• Title/Summary/Keyword: ceramic-metal crown

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MARGINAL FIT OF THE AURO GALVANO CROWN SYSTEM MADE USING THE ELECTROFORMING TECHNIQUE

  • Yang Jae-Ho;Song Tae-Jin;Han Jung-Suk;Lee Jae-Bong;Lee Sun-Hyung
    • The Journal of Korean Academy of Prosthodontics
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    • v.42 no.6
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    • pp.679-684
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    • 2004
  • Statement of problem. There have been few studies about the marginal fit of Auro Galvano Crowns. Purpose. The purpose of this study was to compare the marginal fit of the anterior single restorations. Material and methods. The in vitro marginal discrepancies of metal-ceramic, Auro Galvano Crown and coping were evaluated and compared. The Auro Gavano Crowns were made from one extracted maxillary central incisor prepared by milling machine. 30crowns per each system were fabricated. Measurements of a crown were recorded at 50 points that were randomly selected for marginal gap evaluation. Parametric statistical analysis was performed for the results. Results. Mean marginal gap dimensions and standard deviations at the marginal opening for the anterior single crowns were $74{\pm}21{\mu}m$ for the control (metal-ceramic restoration), $45{\pm}11{\mu}m$ for Auro Galvano Crown coping, and $51{\pm}9{\mu}m$ for the Auro Galvano Crown. Conclusions. Auro Calvano Crown showed significantly smaller (P<.05) marginal gap than the control. Ceramic application did not significantly affected the marginal fit of Auro Galvano Crown. (P>.05)

FRACTURE STRENGTH OF ZIRCONIA MONOLITHIC CROWNS (지르코니아 단일구조 전부도재관의 파절강도)

  • Jeong Hee-Chan
    • The Journal of Korean Academy of Prosthodontics
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    • v.44 no.2
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    • pp.157-164
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    • 2006
  • Purpose: The purpose of this study was to compare the fracture strength of the zirconia monolithic all-ceramic crowns according to the thickness(0.5 mm, 0.8 mm, 1.1 mm) and IPS Empress II ceramic crown of 1.5 mm thickness. Material and method: Eight crowns for each of 3 zirconia crown groups were fabricated using CAD/CAM system(Kavo, Germany) and eight Empress II crowns were made from silicone mold and wax pattern. Each crown group was finished in accordance with the specific manufacturer s instruction. All crowns were luted to the metal dies using resin cement and mounted on the testing jig in a universal testing machine. The load was directed at the center of crown with perpendicular to the long axis of each specimen until catastrophic failure occurred. Analysis of variance and Tukey multiple comparison test(p<.05) were applied to the data. Results and Conclusion: 1. The fracture strength of the zirconia monolithic all-ceramic crown was higher thickness increased(p<.05). 2 The fracture strength of 1.1 mm thickness zirconia monolithic all-ceramic crown was higher than the fracture strength of 1.5 mm thickness IPS Empress II crown(p<.05). 3. The fracture strength of 0.5 mm thickness zirconia monolithic all-ceramic crown exceeded maximum occlusal forces.

COLOR COMPARISON OF VARIOUS POST SYSTEMS WITH EMPRESS 2 CROWNS (포스트의 종류에 따른 Empress 2 도재관의 색상에 관한 비교연구)

  • Lee Young-Soo;Yoo Dong-Yeob
    • The Journal of Korean Academy of Prosthodontics
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    • v.39 no.2
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    • pp.197-207
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    • 2001
  • Development of new ceramics and esthetic needs of patients increase the use of all ceramic restorations. Fractured teeth often need metal post and core as foundation for final restoration. When all ceramic restorations are planned, metal post and core may lead to compromised esthetics because of opacity and gray color of metal post and core. Many techniques have been proposed to solve this problem such as application of an opaque porcelain to the metal core or all ceramic post and core. This study was performed to evaluate effect on color of Empress 2 crown according to various post systems. Color was evaluated by the CIE $L^*a^*b^*$ systems and measured by spectrophotometer (Model CM-3500, Minolta, Japan). Specimens were divided into 4 groups as follows Group 1 : gold cast post specimen + Empress 2 crown specimen Group 2 : application of an opaque porcelain to gold cast post specimen + Empress 2 crown specimen Group 3 : cosmopost specimen + Empress 2 crown specimen Group 4 : In-ceram post specimen + Empress 2 crown specimen. The results obtained as follows, 1. $L^*$ Values showed that group 2, 3, 4 were higher than group 1 with significant difference and group 2, 3, 4 were not significantly different. 2. $a^*$ Values and $b^*$ values also showed that group 2. 3, 4 were higher than group 1 with significant difference and group 2, 3, 4 were not significantly different. 3. ${\Delta}E^* ab$ Values showed that ${\Delta}E^* ab$ 3 was the highest value and ${\Delta}E^* ab$ 5 was the lowest value.

