3Y-TZP세라믹의 소결수축 및 이축강도

이해형,오상천,동진근,송기창 대한치과기재학회 2001 대한치과재료학회지 Vol.28 No.5

고강도 치과용 세라믹

이해형 대한치과의사협회 1999 대한치과의사협회지 Vol.37 No.11

치과용 열가압 글라스 세라믹스의 기계적 성질과 미세구조

이해형,이병택 한국세라믹학회 2004 한국세라믹학회지 Vol.41 No.2

본 연구에서는 치아 수복에 사용되는 상용 글라스 세라믹들을 디스크 모양으로 열가압 성형하여 ball-on-3-bal에 의한 이축강도와 압입시험에 의한 파괴인성을 측정하였다. 시편들로부터 XRD, SEM, TEM을 이용하여 결정상과 미세구조를 분석하였다. 글라스 세라믹내의 결정들은 균열의 진행에 대하여 효과적인 저지를 하지 못하였으나 높은 결정화도가 기계적 성질의 향상에 기여하는 것으로 판단된다. Lithium disilicate결정의 글라스 세라믹은 상대적으로 결정함량이 낮은 leucite 세라믹에 비하여 유의하게 높은 이축강도와 파괴인성을 나타내어 치과용 글라스 세라믹으로서 높은 신뢰성이 기대된다. Biaxial flexure strength (ball-on-3-ball) and fracture toughness (indentation microfracture) of heat-pressable glass-ceramics for dental use were investigated in this study. Crystal phase and microstructure of glass-ceramics were analyzed by XRD. SEM, and TEM. Crack propagation in specimens was not effectively arrested by dispersed crystalline particles. However, higher degree of crystallization probably contributes to strengthening of glass-ceramics. Better clinical reliability can be expected from lithium disilicate glass-ceramic because of its significantly higher biaxial flexure strength and fracture toughness.

Surface Coatings to Enhance Bonding Strength of Dental Titanium-Ceramic Restorative System

이해형 한국세라믹학회 2008 한국세라믹학회지 Vol.45 No.10

Although titanium-ceramic systems have gained substantial interests in dental prosthetic field, bonding problem between porcelain and titanium has not been solved. Main obstacle in titanium-porcelain bonding is excessive oxidation of titanium during porcelain firing. The effects of several coating materials on the bonding strength of titanium-porcelain system were investigated in this study. RF sputtering and electroplating of platinum significantly increased the bonding strength of porcelain-titanium specimen. However, coatings of Ni-Au, Ir, and ceramics (zirconia and hydroxyapatite) did not showed a significant effect on bonding strength. Platinum might be a promising material for the protective layer of excessive oxidation of titanium during porcelain firing, resulting in increase in the bonding strength. Although titanium-ceramic systems have gained substantial interests in dental prosthetic field, bonding problem between porcelain and titanium has not been solved. Main obstacle in titanium-porcelain bonding is excessive oxidation of titanium during porcelain firing. The effects of several coating materials on the bonding strength of titanium-porcelain system were investigated in this study. RF sputtering and electroplating of platinum significantly increased the bonding strength of porcelain-titanium specimen. However, coatings of Ni-Au, Ir, and ceramics (zirconia and hydroxyapatite) did not showed a significant effect on bonding strength. Platinum might be a promising material for the protective layer of excessive oxidation of titanium during porcelain firing, resulting in increase in the bonding strength.

치과용 티타늄-세라믹 시스템들의 결합강도 비교

이해형,송윤희,이순형 대한치과재료학회 2004 대한치과기재학회 학술대회 Vol.2004 No.8

Highly Homogeneous Carbon Nanotube-Polycaprolactone Composites with Various and Controllable Concentrations of Ionically-Modified-MWCNTs

이해형,신원상,Guang-Zhen Jin,김해원 대한화학회 2011 Bulletin of the Korean Chemical Society Vol.32 No.1

For the fabrication of multifunctional biopolymer nanocomposites in the combination of carbon nanotubes (CNTs),recently increasing attention has been paid to an effective homogenization of CNTs within polymer matrices and a fine tuning of the concentration. We developed an efficient method to produce homogeneous CNT-polycaprolactone nanocomposites with various and controllable CNT concentrations using an ionically-modified multi-walled CNT,MWCNT-Cl. The modified MWCNTs could be homogeneously dispersed in tetrahydrofuran (THF). Polycaprolactone (PCL) as a biodegradable and biocompatible polymer was smoothly dissolved in the homogeneous MWCNT-Cl/THF solution without agglomeration of MWCNT-Cl. The physicochemical and mechanical properties of the resultant nanocomposites were examined and the biological usefulness was briefly assessed.

