• Journal of Dental Rehabilitation and Applied Science
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• v.25 no.3
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• pp.225-235
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• 2009

A common procedure of restoration of endodonticlly treated tooth with fiber-reinforced post is followed by core build-up after post cementation. However, this technique is complex and time-consuming. The aim of this study was to compare fracture strength of premolar, restored with various methods of core fabrications on fiber-reinforced posts and casting metal restoration. Forty five freshly extracted human mandibular premolars were obtained and devided into 5 groups acconding to the type of post and methods of core build-up. In Group A, D.T. $Light-post^{(R)}$ were cemented with $DUO-LINK^{TM}$ and then $LIGHT-CORE^{TM}$ was used for core restoration. In Group B, D.T. $Light-post^{(R)}$ and $DUO-LINK^{TM}$ were used for cementing in the postspace, and $DUO-LINK^{TM}$ was used again for core restoration. In Group C, $Light-post^{(R)}$ bonding and the core build-up were performed simultaneously by using $DUO-LINK^{TM}$. In Group D, $LuxaPost^{(R)}$ was bonded by using $LuxaCore^{(R)}-Dual$. Again, $LuxaCore^{(R)}-Dual$ was used for core restoration. In Group E, $LuxaPost^{(R)}$ bonding and the core build-up were performed simultaneously by using $LuxaCore^{(R)}-Dual$. Axial reduction was formed parallelly as possible and 45 degree bevel was made at buccal occlusal surface. Crowns were fabricated and cemented. Each tooth was embedded in self-curing acrylic resin to the level of 2mm below the CEJ. Specimens were fixed on universal testing machin such that the axis of the tooth was at 45 degree inclination to the horizontal plane, and compressive force was applied at a crosshead speed of 1mm/min until failure occurred. The mean fracture strength was the highest in group A followed by descending order in group B, D, E and C. However, there were no statistically significant differences between groups with regard to the fracture strength. The type of the post or build-up methods of the core does not seem to influence the fracture strength.

• Journal of computational fluids engineering
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• v.18 no.3
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• pp.79-86
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• 2013

Preconditioned compressible Navier-Stokes equations are solved for almost incompressible flows. Unstructured meshes are utilized for spatial discretization of complex flow domain. Effectiveness of the current preconditioning algorithm, with respect to various Reynolds numbers and Mach numbers, is demonstrated by the solution of canonical problems for incompressible flows, e.g. driven cavity flows.

• The Science & Technology
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• v.28 no.10 s.317
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• pp.14-15
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• 1995

현대인들은 3백년 전 뉴턴이 축성한 기계론적 절대결정주의 세계관 속에서 살고있다. 과정보다 결론을 중시하는 사회는 뉴턴의 물질만능주의적 세계관의 소산이라고 할 수 있다. 현대사회는 뉴턴의 세계관으로부터 서서히 탈피해야 한다.

• Journal of dental hygiene science
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• v.14 no.3
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• pp.405-410
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• 2014

The purpose of this study in vitro investigation was to compare the marginal and internal fit of Ni-Cr alloy metal ceramic crown before and after porcelain veneering. Furthermore, this study evaluated whether the influence of the porcelain firing on the precision of fit of dental prostheses. The maxillary right incisor was selected as an abutment for experiments. Ten working models were prepared. Ni-Cr alloy cores appropriate for each abutment were prepared by lost wax technique. The marginal area and four internal areas of the crowns were measured at two stages: before veneering process and after upper porcelain firing. Silicone replica techniques were used. The data were statistically analyzed with the paired t-test (${\alpha}=0.05$). $Mean{\pm}SD$ marginal and internal gap were $67.1{\pm}23.3{\mu}m$ for the nickle chrome alloy core group and $74.4{\pm}21.9{\mu}m$ for the metal ceramic crown group. There were statistically significant differences in all investigated areas (p<0.05). Within the limitations of this study, none of the Ni-Cr alloy metal crown values measured after porcelain firing process exceeded $120{\mu}m$, which is the clinically acceptable threshold.

• Journal of Pharmacopuncture
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• v.6 no.1
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• pp.13-13
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• 2003

