• The Journal of Korean Academy of Prosthodontics
• /
• v.34 no.2
• /
• pp.290-298
• /
• 1996

The effects of impression tray disinfection procedures on the bond strength of impression-material adhesive to two of types resin trays were evaluated with a tensile test. Autopolyme-rizing acrylic resin was formed into 1x1x1 cm cubes. A hook was attached to each cube with autopolymerizing acrylic resin. Perforated trays were fabricated with stops to maintain an even 3 cm of impression material over the resin block. Hook on the opposite side of the perforated tray permitted attachment of the metal plate to a mechanical testing machine. Before adhesive was applied, one third of the resin specimens were immersed in a 5% sodium hypochlorite solution : one third in a 2% glutaradehyde solution, and one third were kept in the "as fabricated" condition. Three products(Perfect ups, Exafine, and Exp-ress) of polyvynil siloxane impression material-adhesive system were evaluated. The resin-impression material-metal plate couples were attached to a mechanical testing machine and tensile forces were applied at a separation rate of 10 centimeters per second. The results were as follows; 1. Both disinfectant and adhesive had effects on bond strength values, but adhesive had more effect than disinfectant(p<0.01). However, there was no interaction between dinin-fectant and adhesive(p>0.01). 2. Mean bond strength values for the Perfect materials were about 85% less than that of the Exafine or the Express materials. However, there was no stastically significant difference between the mean bond strength values of the Exafine materials and the Express materials(p>0.05). 3. The use of disinfectants produced significant reduction in bond strength values(p<0.05). But there was no stastically significant difference between the mean bond strength values of the groups treated with disinfectants(p>0.05).

• The Journal of Korean Academy of Prosthodontics
• /
• v.36 no.3
• /
• pp.496-505
• /
• 1998

The purpose of this study was to evalute the effect of immersion disinfection on the dimensional stability of rubber impression materials. The metallic master model was made in order to simulate the intraoral arch form. Impressions were made from four impression materials (Exaflex, Extrude, Reprosil, Impregum-F) and immersed in three disinfectant solutions (Wydex, Vi-Pon, Potadine). Casts from the impressions were measured according to the interpreparation distance. The A-B and The B-D abutment distance were compared with the control group and disinfected groups. The results were as follows; 1. The measurements of the stone cast increased relative to the master model and there was a significant difference (P<0.05). 2. The relative dimensional change of the stone cast as compared with master model ranged from 0.10% to 0.56% in the A-B distance and ranged from 0.04% to 0.27% in the B-D distance. 3. The dimensional change of the disinfected groups as compared with the control group was significantly different in the three impression materials except for Impregum-F (P<0.05). 4. The relative dimensional change of the disinfected groups compared with the control group ranged from 0% to 0.20% in the A-B distance and ranged from -0.09% to 0.11% in the B-D distance. These results suggest that immersion disinfection of rubber impression materials by chemical disinfectants causes very small dimensional change and the change is clinically acceptable for prothesis fabrication

• The Journal of Korean Academy of Prosthodontics
• /
• v.41 no.5
• /
• pp.551-564
• /
• 2003

Statement of problem : Magnesium oxide may increase pH of alginate, and supply magnesium ions to the polymerization reaction of alginate. Purpose : This study was designed to evaluate the influence of incorporation of magnesium oxide to alginate composition. Material and Method : Seven kinds of experimental alginates were prepared and used for the experiments. Components with unchanging concentrations were sodium alginate 15%, calcium sulfate 14%, sodium phosphate 2%, and zinc fluoride 3%. Contents of magnesium oxide were varied as 0%, 1%, 2%, 3%, 4%, 5%, 6%. Diatomaceous earth were added to each experimental groups as balance to be 100%. Control group was a MgO 0% group. Working time, setting time, elastic recovery strain in compression, compressive strength and tear resistance were measured were measured. Sample size for each groups were 10. Arithmetic means were used as each groups representative values. Regression test between MgO contents and results, Duncan's multiple range test, and One-way ANOVA test were done between groups at level of 0.05. Results : 1 Magnesium oxide made the working time and setting time as longer(p<0.0001). 2 Magnesium oxide did not alter the elastic recovery(p>0.05). 3. Magnesium oxide contents between 2% and 4% exhibited the lowest strain in compression on alginates(p<0.0001). 4. Magnesium oxide made the compressive strength and the tear resistance stronger(p<0.0001). Conclusion : These results mean that setting time of alginate maybe controlled and that mechanical properties maybe improved by the incorporation of magnesium oxide into alginate, without any reduction of elasticity.

• Journal of Korean society of Dental Hygiene
• /
• v.12 no.6
• /
• pp.1082-1089
• /
• 2012

Objectives : The aim of this study was to determine the accuracy of digitized stone models, impression materials compared to the master model and the reliability of the computer aided analysis. Methods : A master model(500B-1, Nissin dental product, Japan) with the prepared lower full arch tooth was used. Ten vinyl polysiloxane impressions(Examix$^{(R)}$, GC Industrial Corp, Japan) of master model were taken and type IV stone(aesthetic-base gold$^{(R)}$, Dentona, Germany) were poured in stone models. The linear distance between the reference points were measured and analyzed on the Delcam Copycad$^{(R)}$(Delcam plc, UK). The t-student test for paired samples was used for statistical analysis. Results : The mean differences to master model for stone model and impression material were 0.11~0.19mm, and 0.19~0.29mm, respectively. There were statistical differences in dimensional accuracy for full arch impression between master model and stone model/impressions(p<.05). Conclusions : Two different scanning methods showed clinically acceptable accuracy of full arch digital impression produced by them. These results will have to be confirmed in further clinical studies.

