• The Journal of Korean Academy of Prosthodontics
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• v.45 no.3
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• pp.389-400
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• 2007

Statement of problem. Use of the conventional dental impression procedure is problematic in patients who have difficulty opening their mouth, difficulty breathing through their nose or tendency to gag. Purpose. It is necessary to make individual trays more comfortable for patients during impression taking procedure. It was reported at the KAP Annual Meeting 2001 Seoul that an improved impression technique was suitable for this purpose. In this study, the accuracy of the improved dental impression method for implant was compared with the conventional dental impression method. Material and methods. An oral simulator was made from clear acrylic resin block which had similar form of edentulous ridge. For setting up the standard, five fixtures were installed on it. Study casts were made using two kinds of impression techniques. One was the conventional method that was taken using silicone impression material and an individual resin tray under connection of inter-fixture relation. The other was the improved method in which was the connection of the impression coping and the thermoformed polymethyl methacrylate tray. In addition, two different study casts were made from the improved impression body. The coordinates of the fixture on the study model were measured by three-dimensional coordinate measuring equipment. Then the distances between each fixture were calculated and compared with that of oral simulator. Accuracy of the each impression method was also assessed. Results. The differences of inter-fixture dimension between study casts and simulator in the improved impression technique showed $0.014{\pm}0.016mm$ and $0.017{\pm}0.022mm$, respectively and that of the conventional method was $0.017{\pm}0.014mm$. There was no significant difference between the improved impression technique and conventional method. Conclusion. The improved impression technique is useful for multiple support implants.

• Journal of Digital Convergence
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• v.16 no.4
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• pp.195-203
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• 2018

This study was conducted to investigate the types and methods of dental impression materials used in dental clinics in south Korea, the questionnaire was surveyed by a self-administered method for one dentist in a one dental clinic, the collected data were statistically analyzed using SPSS 20. The most frequently used addition silicone impression materials were used in most dental treatment. It was confirmed that the method of taking impression materials having different flow properties(light body and heavy body) was most preferred at one time, also, the implant impression taking method was the most preferred for two rubber impression materials with different flow properties, both direct and indirect. There were statistically significant differences in age and clinical experience between the methods of impression taking of casting restorations and prosthetic according to general characteristics. These results are expected to be helpful for the development of theoretical and practical work based on the basic data for impression material development and research and the preference of impression materials required for dental professional in clinical practice.

• Restorative Dentistry and Endodontics
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• v.43 no.1
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• pp.9.1-9.6
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• 2018

The objective of this case report is to introduce a simple technique for simultaneously taking a closed-mouth impression and functionally generated path (FGP) for a full coverage crown restoration. A monolithic zirconia crown was the restoration of choice. An alginate impression of the abutment tooth was taken to fabricate a custom-made closed-mouth impression tray covering the abutment tooth and the adjacent teeth. The tray had an FGP table and an abutment tray in cameo and intaglio surfaces, respectively. The impression was taken with silicone impression material after adjusting the abutment tray and inscribing the FGP using self-curing acrylic resins. Plaster casts were made from the impression, and a zirconia crown was fabricated. The crown was cemented to the abutment tooth with minimal adjustments. This simple technique resulted in a well-fitting crown that accounted for mandibular movements. Using the custom closed-mouth impression tray incorporating an FGP table simultaneously aids in fabricating an accurately fitting restoration that incorporates harmonious mandibular movements using a single impression capture.

• Journal of Korean Academy of Dental Administration
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• v.10 no.1
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• pp.84-92
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• 2022

Impression taking is one of the most frequently performed tasks within the legal scope of dental hygienists. This study aims to compare traditional impression and digital impression taking in various aspects with dental hygienists who have experience using digital intraoral scanners. A total of 61 subjects were included in this analysis. Traditional and digital impression taking were compared, and the perception of intraoral scanners was classified into four factors through exploratory factor analysis. After a normality test of the main variables was performed, a non-parametric test was performed. In terms of the adequacy of the size of the tool inserted into the oral cavity, traditional impression taking was more positive, and there was no significant difference in the precision of impression taking, fit of the prosthesis, and time efficiency. In contrast, the digital intraoral scanner was positive in terms of reducing nausea. In the comparison between the items of the digital intraoral scanner, relatively low satisfaction was shown in terms of convenience of use. This study compared traditional impression taking based on the experience of dental hygienists using oral scanners. It is hoped that this will be one step closer to universalization. In addition, appropriate training on how to use them should be provided.

