다층 지르코니아 블록 종류와 설계위치에 따른 지르코니아 코핑의 기계적 특성 비교

강재민,김원영,정인성,전병욱 대한치과기공학회 2019 대한치과기공학회지 Vol.41 No.3

Purpose: This study was investigated the effect of multi-layer zirconia block type and design location on the mechanical properties of zirconia copings. Methods: Three kinds of multi-layered zirconia blocks (Snow princess multi layered block, Multi cherry, Dental zirconia pre-shaded blank) were used to identify the effects of the kinds of multi-layered zirconia blocks, design locations on mechanical characteristics of zirconia copings. 150 Zirconia copings were fabricated and fracture strength, hardness and microstructure were compared and evaluated. Results: Dental zirconia pre-shaded blank(2,256.9N) had the highest fracture strength of zirconia copings on all the design locations, and it was followed by Snow princess multi layered block(2,107.5N) and Multi cherry(917.0N). Snow princess multi layered block(1,949.7Hv) had the highest hardness of zirconia copings on all the design locations, and it was followed by Dental zirconia pre-shaded blank(1,671.7Hv) and Multi cherry(1,383.7Hv). The cervical layer had the highest fracture strength and hardness of zirconia copings in all the blocks, and it was followed by the cervical+gradation layer, the enamel layer, the enamel+gradation layer, and the gradation layer. Conclusion: It was found that the fracture strength and hardness were different according to the kinds of multilayer zirconia block and design location, and it was confirmed that it is lower than the fracture strength of white zirconia.

Evaluation of translucency of monolithic zirconia and framework zirconia materials

İlkin Tuncel,Işıl Turp,Aslıhan Üşümez 대한치과보철학회 2016 The Journal of Advanced Prosthodontics Vol.8 No.3

PURPOSE The opacity of zirconia is an esthetic disadvantage that hinders achieving natural and shade-matched restorations. The aim of this study was to evaluate the translucency of non-colored and colored framework zirconia and monolithic zirconia. MATERIALS AND METHODS The three groups tested were: non-colored framework zirconia, colored framework zirconia with the A3 shade according to Vita Classic Scale, and monolithic zirconia (n=5). The specimens were fabricated in the dimensions of 15×12×0.5 mm. A spectrophotometer was used to measure the contrast ratio, which is indicative of translucency. Three measurements were made to obtain the contrast ratios of the materials over a white background (L*w) and a black background (L*b). The data were analyzed using the one-way analysis of variance and Tukey HSD tests. One specimen from each group was chosen for scanning electron microscope analysis. The determined areas of the SEM images were divided by the number of grains in order to calculate the mean grain size. RESULTS Statistically significant differences were observed among all groups (P<.05). Non-colored zirconia had the highest translucency with a contrast ratio of 0.75, while monolithic zirconia had the lowest translucency with a contrast ratio of 0.8. The mean grain sizes of the non-colored, colored, and monolithic zirconia were 233, 256, and 361 nm, respectively. CONCLUSION The translucency of the zirconia was affected by the coloring procedure and the grain size. Although monolithic zirconia may not be the best esthetic material for the anterior region, it may serve as an alternative in the posterior region for the bilayered zirconia restorations

ZrO₂의 분말크기가 ZTA의 기계적 물성에 미치는 영향

손정호,신형섭,Sohn, Jeongho,Shin, Hyung-Sup 한국재료학회 2014 한국재료학회지 Vol.24 No.12

The purpose of this study was to investigate the microstructures and mechanical properties of zirconia toughened alumina (ZTA) ceramics prepared from two kinds of 3Y-TZP powders. ZTA composites were prepared by adding two kinds of 3Y-TZP powders, 3YEH (BET = $7m^2/g$) and 3YEM (BET = $16m^2/g$), to ${\alpha}$-alumina in the range of 5-25 wt%. It was found that the microstructure photographs of the ZTA composites showed that the average grain size of alumina decreased as the content of zirconia increased. In our present study, specimens containing 3YEM zirconia exhibited smaller grain sizes compared to those of 3YEH zirconia. The Vickers hardness of the ZTA composites that were sintered at $1600^{\circ}C$ for 2 hrs was found to smoothly decrease with increasing zirconia content because of the low Young modulus in zirconia. The Vickers hardness of the ZTA containing 3YEH zirconia was greater than that of the 3YEM zirconia. In substance, the fracture toughness ($K_{1c}$) of the ZTA composites increased as the content of zirconia increased. The fracture toughness ($K_{1c}$) of ZTA containing 3YEM zirconia was greater than that of 3YEH zirconia.

