The purpose of this experiment was to determine the effects of various surface treatments on veneering resin to metal bond for Ni-Cr alloy. @ES The metal surfaces were treated as follows: @EN Group 1 : Ground with carborudum point and followed by silicoating Group 2 : Sandblasted with 50㎛aluminum oxide and followed by silicoating Group 3 : Sandblasted with 250㎛aluminum oxide and followed by silicoating Group 4 : Beaded with 200㎛retention structures and followed by silicoating Group 5 : Silicoated in as cast condition Group 6 : Beaded with 200㎛retention structures only All specimens were veneered with resin. Each group was consisted of 20 specimens. 10 specimens were storaged in 37℃water for 3 days and the rest 10 specimens were thermocycled 1000 times at temperature of 5℃to 55℃. The effects of various surface
treatments on the bond strength between resin and metal interface were studied by means of four-point flexure test. The specimens which bad been ground with carborundum point. sandblasted with 50㎛and 250㎛aluminum oxide. beaded with 200㎛retention structures and not been treated were observed with SEM. @ES The following results were obtained: @EN 1. The bond strength o groups 2, 3, 4 and 6 were higher than the hat of groups 1 and 5(p<0.05) in the case of being storaged in 37℃water for 3 day and there was no statistically significant difference in bond strength among groups 2, 3, 4 and 6. And between groups 1 and 5 (p>0.05) 2. The bond strength of the case of being thermocycled decreased in the following orders : groups 2, group 4, group 3, group 6, group 1, group 5 and there was no statistically significant difference in bond strength among groups 2, 3 and 4, between group 1 and 5 (p>0.05) 3. A statistical difference in bond strength of each group between storaged and being thermocycled was demonstrated for group 5 (p<0.05) 4. The treated surfaces of groups 2, 3 and 4 had more fine undercut than that of groups 1 and 5 with SEM.
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