세라믹-세라믹 관절면을 이용한 시멘트형과 무시멘트형 인공고관절 전치환술의 결과 비교

임수재 ( Soo Jae Yim ),유재호 ( Jae Ho Yoo ),서유석 ( Yu Seok Seo ),김병민 ( Byoung Min Kim ),정기진 ( Ki Jin Jung ),서유성 ( You Sung Suh ),( Seng Chamroeun ) 대한고관절학회 2008 Hip and Pelvis Vol.20 No.3

목적: 세라믹-세라믹 관절면으로 시멘트형 인공 고관절 전치환술을 시행한 군과 무시멘트형 인공 고관절 전치환술을 시행한 군에서 임상적 및 방사선학적 결과를 조사하였다. 대상 및 방법: 2004년 1월부터 2005년 2월까지 시멘트형 인공 고관절 전치환술을 시행하고 3년 이상 추시가 가능하였던 53명 59예와, 같은 기간 무시멘트형 인공 고관절 전치환술을 시행하고 3년 이상 추시가 가능하였던 58명 64예를 대상으로 하였다. 임상적 평가로는 Harris 고관절 점수, WOMAC 점수를 사용하였고, 최종 추시상 고관절부 불편감, 대퇴부 동통 여부를 조사하였다. 방사선학적으로 방사선 투과음영, 대퇴 스템의 침강, 시멘트 맨틀의 등급, 고정의 안정성 등을 관찰하였다. 결과: Harris 점수는 시멘트형 군에서 수술 전 평균 62.7점에서 최종 추시상 평균 92.4점으로 향상 되었으며, 무시멘트형 군에서는 수술 전 평균 61.5점에서 최종 추시상 평균 91.8점으로 향상 되었다(p>0.05). WOMAC 점수는 시멘트형 군에서 수술 전 평균 37.9점에서 최종 추시상 평균 7.0점으로 향상 되었고, 무시멘트형 군에서는 수술 전 평균 38.5점에서 최종 추시상 평균 12점으로 향상 되었다(p<0.05). 시멘트형 군에서는 고관절부 불편감과 대퇴부 동통은 없었으며, 무시멘트형 군에서는 고관절부 불편감 5예, 대퇴부 동통 9예가 있었다. 양 군에서 비구 컵의 골성 고정을 얻었고, 삽입물의 이동 소견은 보이지 않았다. 시멘트형 군에서 대퇴 스템의 침강은 57예에서 1 mm 이내, 2예에서 2 mm 이내였으며, 무시멘트형 군의 모든 예에서 대퇴 스템의 골성 고정을 얻었다. 결론: 세라믹-세라믹 관절면을 이용한 시멘트형 인공 고관절 전치환술은 무시멘트형 인공 고관절 전치환술에 비해 유의하게 임상적으로 양호한 결과를 얻었으며, 세라믹-세라믹 관절면의 높은 강성으로 인한 문제점을 보완하기에 좋은 방법이라고 생각된다. Purpose: The purpose of this study was to evaluate the results of ceramic-on-ceramic bearing primary total hip arthroplasty (THA) using cemented femoral stems and cementless femoral stems. Materials and Methods: We studied 59 cases (52 patients) of THAs using ceramic-on-ceramic bearing cemented femoral stems and 64 cases (58 patients) of THAs using ceramic-on-ceramic bearing cementless femoral stems. All THAs were performed between January 2004 and February 2005 and were followed up for more than 3 years. The clinical results were evaluated using the Harris hip score (HHS), WOMAC score, sense of discomfort, and thigh pain. Radiographic results were assessed with serial radiographs. Results: The mean HHS improved from 62.7 points preoperatively to 92.4 points at the last follow-up in the cemented stem group and improved from 61.5 points to 91.8 points in the cementless stem group (p>0.05). And mean WOMAC score improved from 37.9 points to 7.0 points in the cemented stem group and from 38.5 points to 12 points in the cementless stem group (p<0.05). There were 5 patients with a sense of discomfort and 9 patients with thigh pain in the cementless stem group and no cases in the cemented stem group. There were no instances of acetabular loosening in either group. Subsidence of the cemented femoral stem was less than 1 mm in 57 cases and less than 2 mm in 2 cases. All cementless femoral stems acquired firm bony union. Conclusion: Ceramic-on-ceramic bearing THA using a cemented stem showed clinical results superior to those achieved using a cementless stem. Cemented THA is thought to be good for complementing the problems caused by the hardness of ceramic-on-ceramic bearings.

