• The Journal of Advanced Prosthodontics
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• v.9 no.1
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• pp.1-13
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• 2017

PURPOSE. The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS. Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with ${\alpha}$-level of 0.05. RESULTS. 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION. Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface.

• The Journal of Korean Academy of Prosthodontics
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• v.54 no.4
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• pp.379-386
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• 2016

Purpose: The present study aims at researching the subjective satisfaction of patients who have experienced both conventional impression taking and digital impression taking to measure the possibility of wide clinical application of digital impression. Materials and methods: The study surveyed 170 adult patients over the age of 20, between October 2015 and April 2016, who voluntarily consented to participation and who experienced both conventional impression and digital impression at five dental hospitals that use intraoral digital impression. A total of 128 surveys were used for data analysis, involving frequency analysis, multiple response frequency analysis, descriptive statistics, and contingency table analysis, with the significance level set at 0.05. Results: Responses on the reason for taking impressions using the digital method appeared in the order of 'for implant treatment' (43.8%), 'for crown treatment' (30.5%), and 'for inlay treatment' (15.6%). Patients satisfaction was higher for digital impression taking than conventional impression taking (P<.05). As the preferred choice of impression, digital impression (60.2%) was higher than conventional impression (11.7%). Responses on the reason for choosing digital impression taking appeared in the order of 'no vomiting reflex' (35.1%), 'reliability of 3D digital scanning' (33.8%), and 'short time' (33.8%). Conclusion: The patients preferred digital impression taking to conventional impression taking in terms of satisfaction.

• 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.

• The Journal of Advanced Prosthodontics
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• v.15 no.4
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• pp.179-188
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• 2023

PURPOSE. This in vitro study aimed to evaluate the performance of digital intraoral scanners in a completely edentulous patient with angled and parallel implants. MATERIALS AND METHODS. A total of 6 implants were placed at angulations of 0°, 5°, 0°, 0°, 15°, and 0° in regions #36, #34, #32, #42, #44, and #46, respectively, in a completely edentulous mandibular polyurethane model. Then, the study model created by connecting a scan body on the implants was scanned using a model scanner, and a 3D reference model was obtained. Three different intraoral scanners were used for digital impressions (PS group, TR group, and CS group, n = 10 in each group). The distances and angles between the scan bodies in these measurement groups were measured. RESULTS. While the Primescan (PS) impression group had the highest accuracy with 38 ㎛, the values of 104 ㎛ and 171 ㎛ were obtained with Trios 4 IOSs (TR) and Carestream 3600 (CS), respectively (P = .001). The CS scanner constituted the impression group with the highest deviation in terms of accuracy. In terms of dimensional differences in the angle parameter, a statistically significant difference was revealed among the mean deviation angle values according to the scanners (P < .001). While the lowest angular deviation was obtained with the PS impression group with 0.185°, the values of 0.499° and 1.250° were obtained with TR and CS, respectively. No statistically significant difference was detected among the impression groups in terms of precision values (P > .05). CONCLUSION. A statistically significant difference was found among the three digital impression groups upon comparing the impression accuracy. Implant angulation affected the impression accuracy of the digital impression groups. The most accurate impressions in terms of both distance and angle deviation were obtained with the PS impression group.

• 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.

• The Journal of Korean Academy of Prosthodontics
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• v.53 no.3
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• pp.234-243
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• 2015

Developing of digital technique, it is possible to fabricate implant prostheses for edentulous area using intraoral 3-dimentional information throughout implant diagnosis and treatment process. It is being changed that from the method using CAD/CAM, producing prostheses by model scanning after conventional impression and model processing, to the method of fabricating implant provisional restorations and customized abutments by digital impression after connecting digital impression copings (scanbody) and implant fixtures without models. But, this digital method has not been actively used for implant prostheses not yet. Specially, it is short of intraoral digital impression cases for immediate provisional restorations of the maxillary anterior implants. The gingival contour impression of maxillary anterior area is very important for esthetic restorations. Accordingly, in this case report, the using a digital impression coping (scanbody) and digital impression by CEREC Omnicam (Sirona, Bensheim, Germany) or Trios (3shape, Copenhagen, Denmark) were introduced for immediate provisional restorations in 3 cases needed a single implant restoration in maxillary anterior area. The clinical results were satisfactory on the convenience and accuracy of digital impression technique and the good esthetics of final restorations.

