Marginal Fidelity And Fracture Strength Of Ips Empress 2(R) Ceramic Crowns According To Different Cement Types

Cho, Hyun Ok; Kang, Dong Wan

Abstract

There has been increasing use of IPS Empress 2(R)owing to easy fabrication method, high esthetics similar to natural teeth, good marginal accuracy, and sufficient fracture strength. However, in clinical application, although a luting agent and the tooth cementation bonding procedure influence the marginal accuracy and fracture strength restoration, there has been a controversy in the selection of proper luting agent. This study was to measure the marginal fidelites and fracture strength of IPS Empress 2(R) crowns according to three cement types, Protec cem(R), Variolink II(R) and Panavia 21(R). After construction of 12 experimental dies for each group, IPS Empress 2(R)crowns were fabricated and luted the metal master die prepartion of the maxillary right premolar. Marginal gaps before cementation and after cementation were measured. Buccal incline on the functional cusp of specimens were loaded until the catastrophic failure and fracture strength was measured. The results of this study were as follows: 1. The range of gap was 34.04 +/- 4.84 micro meter before cementation and 37.88 +/- 5.00 micro meter after cementation, which showed significant difference by paired t-test (p<0.05). The difference in the results from marginal accuracy according to measuring point proved to be not statistically significant by two-way ANOVA test (p>0.05). 2. The difference in the results from marginal accuracy according to three cement types proved that The Variolink II(R) cement group had the least gap, 35.43 +/- 5.03 micro meter, and showed superior marginal accuracy while there existed statistic significance in Protec cem(R) cement group, 39.06 +/- 4.41 micro meter or Panavia 21(R)cement group, 39.16 +/- 4.39 micro meter by two-way ANOVA test and multiple range test (p<0.05). 3. The difference in the results from fractures strength testing according to three cement type groups proved to be statistically significant (p<0.05). The Variolink II(R) cement group shows the highest fracture strength of 1257.33 +/- 226.77 N, Panavia 21(R)cement group has 1098.08 +/- 138.45 N, and Protec cem(R) cement group represents the lowest fracture strength of 926.75 +/- 115.75 N. 4. Three different cement groups of different components showed acceptable marginal fidelity and fracture strength. It is concluded that IPS Empress 2(R)crowns luted using Variolink II(R) cement group had stronger fracture strength and smaller marginal gap than the other cement groups. Although Variolink II(R) resin cement seemed acceptable to clinical applications in IPS Empress 2(R)system, the IPS Empress 2(R)system still requires long-term research due to the lack of data in clinical applications