• 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.

• The Journal of the Korean dental association
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• v.38 no.8 s.375
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• pp.757-764
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• 2000

• Journal of Industrial Technology
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• v.36
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• pp.39-43
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• 2016

The purpose of this study is to determine and compare the mechanical and flow properties of polyvinylsiloxane impression pastes. Twelve polyvinylsiloxane impression materials were used. As mechanical properties, tensile strength and tear resistance were measured. Impression materials are subjected to tensile stresses when they are removed from the oral cavity and from stone models and tear resistance is the ability of the material to resist tearing under a tensile stress. Flow is dependent on the ability of the material to resist shear forces. Flow tests were performed to determine the handling characteristics and was measured using a shark fin testing device. An impression material must be able to penetrate the narrow subgingival sulcus and tight interproximal areas. Therefore, it must be able to resist the shear forces as it is pushed between tooth and gingival walls. It is necessary to understand the properties of interocclusal recording materials and is considered that the results obtained in this study will provide guideline information for the manufacturing of impression materials and for selecting appropriate impression materials.

• The Journal of Advanced Prosthodontics
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• v.3 no.1
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• pp.33-36
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• 2011

In process of fabrication of a fixed partial denture, dies are trimmed to expose margins of the preparations. The need for the soft tissue cast is quite evident as the soft tissue emergence profile that surrounds the prepared tooth is destroyed in the process of fabrication. This article describes a modified technique to fabricate the soft tissue cast for the conventional fixed partial denture. The impression made with the polyvinylsiloxane was first poured to prepare the die cast. After retrieval of the cast, the same impression was poured second time with the resin based resilient material to cover the facial and proximal gingival areas. The remaining portion of the impression was poured with the gypsum material. This technique does not require additional clinical appointment, second impression procedure, technique sensitive manipulations with impression, or cumbersome laboratory procedures. The simplicity of this technique facilitates and justifies its routine use in fabrication of the fixed partial denture.

• Journal of dental hygiene science
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• v.14 no.2
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• pp.94-100
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• 2014

The purpose of this study was to evaluate the accuracy of digitized elastomeric impression materials of crown abutment, using non-contact white light scanner and virtual three-dimensional superimpositional analysis. The stone models and impressions were digitized white light scanner to create three-dimensional surface models. Stone models were used as CAD reference model (CRM). The resulting point clouds (ASC file) from digitization of impressions using converting software. Discrepancies between the points in the point clouds and CRM were measured by superimpositional software. Mean and standard deviation of values of discrepancies were analyzed by one-way ANOVA and multiple comparison (${\alpha}=0.05$). The mean discrepancy between the impressions for the extra-light body (XLB), light body (LB), and heavy body (HB) group were $5.10{\pm}1.45{\mu}m$, $6.30{\pm}1.87{\mu}m$, $9.80{\pm}1.52{\mu}m$, respectively. The different impression materials affected the digitization of impressions significantly (p<0.05). As a result, digitization of elastomeric impression materials on dental scanner was influenced by material sort.

• Journal of Industrial Technology
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• v.34
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• pp.11-14
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• 2014

Viscosity and shear stress of the dental impression materials on commercial market(Imprint Garant LB(3M, U.S.A), EXAMIXFINE IT(GC, Japan), Vonflex S LB(Vericom, Korea), S-Silicone LB(Shinwon, Korea)) were measured with increasing shear rate from 50(1/sec) to 100(1/sec). The viscosity of EXAMIXFINE IT was decreased from 20,542(cP) to 14,684(cP), which is the shear thinning property of pseudoplastic as non-Newtonian fluid. Since the pseudoplastic property makes the impression material shear thinning and softly injected from cartridge, EXAMIXFINE IT might be popularly used in dentistry.

• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.1
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• pp.31-40
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• 2009

The rheologic properties of elastic impression materials is a very important role as taking high accuracy impression. But, the studies that are focused on the rheologic properties of Korean elastic impression materials are not sufficient. The purpose of this study is to help clinical high accuracy impression taking by testing rheologic properties of elastic impression material that is made by Korea and other countries. Six type III elastic impression materials are tested. Subjects are 2 Korean polyvinylsiloxane(PVS), 2 imported PVS, 1 polyether, and 1 polysulfide. HAAKE RheoStress $1^{(R)}$(Thermo Electron Co. Germany)is used in measuring. HAAKE RheoStress $1^{(R)}$ is plate to plate type rheometer. All subjects is tested 3 times and measuring time is 900 seconds. We measured G′ and loss tangent after mixing. All elastic impression materials had a sigmoid shape on increasing G′ by time and decreasing loss tangent after setting, maximum G' is appeared highest in polyether, and lowest in polysulfide. Initial loss tangent is highest in polyether, and is lowest in Koreans PVS. Significant difference is showed in initial loss tangent between Korean PVS and imported PVS.