• Journal of Dental Rehabilitation and Applied Science
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• v.21 no.1
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• pp.83-93
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• 2005

This study was designed to investigate the fitness of adjustable dental impression trays. The size and shape of these trays were designed from the results of the dental arch size of Korean adults. Tray samples were made by CAD-CAM working. A hundred dental students(male:50, female:50) were selected for taking irreversible hydrocolloid impression using these trays. The author measured the width and length of impression material on the several measuring points. The results obtained were as follows : 1. Uniform impression material thickness was achieved by controlling the width of the tray using stops and beveled guides. 2. In the upper tray, the impression material thickness was measured to be rather great showing thickness of the labial vestibule 8.3 mm and the midpalatal part 8.6 mm. 3. In the lower tray, length of the impression material of the labial vestibule of first, second premolar contact point was 7.8 mm, and thickness of the lingual part of premolars(1.8 mm) and molars(1.9 mm) showed small values. 4. In the lower tray, the impression material thickness of the buccal shelf area(0.2 mm) and the retromolar pad area(0.6 mm) was measured to be too small.

• The Journal of the Korean dental association
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• v.55 no.1
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• pp.72-81
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• 2017

Regardless of the type of impression being made, the tray is the most important part of the impression-making procedure for completely edentulous patients. Dentists have to make use of a combination of rigid, thermoplastic, and resilient materials and control step-by-step procedure from irreversible hydrocolloid impression to definitive cast fabrication. For successful edentulous impression, some considerable clinical tips were guided.

• The Journal of Korean Academy of Prosthodontics
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• v.44 no.4
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• pp.477-487
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• 2006

Purpose : this study was to evaluate the fitness of adjustable dental impression trays on the Koreans : the trays used in the previous study by Kim et al. as part of the dental adjustable tray development project were improved and modified. Material and method: The patterns of tray were made through CAD-CAM process, and a simple silicone-base molds were made from them. The trial products were reproduced by pouring polyurethane into these molds. 30 male students(Wonkwang University, Dental College) and 30 female students (Wonkwang Health Science College, Department of Dental Hygiene) were selected and Reversible hydrocolloid impression materials were used for this study. The fitness of the trays was evaluated by measuring the width and length of impression materials of each measurement sites. Results and conclusion : 1. In adapting the trays inside the mouth, a uniform width of impression material(3 $\sim$ 6mm) was obtained in most sites due to the tooth stops and the inclined planes accommodating the width of the tray 2. The thickness of impression material in the central part of the palate was a mean 9.8mm, which turned out to be somewhat thick. 3. In the mandible. the thickness of the impression material in the lingual side inferior to the contact point of the 1st and 2nd molars was 2.7mm, and the thickness of the material in the lingual side of the rearmost margin was 2.5 mm. The thickness of the impression material of these areas was relatively thin.

• The Journal of Korean Academy of Prosthodontics
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• v.39 no.5
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• pp.547-555
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• 2001

This study was performed tn investigate the effects of impression method and design of the retainer on the stress of abutment tooth in distal extension RPD. Three different types of direct retainer such as Akers clasp, RPI clasp, and wrought wire clasp were designed. Stress on the abutment tooth was measured and analyzed with strain gauge method. Impressions were anatomic impression technique and functional impression technique. The following conclusions were drawn from this study. 1. The stress at the abutment tooth on all RPD was decreased in functional impression except RPI clasp retained RPD. 2 The stress at the abutment tooth on RPI clasp retained RPD was the most smallest in anatomic Impression. 3. While load is increase the stress at the abutment tooth was increased, but the change of stress at the buccal side of abutment tooth was not too much in functional impression.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.3
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• pp.223-229
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• 2017

Closed mouth impression technique by using bite tray is preferred for single tooth impression taking. However, for implant impression taking, open mouth impression technique by using single arch tray is generally used whether it is for single implant or multiple implant. Closed mouth impression technique by using bite tray can save time and materials. It also decreases the chance of error occurrence when a model is mounted on an articulator. In this case report, we tried to show a satisfying result of fabricating single implant fixed prosthodontics after bite tray impression taking by using two different copings for closed mouth impression.

• Journal of Technologic Dentistry
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• v.33 no.3
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• pp.211-218
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• 2011

Purpose: The purpose of the study was a quantitative evaluation of common errors in digital impression procedure using CEREC$^{(R)}$ AC system. Methods: Two-hundreds digital impression data comprising 174 inlays, 26 onlays by CEREC$^{(R)}$ AC in-office CAD/CAM system were obtained from a dental clinic. One evaluator assessed errors of the digital impression data and divided into five categories of errors: inappropriate scanner positioning (ISP), improper handling with a scanner (IHS), irregular powder arrangement (IPA), improper cavity preparation (ICP), and insufficient scanned data (ISD). Results: The most common errors were IPA(21%), and ISP and ISD were followed by 17% respectively. IHS was found in 14.5% of all digital impression data. ICP comprising only 6.5% was the rarest. Conclusion: Most errors were due to inaccurate manipulation with an intraoral scanner or improper cavity preparation for scanning. A deliberate manipulation to prevent common errors mentioned may deliver an optimal result in the digital impression procedure.