The Influence of Different Cementation Modes on the Frature Re sistance of Feldspathic Ceramic Crowns

One hundred twenty pressed feldspathic ceramic crowns were luted to 20 steel dies using six different cementation modes. Fracture resistance was tested under an angle of 45 degrees and was determined as the maximal fracture load. Crowns were tested with luting agent only (groups A and C) and after etching with hydrofluoric acid, silanating, and the application of a bonding agent (groups B, D, E, and F). The resulting means were: phosphate cement 294.3 (A) and 282.2 (B); glass-ionomer cement 217.2 (C) and 255.4 (D); resin composite 382.2 (E) and 687.6 (F). Statistical analysis revealed significantly greater fracture resistance (P .01) of resin luted crowns. Bonding to the die almost doubled the fracture resistance. Conditioning of the inner surfaces of the crowns did not improve the fracture resistance of crowns luted using ainc phosphate or glass-ionomer cements.