Objective:We sought to determine the accuracy of digital models generated from impressions and casts respectively by an ortho insight 3D laser scanner (Motion View Software,Chattanooga,Tenn)and compare them with surface area analysis method. Methods:Two sets of maxillary and mandibular digital models of 20 subjects were obtained. The models were made from impressions and casts were scanned by ortho insight 3D digital scanner,respectively. Each patient’s matched pairs of maxillary and mandibular models were superimposed by using a software program and a best-fitalgorithm; surface-to-surface analysis was then performed. The average linear differences between the 2 files at all points on the surfaces were measured,and tolerance levels of 0.05,0.1,0.25,0.5,0.75,and 1.0 mm were set to determine the surface correlation amounts between the 2 files. Additionally,6 linear measurements from predetermined landmarks were also measured and analyzed. Results:The average maxillary model linear difference was 0.097 to 0.191 mm,whereas the average mandibular model linear difference ranged between 0.092 and 0.257 mm. Greater than a 94% surface correlation was obtained on average at 0.5 mm tolerance level. The mean differences obtained from the linear measurements indicated strong agreement (0.972≤single measure ICCs≤0.998) between the maxillary and mandibular pairs. Conclusion:Surface-to-surface analysis of digital models generated from impressions and casts by ortho insight 3D digital scanner pointed to a fair overlap between the protocols. Therefore,the digital model generated directly from impressions is an alternative for that from casts.