Abstract: Objective To evaluate the marginal fit in vitro between selective laser melting deposition basal crowns and cobalt chromium alloy casting base crowns.Methods Twenty working dies were created from a single master die and were used to fabricate twenty copings in each as the following groups:A(selective laser melting deposition basal crowns,n＝10),B(cobaltchrome alloy basal crown,n＝10).All the metal copings were fabricated according to manufacturers.The restorations were seated on the master die,and highresolution digital photographs were taken of the marginal area on all four sides.The vertical marginal gap was then measured using a calibrated digital software program.Analysis of Variance was used to determine the differences using SPSS 20.0 software package.Results The mean marginal gaps were:group A:（48.20±4.61）μm; group B：（77.90±6.26）μm .There was significant difference between two groups.Conclusions The marginal gaps of two different metal copings are clinically acceptable.The selective laser melting deposition copings resulted in smaller marginal gaps than cobaltchrome copings,which shows that the marginal fit of elective laser melting deposition copings is better than cobaltchrome copings.

Key words: selective laser sintering, cobaltchrome copings, basal crown, marginal fit