This study examines the ratio of alloy components of six gold crowns discovered in six Silla tombs; Gyo-dong, the north tomb of Hwangnamdaechong, Geumgwanchong, Cheonmachong, Geumnyeongchong and Seobongchong. Concretely, the study looks at whether and how crowns from these various tombs differ in terms of the ratio of alloy components. The analysis of the six Silla crowns found that all of them were made of gold and silver alloy. When comparing the ratio of alloy components in crowns and type of crowns, the Gyo-dong crown which is the oldest of them showed the highest content of gold. Crowns from Hwangnamdaechong and Geumgwanchong in the middle to late 5th century, showed a similar content of gold. Gold content of crowns from the late 5th century to early 6th century tombs decreased in order Cheonmachong, Geumnyeongchong and Seobongchong, thus it confirmed that the older the tomb, the higher its gold content.
PURPOSE. The purpose of this study was to compare the fit of cast gold crowns fabricated from the conventional and the digital impression technique. MATERIALS AND METHODS. Artificial tooth in a master model and abutment teeth in ten patients were restored with cast gold crowns fabricated from the digital and the conventional impression technique. The forty silicone replicas were cut in three sections; each section was evaluated in nine points. The measurement was carried out by using a measuring microscope and I-Soultion. Data from the silicone replica were analyzed and all tests were performed with ${\alpha}$-level of 0.05. RESULTS. 1. The average gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. 2. In marginal and internal axial gap of cast gold crowns, no statistical differences were found between the two impression techniques. 3. The internal occlusal gaps of cast gold crowns fabricated from the digital impression technique were larger than those of the conventional impression technique significantly. CONCLUSION. Both prostheses presented clinically acceptable results with comparing the fit. The prostheses fabricated from the digital impression technique showed more gaps, in respect of occlusal surface.
Kim Young-Oh;Ku Chul-Whoi;Park Young-Jun;Yang Hong-So
The Journal of Korean Academy of Prosthodontics
/
v.42
no.6
/
pp.647-653
/
2004
Statement of problem. The effects of various core buildup materials which differs in the mechanical properties on the fracture strength of metal-free crowns is unknown. Purpose. This study was carried out to evaluate the fracture strengths of Artglass ceromer crowns supported by 3 different core materials in clinically simulated anterior tooth preparation. Material and methods. Ten crowns from each group were constructed to comparable dimensions on the various dies made by gold alloy, Ni-Cr alloy, and composite resin. The ten crowns were then cemented onto the dies and loaded until catastrophic failure took place. Fracture resistance to forces applied to the incisal edges of the anterior crowns supported by three types of dies was tested. Results. The ceromer crowns on the composite resin dies fractured at significantly lower values(287.7 N) than the ceromer crowns on the metal dies(approximately 518.4 N). No significant difference was found between the fracture values of the ceromer crowns on the dies of gold alloy and Ni-Cr alloy. Conclusion. The failure loads of the ceromer crowns on the metal dies were almost the same and not affected by the differences of casting alloys. However, the fracture values of the ceromer crowns on the resin dies were significantly reduced by the relative weak properties of composite resin core material.
Statement of problem: Titanium and its alloy, with their excellent bio-compatibility and above average resistance to corrosion, have been widely used in the field of dentistry. However, the excessive oxidization of titanium which occurs during the process of firing on porcelain makes the bonding of titanium and porcelain more difficult than that of the conventional metal-porcelain bonding. To solve this problem related to titanium-porcelain bonding, several methods which modify the surfaces, coat the surfaces of titanium with various pure metals and ceramics, to enable the porcelain adhesive by limiting the diffusion of oxygen and forming the adhesive oxides surfaces, have been investigated. Purpose: The purpose of this study was to know whether the titanium-porcelain bonding strength could be enhanced by treating the titanium surface with gold and TiN followed by fabrication of clinically applicable porcelain-fused-to-titanium crown Material and method: The porcelain-fused-to-titanium crown was fabricated after sandblasting the surface of the casting titanium coping with $Al_2O_3$ and treating the surface with gold and TiN coating followed by condensation and firing of ultra-low fusing porcelain. To compare with porcelain-fused-to-titanium crowns, porcelain-fused-to-gold crowns were fabricated and used as control groups. The bonding strengths of porcelain-fused-to-gold crowns and porcelain-fused-totitanium crowns were set for comparison when the porcelain was fractured on purpose to get the experimental value of fracture strength. Then, the surface were examined by SEM and each fracturing pattern were compared with each other Result:Those results are as follows. 1. The highest value of fracture strength of porcelain-fused-to-titanium crowns was in the order of group with gold coating, group with TiN coating, group with $Al_2O_3$ sandblasting. No statistically significant difference was found among the three (P>.05). 2. The porcelain-fused-to-gold crowns showed the highest value in bonding strength. The bonding strength of crowns porcelain-fused-to-titanium crowns of rest groups showed bonding strength reaching only 85%-94% of that of PFG, though simple comparision seemed unacceptable due to the difference in materials used. 3. The fracturing patterns between metal and porcelain showed mixed type of failure behavior including cohesive failure and adhesive failure as a similar patterns by examination with the naked eye and SEM. But porcelain-fused-to-gold crowns showed high incidence of adhesive failure and porcelain-fused-to-titanium crowns showed high incidence of cohesive failure. Conclusion: Above results proved that when fabricating porcelain-fused-to-titanium crowns, treating casting titanium surface with gold or TiN was able to enhance the bonding strength between titanium and porcelain. Mean value of masticatory force was found to showed clinically acceptable values in porcelain bonding strength in all three groups. However, more experimental studies and evaluations should be done in order to get better porcelain bonding strength and various surface coating methods that can be applied on titanium surface with ease.
