one on mesial of pontic. 5. Segmented attachment can be efficiently used to cope with long span bridgework and also in case that one piece casting can't be done because of slant of abutment.

• Journal of Technologic Dentistry
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• v.43 no.4
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• pp.202-209
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• 2021

By classifying temporary denture production for surgical guides, digital guide-based surgery, and final prosthesis production, the problems of each process were assessed in advance and the factors that could be improved were confirmed in this study. The manufacturing process of fusion dental prosthesis uses virtual programs and computed tomography images to manufacture devices using the latest technologies of computer-aided design/computer-aided manufacturing and three-dimensional printing, which enables implants to be placed in the desired location in advance. Moreover, implant placement is not dependent on the skill and condition of the dentist, and because it uses a computer system, it can always be performed at a constant and optimal position. This can reduce the remanufacturing rate compared with the general method, shorten the treatment period, and eliminate patient discomfort. Unlike the traditional method of using impression materials and plaster models, digital fusion dental prostheses would be evaluated as a technology for producing prosthesis through professional design technology and communication.

• Journal of Dental Rehabilitation and Applied Science
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• v.29 no.2
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• pp.183-193
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• 2013

The characteristics of dental treatment makes the dental staff frequently contact with patient directly. Also the daily use of high-handpieces, sharp instruments, and needles often causes bleeding on oral cavity. Therefore, the risk of cross transmission grows up. The pathogen from dental practice could spread on not only the practice itself but also the dental laboratory with contaminated impressions and prosthesis. Dental clinic staffs (dentists, dental hygienists and dental technicians) should recognize all the patients have a possibility of cross contamination, and try to prevent the transmission of infection by proper infection control. In this study, we review the articles about disinfection methods and chemical infection agents used for dental impressions, and try to figure out the suitable and effective infection control system of dental impressions.

• The Journal of Korean Academy of Prosthodontics
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• v.62 no.3
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• pp.224-233
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• 2024

The patient was a 69-year-old male who had decreased VDO and overbite of the anterior teeth due to severe teeth wear. Complete mouth rehabilitation was planned to restore esthetics and function. Due to the presence of a subgingival finish line, poor fit of the margin of the temporary crown, and insufficient oral hygiene management, gingival overgrowth and bleeding occurred in many teeth, and inaccurate impressions were taken. After dividing each arch and taking partial impressions, a transfer coping was made using pattern resin on each working model die, and after being placed on the abutment teeth, a master cast was made through pick-up impression taking to produce prosthesis. In this case, the final prosthesis produced on the second master cast were fitted in terms of proximal contact, marginal fit, vertical occlusal dimension, facial appearance, esthetics, and occlusion. After complete mouth rehabilitation, the patient was satisfied with function and esthetic appearance.

• Journal of Korean society of Dental Hygiene
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• v.17 no.2
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• pp.271-281
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• 2017

Objectives: This study was conducted to promote the value of field practice courses by installing an efficient field practice program through understanding the relationship between career decision/ behavior and the pre-/post satisfaction of dental hygiene students in field practice. Methods: The subjects of the study were students in Gyeongnam and Busan majoring in dental hygiene, from which 218 questionnaires were obtained from 23 November 2015 to 30 July 2016. Results: In terms of career decision/ behavior, the post-satisfaction scores in ideas about their major, about whether it was helpful to selecting their speciality and positive impression of dental hygienists, interest and understanding in training course were significantly lower than the pre-satisfaction scores (p<0.05). Relationship between satisfaction in field training and career decision/ behavior following the field training, pre-/post-satisfaction on site-training content (r=0.371, p<0.01), pre-/post satisfaction in training instructions (r=0.267, p<0.01), and pre-/post-satisfaction in the training sites (r=0.436, p<0.01) were all proportionally correlated to the after-training career decision and behavior. Conclusions: It is necessary for training instructors to maintain close relationships with the students in field practice program courses. In advance, it is expected to promote students' satisfaction in field practice and serve as a starting point where students can build self-esteem as a future dental hygienist by positively influencing their career decisions and behaviors.