최근 치과용 세라믹스의 가공과 강화

이해형 대한치과기재학회 2000 대한치과재료학회지 Vol.27 No.1

미소압입시험법과 SEM/EPMA를 이용한 치과용 금속-세라믹 시스템의 계면특성 연구

이해형,송윤희,이수종,Yokoyama, Gen,Akimoto, Naotake,Hirano, Susumu 大韓齒科器材學會 2003 대한치과재료학회지 Vol.30 No.2

The purposes of this study were to investigate the interface area of dental metal-ceramic systems by using nanoindentation technique and SEM/EPMA. Gold (PFG) and Ni-Cr-Be alloy (PFM) coupons (10×10×1 ㎜) were cast and veneered with Ceramco Ⅱ opaque and body porcelain. Specimens tired once (one-tiring) and nine times (nine-firing) of body porcelain were prepared and compared in this study. The metal-ceramic interfaces embedded in epoxy resin were exposed and received 0.25-㎛ finish. Nanoindentation test (ENT-1100a, Elionix, Japan) was conducted at the interlaces with a load of 100 ㎎f (0.98 mN). Sixty indentations were made at two specimens of each metal-ceramic group. Nanoindentation marks were confirmed to allot their positions under a reflected microscope. Mean indentation hardness and elastic modulus values were determined at the area of metal area >5㎛ (M) and <5㎛ (MI) from interface, and porcelain area (P). Indentation hardness value was also compared with Knoop hardness values. Distribution of trace elements in alloys was examined at the metal-ceramic interfaces through X-ray mapping obtained from SEM/EPMA. From this study, following results were discussed. Mean indentation hardness values of gold alloy and porcelain were agreed with their Knoop hardness data, except for the base metal. There were no abrupt changes of mechanical property at the interlace areas of PFG and PFM specimens, although transition area of mechanical properties was not observed clearly at the interlace However, elastic modulus values obtained by nanoindentation were higher than their respect literature values. These results were probably caused by residual stress arisen at the metal-ceramic area, even though further study should be considered. High resolution SEM/EPMA study successively revealed fine mapping of trace elements at the metal-ceramic interfaces. A high concentration of Indium was observed at the gold-ceramic interface. Beryllium was not concentrated at the interface of PFM, although they appeared in NiBe phase. Generally, mechanical properties and distribution of trace elements of metal-ceramic interface were not significantly changed with increased firing times. Nanoindentation technique was useful to analyze interface properties of metal-ceramic systems.

최근 치과용 지르코니아 CAD/CAM 수복물의 임상적 고찰

이해형(Lee Hae-Hyoung) 대한치과의사협회 2011 대한치과의사협회지 Vol.49 No.5

Currently there is no dental ceramic material can be used in all dental situations need to be restored. However, in view of recent clinical reports, the most viable alternative is zirconia ceramic. Clinical success of dental zirconia restorations strongly depends on proper selection of materials, accurate laboratory procedure and final cementation, which can be achievable with the correct understanding of zirconia. As dental materials, zirconia ceramics have a very bright future, because they are being used increasingly in the anterior region as implant fixtures, as well a s crown and bridge restorations and implant abutments. Many dental ceramics showing poor clinical performance have been gone from the dental market. However in terms of outstanding mechanical properties and esthetic nature, new dental materials can replace zirconia ceramics will not be available in the foreseeable future.

치과 보철수복용 생체재료

이해형 ( Hae Hyung Lee ) 대한금속재료학회 2009 재료마당 Vol.22 No.1