The marginal integrity of the crown can be broken during endodontic access cavity preparation due to the vibration of burs. Therefore, the purpose of this study was to evaluate the effect of endodontic access cavity preparation on the marginal leakage of full veneer gold crowns. 24 intact molars were mounted in acrylic resin blocks and prepared for crowns by a restorative dentist and crowns were cast with gold alloy. 20 Crowns were cemented with glass ionomer cement and 2 crowns were not cemented for positive control. 200 thermo-cycles from 5$^{\circ}C$ to 5$0^{\circ}C$ with a travel time of 20s were completed. Then samples were randomly divided into 2 experimental groups of 9 each. Endodontic access preparation and zinc-oxide eugenol temporary fillings were done in Group 1. Teeth in Group 2 were not treated. Samples were coated with 2 layers of nail varnish and were immersed in 1% methylene blue dye for 20 hrs. Endodontic access was prepared in 2 samples, which were coated with nail varnish on all surfaces for negative control. After washing in running water gold crowns were cut with a #330 bur. Four buccolingual sections, 2 mm apart, were cut from the central section of each tooth and were examined and scored under the microscope for dye leakage. Score 1: leakage to the cervical 1/3 of the axial wall, Score 2: leakage to the middle 1/3 of the axial wall, Score 3: leakage to the coronal 1/3 of the axial wall, Score 4: leakage to the occlusal surface. The median value for Group 1 is 4 and for Group 2 is 2. The result of this study showed that samples in Group 1 leaked more than those in Group 2. This finding was significant(P<0.001).
Metal brackets and ceramic brackets were bonded to natural teeth, porcelain crowns and gold crowns After stored in artificial saliva solution for 72 hours at $37^{\circ}C$, the shear bond strengths were measured by Instron and compared with them, the bonding sites and bracket bases were examined by scanning electron microscope and light optical stereomicroscope. The results were as follows: 1. The shear bond strengths of the group which metal brackets were bonded to natural teeth and the groups which ceramic brackets were bonded to natural teeth and porcelain crowns were comparable to each other, the shear bond strength of the group which metal brackets were bonded to gold crowns was significantly low. 2. The bond failed predominantly at the bracket base/adhesive interface with the bulk of adhesive remaining on enamel in the group which metal brackets were bonded to natural teeth. 3. The bond failed consistently at the crown/adhesive interface with all of adhesive remaining on the bracket babes in the group which metal brackets were bonded to gold crowns. 4. The bond failed at the enamel or crown/adhesive interface with the bulk of adhesive remaining on the bracket bases in the groups which cramic brackets were bonded to natural teeth and porcelain crowns. 5. The shear bond strengths of the groups which ceramic brackets were bonded to porcelain crowns were not affected by etching time.