CAM Zirconia 완전도재 구조물의 정밀 적합도에 관한 연구

전미현,전영찬,정창모,임장섭,정희찬,Jeon Mi-Hyeon,Jeon Young-Chan,Jeong Chang-Mo,Lim Jang-Seop,Jeong Hee-Chan 대한치과보철학회 2005 대한치과보철학회지 Vol.43 No.5

State of problem: Zirconia all-ceramic restoration fabricated with CAM system is on an increasing trend in dentistry. However, evaluation of the marginal and internal fits of zirconia bridge seldomly have been reported. Purpose: This study was to evaluate the at of margin and internal surface in posterior 3-unit zirconia bridge framework fabricated with CAM system(DeguDent, Germany). Material and Method: Preparations of secondary premolar and secondary molar on artificial resin model were performed for fabrication of 3-unit posterior bridge framework. Fits of 5 zirconia bridge framework were compared with 5 precious ceramo-metal alloy framework(V-GnathosPlus, Metalor, Switzerland), and prepared margins were designed to chamfer and shoulder finishing line. Each framework was cemented to epoxy resin model with reinforced glass ionomer(FujiCEM, GC Co., Japan), embedded in acrylic resin and sectioned in two planes, mesio-distal and buccolingual. Samples were divided into six pieces by sectioning and had two pieces of each surface(i.e mesial, distal, buccal and lingual surface) per abutment, so there were eight measuring points in each abutment. External gap was measured at the margin and internal gaps were measured at the margin, axial and occlusal surface. Gaps were observed under the measuring microscope(Compact measuring microscope STM5; Olympus, Japan) at a magnification of $\times100$. T-test were used to determine the statistic significance of the different gaps between zirconia and metal framework. Results and Conclusion: 1. External and internal marginal gaps of zirconia and metal framework were in clinically acceptable range. External marginal gaps were not different significantly between zirconia$(81.9{\mu}m)$ and metal $(81.3{\mu}m)$ framework and internal marginal gaps of zirconia $(44.6{\mu}m)$ were smaller than those of metal framework $(58.6{\mu}m)$. 2. Internal axial gaps of zirconia framework$(96.7{\mu}m)$ were larger than those of metal frame-work$(78.1{\mu}m)$ significantly and adversely, internal occlusal gaps of zirconia frame-work$(89.4{\mu}m)$ were smaller than those of metal framework $(104.9{\mu}m)$ significantly. 3. There were no significant differences in external and internal marginal gaps between chamfer and shoulder finish line when zirconia frameworks were fabricated.

Effect of coloring treatment of translucent zirconia on the masking ability of metal abutment

이명재,박미경 대한치과재료학회 2023 대한치과재료학회지 Vol.50 No.3

Translucent monolithic zirconia is widely used because it has continuously enhanced color and translucency. However, when translucent monolithic zirconia are used for esthetic zone like anterior, it has problem to be exposed to color of titanium abutment. The purpose of this study was to evaluate the effect of coloring and cementing of translucent zirconia on the color masking of titanium abutments. The CIE L*, a*, and b* values were measured using a spectrophotometer in three subgroups after coloring with A2 colorant and white opaque colorant, and the color difference and translucency of each group were analyzed. In the A2 colorant application group, the color difference (ΔE* ) between zirconia and zirconia on titanium abutments was not clinically acceptable (ΔE* >3.3). In the white opaque group and the white opaque plus A2 colorant group, the color difference (ΔE* ) between zirconia and zirconia on titanium abutments was clinically acceptable (1<ΔE* <3.3). The translucency of zirconia was significantly affected by the coloring treatment (P<.001). The Pearson correlation between color difference and translucency parameters was high (r=0.982, R2=0.965). The white coloring treatment to translucent zirconia affected masking of titanium abutment. The combination of A2 colorant and white opaque colorant increased the color masking effect of titanium abutments and achieved a shade similar to natural teeth. Resin cement adhesion to translucent zirconia did not affect the color masking of titanium zirconia. As the zirconia translucency increases, it had less of an effect on the titanium abutment.

