치기공용 금속의 고객 만족도 평가에 관한 연구 - 귀금속 합금을 중심으로

김웅철(Woong-Chul Kim),오세윤(Sae-Yoon Oh),김지환(Ji-Hwan Kim),이세훈(Se-Hoon Lee),유진호(Chin-Ho Yu),김태석(Tae-Suk Kim),현혜정(Hye-Jung Hyun) 고려대학교 보건과학연구소 2004 보건과학논집 Vol.30 No.1

  A questionnaire tool was newly developed to assess customer satisfaction indexs with dental precious alloys. The questionnaire was mailed to randomly selected 388 dental laboratory technicians who were owners of dental laboratory.<BR>  All the data obtained from 145 persons who filled out the questionnaire were coded and analyzed with PC/SAS 8.1 program. Qualities of the products and services of some dental precious alloys, presently available in Korean dental market, were assessed for customer satisfaction index.<BR>  The results were as follows :<BR>  Customer satisfaction index was highest in W Co.(69), A Co.(69), H Co.(69) and followed by S Co.(63) in descending order.<BR>  Statistically significant factors by multiple regression analysis affecting the latent variables were customer expectation(R² = 0.6973), service quality (R² = 0.1458), perceived value(R² = 0.0494), and general satisfaction (R² = 0.0203).<BR>  Mean values of measurement variables related to customer satisfaction were lower most in a rating of performance relative to customer"s ideal product or service quality(2.90 ± 0.96), quality given price(2.92 ± 0.94), and perceived reliability value(2.97 ± 0.99), while that was highest in customer complaints(4.19 ± 1.15).<BR>  With the above results considerations in mind, customer satisfaction with those dental precious alloys was affected by many proxies. Therefore it was suggested that the manufacturers and distributors endeavor to improve the customer satisfaction barometers through the proper control for the variables affecting them.

치과 캐드캠 시스템의 가공 방식에 따른 금속 코핑의 적합도 비교

김동연 ( Dong Yeon Kim ),전진훈 ( Jin Hun Jeon ),박진영 ( Jin Young Park ),김지환 ( Ji Hwan Kim ),김혜영 ( Hae Young Kim ),김웅철 ( Woong Chul Kim ) 한국치위생과학회 2015 치위생과학회지 Vol.15 No.1

The purpose of this study was to evaluate the marginal and internal gap of metal coping fabricated using additive manufacturing (AM) group and subtractive manufacturing (SM) group by dental computer-aided design (CAD)/computer-aided manufacturing (CAM) systems. Twenty same cases of stone models of abutment teeth 16 by the universal numbering system were manufactured and scanned. Ten metal copings of control group were fabricated using SM and ten metal coping of experimental group were fabricated using AM. Marginal and internal gap of copings were measured using the silicone replica technique and digital microscope (×140). The data were analyzed using IBM SPSS 21.0 Statistical Software for independent samples t-test (α=0.05). Mean± standard deviation (SD) of marginal and internal gap total size of SM group was 101.00±40.33 μm of AM group was 83.61±40.37 μm. Mean±SD of marginal and internal gap total size of SM group was significantly greater than that of AM group (p<0.05). This study showed that AM metal copings had a better marginal and internal gap than SM metal copings.

CEREC$^{(R)}$ AC system으로 채득된 디지털 인상의 재현성, 정확성 평가에 관한 연구

김재홍,김기백,김혜영,김정애,김웅철,김지환,Kim, Jae-Hong,Kim, Ki-Baek,Kim, Hae-Young,Kim, Jung-Ae,Kim, Woong-Chul,Kim, Ji-Hwan 대한치과기공학회 2012 대한치과기공학회지 Vol.34 No.2