Ceramic-on-Ceramic Total Hip Arthroplasty: Minimum of Six-Year Follow-up Study

Won Sik Choy,김갑중,이상기,Kyoung Wan Bae,Yoon-Sub Hwang,Chang Kyu Park 대한정형외과학회 2013 Clinics in Orthopedic Surgery Vol.5 No.3

Background: This study examines the clinical and radiologic results of ceramic-on-ceramic total hip arthroplasties with regard towear, osteolysis, and fracture of the ceramic after a minimum follow-up of six years. Methods: We evaluated the results of a consecutive series of 148 primary ceramic-on-ceramic total hip arthroplasties that hadbeen performed between May 2001 and October 2005 in 142 patients. The mean age was 57.2 years (range, 23 to 81 years). Themean follow-up period was 7.8 years (range, 6.1 to 10.1 years). Preoperative diagnosis was avascular necrosis in 77 hips (52%),degenerative arthritis in 36 hips (24.3%), femur neck fracture in 18 hips (12.2%), rheumatoid arthritis in 15 hips (10.1%), and septichip sequelae in 2 hips (1.4%). Clinical results were evaluated with the Harris hip score, and the presence of postoperative groinor thigh pain. Radiologic analysis was done with special attention in terms of wear, periprosthetic osteolysis, and ceramic failures. Results: The mean Harris hip score improved from 58.3 (range, 10 to 73) to 92.5 (range, 79 to 100) on the latest follow-up evaluation. At final follow-up, groin pain was found in 4 hips (2.7%), and thigh pain was found in 6 hips (4.1%). Radiologically, all femoralstems demonstrated stable fixations without loosening. Radiolucent lines were observed around the stem in 25 hips (16.9%), andaround the cup in 4 hips (2.7%). Endosteal new bone formation was observed around the stem in 95 hips (64.2%) and around thecup in 88 hips (59.5%). No osteolysis was observed around the stem and cup. There were 2 hips (1.4%) of inclination changes ofacetabular cup, 2 hips (1.4%) of hip dislocation, 1 hip (0.7%) of ceramic head fracture, and 1 hip (0.7%) of squeaking. The Kaplan-Meier survival rate of the prostheses was 98.1% at postoperative 7.8 years. Conclusions: The ceramic-on-ceramic total hip arthroplasty produced excellent clinical results and implant survival rates with nodetectable osteolysis on a minimum six-year follow-up study. The ceramic-on-ceramic couplings could be a reasonable option ofprimary total hip arthroplasty for variable indications.

스톱모션 애니메이션에서 도자기 재료를 통한 도자기 애니메이션의 활용과 분류

왕로,김지홍 한국디자인리서치학회 2021 한국디자인리서치 Vol.6 No.2

This paper studied the application and classification of ceramic animation through ceramic materials in stop motion animation. Because animation uses various production techniques and materials, there is variety in types and classifications, but compared to classification through materials such as paper, clay, dolls, objects, and glass, ceramic animation does not exist. Although there are animation works with rarity and workability despite the technical expertise and difficulty of producing ceramic animation, the need for a study on the applicability and classification of ceramic materials has been raised. Based on animation and ceramics studies in literature study, the material properties of ceramics and stop motion animation were identified in animation. Therefore, four distinct elements for the implementation of ceramic animation were extracted. In other words, the material element for pottery and porcelain, the spatial element for 3 Dimension, the temporal element for the Limited technique, and the production element for the Straight Ahead technique. As a case study, 'Porcelain Dolls' (1982), 'Dispute (1982)', 'Fish Tray (1988)', and 'Sir Sea (2014)' were selected as a case study using a total of four ceramics since the 1980s. By applying the four elements for the realization of ceramic animation, the existence of the four elements was identified, and the classification validity of the animation was thus confirmed. As a result of the study, the utilization of ceramic animation using stop motion technique was identified through the four realization elements of stop motion animation, and the classification versatility of animation was confirmed through the material distinctive qualities of ceramics. Through this, a rationale for the taxonomic proposal of porcelain animation in animation was presented. 본고는 스톱모션 애니메이션에서 도자기 재료를 통한 도자기 애니메이션의 활용과 분류에 관해 연구하였다. 애니메이션은 다양한 제작 기법과 재료들을 사용하므로 종류와 분류에서도 다양성이 나타나지만, 종이, 클레이, 인형, 오브제, 유리 등의 재료를 통한 분류에 비하면 도자기 애니메이션은 존재하지 않고 있는 실정이었다. 비록 도자기 애니메이션 제작의 기술적 전문성과 제작의 어려움에도 불구하고 희소성과 작품성을 지닌 애니메이션 작품이 존재하므로 도자기 재료를 활용성과 분류에 관한 연구의 필요성이 제기되었다. 문헌 연구에서 애니메이션학과 도자학에 기반하여 애니메이션에서 도자기의 재료적 특성과 스톱모션 애니메이션을 파악하였다. 그러므로 도자기 애니메이션의 구현을 위한 변별적 요소를 네 가지를 추출하였다. 즉 재질적 요소인 도기(Pottery)와 자기(Porcelain), 공간적 요소인 실재적인 입체(3 Dimension), 시간적 요소인 리미티드(Limited) 기법, 제작적 요소인 스트레이트 어헤드(Straight Ahead) 기법이었다. 사례 분석으로 1980년대 이후의 총 4편의 도자기를 활용한 스톱모션 애니메이션 ‘도자기 인형’(1982), ‘분쟁(1982)’, ‘생선 쟁반(1988)’, ‘바다 공자(2014)’를 선정하여 도자기 애니메이션의 구현을 위한 네 가지 요소를 적용함으로써 네 가지의 요소에 대한 존재를 파악하였고 따라서 애니메이션의 분류적 타당성을 확인하였다. 연구 결과는 스톱모션 기법을 활용한 도자기 애니메이션의 활용은 도자기 애니메이션의 구현 요소 네 가지를 통해 파악되어 도자기의 재료적 변별적 자질을 통해 애니메이션 분류적 타당성이 확인되었다. 이를 통해 애니메이션에서 도자기 애니메이션의 분류적 제안을 위한 기본적인 이론적 근거를 제시하였다.