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Effect of the marginal position of prosthesis on stress distribution of teeth with abfraction lesion using finite element analysis (보철물 변연의 위치가 abfraction된 치아의 응력 분포에 미치는 영향에 대한 유한요소법적 분석)

  • Kim, Myeong-Hyeon;Lee, Cheong-Hee
    • The Journal of Korean Academy of Prosthodontics
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    • v.52 no.3
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    • pp.202-210
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    • 2014
  • Purpose: The aim of this study was to evaluate the stress concentration and distribution whether restoring the cavity or not while restoring with metal ceramic crown on tooth with abfraction lesion using finite element analysis. Materials and methods: Maxillary first premolar was selected and made a total of 10 finite element model. Model 1 was natural tooth; Model 2 was tooth with metal ceramic crown restoration which margin was positioned above 2 mm from CEJ; Model 3 was tooth with metal ceramic crown restoration which margin was positioned on CEJ; Model 4 was natural tooth which has abfraction lesion; Model 5 and 6 had abfraction lesion and the other condition was same as model 2 and 3, respectively; Model 7 was natural tooth which had abfraction lesion restored with composite resin; Model 8 and 9 was tooth with metal ceramic crown after restoring on abfraction lesion with composite resin; Model 10 was restored tooth on abfraction lesion with composite resin and metal ceramic crown restoration which margin is positioned on lower border of abfraction lesion. Load A and Load B was also designed. Von Mises value was evaluated on each point. Results: Under load A or load B, on tooth with abfraction lesion, stress was concentrated on the apex of lesion. Under load A or load B, on tooth that abfraction lesion was restored with composite resin, the stress value was reduced on the apex. Conclusion: In case of abfraction lesion was restored with composite resin, the stress was concentrated on the apical border of restored cavity regardless of marginal position. It was favorable to place crown margin on the enamel for restoring with metal ceramic crown.

FRACTURE STRENGTH OF THE IPS EMPRESS CROWN:THE EFFECT OF OCCLUSAL DEPTH AND AXIAL INCLINATION ON UPPER FIRST PREMOLAR CROWNS (IPS Empress 도재관의 파절강도 : 상악제1소구치에서 교합면 두께와 축면 경사도에 따른 영향)

  • Dong, Jin-Keun;Oh, Sang-Chun;Kim, Sang-Don
    • The Journal of Korean Academy of Prosthodontics
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    • v.37 no.1
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    • pp.127-133
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    • 1999
  • The purpose of this study was to compare the fracture strength of the IPS Empress ceramic crown according to the occlusal depth (1.5mm, 2.0mm, 2.5mm) and axial inclination ($4^{\circ},\;8^{\circ},\;12^{\circ}$) of the upper first premolar. After 10 metal dies were made fir each group, the IPS Empress ceramic crowns were fabricated and each crown was cemented on each metal die with resin cement. The cemented crowns mounted on the testing jig were inclined 30 degrees and a universal testing machine was used to measure the fracture strength. The results were : 1. The fracture strength of the ceramic crown with 2.5mm depth and $12^{\circ}$ inclination was the highest (630N). Crowns of 1.5mm depth and $4^{\circ}$ inclination had the lowest strength(378N). There were no significant differences of the fracture strength by axial inclination in same occlusal depth group. 2. The fracture mode of the crowns was similar. Most of fracture lines began at the loading area and extended through proximal surface perpendicular to the margin, irrespective of occlusal depth.

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A Finite Element Analysis of Stress Distribution in the Tooth and Crown According to Design of Esthetic Crown (유한요소법을 이용한 심미치관보철의 설계에 따른 치아와 보철물의 응력분산에 관한 연구)

  • Lee, Myung-Kon;Chung, In-Sung;Kim, Ji-Hwan
    • Journal of Technologic Dentistry
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    • v.21 no.1
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    • pp.115-121
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    • 1999
  • This investing was carried out to evaluate the alteration of stress distribution on teeth and esthetic crowns. Analyzing the stress distribution by the two-dimensional finite element methods, a model of lower 1st molar according to the porcelain fused metal crown an the porcelain fused glass ceramic core crown and the all glass ceramic crown. 1. The pattern of stress distribution showed no apparent differences. 2. The greatest von Mises values were concentrated around the central fossa of all esthetic crowns. The greatest Maximum principle value were concentrated around the interface between the base of esthetic crown and the abutment tooth. It was found that the apatite glass ceramic could be applicable for use in dental crown prosthesis.

