• Journal of the Korean Ceramic Society
• /
• v.29 no.5
• /
• pp.391-395
• /
• 1992

In order to improve the compactness and uniformity in ceramic green body, we have developed dynamic CIP(Cold Isostatic Pressing) as a new forming method in which the CIP and the vibratory pressing were combined. In dynamic CIP, bulk density on alumina compacts was linearly increased with higher │Pmax-Pbias│and maximum pressure of dynamic-CIP was decreased over one-third of that of conventional CIP to obtain the same bulk density.

• Journal of the Korean Ceramic Society
• /
• v.30 no.4
• /
• pp.251-258
• /
• 1993

A constitutive model is proposed to analyze creep densification and grain growth of ceramic powder compacts. The creep strain rates for powder compacts are obtained from constitutive equations proposed by Rahaman et al. and Helle et al. The grain-growth rate is obtained by assuming time, grain size, and strain rate as its internal state variables. the proposed constitutive model is compared with experimental data for alumina compacts obtained by Venkatachari and Raj for sinter forging and by Son et al. for hot pressing.

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.120.2-120
• /
• 2003

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.04a
• /
• pp.132.2-132
• /
• 2003

• Journal of the Korean Ceramic Society
• /
• v.36 no.11
• /
• pp.1217-1227
• /
• 1999

• Proceedings of the KWS Conference
• /
• 1999.10a
• /
• pp.124-127
• /
• 1999

• Proceedings of the Korean Ceranic Society Conference
• /
• 2004.04b
• /
• pp.41.3-41.3
• /
• 2004

• Ceramist
• /
• v.12 no.3
• /
• pp.30-34
• /
• 2009

• Proceedings of the Korean Ceranic Society Conference
• /
• 2003.10a
• /
• pp.126.2-126
• /
• 2003

• The Journal of Korean Academy of Prosthodontics
• /
• v.39 no.6
• /
• pp.641-658
• /
• 2001

All-ceramic restorations have become an attractive alternative to porcelain-fused-to-metal crowns. In-Ceram, and more recently IPS Empress 2 were introduced as a new all-ceramic system for single crowns and 3-unit fixed partial dentures. But their strength and marginal fit are still an important issue. This study evaluated the fracture resistance and marginal fit of three systems of 3 unit all-ceramic bridge fabricated on prepared maxillary anterior resin teeth in vitro. The 3 all-ceramic bridge systems were: (1) a glass-infiltrated, sintered alumina system (In-Ceram) fabricated conventionally, (2) the same system with copy-milled alumina cores (copy-milled In-Ceram), (3) a heat pressed, lithium disilicate reinforced glass-ceramic system (IPS Empress 2). Ten bridges of each system with standardized design of framework were fabricated. All specimens of each system were compressed at $55^{\circ}$ at the palatal surface of pontic until catastrophic fracture occurred. Another seven bridges of each system were fabricated with standard method. All of the bridge-die complexes were embedded in epoxy resin and sectioned buccolingually and mesiodistally. The absolute marginal discrepancy was measured with stereomicroscope at ${\times}50$ power. The following results were obtained: 1. There was no significant difference in the fracture strength among the 3 systems studied. 2. The Weibull modulus of copy-milled In-Ceram was higher than that of In-Ceram and IPS Empress 2 bridges. 3. Copy-milled In-Ceram($112{\mu}m$) exhibited significantly greater marginal discrepancy than In Ceram ($97{\mu}m$), and IPS Empress 2 ($94{\mu}m$) at P=0.05. 4. The lingual surfaces of the ceramic crowns showed smaller marginal discrepancies than mesial and distal points. There was no significant difference between teeth (incisor, canine) at P=0.05. 5. All-ceramic bridges of three systems appeared to exhibit sufficient initial strength and accept able marginal fit values to allow clinical application.