세라믹-세라믹형 인공 고관절 전치환술 -최소 10년 이상 추시 보고-

문도현 ( Do Hyun Moon ),최장석 ( Jang Seok Choi ),김동환 ( Dong Whan Kim ),김광희 ( Kwang Hee Kim ) 대한고관절학회 2011 Hip and Pelvis Vol.23 No.2

목적: 세라믹-세라믹 관절면을 이용한 무시멘트 인공고관절 전치환술 후 10년 이상의 추시 관찰한 임상적, 방사선학적 결과를 보고하고자 한다. 대상 및 방법: 1998년 8월부터 2000년 2월까지 세라믹-세라믹 관절면을 이용한 무시멘트 인공 고관절 전치환술을 시행한 환자 중 10년 이상 추시 가능하였던 44명, 51예의 고관절을 대상으로 하였다. 44명의 환자 중 남자 28명, 여자 16명이었으며, 수술시 평균연령은 49세(26~77세)였다. 원인 질환으로는 대퇴 골두 무혈성 괴사 36예, 퇴행성관절염 4예, 고관절 이형성증 4예, 화농성 및 결핵성 고관절 후유증 7예였다. 임상적 평가는 Harris 고관절 점수에 근거하였으며, 방사선학적 평가는 대퇴삽입물의 경우 수직침강의 정도, 삽입물 주위의 골용해, 골내막 신생골의 형성, 피질골 비후의 유무, 삽입물의 최종 고정 상태를 관찰하였다. 비구컵의 경우 비구컵 주위의 경화선, 골내막 신생골 형성, 비구 골용해, 비구컵의 수직, 수평 이동을 관찰하였다. 결과: 임상 결과는 Harris 고관절 점수가 술 전 평균 59점에서 최종 추시 시 93점으로 향상되었다. 비구컵과 대퇴 삽입물 주위의 골 용해 소견은 없었고, 대퇴 스템의 침강은 평균 2 mm 이하로 의미 있는 침강소견을 보이는 경우는 없었다. 합병증으로 수술시 대퇴골 선상골절이 6예, 술 후 재발성 고관절 탈구가 1예, 세라믹 골두 파손이 1예, 라이너 파손이 2예에서 발생하였다. 결론: 세라믹-세라믹 관절면을 이용한 무시멘트 인공 고관절 전치환술을 시행 받은 51예의 10년이상 추시결과 Harris 고관절 점수의 향상과 전례에서 골용해 소견 관찰되지 않았고 안정적인 골침습적 고정을 보이는 양호한 결과를 관찰할 수 있었다. 그러나 세라믹 골두의 파손이 1예, 라이너의 파손이 2예에서 발생하여 향후 보다 많은 예의 장기적인 추시 관찰이 필요할 것으로 사료된다. Purpose: We wanted to evaluate the clinical and radiographic results of ceramic on ceramic bearing cementless total hip arthroplasty with a minimum of 10-years follow up. Materials and Methods: This study was performed on 44 patients and 51 hips, and the patients were recruited among the patients who underwent ceramic-ceramic type cementless total hip arthroplasty from August 1998 to February 2000 and they were available for 10-years or longer follow up. The gender ratio was 28 males and 16 females, and the mean age at the time of surgery was 49 years (range: 26~77 years). Regarding the causality of disease, osteonecrosis was noted in 36 cases, degenerative arthritis was noted in 4 cases, acetabular dysplasia was noted in 4 cases and septic or tuberculous hip sequelae was noted in 7 cases. The clinical evaluation was performed according to the Harris hip score, and for the radiological evaluation of the femoral component, we assessed the degree of subsidence and the presence of periprosthetic osteolysis, endosteal new bone formation and cortical hypertrophy, and the final fixation state of the implant. In the cases with an acetabular cup osteoscleostic line in the vicinity of the acetabular cup, endosteal new bone formation, acetabular osteolysis and the vertical migration as well as the horizontal migration of the acetubular cup were assessed. Results: Regarding the clinical outcomes, the Harris hip score was improved from an average 59 points to 93 points at the final follow up. For the radiological results, osteolysis was not detected in the acetabular and femoral components, the subsidence of femoral stem was not beyond 2 mm on average and significant subsidence was not detected. In regard to complications, linear fracture during surgery was noted in 6 cases and postoperative hip dislocation was noted in 1 case. A ceramic head fracture occurred in one case and a ceramic liner fracture occurred in 2 cases. Conclusion: This type of articulation is a promising option at a minimum of 10-years follow up of 51 hips that underwent ceramic-ceramic bearing cementless total hip arthroplasty. However, our results demonstrated that surgeons should be aware of the potential risks of ceramic fracture when using ceramic-on-ceramic bearing surfaces. Additional longer-term follow-up is necessary.