표면 불산처리가 레진시멘트와 지르코니아 하부구조물의 전단결합강도에 미치는 영향

김사학(Sa-Hak Kim),김선문(Sun-Moon Kim),김종견(Chong-Kyen Kim) 한국콘텐츠학회 2018 한국콘텐츠학회논문지 Vol.18 No.10

이 연구의 목적은 불화 수소산 에칭 처리가 안정화된 정방 정계 지르코니아 다결정 (Y-TZP)의 결합 강도에 미치는 영향을 평가하는 것이었다. 4 그룹의 지르코니아 – 수지 시멘트 시편을 준비 하였다. 1) ZGS그룹 (zirconia, no treatment) 2) ZGSH 그룹 (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS그룹 (Hybrid zirconia, no treatment) 4) H-ZGSH 그룹 (Hybrid zirconia, hydrofluoric acid etching treatment). 지르코니아와 도재 사이의 전단 결합 강도는 Instron Universal Testing Machine(ModelBBP-500, Instron Corporation, Kyunggi, Korea)을 사용하여 측정 하였다. 독립표본 t-test와 two-way ANOVA (α = 0.05)를 사용하여 데이터를 통계적으로 분석했다. 세라믹 – 수지 시멘트 결합강도는 불화 수소산 에칭 처리에 영향을 받았다 (p <0.05). 파단 표면의 디지털 현미경 검사는 불화 수소산에칭 처리한 표면처리 된 지르코니아 및 하이브리드 지르코니아 그룹에서 접착성 및 응집성 파절이 동시에 발생하는 결함을 보였다. The purpose of this study was to evaluate the influence of hydrofluoric acid etching treatment on the bonding strength of yttria-stabilized tetragonal zirconia polycrystal(Y-TZP). Four groups of zirconia-resin cement specimens were prepared; 1) ZGS group (zirconia, no treatment), 2) ZGSH group (zirconia, hydrofluoric acid etching treatment) 3) H-ZGS group (Hybrid zirconia, no treatment) 4) H-ZGSH group (Hybrid zirconia, hydrofluoric acid etching treatment). The shear bond strength between zirconia and porcelain was measured using a Instron Universal Testing Machine(Model DBBP-500, Instron Corporation, Kyonggi, Korea). Data were statistically analyzed using independent t-test and two-way ANOVA(α=0.05). The ceramic-resin cement bonding strength was affected by hydrofluoric acid etching treatment(p<0.05). Digital microscope examination of the fracture surface showed mixed failures with adhesive and cohesive types in hydrofluoric acid etching treatment with treated zirconia and hybrid zirconia groups.

고비표면적 지르코니움 산화물의 제조 및 특성 분석: pH 영향

정예슬,신채호 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.7

침전법으로 환류방법 또는 수열합성법을 이용하여 산·염기점을 갖는 고비표면적 지르코니아를 합성하였다. 제조된지르코니아는 침전제로 수산화암모늄 수용액을 사용하여 Zr 용액의 pH를 2에서 10 범위 내에서 조절하였으며 질소흡착분석, X-선 회절분석(XRD), 이소프로판올 승온탈착법(IPA-TPD), 주사전자현미경 분석, X-선 광전자분광분석, 산-염기점 분석을 통해 IPA 분해반응의 촉매활성과 연관하여 특성분석을 수행하였다. 환류방법을 사용할 시, tetragonal 상이높은 지르코니아를 얻기 위해서는 Zr 용액의 pH가 높아야 하며, pH 9 이상에서는 순수한 tetragonal 상의 지르코니아 합성이 가능하였다. 또한, 비표면적이 큰 지르코니아를 얻기 위해서는 높은 pH가 요구되었으며, pH 10에서 합성한 경우에는 600 oC에서 소성 후에도 260 m2 g-1의 높은 비표면적이 얻어졌다. 하지만 같은 조건 하에서 고압이 수반되는 수열합성에는 40 m2 g-1 이하의 매우 낮은 비표면적을 보였으며, monoclinic 상의 지르코니아가 합성되었다. 고 비표면적tetragonal 상의 지르코니아를 얻기 위해서는 용액의 pH가 가장 큰 영향을 미쳤으며, 용액의 pH와 무관하게 높은 압력이 필요한 수열합성에서는 monoclinic 지르코니아가 생성되었으며 상대적으로 비표면적이 낮게 나타났다. 높은 비표면적과 tetragonal 상을 갖는 지르코니아는 염기점에 비해 산점이 우세하여 IPA 분해반응에서 선택적 탈수반응만 진행되는프로필렌만 생성되었다. High specific surface area zirconia with acid-basic property was synthesized by precipitation using reflux method or hydrothermal synthesis method using ammonium hydroxide solution as precipitant in the range of pH of Zr solution from 2 to 10. The prepared zirconia was characterized by the nitrogen adsorption, X-ray diffraction (XRD), isopropanol temperature programmed desorption (IPA-TPD), scanning electron microscopy and X-ray photoelectron spectroscopy, and the catalytic activity in the IPA decomposition reaction was correlated with the acid-basic properties. When using reflux method, high pH of Zr solution was required to obtain high fraction of tetragonal zirconia, and pure tetragonal zirconia was possible at pH 9 or higher. High pH was required to obtain high specific surface area zirconia, and the hydrous zirconia synthesized at pH 10 had high specific surface area zirconia of 260 m2 g-1 even after calcination at 600 °C. However, hydrothermal synthesis with high pressure under the same conditions resulted in very low specific surface area below 40 m2 g-1 and monoclinic phase zirconia was synthesized. High pH of the solution was required to obtain high specific surface area tetragonal phase zirconia. In hydrothermal synthesis requiring high pressure, monoclinic zirconia was produced irrespective of the pH of the solution, and the specific surface area was relatively low. Zirconia with high specific surface area and tetragonal phase was predominantly acidic compared to basicity and only propylene, which was observed as selective dehydration reaction in IPA decomposition reaction, was produced.