1. 도입 및 배경 Lou Gehrig 병이라고 알려져 있는 근위축성 측삭경화증은 중추신경계 중 운동신경의 퇴행성 변화에 의한 진행성 질환이다. 이 병은 근육의 마비와 약화, 강직의 진행과 더불어 언어장애, 연화장애, 호흡장애가 동반된다. ALS는 환자나 가족들에게 엄청난 고통을 주는 질환으로 이병은 발병 후 3-5년 내에 약 $75\%$가 사망한다. 그리고 연하장애가 주된 증상이거나 고령에서 발병하였을 때에는 생존기간이 더욱 단축되는 경향을 나타낸다. 그리고 치명적인 호흡장애로 인해 대부분 사망하게 된다. 현재 의학계에서는 이 병의 원인도 알고 있지 못하고, 증상에 대한 아무런 치료방법도 제시하지 못하고 있는 실정이다. 2. 역학 원발성 운동신경원성 질환의 발생률은 100,000당 약 7명이고, ALS는 이 중 약 $65-85\%$를 차지한다. 전 세계적으로 1년에 약 2-4명/100,000이 발생하고 있으며 시간이 경과할수록 점차 증가하고 있는 추세이다. 3. 연구방법 EMG나 Biopsy 등을 통해 신경과 전문의가 ALS로 진단한 환자 중 상지대학교 부속한방병원에서 3개월 이상 입원치료를 받은 환자 18명을 대상으로 임상연구를 진행하였고, 설문조사는 외래에 내원한 환자 중 설문에 응답한 환자 28명을 포함한 총 46명의 환자들을 대상으로 시행하였다. 치료방법은 침, 약침, 봉약침, 한약 등을 환자의 체질을 고려하여 변증에 따라 적용하였고, 환자의 상태 변화는 ALSFRS(ALS Functional Rate Scale)를 사용하여 관찰하였다. 4. 결과 본 연구결과 ALS의 치료에 한의학적 치료방법은 유효한 것으로 나타났다. 특히 본 질환이 시간이 경과하면서 $100\%$ 악화되는 질환임을 감안한다면 한의학적 치료를 통해 약 $40\%$의 환자에서 몸의 상태나 언어장애, 만성적 피로 등이 호전되었고, 근력도 증가되는 결과를 나타내었다.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.5
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• pp.528-534
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• 2008

Purpose: Marginal fit is one of the important components for the successful prosthodontic restoration. Poor fitting margin of the restoration causes hypersensitivity, secondary caries, and plaque accumulation, which later result in prosthodontic failure. CAD/CAM zirconia all-ceramic restorations, such as $LAVA^{(R)}$ (3M ESPE, St.Paul, MN) and $EVEREST^{(R)}$ (KaVo Dental GmbH, Biberach, Germany) systems were recently introduced in Korea. It is clinically meaningful to evaluate the changes of the marginal fit of the CAD/CAM zirconia systems before and after build-up. The purposes of this study are to compare the marginal fit of the two CAD/CAM all-ceramic systems with that of the ceramometal restoration, before and after porcelain build-up Material and methods: A maxillary first premolar dentiform tooth was prepared with 2.0 mm occlusal reduction, 1.0 mm axial reduction, chamfer margin, and 6 degree taperness in the axial wall. The prepared dentiform die was duplicated into the metal abutment die. The metal die was placed in the dental study model, and the full arch impressions of the model were made. Twenty four copings of 3 groups which were $LAVA^{(R)}$, $EVEREST^{(R)}$, and ceramometal restorations were fabricated. Each coping was cemented on the metal die with color-mixed Fit-checker $II^{(R)}$ (GC Cor., Tokyo, Japan). The marginal opening of each coping was measured with $Microhiscope^{(R)}$ system (HIROX KH-1000 ING-Plus, Seoul, Korea. X300 magnification). After porcelain build-up, the marginal openings of $LAVA^{(R)}$, $EVEREST^{(R)}$,and ceramometal restorations were also evaluated in the same method. Statistical analysis was done with paired t-test and one-way ANOVA test. Results: In coping states, the mean marginal opening for $EVEREST^{(R)}$ restorations was $52.00{\pm}11.94\;{\mu}m$ for $LAVA^{(R)}$ restorations $56.97{\pm}10.00\;{\mu}m$, and for ceramometal restorations $97.38{\pm}18.54\;{\mu}m$. After porcelain build-up, the mean marginal opening for $EVEREST^{(R)}$ restorations was $61.69{\pm}19.33\;{\mu}m$, for $LAVA^{(R)}$ restorations $70.81{\pm}12.99\;{\mu}m$, and for ceramometal restorations $1115.25{\pm}23.86\;{\mu}m$. Conclusion: 1. $LAVA^{(R)}$ and $EVEREST^{(R)}$ restorations in comparison with ceramometal restorations showed better marginal fit, which had significant differences (P < 0.05) in coping state and also after porcelain build-up . 2. The mean marginal opening values between $LAVA^{(R)}$ and $EVEREST^{(R)}$ restorations did not showed significant differences after porcelain build-up as well as in coping state (P > .05). 3. $EVEREST^{(R)}$, $LAVA^{(R)}$ and ceramometal restorations showed a little increased marginal opening after porcelain build-up, but did not show any statistical significance (P > .05).

