• The Journal of Korean Academy of Prosthodontics
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• v.37 no.4
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• pp.506-515
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• 1999

Dental practice can produce and spread some infectious diseases from patients to dentist, dental assistant, and dental labors. One possible method for preventing these cross-contamination is to immerse dental impression in chemical disinfectants. So for many investigators studied on the dimensional changes of dental impressions and on the surface qualities of stone casts made from impression following immersion in disinfectants. This study was proposed to evaluate some popular impression disinfectant combination from the point of dimensional stability. Impression was taken from dental arch-shaped metal model. Irreversible hydrocolloid and 3 elastomers(polyvinyl siloxane, polysulfide, polyether) were immersed in 3 disinfectants (2% glutaraldehyde, 1% povidone-iodine, 0.5% sodium hypochlorite) for 10 minutes and measured both cross-arch and anterior-posterior distance under stereo microscope to evaluate dimensional change. The results obtained were as follows: 1. Dimensional changes of irreversible hydrocolloid impression was statistically different in cross-arch and anterior-posterior distance when immersed in 2% glutaraldehyde solution and in anterior-posterior distance when immersed in 0.5% sodium hypochlorite solution from control group (p<0.05). 2. Dimensional changes of polyvinyl siloxane and polysulfide impression were not statistically different from control group (p>0.05). 3. Dimensional changes of polyether impression was statistically different in cross-arch distance when immersed in 0.5% sodium hypochlorite solution and in anterior-posterior distance when immersed in 1% povidone-iodine solution from control group (p<0.05). 4. In all cases, dimensional changes were less than 0.1% from the original dimension and concluded clinically acceptable.

• The Journal of Advanced Prosthodontics
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• v.10 no.5
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• pp.335-339
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• 2018

PURPOSE. The purpose of the present study was to compare scanning trueness and precision between an abutment impression and a stone model according to dental computer-aided design/computer-aided manufacturing (CAD/CAM) evaluation standards. MATERIALS AND METHODS. To evaluate trueness, the abutment impression and stone model were scanned to obtain the first 3-dimensional (3-D) stereolithography (STL) file. Next, the abutment impression or stone model was removed from the scanner and re-fixed on the table; scanning was then repeated so that 11 files were obtained for each scan type. To evaluate precision, the abutment impression or stone model was scanned to obtain the first 3-D STL file. Without moving it, scanning was performed 10 more times, so that 11 files were obtained for each scan type. By superimposing the first scanned STL file onto the other STL files one by one, 10 color-difference maps and reports were obtained; i.e., 10 experimental scans per type. The independent t-test was used to compare root mean square (RMS) data between the groups (${\alpha}=.05$). RESULTS. The $RMS{\pm}SD$ values of scanning trueness of the abutment impression and stone model were $22.4{\pm}4.4$ and $17.4{\pm}3.5{\mu}m$, respectively (P<.012). The $RMS{\pm}SD$ values of scanning precision of the abutment impression and stone model were $16.4{\pm}2.9$ and $14.6{\pm}1.6{\mu}m$, respectively (P=.108). CONCLUSION. There was a significant difference in scanning trueness between the abutment impression and stone model, as evaluated according to dental CAD/CAM standards. However, all scans showed high trueness and precision.

• Journal of Institute of Control, Robotics and Systems
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• v.17 no.3
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• pp.254-257
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• 2011

This study was performed to development a dental three-dimensional laser scanning system and measure the accuracy of new adjustable lower dental impression trays. Multiple impressions of a resin master model were made with custom, stock and new adjustable trays and vinyl polysiloxane impression material. The lower master model and resulting cast were compared using an dental scanning system. Each 3D image was superimposed onto the lower master model image and analyzed with custom software. Multiple measurements of the lower master model and casts were analyzed to determine the accuracy of tray types.

• Journal of Korean society of Dental Hygiene
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• v.8 no.4
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• pp.89-99
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• 2008

In this study, polyvinylsiloxane impression materials were investigated to examine the characteristics of the impression materials that affect the accuracy of the final restoration. The flow property of impression materials which can reproduce the detail in the oral cavity and accurately duplicate it, and the tear strength and strain-in-compression which can cause problems when it is being removed from the oral cavity were studied. The results are as follows. 1. As for the flow properties of impression materials, Imprint II was 18.24${\pm}$0.30, which was the highest: and Twinz was 8.9${\pm}$0.62, which was the lowest. There was no significant difference among Imprint II, Examixfine, and Genie(p<0.05). 2. As for the tear strength of impression materials, Imprint II had the highest level, while Genie had the lowest value. There was no significant difference between Twinz and Genie(p<0.05). 3. As for the strain-in-compression, there were significant differences by impression material groups(p<0.05); the strain-in-compression of Examixfine was shown to be the highest at 5.56${\pm}$0.56, Twinz and Imprint II followed respectively, and Genie has the lowest at 3.19${\pm}$0.23. 4. Flow showed the correlation with tear strength but no significant connection to strain-in-compression. Also, there was no significant correlation between the tear strength and strain-in-compression (p<0.05). Making impression to reproduce oral tissue and tooth is an important part of making final restoration. The accuracy of impressions is influenced by the methods of taking impression or other condition. However the property itself of impression materials is the most essential and the materials with proper qualities should be selected.