Purpose: The aim of this study was to determine the reliability and accuracy of measurements in digital models(CEREC$^{(R)}$ AC) compared to stone models. Methods: A master model(500B-1, Nissin Dental Product, Japan) with the prepared upper full arch tooth was used. Conventional impression and then stone model(n=10) were produced from this master model, and on the other hands, digital impressions were made with the CEREC$^{(R)}$ AC intra-oral scanner(n=10). One examiner measured two times the intercanine, intermolar distance, dental arch length. The stone model were measured using a digital caliper. The t-student test for paired samples and intraclass correlation coefficient(ICC) were used for statistical analysis. Results: The measurement of two methods showed very good reliability. At the intra-examiner reliability of measurement, ICC at the stone and CEREC$^{(R)}$ AC model were 0.81 and 0.94. The mean difference between measurements made directly on the stone models and those made on the CEREC$^{(R)}$ AC model was 0.20~0.28mm, and was statistically significant(P=0.001). Conclusion: These in vitro studies show that accuracy of the digital impression is similar to that of the conventional impression. These results will have to be confirmed in further clinical studies.

치기공과 학생의 취업스트레스와 진로결정 자기효능감의 연관성

강월,김웅철,김지환,Kang, Wol,Kim, Woong-Chul,Kim, Ji-Hwan 대한치과기공학회 2016 대한치과기공학회지 Vol.38 No.3

Purpose: This study is to analyse the job seeking stress, to see the relationship Between Job Seeking Stress and career decision-making self-efficacy in students of department of dental technology. Method: For this, the students of department of dental technology in daegu and daejeon and wonkwang university selected at May 2016. A question investigation was used in a entry method of self-estimation. Furthermore a total of 151 person was used as final analysis data. Statical analysis was performed with SPSS 22.0. An analysis of frequency, two sample t-test, one-way ANOVA, Multiple regression was used. Results: Firstly, personal expenses affected beneficially statistically the Job Seeking Stress(p<.05). Secondly, sex, Score, Major satisfaction, personal expenses affected beneficially statistically the career decision-making self-efficacy(p<.05). Thirdly, University environment and academic stress in the Job Seeking Stress affected beneficially statistically the career decision-making self-efficacy(choice target). Conclusion: The study found out that there was significant effect when increased to university environment and academic stress in Job Seeking Stress, the career decision-making self-efficacy was decreased. So the study proved that when helping students facing difficulties due to the career decision-making self-efficacy, it is important to decreased their university environment and academic stress.

ShadeEye$^{(R)}$ NCC system을 이용한 Vita CAD/CAM Ceramic Block의 크기에 따른 색조 일치성 비교연구

김재홍,김혜영,김웅철,김지환,Kim, Jae-Hong,Kim, Hae-Young,Kim, Woong-Chul,Kim, Ji-Hwan 대한치과기공학회 2011 대한치과기공학회지 Vol.33 No.3

Purpose: The purpose of this study was to compare color correspondence of different sizes of Vita Mark II$^{(R)}$ and TriLuxe$^{(R)}$ Feldspar blocks. Methods: The three commercially available shades(1M2, 2M2, 3M2) of Mark II & TriLuxe blocks for the CEREC$^{(R)}$ CAD/CAM system were examined. For each of three colors, three different sizes were tested, 5 blocks each. The measurements were made using a spectrophotometer equipped with an integrating sphere using the CIE $L^*$, $a^*$, $b^*$ colorimetric system. Results: The $L^*$, $a^*$, $b^*$ value of Vita Mark II$^{(R)}$ ceramic block showed significantly higher than TriLuxe$^{(R)}$ ceramic block(p<0.05). In comparing the Vita Mark II$^{(R)}$ specimen of the three different shade, color differences between materials(${\Delta}E^*$) showed the lowest value of 2.09, and the highest was 2.24. ${\Delta}E^*$ values of the materials of Vita Mark II$^{(R)}$ were higher than 2. As the size of ceramic block differed, the color correspondence of Vita Mark II$^{(R)}$ showed statistically significant difference but, this result is clinically acceptable. Conclusion: All the different sizes of the different shades of Vita TriLuxe$^{(R)}$ blocks for the CEREC$^{(R)}$ system showed the high degree of color correspondence necessary in industrially prefabricated CAD/CAM blocks. The results of the present study suggested that it would be necessary to establish the reproducible and constant color specification system for an esthetic restoration.