• The Journal of the Korean dental association
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• v.56 no.7
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• pp.366-374
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• 2018

Purpose : The purpose of this study was to compare the marginal fit of monolithic zirconia restorations fabricated form the conventional and the digital impression technique. Materials and methods : Ten patients were restored with monolithic zirconia restorations fabricated from the digital and the conventional impression technique. Before definitive insertion, silicone replicas were produced from all twenty crowns. The silicone replicas were cut in three sections; each section was evaluated at two points. The measurement was carried out by using a measuring microscope (Olympus BX 51) and I-Solution. Data from the silicone replica scores were analyzed by Shapiro-Wilk test for normal distribution and the t-test for equality of two population's mean. All tests were performed with ${\alpha}-level$ of 0.05. Results : The average marginal gaps of monolithic zirconia restorations were $133.81{\pm}36.46{\mu}m$ for the conventional impression technique, $90.07{\pm}9.47{\mu}m$ for the digital impression technique. No statistical differences were found between the two impression techniques Conclusion : Both prostheses presented clinically acceptable results with comparing the marginal fit.

• The Journal of the Korean dental association
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• v.57 no.9
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• pp.524-528
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• 2019

With the advances of CAD-CAM (computer-aided design and computer-aided manufacturing) technology, the field of modern clinical dentistry has been dramatically changed. The first step in the digital workflow for tooth-supported dental prosthesis is a data acquisition with intraoral digital or conventional impression techniques. For the accuracy of intraoral digital impression data, the basic principles of conventional impression should be applied. It is necessary to obtain a good visibility with properly-dried field and well-exposed margin of the prepared abutment. Currently, the equi- or supra-gingival finish line can be recommended as an indication for intraoral digital impression. The scan data are generally exported to '.stl' file format, which has only morphological information of black and whitem while '.obj' file format can store data on color and texture.

• The Journal of Advanced Prosthodontics
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• v.11 no.5
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• pp.262-270
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• 2019

PURPOSE. The purpose of this in vitro study was to evaluate the marginal misfits of three-unit frameworks fabricated with conventional and digital impressions techniques. MATERIALS AND METHODS. Thirty brass canine and second premolar abutment preparations were fabricated by using a computer numerical control machine and were randomly divided into 3 groups (n=10) as follows: conventional impression group (Group Ci), Cerec Omnicam (Group Cdi), and 3shape TRIOS-3 (Group Tdi) digital impression groups. The laser-sintered metal frameworks were designed and fabricated with conventional and digital impressions. The marginal adaptation was assessed with a stereomicroscope at ${\times}30$ magnification. The data were analyzed with 1-way analysis of variances (ANOVAs) and the independent simple t tests. RESULTS. A statistically significant difference was found between the frameworks fabricated by conventional methods and those fabricated by digital impression methods. Multiple comparison results revealed that the frameworks in Group Ci (average, $98.8{\pm}16.43{\mu}m$; canine, $93.59{\pm}16.82{\mu}m$; premolar, $104.10{\pm}15.02{\mu}m$) had larger marginal misfit values than those in Group Cdi (average, $63.78{\pm}14.05{\mu}m$; canine, $62.73{\pm}13.71{\mu}m$; premolar, $64.84{\pm}15.06{\mu}m$) and Group Tdi (average, $65.14{\pm}18.05{\mu}m$; canine, $70.64{\pm}19.02{\mu}m$; premolar, $59.64{\pm}16.10{\mu}m$) (P=.000 for average; P=.001 for canine; P<.001 for premolar). No statistical difference was found between the marginal misfits of canine and premolar abutment teeth within the same groups (P>.05). CONCLUSION. The three-unit frameworks fabricated with digital impression techniques showed better marginal fit compared to conventional impression techniques. All marginal misfit values were clinically acceptable.

• The Journal of Advanced Prosthodontics
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• v.7 no.6
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• pp.460-467
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• 2015

PURPOSE. The aim of this study is to evaluate the appropriate impression technique by analyzing the superimposition of 3D digital model for evaluating accuracy of conventional impression technique and digital impression. MATERIALS AND METHODS. Twenty-four patients who had no periodontitis or temporomandibular joint disease were selected for analysis. As a reference model, digital impressions with a digital impression system were performed. As a test models, for conventional impression dual-arch and full-arch, impression techniques utilizing addition type polyvinylsiloxane for fabrication of cast were applied. 3D laser scanner is used for scanning the cast. Each 3 pairs for 25 STL datasets were imported into the inspection software. The three-dimensional differences were illustrated in a color-coded map. For three-dimensional quantitative analysis, 4 specified contact locations(buccal and lingual cusps of second premolar and molar) were established. For two-dimensional quantitative analysis, the sectioning from buccal cusp to lingual cusp of second premolar and molar were acquired depending on the tooth axis. RESULTS. In color-coded map, the biggest difference between intraoral scanning and dual-arch impression was seen (P<.05). In three-dimensional analysis, the biggest difference was seen between intraoral scanning and dual-arch impression and the smallest difference was seen between dual-arch and full-arch impression. CONCLUSION. The two- and three-dimensional deviations between intraoral scanner and dual-arch impression was bigger than full-arch and dual-arch impression (P<.05). The second premolar showed significantly bigger three-dimensional deviations than the second molar in the three-dimensional deviations (P>.05).