• The Journal of Korean Academy of Prosthodontics
• /
• v.25 no.1
• /
• pp.317-325
• /
• 1987

A study on the shear bonding strength between dental alloy and porcelain according to various kidns of sputtered metallic thin films was established by Ingtron universal testing machine, and the change of the elemental weight % at the surface of dental alloy was studied by E.D.S. The kind of metallic thin films were Al, Ni, In, Cr. Ti and Sn with $0.3{\mu}m$ thickness. The dental alloys were Verabond made by Aalba Dent. Co. and Degudent H manufactured by Degussa Co. The control groups were Verabond and Degudent H. The obtained results were as follows; 1. The shear bonding strength of Al plated sample was the strongest of all. 2. The shear bonding strength of Ni plated sample was stronger than that of Degudent H, Sn plated samples. 3. The shear bonding strength of Verabond was weaker than that of Al, Ni, In, Cr, plated samples. 4. After degassing, it is more weight % of Ni at the alloy surface of the Ni sputtered specimen than the Sn sputtered sample.

• The Journal of Korean Academy of Prosthodontics
• /
• v.20 no.1
• /
• pp.19-23
• /
• 1982

귀금속의 가격 앙등은 치과보철치료에 있어서 비귀금속합금의 이용을 촉진 시키고 있다. 가공의치 제작에 비귀금속합금을 이용할 경우에는 납착상태에 대한 신빙성 문제로 인하여 one-piece cast법이 널리 사용되고 있으나 이에 의하여 제작된 가공의치의 적합도에 관하여는 논의가 분분하다. 고로 저자는 one-piece cast법에 의한 비귀금속 가공의치에 있어서 경화수축에 따른 거리변화를 계측현미경을 이용하여 연구한 결과 다음과 같은 결론을 얻었다. 1. 4개 치아를 포함하는 가공의치 제작에 있어서 Hi-Temp 매몰재는 비귀금속합금(Lite-Cast B)의 수축을 보상하고도 남음이 있다. 2. Hi-Temp에 사용되는 액(液)을 증류수로 희석할 경우 그 농도 조절에 의하여 Hi-Temp 매몰재의 팽창을 크게 변화시킬 수 있다. 3. one-piece cast법에 의한 가공의치 제작의 문제점은 두 지대치의 서로 바라보고 있는 인접면간의 거리는 증가됨이 없이 외측 인접면간의 거리만 다소 증가되어야 한다는 것이다. 4. 비귀금속합금을 이용하여 수직적인 큰 변형없이 4개 치아가 포함되는 가공의치를 제작할 수 있다. 5. 수개 치아를 포함하는 가공의치의 주조 정확도를 계측할 수 있는 새로운 방법을 창안하였다.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.22 no.3
• /
• pp.203-210
• /
• 2006

Although porcelain fused to metal crowns made from non-precious metal have good mechanical properties, they also have disadvantages such as the poor biological acceptability and the low corrosional resistance. Titanium is used as the alternative metal for porcelain fused to metal crowns, in spite of difficulties in casting. For that reason non-precious alloy including titanium which is easy to cast is currently used. This study evaluated the bond strength between non-precious alloy including titanium and Ni-Cr alloy. $Tilite^{(R)}V$ as non-precious alloy including titanium, $Rexilium^{(R)}V$ as Ni-Cr alloy and $Omega900^{(R)}$ and $Vintage(Regular)^{(R)}$ as porcelain powders were used. The results were as follows. 1. In comparison with the kind of alloy, the bond strength of $Tilite^{(R)}V$ was lower than that of $Rexilium^{(R)}V$. There was no significant difference between two groups. 2. In comparison with the kind of porcelain powder, the bond strength of $Omega900^{(R)}$ was higher than that of $Vintage(Regular)^{(R)}$ in $Tilite^{(R)}V$. There was significant difference between two groups(p < 0.05).

• Journal of Technologic Dentistry
• /
• v.39 no.3
• /
• pp.153-159
• /
• 2017

Purpose: In this study, a corresponding porcelain coating material was applied to dental Co-Cr metal among PFM. Methods: The bonding strength of the fired specimens was measured by a three-point flexural rigidity test. SEM/EDS was used to observe the surface component of specimens. Results: First, All groups were higher than the minimum bonding strength of 25 MPa specified in ISO 9693 for dental metal-ceramics specimens. Second, The bonding strength of control group(WO) is 44.64 MPa. Experimental group DM was 35.45 MPa and DP was 31.82 MPa(P<0.05). Tukey's HSD tests results have shown that the bonding strength in control group(WO) is higher than that of experimental group(DM, DP). Third, In the case of metal - porcelain bonding strength, the application of opaque porcelain and firing were higher than those of the group treated with degassing process. Conclusion: The bonding strength was higher when the powder opaque porcelain was applied than the paste opaque porcelain.