치과 CAD/CAM 시스템으로 제작한 코발트-크롬 소결 금속 코핑의 변연 및 내면 적합도 평가

김동연 ( Dong Yeon Kim ),신천호 ( Chun Ho Sin ),정일도 ( Il Do Jung ),김지환 ( Ji Hwan Kim ),김웅철 ( Woong Chul Kim ) 한국치위생과학회 2015 치위생과학회지 Vol.15 No.5

본 연구에서는 CAD/CAM 시스템을 이용하여 제작한 코발트-크롬 주조 금속 코핑과 코발트-크롬 소결 금속 코핑의 변연 및 내면 적합도를 비교 평가하여 다음과 같은 결론을 도출하였다. 코발트-크롬 금속 코핑의 변연 및 내면 적합도를 비교 평가는 기존의 주조방식인 CCM 그룹보다 소결과정만으로 제작한 CSM 그룹이 전반적으로 모두 우수하였다. 또한 CSM 그룹의 변연 적합도는 임상적으로 허용할 수 범위인 120 μm 이내 존재하였다는 결과를 통해서 그동안 매몰, 소환, 주조인 복잡한 과정을 거치면서 보철물의 오차가 발생하였으나 소결과정만으로 공정 과정의 오차를 줄임으로써 완성도 높은 코발트-크롬 금속 코핑 제작이 가능하다고 생각된다. The purpose of this study was to evaluate the marginal and internal gap of Cobalt (Co)-Chromium (Cr) sintering metal coping fabricated by dental computer-aided design/computer-aided manufacturing systems. Abutment tooth 46 of universal numbering system was selected for the study. Twenty Co-Cr metal copings of two groups were manufactured and scanned. Co-Cr cast metal copings (CCM) group of ten were fabricated using investment, burnout and casing after subtractive manufacturing of wax block. Also, Co-Cr sintering metal copings (CSM) group of ten were fabricated using sintering processing after subtractive manufacturing of Co-Cr soft metal bock. Marginal and internal gap of Co-Cr metal copings of twenty were measured by digital microscope (×160) with silicone replica technique. The data was analyzed from IBM SPSS Statistics ver. 22.0 Statistical software for Mann-Whitney U test (α=0.05). Mean±standard deviation of marginal gap of CCM group was 90.12±61.73 μm of CSM group was 60.17±24.83 μm. However, two groups was statistically not different (p>0.05). This study showed that CSM group was clinically acceptable adaptation.

Vent의 형성이 도재전장 비귀금속합금 주조체의 변연부 적합도에 미치는 영향

김태석,이성욱,오세윤,김웅철,김지환,유진호,Kim, Tae-Suk,Lee, Sung-Uk,Oh, Sae-Yoon,Kim, Woong-Chul,Kim, Ji-Hwan,Yoo, Jin-Ho 대한치과기공학회 2001 대한치과기공학회지 Vol.23 No.1

This study was performed to investigate the effect of vent on the marginal discrepancy of PFM base metal castings. Eighteen identical wax patterns of a maxillary 3 unit anterior bridge were fabricated. Nine cases out of them were vented with $\phi$2.5mm sprue wax, for direct comparison as to the marginal discrepancy of the castings with the other non vented 9 ones. The mean value of marginal discrepancies of the vented castings was $85.02{\pm}25.57{\mu}m$, and that of the non vented was $163.21{\pm}69.88{\mu}m$ respectively. Statistical analysis revealed that marginal discrepancy of the vented casting was significantly reduced(p<0.05).

다양한 중합 방법으로 제작한 간접 수복물용 복합레진의 굴곡 강도

김동연,박진영,강후원,김지환,김웅철,Kim, Dong-Yeon,Park, Jin-Young,Kang, Hoo-Won,Kim, Ji-Hwan,Kim, Woong-Chul 대한치과기공학회 2018 대한치과기공학회지 Vol.40 No.2

Purpose: The aim of this study is to evaluate composite resins of indirect restorations for testing of flexural strength according to various polymerization methods. Methods: Specimen was produced a total of 40 to 10 per each group with a length 25 mm, width 2 mm, thickness 2 mm using a Teflon zig. The polymerization groups were classified into four groups. The first group proceeded with light curing only(LC group). The second group proceeded with light and heat curing(LHC group). The third group proceeded with air press and light curing(ALC group). The fourth group proceeded with air press, light and heat curing(ALHC group). Each prepared group was evaluated by flexural strength test. Statistical analysis was performed by one-way ANOVA. Post-test was performed with Tukey test. Results: The lowest in the ALC group was 119.18 MPa and the highest in the ALHC group was 168.15 MPa. There were statistically significant differences. Conclusion : The composite resin of the indirect restoration is recommended to heat curing along with the air press.

