BASIC SCIENCE RESEARCH Comparison of Bond Strength of a Pressed Ceramic Fused to Metal versus Feldspathic Porcelain Fused to Metal Daniel M. Schweitzer, DDS; 1 Gary R. Goldstein, DDS; 2 John L. Ricci, PhD; 3 N.R.F.A. Silva, DDS, PhD; 4 and Eugene L. Hittelman, MA, EdD 5 Purpose : To compare the debonding/crack initiation strength (D/CIS) of a low-fusing pressable leucite-based glass ceramic (PC) fused to metal to a feldspathic porcelain (FP) fused to metal. Materials & Methods : As per ISO 9693:1999, 40 rectangular metal specimens (25.0 mm × 0.5 mm × 3.0 mm) were prepared. Twenty of the specimens were cast in a base metal nickel-chromium alloy (BA), and 20 were cast in a noble metal palladium-silver alloy (NA). Ten randomly selected NA and BA alloy specimens had FP applied. The remaining 10 NA and BA alloy specimens had ash-free wax patterns applied, the metal-wax complexes invested, and were pressed with a PC. The dimensions of the ceramic specimens were 8.0 mm × 1.0 mm × 3.0 mm, creating a combined metal-ceramic complex thickness of 1.5 mm. All specimens were subject to a three-point bending test at a crosshead speed of 1.5 mm/min. Fracture loads were recorded in Newtons and D/CISs calculated by the formula τ b = k × F fail . Results : Mean D/CISs, measured in MPa (standard deviations): NA-FP 32.56 (4.62), NA-PC 30.23 (5.06), BA-FP 30.98 (4.41), and BA-PC 31.81 (3.48). A two-way ANOVA (p > 0.05) did not demonstrate significant difference between groups. Conclusion : The debonding/crack initiation strength of a low-fusing pressable leucite-based glass ceramic fused to metal was equivalent to that of a feldspathic porcelain fused to metal. J Prosthodont 2005;14:239-247. Copyright C  2005 by The American College of Prosthodontists. INDEX WORDS: Schwick crack-initiation test, three-point bending test, pressable ceramic, metal- ceramic bond strength C ONVENTIONAL PORCELAIN fused to metal (PFM) restorations have demonstrated 1 Resident, Advanced Education Program in Prosthodontics, New York University College of Dentistry, New York, NY. 2 Professor, Department of Prosthodontics, New York University College of Dentistry, New York, NY. 3 Associate Professor, Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY. 4 Visiting Scientist, Department of Biomaterials and Biomimetics, New York University College of Dentistry, New York, NY. 5 Associate Professor, Department of Epidemiology and Health Pro- motion, New York University College of Dentistry, New York, NY. Accepted November 2, 2004. Funded, in part, by Chemichl AG, Vaduz, Liechtenstein. Presented at the International Association Dental Research, Gote- borg, Sweden, June, 2003; ACP, John J. Sharry Prosthodontics Research Competition, Dallas, TX, October, 2003 (1st Place); Greater New York Academy of Prosthodontics, New York, NY, December, 2004; Academy of Prosthodontics, Scottsdale, AZ, May, 2005. Correspondence to: Dr. Daniel Schweitzer, 133 East 58th Street, #803, New York, NY 10022. E-mail: danielmschweitzer@yahoo.com Copyright C  2005 by The American College of Prosthodontists 1059-941X/05 doi:10.1111/j.1532-849X.2005.00052.x superior fracture resistance over all-ceramic restorations because of an alloy framework. 1 Ac- cording to Craig et al, the failure rate of most PFM restorations at 10 years in vivo has been found to be significantly less than all-ceramic restora- tions; 2 however, ceramics used for all-ceramic restorations have many advantages over those tra- ditionally used for PFM restorations. All-ceramic materials have higher flexural and compressive strength with less porosities than conventional feldspathic porcelain (FP), provide better esthet- ics with increased translucency, shrink less dur- ing processing, and have excellent marginal fit. 3-6 Moreover, pressed ceramics (PC), used for all- ceramic restorations, have the additional advan- tage of being technically less challenging by use of the lost-wax technique. This allows for the conve- nience of a full-contour ceramic wax-up as opposed to the more technique-sensitive layering method. Conceptually, combining such a ceramic with the clinically proven reinforcing ability of a metal framework would be advantageous; however, PCs Journal of Prosthodontics, Vol 14, No 4 ( December), 2005: pp 239-247 239