Marginal and Internal Fit of CAD/CAM and Slip-Cast Made Zirconia Copings

BACKGROUND AND AIMS: CAD/CAM systems facilitate the use of zirconia substructure materials for all-ceramic copings. This in vitro study investigated the marginal and internal fit of zirconia copings made with CAD/CAM system and slip-casting method. MATERIALS AND METHODS: Sixteen CAD/CAM made zirconia copings and 16 slip-cast made zirconia copings were fabri-cated and cemented with glass-ionomer cement to their respective master abutment models, and thickness of the cement layer was measured at specific measuring points with stereomicroscope. RESULTS: In the left wall, the mean axial internal gap was greater in group one than group two (62.49 vs. 48.14) (P =0.007), in the right wall the mean axial internal gap was greater in group one than group two (44.87 vs. 40.91) (P = 0.465). The oc-clusal internal gap was greater in group one than group two (118.81 vs. 102.11) (P =0.423). The mean marginal gap also was greater in group one than group two (46.67 vs. 44.29) (P = 0.863). The differences in marginal fit between these two methods were not statistically significant, except for left axial internal gap that was significantly greater in the CAD/CAM system than conventional slip-cast technique (P =0.007). CONCLUSION: It was concluded that this CAD/CAM system can compete well with conventional systems for clinical fit, and can achieve good in vitro marginal fit.