치과용 임플란트 적용 비귀금속 코어와 관련된 전조골세포의 변화

박정현,강신영,김종우,김장주,김웅철,김지환,Park, Jung-Hyun,Kang, Seen-Young,Kim, Jong-Woo,Kim, Jang-Ju,Kim, Woong-Chul,Kim, Ji-Hwan 대한치과기공학회 2018 대한치과기공학회지 Vol.40 No.2

Purpose: The purpose of this study is to investigate the non-precious metal core materials used in the dental laboratory to fabricate the implant superstructure by CAD / CAM method. And to observe and compare the morphology and distribution of the osteoblasts in relation to implant osseointegration. Methods: In this study, the mandibular right first molar tooth model was selected as an international standard to produce a single core. Using this model, the impression was made with the silicone rubber, the tooth model was scanned, and a single core was designed and 5-axis milling was performed. The materials used were Cobalt-Chromium and Nickel-Chromium, and the cores for dental implant top structures were fabricated according to the procedures of the dental labs. After the fabrication, the marginal area of the core was separated and cell culture experiment was performed. The osteoblast cells used MC3T3-E1, which is currently widely used. For morphological analysis of osteoblasts, cells were posttreated and observed using CLSM (Confocal Laser Scanning Microscope) and compared. Results: The cell adhesion behavior of the specimen surface measured by CLSM was uniformly distributed in specimen A (Cobalt-Chromium) than in specimen B (Nickel-Chromium). The distribution and changes of the cells were different in the two specimens. Conclusion : It is possible to confirm that specimen A (Cobalt-Chromium) is suitable for the living body through adhesion and proliferation of osteoblasts related to implant osseointegration in the non-precious metal superstructure used after implantation. It is considered that it is preferable to use Co-Cr when fabricating the superstructure.

지르코니아 표면에칭처리와 저온열화현상이 지르코니아와 전장도재의 결합강도에 미치는 영향

박진영 ( Jin Young Park ),김재홍 ( Jae Hong Kim ),김웅철 ( Woong Chul Kim ),김지환 ( Ji Hwan Kim ),김혜영 ( Hae Young Kim ) 한국치위생과학회 2014 치위생과학회지 Vol.14 No.2

The purpose of this study was to investigate the influence of etching surface treatment and aging treatment of zirconia on the shear bond strength between zirconia core and veneered ceramic. Four groups of zirconia-ceramic specimens were prepared; 1) NEZ group (no etching zirconia), 2) EZ group (etching zirconia), 3) ANEZ group (aging and no etching zirconia), 4) AEZ group (aging and etching zirconia). The shear bond strength between zirconia and porcelain was measured using Instron Universal Testing Machine. Surface texture with crystalline structure of zirconia surface was examined by the field emission scanning electron microscopy (FE-SEM) with ingredient analysis. The fractured surfaces of specimens were examined to determine the failure pattern by a digital microscope. The mean±standard deviation of shear bond strengths were 23.47±3.47 Mpa in NEZ, 28.30±4.34 Mpa in EZ, 21.85±4.65 Mpa in ANEZ, 24.65±3.65 Mpa in AEZ group, respectively, and were significantly different (p<0.05). The average shear bond strength was largest in EZ group, followed by AEZ, NEZ, and ANEZ groups. Most specimens in NEZ group showed adhesive failure and most specimens in EZ, AEZ, and ANEZ group showed mixed failure. Surface of etching treatment group (EZ and AEZ) showed complex micro-structure and irregular surface texture which may facilitate mechanical interlocking, while untreated zirconia surface presented simpler micro-structure. In conclusion, an etching treatment improved bonding strength between zirconia and porcelain by forming mechanical interlocking.