• Journal of Technologic Dentistry
• /
• v.21 no.1
• /
• pp.87-96
• /
• 1999

In order to examine the influence of sprue(used to make crown supplements) on casting, 3 kinds of sprue materials(wax, wood, plastic) and 3 types of sprue(round, square, triangle) were made and buried and cast, then the comparison and analysis of casting characters among sprue materials and among sprue type show the following results : 1. The comparison of casting characters in accordance with sprue materials shows wax sprue of 83.3%, wood sprue 81.3%, and plastic sprue of 80.7%, Wax sprue was the bast materials for casting, However there was no statistically significant difference of casting characters among was, plastic and wood. 2. The comparison of casting in accordance with sprue types shows square sprue of 94.0%, round sprue of 86.9% and triangle sprue of 84.2%. square sprue had a best casting character. 3. When a ring cast using wood sprue was classified from burying materials. its cutting of casting body and sprue indicated much more than any other sprue material. It seems to be caused by the influence of wood residuals and carbon occurrence.

• Proceedings of the KIEE Conference
• /
• 2007.07a
• /
• pp.1520-1521
• /
• 2007

고분자 전해질 연료전지(PEMFC, polymer electrolyte membrane fuel cell)는 수소이온특성을 갖는 고분자막을 전해질로 사용하는 연료전지로서 무공해 차량의 동력원, 가정용 발전, 우주선용 전원, 군사용 전원 등 매우 다양한 부분에서 사용되어질 것으로 사료된다. 하지만 현재 높은 가격과 짧은 수명 등의 문제로 상용화에 이르지 못하고 있다. 고분자전해질 연료전지의 스택 가격을 부품별로 조사하여 보면 분리판이 전체 스택가격의 60% 정도가 가장 높은 비중을 차지하며 기체 확산층으로 사용되는 탄소재료가 12%,전해질이 10%, 촉매가 8% 정도를 차지한다. 촉매 또한 저가의 비귀금속 촉매를 개발하거나 백금 촉매의 성능을 향상시켜 촉매 사용량을 낮춤으로써 가격을 낮추기 위한 연구가 진행되어지고 있으며 전해질로 사용하는 고분자막도 가격이 매우 높은 Nafion 대신 저가 고분자를 개발하거나, 또는 가능한 얇은 전해질을 사용하기 위한 노력이 이루어지고 있다. 하지만 아직까지는 뚜렷한 진척성과가 없는 것으로 알려져 있다. 그래서 본 연구에서는 고분자 전해질 연료전지의 고분자 Membrane의 특성을 향상시키고 또한 박막의 배양성과 특성에 대해서 고찰해 보고자한다.

• Journal of Technologic Dentistry
• /
• v.35 no.1
• /
• pp.1-17
• /
• 2013

Purpose: This study was to assess the extents of the release of metals from the non-precious alloys used for dental casting by measuring the differences in the extents of the release of metals by types of alloys, pH level and elapsed time. Methods: Uniform-sized specimens(10 each) were prepared according to the Medical Device Standard of the Korea Food and Drug Administration(2010) and International Standard Organization(ISO22674, 2006), using four types of alloys(one type of Ni-Cr and one type of Co-Cr used for fixed prosthesis, and one type of Ni-Cr and one type of Co-Cr used for removable prosthesis). A total of 12 metal-release tests were performed at one-day, three-day, and two-week intervals, for up to 20 weeks. The metal ions were quantified using an Inductively Coupled Plasma-Atomic Emission Spectrometer. Results: The results showed that the extent of corrosion was higher in the ascending order of Jdium-$100^{(R)}$, Bellabond-$Plus^{(R)}$, Starloy-$C^{(R)}$, and Biosil-$F^{(R)}$. The lower the pH and the longer the elapsed time were, the greater the increase in metal corrosion. At pH 2.4, the release of Ni from Jdium-$100^{(R)}$, a Ni-Cr alloy, was up to 15 times greater than the release of Co from the Co-Cr alloy from two weeks over time, indicating that the Ni-Cr alloy is more susceptible to corrosion than the Co-Cr alloy. Conclusion: It is recommended that Co-Cr alloy, which is highly resistant to corrosion, be used for making dental prosthesis with a non-precious alloy for dental casting, and that non-precious alloy prosthesis be designed in such a way as to minimize the area of its oral exposure. For patients with non-precious alloy prostheses, a test of the presence or absence of periodontal tissue inflammation or allergic reaction around the prosthesis should be performed via regular examination, and education on the good management of the prosthesis is needed.

• Journal of dental hygiene science
• /
• v.9 no.2
• /
• pp.153-160
• /
• 2009

The purposed of this study was to investigate the effect of Gold bonding agent as intermediate layer between metal substrate and ceramic coating. Gold bonding agent used to seal off any surface porosity, to mask the greyish color of the metal, and to provide an underlying bright golden hue to the ceramic coverage. The adhesion between metal substrate and ceramic is related to diffusion of oxygen during ceramic firing. The oxide layer produced on non-precious alloy anti titanium was considered to have a potentially adverse effect on metal-ceramic bonding. The oxidation characteristics of titanium and non-precious alloys are the main problem. Every group were divided into test and control groups. Control groups are carried out process of degassing for product oxide layer. Au coating was applied on each Ni-Cr, Co-Cr alloys and cp-Ti specimens with difference surface condition or degassing. Specimens surfaces and cutting plane was characterized by SEM/EDS. Results suggested that Au coating is effective barriers to protect metal oxidation during ceramic firing.

