TENSILE BOND STRENGTH OF A RESINOUS CEMENT TO A NICKEL-CHROMIUM ALLOYMODIFIED WITH 5 SURFACE TREATMENTS

A problem associated with resin-bonded fixed partial dentures is inadv ertent dislodgment at the metal/cement interface. It has been suggeste d that Panavia Ex resinous cement requires only air abrasion of the al loy with 50 mu m aluminum oxide particles to record reliable bond stre ngth values. The purpose of this study was to discuss the consequences of changes in the type of air abrasion and surface oxidation of the a lloy. Fifty pairs of disks of a Ni Cr alloy were treated by five metho ds: (1) air abrasion with 50 mu m aluminum oxide (control), (2) air ab rasion with 50 mu m glass beads, (3) air abrasion with a mixture of al uminum oxide and glass beads (ratio 1:1), (4) air abrasion with alumin um oxide and immersion in acid solution of potassium permanganate, and (5) air abrasion with aluminum oxide and immersion in aqueous solutio n of potassium permanganate. The disks were cemented to each other wit h Panavia Ex composite resinous cement and tensile tests were conducte d at a crosshead speed of 0.5 mml minute. No statistically significant differences were recorded among the treatments for the alloys used in this study except air abrasion with glass beads, which exhibited the lowest bond strength values.