The number and the distribution of fixed restorations including crowns, fixed bridges, Maryland bridges, periodontal splints and cast cores were statistically investigated with two thousand seven hundred and thirty cases of crowns and bridges placed at the Department of Prosthodontics of Seoul National University Hospital, from January 4th to December 31st, 1988. The results were as follow : 1. Among the fixed restorarions, single crowns were 46.9% , fixed bridges were 41.9%, Maryland bridges were 5.0%, periodontal splints were 0.6% and cast cores were 5.6%. 2. Three thousand nine hundred and ninty two teeth were restored with the fixed restorations, among them cast gold restorations were 47.2% and metal-ceramic restorations were 52.8%. 3. Cast gold restorations of the maxillary posteriors occupied 98.5% of the maxillary cast gold restorations, and 99.7% of the mandibular cast gold restorations and metal-ceramic restoration of maxillary anteriors occupied 68.4% of the maxillary metal-ceramic restorations, and 38.7% of the mandibular metal- ceramic restorations. 4. It is recommended that the curriculum of the dental school for undergraduated students and graduated students should be changed to accomodate the relative importance of the restorations.
This study conducted non-destructive analyses of the material features of seven gilt-bronze crowns of Baekje Kingdom that were excavated in the Cheonan, Gongju, Seosan, Iksan, Naju, and Hapcheon areas. A typical Baekje gilt-bronze crown has a conical inner crown and an outer crown embellished with vertical ornaments on the front and the back, a tube topped with a hemispherical ornament, and other ornamentation. Diverse designs (e.g., dragon, bonghwang, flowers, and plants) were applied using a range of techniques, including repoussé, chasing, openwork, and engraving. Formal features differ among the crowns according to their period of production and site of excavation. The substrate metal of the crowns is either pure copper or mixed copper with a small amount of lead. The crowns were amalgam-plated on the surface with pure gold or gold with a small amount of silver. The crown from Okjeon Tomb No. 23 in Hapcheon in the ancient Gaya region has a high silver content, which appears to be a regional feature. In addition, this crown from Okjeon Tomb No. 23, which can be categorized as Baekje-style gilt-bronze crown, seems to be plated at most three times, while the gilt-bronze crowns found within Baekje Kingdom territory were plated once or twice.
PURPOSE. To assess the clinical performance of monolithic CAD-CAM lithium disilicate glass-ceramic (LDGC) crowns and metal-ceramic (MC) crowns provided by predoctoral students. This study also assessed the effects of patient and provider-related factors on their clinical performance as well as patient preference for these types of crowns. MATERIALS AND METHODS. Twenty-five patients who received 50 crowns (25 LDGC CAD-CAM and 25 MC) provided by predoctoral students were retrospectively examined. LDGC CAD-CAM crowns were milled in-house using the CEREC Bluecam system and cemented with either RelyX Unicem or Calibra Esthetic resin cements. MC crowns were cemented with RelyX Unicem cement. Clinical assessment of the crowns and the supporting periodontal structures were performed following the modified California Dental Association (CDA) criteria. Patients' preference was recorded using a visual analog scale (VAS). The results were statistically analyzed using log-rank test, Pearson Chi-squared test and Kaplan-Meier survival analysis. RESULTS. Twelve complications were observed in the MC crown group (9-esthetic, 2-technical and 1-biological). In comparison, 2 complications in the LDGC CAD-CAM crown group were observed (1-technical and 1-esthetic). The 6-year cumulative survival rates for MC crowns and LDGC CAD-CAM were 90.8% and 96%, respectively, whereas the success rates were 83.4% and 96%, respectively. Overall, patients preferred the esthetic outcomes of LDGC CAD-CAM crowns over MC crowns. CONCLUSION. The high survival and success rates, low number of complications, and the high level of patients' acceptance of monolithic LDGC CAD-CAM crowns lend them well as predictable and viable alternatives to the "gold standard" MC crowns.
Purpose: The purpose of this study was to investigate the production environment of crown prosthesis for National Health Insurance(NHI) benefit. Methods: This study carried out self-administered questionnaire survey from September 1, 2016 to October 31 by having research subjects as 261 dental technician. Except 100 copies with incomplete response, 161 copies were used as the materials of final analysis. Results: Unlike gold crowns, the material cost of metal crowns was paid at the dental laboratory(86.3%). Total material consumption for making metal crown was more than gold crown(63.4%), especially for the finishing and polishing processes(78.3%). The subjects responded that a routine dental laboratory fee of crown prosthesis is unreasonable, and it is necessary to adjust and improve it(metal crown 96.2%, gold crown 96.9%). NHI coverage dental prosthesis was not marked on the order form(46.0%), and the dental laboratory fee of that was nor received(64.0%). Conclusion : It is necessary to estimate the NHI cost level of the crown prosthesis by reflecting the production environment and engineering process in dental laboratories. In addition, institutional arrangement should be backed up so that dental laboratories can receive appropriate dental laboratory fee.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.