• The Journal of Korean Academy of Prosthodontics
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• v.41 no.1
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• pp.61-70
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• 2003

The purpose of this study was to investigate the contact angles and wettability of conventional dental stones and improved dental stones and newly developed dental stones on several impression materials. Materials included in this study were several dental stones and newly developed dental stone ; 2 type III stones (Snow Rock, New Diastone), 6 type IV stones(Crystal Rock, Vel Mix, Fuji Rock, Tuff Rock, Resin Rock and newly developed dental stone) and 1 type V stone (Die Keen). Contact angles on the impression materials were measured with contact angle measuring device. Ten specimens for each material, total 180 specimens were made on void entrapment model. The two impression materials (Handae, GC) were used to produce 9 groups of die stone casts form void entrapment model. Voids in the stone casts were counted under a stereoscopic microscope. The grad for the reproduction ability of each materials on the void entrapment model was calculated from the casts by one examiner. From the experiment, the following results were obtained : 1. The newly developed stones showed smallest contact angle. Type III dental stone had larger contact angles than type IV and V stones. Contact angle was much affected by the impression materials. 2. Resin containing die materials such as Tuff Rock and Resin Rock had smallest void number than any other groups. 3. In comparing reproduction parameters, Tuff Rock and Resin Rock presented superior results, while Vel Mix showed lowest reproduction ability.

• Journal of Korean society of Dental Hygiene
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• v.1 no.2
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• pp.171-180
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• 2001

The purpose of this study was to compared with the properties of commercial polyvinyl siloxane impression materials on the Korean product and the other country one. The materials used in this study were 5 hydrophilic polvinyly siloxane impression materials of light body automixing type (Perfect-F, Handae Chemical, Korea; Examix, GC, Japan; Contrast, VOCO, Germany; Express, 3M, U.S.A; Extrude, Kerr, U.S.A.). Specimens of each impression material were fabricated from a mold with dimensions identical to that specified in ASTM D624-91 and were subjected to tensile lode at 500 mm/min until failure for tear strength. Properties of consistency, strain in compression, recovery from deformation, detail reproduction and linear dimensional change were tested according to the testing methods of the ISO specification no.4823(1992). From this study, the follow ing results were obtained 1. The tear strength values were high ET(3.4kN/m), EP(3.4kN/m), PF(3.0kN/m), CT(3.0kN/m), but the lowest was EM(2.2kN/m)(p<0.05). 2. In the consistency, CT(47 mm) had the highest value, followed by PF(42.1 mm), ET(41.2 mm), and EM(39.6 mm), EP(39.2 mm)(p<0.05). It means more flow that the consistency value is high. 3. The strain in compression values were high followed by EM(5.8%), PF(52%), CT(4.6%), ET(4.1%), EP(2.9%)(p<0.05). 4. In the recovery from deformation, ET(99.95%) and PF(99.90%) had the highest value, followed by EP(99.75%), EM(99.74%) without statistical signification, CT(99.64%) had the lowest value(p<0.05). 5. Detail reproduction reappeared to line $20{\mu}m$ all products. 6. The linear dimensional change was a little shrinked all products. and there were not statistical signification (p>0.05). All products were satisfied the ISO specification.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.240-244
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• 2018

There is growing concern about cross infection among the patients to patients, patients to staffs, and tools to patients in healthcare facilities, especially in dentistry. In this study, the most widely used dental impression materials were prepared and the synergy effect of Chlorhexidine and essential oil on antimicrobial activity was examined in the impression materials. Chlorhexidine concentration of 0.1 wt% and 0.5 wt% showed no antimicrobial activity on Escherichia coli (E. coli) and Candida albicans. At 1.0 wt% Chlorhexidine, 0% of E. coli and 34.7% of Candida albicans were survived. Bergamot (Essential oil) concentration of 0.5 wt% and 1.0 wt% showed no antimicrobial activity on E. coli. At 2.0 wt% Bergamot oil, 71.9% of E. coli were survived. Tea tree oil (Essential oil) of 0.5 wt% showed no antimicrobial activity on E. coli. At 1.0 wt% Tea tree oil, 11.2% of E. coli was survived. At 2.0 wt% Tea tree oil, no E. coli was survived. However, no E. coli was survived at the concentration of 0.8 wt% Bergamot with 0.3 wt% Chlorhexidine. At the concentration of 0.8 wt% Tea Tree oil with 0.3 wt% Chlorhexidine, 1.3% of E. coli were survived. The experimental results showed that the synergy effects between Chlorhexidine and essential oils on antimicrobial activity were prominent.