• Journal of Korean society of Dental Hygiene
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• v.9 no.3
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• pp.369-379
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• 2009

This study investigated the polymerization inhibition effect of latex gloves on addition silicone impression material. Three different kinds of addition silicone impression materials and a natural latex gloves were used in this study. The results were as follows. 1. Compared to the control group, all of those three kinds of impression materials took longer curing time in order of unwashed, alcohol and washed group, on the other hand, degloving group had shorter curing time than control group(p<0.05). 2. By the type of impression materials, there was no significant difference observed between Exafine and Twinz in ungloved group, Exafine and Imprint II in unwashed group, and Exafine and Twinz in degloving group(p>0.05). 3. The degree of polymerization at 6 minutes after mixing impression materials was evaluated by dividing its range into score 1 to 5. All of the impression materials got score 5 in control group and degloving group, which implies perfect polymerization. In unwashed group, most of them appeared to be score 2 while score 3 were most frequently observed in alcohol group and score 4 in washed group. Thus each group showed differences in the degree of polymerization(p<0.05).

• The Journal of Advanced Prosthodontics
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• v.9 no.4
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• pp.287-293
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• 2017

PURPOSE. To compare the dimensional accuracy of three impression techniques- a separating foil impression, a custom tray impression, and a stock tray impression. MATERIALS AND METHODS. A machined mandibular complete-arch metal model with special modifications served as a master cast. Three different impression techniques (n = 6 in each group) were performed with addition-cured silicon materials: i) putty-wash technique with a prefabricated metal tray (MET) using putty and regular body, ii) single-phase impression with custom tray (CUS) using regular body material, and iii) two-stage technique with stock metal tray (SEP) using putty with a separating foil and regular body material. All impressions were poured with epoxy resin. Six different distances (four intra-abutment and two inter-abutment distances) were gauged on the metal master model and on the casts with a microscope in combination with calibrated measuring software. The differences of the evaluated distances between the reference and the three test groups were calculated and expressed as mean (${\pm}SD$). Additionally, the 95% confidence intervals were calculated and significant differences between the experimental groups were assumed when confidence intervals did not overlap. RESULTS. Dimensional changes compared to reference values varied between -74.01 and $32.57{\mu}m$ (MET), -78.86 and 30.84 (CUS), and between -92.20 and 30.98 (SEP). For the intra-abutment distances, no significant differences among the experimental groups were detected. CUS showed a significantly higher dimensional accuracy for the inter-abutment distances with -0.02 and -0.08 percentage deviation compared to MET and SEP. CONCLUSION. The separation foil technique is a simple alternative to the custom tray technique for single tooth restorations, while limitations may exist for extended restorations with multiple abutment teeth.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.47 no.2
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• pp.82-90
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• 2021

Objectives: Cleft lip and palate (CLP) is one of the most common congenital deformities with worldwide prevalence. It causes a range of issues for infants that mainly involve difficulty in feeding due to abnormal oronasal communication. For this purpose, feeding plates are provided to infants to act as an artificial palate to aid in feeding. The most crucial procedure in fabrication of a feeding plate is creation of the impression using the traditional finger technique or impression trays. This preliminary research aims to compare the effectiveness of novel impression trays with that of the traditional finger technique for recording impressions of infants with CLP. Materials and Methods: This randomized controlled trial was conducted among 30 infants who were divided into two groups based on the method of obtaining impressions: Group I, finger technique; Group II, specialized acrylic tray (cleftray). Results: Use of cleftray required less impression time, a reduced amount of material, no incidence of cyanosis/choking in infants, and lower anxiety among doctors compared to the traditional method. Additionally, there was no distortion of cleft impressions, recorded maxillary tuberosity, or other fine details. Therefore, the novel impression tray (cleftray) exhibited superior outcomes in all the parameters compared to the finger technique. Conclusion: Within the limitations of this study, we conclude that impression trays are superior to the traditional finger, spoon, or ice cream stick methods of creating impressions of CLP. However, it is necessary to conduct more clinical trials on a larger population based on other parameters to compare the effectiveness of the two techniques to draw definitive conclusions.