• Journal of Dental Rehabilitation and Applied Science
• /
• v.30 no.2
• /
• pp.112-120
• /
• 2014

Purpose: This study compared the shear bond strength of heat pressed and feldspathic porcelain to metal. Through thermocycling, the clinical aspect of heat pressed porcelain fused metal was estimated. Materials and Methods: 90 non-precious metal specimens were made ($4{\times}4{\times}8 mm$) and divided to three groups. All spicimens were treated and built-up with the porcelain ($4{\times}4{\times}3 mm$) by 2 different methods according to group: Group I: $Inspiration^{(R)}$, Group II: Ivoclar, IPS $Inline^{(R)}PoM$, Group III: GC Initial IQ-One $Body^{(R)}PoM$. The half of each group's specimens were thermocycled. All specimens' shear bond strength were measured by Instron universal testing machine. Exact measuring point was far 1 mm from porcelain/metal interface to the porcelain side. For the statistical analysis, 2-way ANOVA was used. Results: In no-thermocycling specimens, the shear bond strength showed no statistical significance between each group (P > 0.05). In comparison between nothermocycling and thermocycling specimens in each group, the shear bond strength was decreased according to thermocycling, but there was no statistical significance (P > 0.05). In thermocycling specimens, there was no statistical significance between each group (P > 0.05). Conclusion: In feldspathic porcelain and other two types heat pressed porcelain, there was no statistical difference in the shear bond strength of porcelain to metal. The heat pressed porcelain seems to be clinically useful for the aspect of the shear bond strength.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2016.11a
• /
• pp.196-196
• /
• 2016

치과나 기공소로부터 높은 원가로 인한 재료선택에 어려움을 겪고 있어 귀금속 금합금의 물성을 가질 수 있도록 하면서 가격급등으로 인한 문제 해결하기 위한 비귀금속 합금으로 대체가 필요하기에 이에 따른 연구가 이루어져 국산 제품의 상품화를 위해 파라듐을 이용하여 적합한 새로운 합금을 개발하는 것이 필요하다. 치과용 골드합금은 미국치과의사 협회의 구정에 의하면 1형부터 4형까지 분류하고 있으며 3형에 해당하는 강도와 기계적인 특성을 갖도록 파라듐으로 대체하는 연구가 진행중이거나 시판되고 있다. 따라서 본 연구에서는 2형, 3형 및 4형을 대체가능하도록 팔라듐을 기반으로 한 새로운 합금을 설계하고 합금의 성분원 소인 Au(1~5), Pd(20~25), Ag(70~75), In(1.5) 및 Zn(2)등으로 조성을 변화시켜 측량 후 합금을 제조하기 위하여 아르곤 분위기하의 진공아크용해로를 이용하여 용해하였다. 정량된 금속을 진공아크 용해로에 장입하고 용해는 균질한 합금이 되도록 최소한 6회 이상 용융을 실시하며 합금성분의 손실이 발행하지 않도록 보정을 하였다. 합금의 미세조직 관찰을 위하여 샘플을 고속 다이아몬드 정밀 절단기(Acculom-5, STRUERS, Denmark)를 이용하여 절단한 후 2000 grit의 Sic 연마지에서 단계적으로 $0.3{\mu}m$ 알루미나 분말까지 연마한 후 초음파 세척을 하였다. 준비한 시편은 KCN과 $(NH_4)_2S_2O_8$을 1:1로 혼합한 부식액으로 에칭한 후 OM과 SEM을 이용하여 조직을 관찰하였으며 각 샘플의 성분변화는 EDS 분석을 통해 확인하고 결정구조는 XRD를 사용하여 분석하였다. 경도시험은 비커스경도시험기를 이용하여 5kg의 하중을 30초간 작동시켜 압흔을 연결된 micron으로 평균값을 측정하였다. 각 시편의 부식거동은 POTENTIOSTAT(Model PARSTAT 2273, EG&G, USA)을 이용하여 구강 내환경화 유사한 $36.5{\pm}1^{\circ}C$의 0.9% NaCl에서 실시하였다. 인가전위는 -1500mV에서 1000mV까지 1.67 mV/min의 주사속도로 인가하여 시험을 수행하였으며 분극곡선으로부터 부식전위와 부식전류밀도 및 부동태영역의 전류밀도로 금속의 용출거동을 조사하였으며 부식이 끝난 시편은 FE-SEM과 EDS를 사용하여 조사하였다. 기계적인 특성은 Pd-Ag에 3wt%의 Au를 첨가한 합금이 Pd-Ag에 1.5wt%합금을 첨가한 경우에 비하여 기계적인 특성이 증가하고 내식성이 크게 증가하였다. 이들 합금에 Cu를 11wt%를 첨가한 경우는 비커스경도가 200이상으로 높게 나타났지만 내식성이 크게 감소하였다.