• The Journal of the Korean dental association
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• v.54 no.2
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• pp.108-122
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• 2016

Prosthetic-driven implant placement is a concept considering the dental implant restoration first based on the final form of that prosthesis to be restored. The latest development of the imaging technology and digital dentistry was able to be obtained the high quality images of CBCT with low radiation exposure and it has also enabled the process to reconstruct the intraoral state in three dimensions due to the development of the intraoral, model and impression scanner. Computer-guided implant placement simulations and template production was able to be more widely used in this context. In this narrative review, the features and the types of implant surgical guides will be introduced. It will also be described the diagnosis and treatment plan using computerguided implant software to reduce the number of visit and to increase the accuracy of the implant surgery through the top-down approach based on the shape and location of the final prosthesis.

• The Journal of Advanced Prosthodontics
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• v.13 no.4
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• pp.205-215
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• 2021

PURPOSE. The purpose of this study was to compare the accuracy of three intraoral scanner (IOS) systems with three different dental arch widths. MATERIALS AND METHODS. Three dental models with different intermolar widths (small, medium, and large) were attached to metal bars of different lengths (30, 40, and 50 mm). The bars were measured with a coordinate measuring machine and used as references. Three IOSs were compared: TRIOS 3 (TRI), True Definition (TD), and Dental Wings (DW). The relative length and angular deviation of both ends of the metal bars from the scan data set (n = 15) were calculated and analyzed. RESULTS. Comparing among scanners in terms of trueness, the relative length deviation of DW in the small (1.28%) and medium (1.08%) arches were significantly higher than TRI (0.46% and 0.48%) and TD (0.33% and 0.18%). The angular deviation of DW in the small (1.75°) and medium (1.83°) arches were also significantly greater than TRI (0.63° and 0.40°) and TD (0.55° and 0.89°). Comparing within scanner, the large arch of DW showed better accuracy than other arch sizes (P < .05). On the other hand, the larger arch of TD presented a greater tendency of angular deviation in terms of trueness. No significant differences were found in terms of trueness between the arch widths of TRI group. CONCLUSION. The different widths of the dental arches can affect the accuracy of some intraoral scanners in full arch scan.

• The korean journal of orthodontics
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• v.44 no.2
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• pp.69-76
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• 2014

Objective: This study aimed to evaluate the accuracy and precision of polyurethane (PUT) dental arch models fabricated using a three-dimensional (3D) subtractive rapid prototyping (RP) method with an intraoral scanning technique by comparing linear measurements obtained from PUT models and conventional plaster models. Methods: Ten plaster models were duplicated using a selected standard master model and conventional impression, and 10 PUT models were duplicated using the 3D subtractive RP technique with an oral scanner. Six linear measurements were evaluated in terms of x, y, and z-axes using a non-contact white light scanner. Accuracy was assessed using mean differences between two measurements, and precision was examined using four quantitative methods and the Bland-Altman graphical method. Repeatability was evaluated in terms of intra-examiner variability, and reproducibility was assessed in terms of interexaminer and inter-method variability. Results: The mean difference between plaster models and PUT models ranged from 0.07 mm to 0.33 mm. Relative measurement errors ranged from 2.2% to 7.6% and intraclass correlation coefficients ranged from 0.93 to 0.96, when comparing plaster models and PUT models. The Bland-Altman plot showed good agreement. Conclusions: The accuracy and precision of PUT dental models for evaluating the performance of oral scanner and subtractive RP technology was acceptable. Because of the recent improvements in block material and computerized numeric control milling machines, the subtractive RP method may be a good choice for dental arch models.

• Journal of Technologic Dentistry
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• v.46 no.1
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• pp.15-19
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• 2024

An ideal post material should have physical properties similar to those of dentin. Post materials with high elastic moduli may cause root fractures. This clinical report describes the treatment of a severely damaged tooth using a recently introduced material. Polyetherketoneketone (PEKK) is a semicrystalline high-performance thermoplastic polymer. PEKK is a promising material for custom post-and-core fabrication because of its elasticity close to that of dentin, good shock absorbance, machinability, and low cost. A laboratory scanner was used to digitize the conventional impression of a severely damaged maxillary right first molar. A custom PEKK post-and-core was designed and milled using computer-aided design and computer-aided manufacturing technology. Using the proposed technique, a custom PEKK post-and-core was fabricated accurately and human error was reduced. Restoration was luted with resin cement. Custom PEKK post-and-core restorations are a viable alternative for treating severely damaged teeth.