• Journal of Korean society of Dental Hygiene
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• v.8 no.2
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• pp.53-66
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• 2008

There was to purpose of this study improves analyzing cause that prosthesis brings bite engaging that is inaccurate in patient's mouth, when supposed that all conducts that do in operatory and dental laboratory are perfect. Impression did check bite by alginate impression material and polymerization style silicon impression material that use usually in presence at a sickbed Irreversibility, hydrocolloid, alginate impression material washed in flowing water and poured anhydrite after wait about 8 minutes so that region that charge interest after impression check bite may become undoing. And hydrophile property addition polymerization style impression material poured anhydrite after blow 30 considering impression material dwell time and H2 gas occurrence time (5~15 minute) after have washed in flowing water. I got each 7 models, result that manufactures total 28 and measures by third dimension measuring instrument (Meteo, Korea) following sequence curing in tray holder and floor 1, By Alginate impression when is hardened in tray holder and when is hardened in the floor after do check bite, SPH 4, SPH5 all as there is synonymy appeared(P<0.05). By in case do not use average 0.1741 in case use tray holder in 0.0447 SPH5s in case do not use average 0.2838 pastas in case use tray holder in SPH4 0.0309, When did not use both SPH4 and SPH5 tray holder, when used tray holder, 1 appeared more greatly. 2. By amity sex addition polymerization style silicon impression when is hardened in tray holder after do check bite and when is hardened in the floor SPH 4, a11 of the SPH5s very big synonymy be(P>0.05). And in case use tray holder in 0.000657 pasta SPH5s in case do not use average 0.000129 pastas in case use tray holder in SPH4 average 0.000114 pastas, by in case do not use 0.000757, I appeared more greatly when used tray when did not use both SPH4 and SPH5 tray holder, but 1 appeared is not level to keep in mind(Table 8~9). 3 SPH4 was looked very big mindfulness in model that manufacture doing impression check bite by Alginate and model that do impression check bite by amity sex accessory penalty silicon without using tray holder(P< 0.001). I use tray holder and SPH4 did not appear synonymy in model that manufacture doing impression check bite by Alginate and model that do impression check bite by amity sex accessory penalty silicon(P>0.05). Study finding of above when see synthesis Alginate certainly tray holder use must and I could know that hardening method does not exert big influence on volume stability if remove impression sieve of excess because amity sex accessory penalty silicon passes over tray, Also, Alginate impression material previewed can get heading a conspiracy style that volume stability of accessory penalty silicon impression material degree is if use tray holder.

• Journal of Korean Dental Science
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• v.7 no.2
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• pp.80-86
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• 2014

Purpose: Current common method of cytotoxicity evaluation for elastomeric impression materials use animal based cell lines, which the clinical relevance has been often questioned. Hence, the purpose of this study was to examine the difference in results with both human based and animal based fibroblast cell line. Materials and Methods: Three types of fibroblast cells were used in this study; conventional mouse fibroblasts of L929, human gingival fibroblasts (HGF-1), and immortalized human oral fibrobalsts (hTERT-hNOF). Test on extract and test by direct contact using different commercially available elastomeric impression materials were carried out according to the international standards. Result: There was significant difference in cell viability between types of fibroblasts cell used, where HGF-1 showed highest cell viability and L929 the lowest. Conclusion: Within the limitation of this study, careful consideration must be given when selecting the cells and interpreting the results for cytotoxicity evaluation of elastomeric impression materials, where use of human based cell lines such as hTERT-hNOF would be appropriate for both ease of cytotoxicity test and clinical relevance.

• Journal of Institute of Control, Robotics and Systems
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• v.16 no.3
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• pp.300-304
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• 2010

This study was performed to development a dental three-dimensional laser scanning system and measure the accuracy of new adjustable upper dental impression tray. The metal stock, individual, and new adjustable stock trays were used for 30 stone casts(10 casts each) duplicated a resin master model of maxilla. The dental stone was poured in a vinyl polysiloxane impressions and allowed to set for on hour. The master model and the duplicated casts were digitized using an dental scanning system. The distance between the reference points were measured and analyzed on the graphic image of 3D graphic software of CATIA. The statistical significance of the differences between the groups was determined by a two-way ANOVA. There were no significant differences between the accuracies of the adjustable stock tray and the master model except only anterior arch width on the upper arch. The adjustable upper stock tray showed clinically acceptable accuracies of the study cast produced by them.