• The Journal of the Korea Contents Association
• /
• v.14 no.8
• /
• pp.277-286
• /
• 2014

The purpose of this study was to identify the relationship between the health insurance perception level and health insurance satisfaction for national health insurance subscriber. The collected data were analyzed by $X^2$-test, t-test, ANOVA using the SPSS/WIN (ver.14.0). Research results can be summarized as follows. The relationship between the health insurance perception level and health insurance satisfaction was relatively high. The study showed significantly high levels in the score of health insurance satisfactions according to perception of security level, health insurance premium, positive thinking, and fair in premium charge. Also health insurance satisfaction scores were significantly low levels according to perception of raise health insurance premium and burden on households. This study investigated the relationship between the detail perception and satisfaction for national health insurance. Therefore, we are setting the overall direction of national health insurance perception, and look forward to utilizing the basis data as help to improve the system of health insurance for people.

• Journal of Korean society of Dental Hygiene
• /
• v.8 no.4
• /
• pp.89-99
• /
• 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
• /
• v.37 no.4
• /
• pp.506-515
• /
• 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 Korean Academy of Prosthodontics
• /
• v.41 no.2
• /
• pp.243-257
• /
• 2003

The purpose of this study was to search the influences of the increase of the contents of sodium alginate in the experimental alginates on the some mechanical properties. 3 commercial alginates were selected for the purpose of comparison of the results of experiments. 7 experimental alginates were manufactured with the rise of contents of sodium alginate from 8.8% to 18.3% with the decrease of contents of diatomaceous earth and with the constant contents of calcium sulfate 12.5%. sodium phosphate 2.2%, zinc fluoride 2.0%. Splitable metal mold with 12.5mm diameter and 20.0mm height was filled with mixed alginate to prepare the cylinder shaped specimens. Strain in compression, elastic recovery, compressive strength were tested using the ISO specification number 1563, alginate impression material. Experimental groups were 7, and 10 specimens were used for each test items and each groups. Following results were obtained ; 1. Strain in compression was decreased with the increase of sodium alginate contents (p=0.0077, r2 = 0.6302). 2. Elastic recovery was decreased with the increase of sodium alginate contents but was not significant(p=0.0639, r2=0.7449). 3. Compressive strength was increased with the increase of sodium alginate contents (p<0.0001, r2 = 0.9617). These results mean that the increase of sodium alginate contents make alginate harder but may result the increased permanent deformation.

• KAPE Magazine
• /
• no.5 s.141
• /
• pp.7-8
• /
• 2008

현재 시장의 개방화, 사료비 인상, 조류인플루엔자 및 돼지산업에서는 만성소모성질환으로 많은 농가들이 어려움을 겪고 있다. 이러한 시기에 양돈산업이 국제 경쟁력을 갖추기 위해서는 생산비 절감과 차별화가 큰 대안이 될 수 있다. 하지만 생산비의 절반 이상을 차지하는 사료 대부분을 외국에서 수입하는 현실에서 생산비 절감 부분은 그 한계가 있을 수 있기 때문에 수입돈육과 경쟁하기 위해서는 국내에서 생산되는 돈육의 품질고급화 및 차별화에 초점을 맞추어야 할 것이다. 이러한 차별화를 위한 방안으로 유기축산, 무항생재, 기능성돈육, 고급육 등 많은 대안들이 제시되고 있다. 그리고 현재는 2007년 7월부터 축산물등급판정소에서 돈육의 육질등급 제도를 실시하면서 등급에 따른 가격차이가 발생하고 있어 브랜드 업체나 양돈농가 또한 고품질의 돈육생산에 관심을 가지기 시작했다. 현재 농촌진흥청 축산과학원 양돈과에서는 듀록품종의 계통조성을 '축진듀록'을 완성하여 돼지인공수정센터에 공급하였으며 축진듀록과 연계하여 종돈의 육질개량에 대해 알아보고자 한다.

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2004.05a
• /
• pp.372-374
• /
• 2004

최근들어 비금속광물의 구조적 특성을 이용한 활용분야가 매우 다양해지고 있다. 특히 판상광물은 차폐(은폐)력이 매우 우수하고, 층간특성을 이용한 흡착 및 저장특성이 매우 우수하다. 본 연구에서는 이와 같은 판상광물의 기본의 특성에 또 다른 기능성 물질을 흡착시킴으로써 부가적인 새로운 기능성을 갖는 친환경성 건축소재를 개발하고자 천연산 인상흑연 및 견운모를 기능성 모소재로 사용하고 미립화 및 표면 환경기능화를 위하여 BMK로 흑연입자 표면을 기능화하였다. 제조된 기능성 마감재인 닥터하우스를 모르타르에 도포하여 다양한 기능성을 측정한 결과 78% 이상의 유해가스(포름알데히드) 정화제거효과 및 99.9% 이상의 항균, 항곰팡이 효과를 갖는 것으로 나타났다.