청자 파도자기를 활용한 도자기 소지 개발

이제일,박주석,이용석,이병하,Lee, Jea-Il,Park, Joo-Seok,Lee, Yong-Seok,Lee, Byung-Ha 한국세라믹학회 2009 한국세라믹학회지 Vol.46 No.6

The yield is increasing as the manufacturing technology of ceramics progresses, however, there are many ceramics of poor quality due to variables upon producing ceramics. Some of those waste ceramics are recycled by sanitary ware or tile manufacturers, but most of them are filled in making environmental problem. Therefore, a research begins to recycle waste ceramic ware as alternative to some imported ceramic ware materials and to reduce environmental pollution. This study, succeeding last study which applied waste white ware as ceramic body material, aimed to solve problems of environment and materials by recycling waste ceradon generated in specially formed areas for ceramic in Gyeonggi-do such as Icheon, Yeoju and Gwangju as the ceramic body material. Consequently, the addition of waste ceramic ware into the ceramic body was judged to have limit up to 30% according to plasticity measurement. As we added shredded waste ceramic ware as much as 30% into basic ceramic body and checked its features, the pore rate and absorption rate were good to be average 4% and 3% respectively. In addition, it showed strength more than 720 kgf/$cm^2$ which is higher than existing ceradon body on the market with good sinter state; so it is judged to be available or developed as new ceramic body.

Ceramic Head Fracture in Ceramic-on-Polyethylene Total Hip Arthroplasty

노재휘,박종석,송의섭,김우종,서유성 연세대학교의과대학 2013 Yonsei medical journal Vol.54 No.6

Revision rates of total hip arthroplasty have decreased after introducing total hip arthroplasty (THA) using ceramic component, since ceramic components could reduce components wear and osteolysis. The fracture of a ceramic component is a rare but potentially serious event. Thus, ceramic on polyethylene articulation is gradually spotlighted to reduce ceramic component fracture. There are a few recent reports of ceramic head fracture with polyethylene liner. Herein, we describe a case of a ceramic head component fracture with polyethylene liner. The fractured ceramic head was 28 mm short neck with conventional polyethylene liner. We treated the patient by total revision arthroplasty using 4th generation ceramic on ceramic components.

