To explore the influence of different cement spaces on the marginal adaptation of CAD/CAM zirconia inlay.

30 teeth extracted for orthodontic purpose were selected and divided into 3 groups (Group A 10 μm, Group B 30 μm, Group C 50 μm). The marginal spaces of inlays were recorded by the light-body Silicone impression material, and measured by microscope. The data were analyzed by SPSS 13.0.

All the inlays fitted very well and all the marginal spaces were less than 120 μm. The shoulder of Group A was statistically lower than Group B and Group C (P＜0.05). The axial surface of Group B was statistically lower than Group C (P＜0.05).

CEREC zirconia inlay is satisfactory when the cement space is between 10-50 μm.