• The Korean Journal of Rehabilitation Nursing
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• v.16 no.2
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• pp.122-132
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• 2013

Purpose: This study measured the quality of life in patients with amyotrophic lateral sclerosis (ALS). Methods: The participants consisted of consecutive patients with ALS who visited the neurology outpatient department from January to July, 2008. To collect the data, face-to-face interviews were applied at S national university hospital in Seoul. Using multivariate analysis, factors to predict QOL in ALS patients including demographic factors, functional independence, depression, anxiety, social support and quality of life were analyzed. Results: The final analysis included 69 patients. The mean score for the physical health and mental health components was $34.4{\pm}21.3$ and $44.7{\pm}20.6$, respectively. The mean score for the ALS functional rating scale was $24.3{\pm}10.8$ out of 40. Anxious and depressed patients accounted for 44.9% and 71%, respectively. Quality of life in ALS patients was significantly affected by functional independence, depression and anxiety level. Conclusion: To improve the quality of life in ALS patients with declining functional independence, comprehensive interventions are necessary to manage depression and anxiety.

• Journal of Dental Rehabilitation and Applied Science
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• v.28 no.3
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• pp.223-232
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• 2012

The purpose of this study was to investigate the effect of various thickness of porcelain on shear bond strength between metal coping and porcelain. So, various thickness of feldspathic porcelain and heat-pressed porcelain were built up and compared. 120 metal cube($4{\times}4{\times}4mm$) specimens were prepared. 60 specimens were applied to feldspathic porcelain and the others were applied to heat-pressed porcelain by 1mm, 1.5mm, 2mm, 2.5mm, 3mm and 3.5mm thickness. The measurement of shear bond strength was performed by Instron universal testing machine. The following results were obtained from this study. 1. As thickness of feldspathic porcelain increases, shear bond strength has decreased. Feldspathic specimens with 1mm porcelain thickness were significantly stronger than other feldspathic subgroups. 2. There was no significant difference of shear bond strength according to porcelain thickness in heat-pressed porcelain group. 3. In comparison between subgroups with same thickness, feldspathic porcelain group had stronger shear bond strength than heat-pressed porcelain. There were significant difference between 1mm and 3mm porcelain thickness group. 4. In almost cases, fracture surface was found on both metal and porcelain surfaces. As thickness of porcelain was increased, metal exposure was decreased.

• Journal of dental hygiene science
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• v.12 no.2
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• pp.123-129
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• 2012

The aim of study was to compare the color parameters and mean color difference of porcelain specimens by different veneering technique in order to examine the effect of veneering technique on esthetics of yttria-stabilized tetragonal zirconia polycrystalline(Y-TZP) all ceramic restoration. Three groups of square-shaped core ceramic specimens(14mm in diameter and 0.3, 0.5, 0.7 mm) and two groups of veneering ceramic specimen were prepared for analysis. Color parameter($L^*,a^*,b^*$) and color difference of zirconia core squares and core-veneer specimens were measured with ShadeEye $NCC^{(R)}$ spectrophotometer, respectively. Mean color difference(${\Delta}E^*$)were calculated using color difference formula. Two-way analysis of variance(ANOVA) combined with a Tukey multiple-range test were used to analysis the data(${\alpha}=0.05$). ${\Delta}E^*$ values were not significantly affected by core thickness and veneering porcelain(p=0.083). The color differences(${\Delta}E^*$) of core-veneer specimens with 0.5, 0.7 mm-A1,A2,A3.5 shade were mostly below 3.7 which was within the clinically acceptable range, while color differences between 0.3 mm-A1,A2 showed more than 3.7. All-ceramic system has color characteristics that clinicians have to consider when selecting materials. Also, manufacturers of different porcelain systems must make every effort to achieve color reproducibility.

• Economic and Environmental Geology
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• v.19 no.spc
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• pp.207-226
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• 1986

The skarn type tungsten deposits in Jechon area are developed in the contact aureole of Jurassic granodiorite and lower Paleozoic limestone beds. The Tong Myeong mine contains scheelitebearing skarns found at and near the contacts between crystalline limestone and hornfels. Although the skarns are heterogeneous, there are clear patterns in the preferred associations and nonassociations of minerals on all scales. The skarn show a zonal arrangement from limestone to hydrothermal vein as follow: wollastonite skarn, clinopyroxene skarn, clinopyroxene-garnet skarn, garnet skarn, and vesuvianite skarn. Scheelite, abundant in all skarn units except wollastonite skarn and also in quartz veins near orebodies, is everywhere strongly correlated with pyrrhotite. It is implied that it was a stable phase throughout the evolution of the zoned skarns, at least in pyrrhotite.forming environments. Deposition of scheelite was probably widely caused by increasing $a_{Ca^{2+}}$ in the fluid, resulting from associated and interrelated reactions: $FeCl_2\;aq+H_2S\;aq{\rightarrow}FeS+2H^{+}+2Cl^-$; and $CaCO_3+2H^+{\rightarrow}Ca^{+2}+H_2CO_3$. The spectral reflection powers of nine sulfide species were studied, for three mineralization stage. The shapes and characteristics of the spectral reflectivity profiles are significant in their control of other optical properties. The characteristics of the Vickers microhardness and the optical symmetry for the minerals studied are discussed. Broad radicle groupings of the sulfides can be made with regard to the reflectivity-microhardness values.