세라믹-세라믹 관절면을 이용한 고관절 전치환술: 5년 중기 추시결과

임수재 ( Soo Jae Yim ),장문석 ( Mun Suk Jang ),윤준희 ( Joon Hee Yoon ),이상혁 ( Sang Hyok Lee ),강희경 ( Hee Kyung Kang ) 대한고관절학회 2011 Hip and Pelvis Vol.23 No.4

목적: 세라믹에서 나타나는 강성 성질을 완화하여 세라믹-세라믹 관절면에서 나타나는 합병증을 시멘트형 대퇴 스템을 사용함으로써 감소 시킬 수 있을 것으로 생각하여 중기 추시의 효과를 알아보고자 하였다. 대상 및 방법: 2004년 1월부터 2005년 12월까지 시멘트형, 무 시멘트형 고관절 전치환술을 시행하고 5년 이상 추시 가능하였던 각각 30명 32예와 31명 33예를 대상으로 임상적 평가와 방사선학적 평가를 시행하였다. 결과: Harris 점수와 WOMAC 점수는 시멘트형 군과 무 시멘트형 군에서 수술 전 보다 최종 추시상 모두 향상되었다(P<0.05). 그러나 Harris 점수나 WOMAC 점수의 시멘트형과 무 시멘트형 간의 증가에 대한 특이한 차이는 없었다(P=0.304, P=0.769). 무 시멘트형 군에서만 보행 시 발생한 고관절부 불편감 3예, 대퇴부 통증 5예가 있었다. 양군에서 비구 컵의 골성 고정을 얻었고, 삽입물의 이동소견은 보이지 않았다. 시멘트형 군에서 대퇴 스템의 침강은 30예서 1 mm이내, 2예에서 2 mm 이내였으며, 무 시멘트형 군의 모든 예에서 대퇴 스템의 골성 고정을 얻었다. 결론: 세라믹-세라믹 관절면을 이용한 무 시멘트형과 시멘트형 고관절 전치환술의 중기 추시 결과는 통계학적으로 효과를 얻을 수 없었다. Purpose: We believe that cemented femoral stems will relieve the stiffness of ceramic-based bearings, resulting in reduced complication of ceramic-on-ceramic bearing total hip arthroplasty (THA). The purpose of this study was to evaluate the midterm effect of ceramic-on-ceramic bearing THA using cemented femoral stems. Materials and Methods: We studied 32cases (30 patients) of THA using ceramic-on-ceramic bearing cemented femoral stems and 33 cases (31 patients) of THA using ceramic-on-ceramic bearing cementless femoral stems. All total hip arthroplasties were performed between January 2004 and December 2005 and were followed up for more than 5 years. The clinical results and radiographic results were evaluated. Results: The mean HHS improved from points pre-operatively to points at the last follow-up in both the cemented and cementless stem groups (P<0.05). The mean WOMAC score also improved from points pre-operatively to points at the last follow-up in both the cemented and cementless stem groups (P<0.05). But no statistically significant difference was noted between the cemented and cementless stem groups in HHS and WOMAC scores (P=0.304, P=0.769). There were 3 patients with a sense of discomfort on ambulation and 5 patients with thigh pain in the cementless stem group and no cases in the cemented stem group. There was no instance of acetabular loosening in either group. Subsidenc of the cemented femoral stem was less than 1mm in 30 cases and less than 2 mm in 2 cases. All cementless femoral stems acquired firm bony union. Conclusion: Midterm results showed no statistical links between ceramicon-ceramic-bearing THA using cemented femoral stems or cementless femoral stems.

수종의 전부도재관 코어의 두께에 따른 파절강도의 비교 연구

김두용,이영수,박원희,Kim Doo-Yong,Lee Young-Soo,Park Won-Hee 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.1

Statement of problem : The increased awareness of esthetics in dentistry has brought the esthetic consideration in prosthetic restorations . Dental ceramics offer better esthetics for use of prosthetic restorations. Unfortunately, dental ceramic materials are not always the most suitable candidate materials since their inherently brittle nature. In recent years, basic research in ceramic science has led to the recognition or several approaches to strengthen and to enhance esthetics of ceramics. Several all ceramic systems use ceramic core and porcelain build up structures . Ceramic cores influence to strength of all ceramic crowns . So the strength of ceramic cores is important to all ceramic crowns. Purpose : The purpose of this study is to estimate the flexural strength of ceramic cores in some all ceramic systems. Material and method : A biaxial flexure test was conducted on three groups(Cergo, Empress 2, In-Ceram). Each group consisted of 30 discs of nearly identical dimension with a 0.5mm, 1.0mm, 1.5mm thickness and 12mm in diameter. The fracture load was recorded by Instron. Analysis of valiance(ANOVA) and Tukey's tests were performed using SAS statistical software. Results : 1.5mm thickness of specimens were significantly stronger than 0.5mm and 1.0mm thickness of specimens in Cergo and In-Ceram. But each sepecimen group of Empress 2 was no significantly strength by thickness. In order of In-Ceram, Empress 2 and Cergo has significantly stronger strength in the same thickness. Conclusion : In-Ceram is the strongest ceramic material in 3 materials. All the materials can be used according to the required characters.