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Comparison of the marginal fit of POM restorations with different thickness of metal copings (코핑 두께의 차이에 따른 POM 보철물의 변연적합도 연구)

  • Lim, Hyung-Tek
    • Journal of Technologic Dentistry
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    • v.34 no.2
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    • pp.135-143
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    • 2012
  • Purpose: The purpose of this in vitro study was to compare the marginal fit of POM restorations with 3 different thickness of metal coping. Methods: 2.0mm Occlusal reduction, 1.0mm preparation of axial wall with 6degree taper, and chamfer margin was prepared a maxillary first premolar on dentiform. Duplicate prepared die and, make 30 individual dies with Ni-Cr metal. Make 3 groups of 30 press ceramic on Metal crown with different thickness of metal coping; 10 of 0.1mm, 10 of 0.3mm, 10 of 0.5mm thickness metal coping. The marginal fit of the crowns was evaluated 50 points per 1 crown, around the crown margin circumference under a optical microscope at original magnification ${\times}100$. A 1-way analysis of variance (ANOVA) was used to compare data. Results: The mean marginal discrepancy for POM with 0.1mm metal copings was $72.56{\mu}m$, $67.83{\mu}m$ for 0.3mm metal coping POMs, and $72.56{\mu}m$ for 0.5mm metal coping POM. The 1-way ANOVA showed significant difference among 3 groups. Conclusion: The marginal fit of pressed-on-metal (POMs) was best with 0.3mm thickness of metal coping, fallowing by 0.1mm, and 0.5mm in the order.

Alternate metal framework designs for the metal ceramic prosthesis to enhance the esthetics

  • Vernekar, Naina Vilas;Jagadish, Prithviraj Kallahalla;Diwakar, Dr Srinivasan;Nadgir, Ramesh;Krishnarao, Manjunatha Revankar
    • The Journal of Advanced Prosthodontics
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    • v.3 no.3
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    • pp.113-118
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    • 2011
  • PURPOSE. The objective of the present study was to evaluate the effect of five different metal framework designs on the fracture resistance of the metal-ceramic restorations. MATERIALS AND METHODS. For the purpose of this study, the central incisor tooth was prepared, and the metal analogue of it and a master die were fabricated. The counter die with the 0.5 mm clearance was used for fabricating the wax patterns for the metal copings. The metal copings with five different metal framework designs were designed from Group 1 to 5. Group 1 with the metal collar, Group 2, 3, 4 and 5 with 0 mm, 0.5 mm, 1 mm and 1.5 mm cervical metal reduction respectively were fabricated. Total of fifty metal ceramic crown samples were fabricated. The fracture resistance was evaluated with the Universal Testing Machine (Instron model No 1011, UK). The basic data was subjected to statistical analysis by ANOVA and Student's t-test. RESULTS. Results revealed that the fracture resistance ranged from 651.2 to 993.6 N/$m^2$. Group 1 showed the maximum and Group 5 showed the least value. CONCLUSION. The maximum load required to fracture the test specimens even in the groups without the metal collar was found to be exceeding the occlusal forces. Therefore, the metal frameworks with 0.5 mm and 1 mm short of the finish line are recommended for anterior metal ceramic restoration having adequate fracture resistance.

Microstructures and Mechanical Properties of Beryllium(Be)-free Ni-Cr-Mo based Alloys for Metal-Ceramic Crown (베릴륨(Be)이 미 첨가된 치과도재소부용 Ni-Cr-Mo계 합금의 미세조직 및 기계적 성질 특성)

  • Song, Kyung-Woo;Go, Eun-Kyoung;Lee, Jung-Hwan;Jung, Jong-Hyun;Noh, Hak;Han, Jae-Ick
    • Journal of Technologic Dentistry
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    • v.28 no.2
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    • pp.321-329
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    • 2006
  • The popularity of Ni-Cr-Mo based metal alloys for metal-ceramic crown have increased recently because of low price, superior yield strength and rigidity. the use of these alloys give them the potential advantage of thinner copping with the required rigidity for long span bridges. The purpose of this study was to assess the microstructures and mechanical properties of Ni-Cr-Mo-(Si,Al,Nb,Zr,Ti.Cu,Mm) based Alloys not containing beryllium(Be) related toxic effects. The abtained results indicated that as-cast these specimen alloys showed compositional and microstructural differences, and mechanical properties values of Ni69Cr20Mo5Si2Al4 alloy among these specimen alloys was found to be superior to those of commercial Ni-Cr based alloy using in market place today.

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A Study on All Ceramic Crown Manufactured Using Gold Plating Upon Refractory Cast Die (매몰재 Die 위에 금도금을 이용한 전부 도재관 제작에 관한 연구)

  • Shin, Moo-Hak;Kim, Yeoun-Soo;Chung, Hee-Sun
    • Journal of Technologic Dentistry
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    • v.22 no.1
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    • pp.49-55
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    • 2000
  • In manufacturing the all-ceramic crown whick look close to natural teeth, the effectiveness of the improved technique is expectected the technique of the heat treatment of gold plating coating die was experimented of a refractory cast model. The following results were obtainde 1. An advantage of build up on east die with out manufacturing veneer, crown, core, or masking(reduction of technical process, and retrenchment of time and money) 2. Esthetically more close to natural teeth than other technique 3. Easy to remove a refractors cast die 4. In manufacturing ceramo-metal crown the enomous effectiveness was obtainde on applying in the areas of cervical margin, the metal surface, and in the treatment of pinhole.

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