치과용 지르코니아 이장재 처리에 따른 지르코니아와 도재의 전단결합강도 비교

서정일,박원욱,김양근 대한치과기공학회 2017 대한치과기공학회지 Vol.39 No.1

Purpose: Physical and chemical properties of gold is most suitable to be restored of teeth to its original state. Recently zirconia was used instead of gold because of esthetical and intimacy of human body. Because of high strength and high abrasion resistance of zirconia, all zirconia artificial tooth lead to wear the original tooth of opposite site. To preserve this original tooth, zirconia artificial tooth covered with dental ceramic glass was used. When joining the zirconia core and dental ceramic glass, difference of their thermal expansion coefficient and wetting ability is generated the residual stress at interface lead to crack. In order to solve this problem, intermediate layer what is called zir-liner was imported to decrease the residual stress and increase the bonding strength. Methods: In this study, to identify the optimum conditions for manufacturing process, various methods to rough the surface of zirconia core were adopted, and vary the thickness of interlayer, and analyzed bond strength. Results: Bond strength of sanding specimens group showed higher than that of non-sanding specimens group, and once applied intermediate layer with sanding specimens showed highest bond strength with 28 MPa. SEM photomicrographs of zirconia cores fired at 1500℃ showed parallel straight lines in sanding and pockmarked surface in blasting surfaces as abrasion traces. Observation of the destruction section after shear test by SEM were carried out. Liner applied non-sanding group and non-liner applied sanding group all showed interfacial crack. Sandblasting group with non-liner showed remained dental ceramic glass on the surface of zirconia. Sandblasting group with once applied liner showed partially remained liner and dental ceramic glass on the surface of zirconia. XRD analysis revealed that sandblasting group showed higher monoclinic peaks than other specimens group and this result was due to the high collision energy for stress induced phase transformation. Conclusions: A study on the improvement of bonding strength between zirconia and dental ceramic glass steadily carried out for the future to practical use.

고비표면적 지르코니움 산화물의 제조 및 특성 분석: pH 영향

정예슬 ( Ye-seul Jeong ),신채호 ( Chae-ho Shin ) 한국화학공학회 2019 Korean Chemical Engineering Research(HWAHAK KONGHA Vol.57 No.1

High specific surface area zirconia with acid-basic property was synthesized by precipitation using reflux method or hydrothermal synthesis method using ammonium hydroxide solution as precipitant in the range of pH of Zr solution from 2 to 10. The prepared zirconia was characterized by the nitrogen adsorption, X-ray diffraction (XRD), isopropanol temperature programmed desorption (IPA-TPD), scanning electron microscopy and X-ray photoelectron spectroscopy, and the catalytic activity in the IPA decomposition reaction was correlated with the acid-basic properties. When using reflux method, high pH of Zr solution was required to obtain high fraction of tetragonal zirconia, and pure tetragonal zirconia was possible at pH 9 or higher. High pH was required to obtain high specific surface area zirconia, and the hydrous zirconia synthesized at pH 10 had high specific surface area zirconia of 260 m² g^-1 even after calcination at 600 °C. However, hydrothermal synthesis with high pressure under the same conditions resulted in very low specific surface area below 40 m² g^-1 and monoclinic phase zirconia was synthesized. High pH of the solution was required to obtain high specific surface area tetragonal phase zirconia. In hydrothermal synthesis requiring high pressure, monoclinic zirconia was produced irrespective of the pH of the solution, and the specific surface area was relatively low. Zirconia with high specific surface area and tetragonal phase was predominantly acidic compared to basicity and only propylene, which was observed as selective dehydration reaction in IPA decomposition reaction, was produced.

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.