치과 CAD/CAM용 Nano Hybrid Ceranic 소재를 이용한 심미 치과보철물의 제작

최범진,Choi, Beom-jin 대한심미치과학회 2016 Journal of the Korean Academy of Esthetic Dentistr Vol.25 No.2

전통적인 Metal-ceramic 보철 제작 방식으로부터 All-ceramic 보철에 이르기까지 최근 신소재 개발에 영향을 주는 가장 큰 요인은 심미적인 욕구일 것이다. 우리가 사용하는 각각의 치과용 수복 재료는 재료 별로 강도, 인성, 기계 가공의 효율성 및 사용에 필요한 다양한 과정을 기반으로 임상에서 다양하게 사용되고 있다. 예를 들어 Glass ceramic과 같은 단일 소재의 경우 약한 물성을 고려하여 주로 싱글 크라운과 같은 간단한 보철에 사용하고 있으며 상대적으로 높은 파괴 인성을 가진 지르코니아 재료의 경우 싱글 크라운은 물론 브릿지의 제작에도 널리 사용하고 있다. 하지만 지르코니아 재료는 제작 과정에서 긴 Sintering 시간을 필요로 하므로 Chair side에서 빠른 보철물 제작에 쉽지 않은 부분이 있으며 주로 Lab. side에서 사용하고 있다. CAD / CAM 시스템을 이용하여 보철물을 제작하는 용도로 개발 된 Hybrid ceramic 소재는 Resin Nano Hybrid Ceramic이라고도 하며, 개선 된 물성을 포함한 나노 세라믹 요소를 기반으로 하고 있다. 이러한 특징들은 심미적이며 기능적인 보철물의 제작이 용이한 과정과 결과를 보이고 있으며 동시에 향상된 내구성을 바탕으로 보철물의 제작 과정에 유리한 조건들을 가지고 있다. 새로운 Nano Hybrid Ceramic 재료는 Composite Resin과 Glass ceramic과 같은 단일 소재들이 가진 장점들을 이용하여 술자들의 요구사항을 바탕으로 오랜 연구를 통해 개발된 치과 수복 아이템이며 Nano ceramic filler가 혼합된 구조로 되어있어 치과 수복용 복합소재로서 널리 사용하고 있다. 또한 Nano Hybrid Ceramic소재는 Composite resin의 가공 과정에서 쉽게 파절되지 않는 개선된 물성과 Glass ceramic이 가진 심미성 동시에 포함하고 있는 것이 특징이다. 따라서 Chair side와 Lab. side에서 CAD/CAM 시스템을 이용하여 보철물을 제작할 때 임상적용이 쉽고 유용한 장점을 가지고 있어 추가적인 연구가 필요하다. In recent days, perhaps the biggest driver in new material development is the desire to improve restorations esthetics compared to the traditional metal substructure based ceramics or all-ceramic restorations. Each material type performs differently regarding strength, toughness, effectiveness of machining and the final preparation of the material prior to placement. For example, glass ceramics are typically weaker materials which limits its use to single-unit restorations. On the other hand, zirconia has a high fracture toughness which enables multi-unit restorations. This material requires a long time sintering procedure which excludes its use for fast chair side production. Hybrid ceramic material developed for CAD/CAM system is contained improved nano ceramic elements. This new material, called a Resin Nano Hybrid Ceramic is unique in durability of function and aesthetic base compositions. The new nano-hybrid ceramic material is not a composite resin. It is also not a pure ceramic. The material is a mixture of both and consists of nano-ceramic fillers. Like a composite, the material is not brittle and is fracture resistant. Like a glass ceramic, the material has excellent polish retention for lasting esthetics. The material is easily machined by chair side or in a dental lab side, could be an useful restorative option.

수종의 post와 IPS-Empress Ingot 두께가 전부 도재 수복물 최종색조에 미치는 영향

복원미,최근배,박찬운,안승근,Bok Won-Mi,Choi Keun-Bae,Park Charn-Woon,Ahn Seung-Geun 대한치과보철학회 2004 대한치과보철학회지 Vol.42 No.5

Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.