• 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.

• 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 the Korean dental association
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• v.4 no.1
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• pp.5-7
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• 1963

The purpose of this investigation was to study the preperty of flow for seven different impression materials presently available in KOREA. In this study ,200 grams of a load was applied at regular intervals. As the result of this study, following points were revealed in terms of flow property of respective materials. 1)Impression plaster and irreversible hydrocolloid impression materials were found to have insufficient working time due to their tendency to set rapidly after mixing. 2)Regarding to impresssion pastes, it was found that it has manifested an ideal flow property until 2 minutes after mixing. Clinically, this material seems to allow sufficient working time for its manipulation.

• 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 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.

• The Journal of Advanced Prosthodontics
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• v.13 no.6
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• pp.361-372
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• 2021

PURPOSE. To improve the clinical effects of complete denture use and simplify its clinical application, a digital complete denture restoration workflow (Functional Suitable Digital Complete Denture System, FSD) was proposed and preliminary clinical evaluation was done. MATERIALS AND METHODS. Forty edentulous patients were enrolled, of which half were treated by a prosthodontic chief physician, and the others were treated by a postgraduate student. Based on the primary impression and jaw relation obtained at the first visit, diagnostic denture was designed and printed to create a definitive impression, jaw relation, and esthetic confirmation at the second visit. A redesigned complete denture was printed as a mold to fabricate final denture that was delivered at the third visit. To evaluate accuracy of impression made by diagnostic denture, the final denture was used as a tray to make impression, and 3D comparison was used to analyze their difference. To evaluate the clinical effect of FSD, visual analogue scores (VAS) were determined by both dentists and patients. RESULTS. Two visits were reduced before denture delivery. The RMS values of 3D comparison between the impression made via diagnostic dentures and the final dentures were 0.165 ± 0.033 mm in the upper jaw and 0.139 ± 0.031 mm in the lower jaw. VAS ratings were between 8.5 and 9.6 in the chief physician group, while 7.7 and 9.5 in the student group; there was no statistical difference between the two groups. CONCLUSION. FSD can simplify the complete denture restoration process and reduce the number of visits. The accuracy of impressions made by diagnostic dentures was acceptable in clinic. The VASs of both dentists and patients were satisfied.

• The Journal of Korean Academy of Prosthodontics
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• v.37 no.3
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• pp.301-312
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• 1999

The purpose of this study was to compare the accuracy of currently used elastomeric impression materials for complete arch impression taking. Five elastomers (Impregum, Permlastic, Express, Extrude, Examix) and one Irreversible hydrocolloid (Aroma-fine) were tested. For each material, 5 impressions were made of stainless steel model to which five tapered posts were attached. Custom trays were used for polyether and polysulfide impression materials, and putty/wash two step technique was used for addition polyvinylsiloxane impression materials. Improved stone mod els were poured to all impressions. Accuracy of the materials was assessed by measuring ten distances on stone dies poured from impressions of the master model. All measurements for master and improved stone models were made with three dimensional measuring machine. The results were as follows 1. The dimensional accuracy of polyether, extrude, and examix were significantly superior to poly-sulfide, exress, and alginate in reproducing full arch mode (p<0.05) 2. There were no statistical differences in dimensional accuracy for full arch impression between polyether extrude and examix (p>0.05). 3. there were no statistical differences in dimensional accuracy between polysulfide, express, and alginate(p>0.05). 4. There were no statistical differences between addition polyvinyl siloxane materials (p>0.05) 5. There were no statistical differences between anterior-posterior and lateral dimensional changes of all impression materials (p>0.05).

• 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 Advanced Prosthodontics
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• v.9 no.3
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• pp.182-187
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• 2017

PURPOSE. Vinyl polyether silicone (VPES) has a different composition from other elastomeric impression materials as it combines vinyl polysiloxane (VPS) and polyether (PE). Therefore, it is important to study its properties and behavior under different test conditions. This study investigated the dimensional stability of 5 VPES consistencies when stored for up to 2 weeks, with and without using a standard disinfection procedure. MATERIALS AND METHODS. 40 discs of each VPES consistency (total 200) were made using a stainless steel die and ring as described by ANSI /ADA specification No. 19. 20 discs of each material were immersed in a 2.5% buffered glutaraldehyde solution for 30 minutes. Dimensional stability measurements were calculated immediately after fabrication and repeated on the same discs after 7 and 14 days of storage. The data was analyzed using two-way ANOVA with a significance level set at ${\alpha}=0.05$. RESULTS. The discs mean contraction was below 0.5% at all test times ranging from $0.200{\pm}0.014$ to $0.325{\pm}0.007$. Repeated measures ANOVA showed a statistically significant difference after 2-week storage between the disinfected and non-disinfected groups (P < .001). Although there was no statistically significant difference between the materials at the time of fabrication, the contraction of the materials increased with storage for 1 and 2 weeks. CONCLUSION. The dimensional changes of VPES impression discs after disinfection and prolonged storage complied with ANSI/ADA standard. The tested VPES impression materials were dimensionally stable for clinical use after disinfection for 30 minutes in glutaraldehyde and storage for up to 2 weeks.

• 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.