effect of the computer luting space setting on the fracture strength of CAD/CAM generated ceramic copings

To evaluate the effect of different luting space thicknesses on the fracture strength of In-Ceram alumina [IA] and In-Ceram Zirconia [IZ] copings, and the effect of different coping materials on the fracture strength within the luting space. Material and IA and IZ copings [30 copings for each material] were machined with luting space thicknesses [20, 30, and 40 microm] for each coping thickness [0. 6, 0.8mm]. The copings were luted with Panavia 21 to composite resin dies and loaded using on Instron at a rate of 0.5mm/min until failure. Analysis of variance and t-tests were used to assess differences. There was no significant effect [p>0.05] of different luting space thicknesses on the fracture strength for each coping thickness of IA and IZ materials. There was no significant difference [P>0.05] of 20 pm between IZ [1558 +/- 82 N] and IA [1536 +/- 27 N], 30 pm be-tween IZ [1514 +/- 103 N] and IA [1589 +/- 71 N], and 40 pm between IZ [1640 +/- 102 N] and IA [1479 +/- 71 N] for 0.6 mm coping thickness. There was no significant difference [P>0.05] of 20 pm between IZ [1708 +/- 124 N] and IA [1578 +/- 80 N], 30 pm between IZ [1672 +/- 87 N] and IA [1603 +/- 131 N], and 40 pm between IZ [1588 +/- 131 N] and IA [1695 +/- 143 N] for 0.8mm coping thickness. The fracture strength of the copings was not affected by various luting space thicknesses