Purpose: To investigate the differences in accuracy (trueness and precision) of five different optical impression systems.

Materials and methods: The accuracy of the following optical impression systems was tested: (1) CEREC Bluecam (BL; Dentsply Sirona), (2) CEREC Omnicam (OM, Dentsply Sirona); (3) PlanScan (PL; Planmeca); (4) True Definition Scanner (TD; 3M ESPE); and (5) Trios 3 (TR; 3Shape). A standard plastic study model represented a patient with a fully dentate maxilla (ANA-4 V CER, frasaco). Three clinical situations were simulated: Patient 1 (P1): fully dentate; Patient 2 (P2): anterior partial edentulism (two missing incisors); and Patient 3 (P3): posterior partial edentulism (P3) (missing premolar and molar). The models were scanned with a reference scanner (IScan D104i, Imetric), and the digitalized models were used as reference for all comparisons. Then, optical impressions were made for the three clinical scenarios (n = 10 per group).

Results: In situation P1, the TD group provided the highest trueness (180.2 ± 46.3μm). In situation P2, the highest trueness was found in the TD (97.9 ± 27.6 μm) and TR (105 ± 9.5μm) groups, and in situation P3, TR had the highest trueness (P < .05) with a median RMS value of 76.2 ± 5.6 μm. In terms of precision, TR provided the highest precision (P < .05) in all three clinical situations, with RMS values 76.7 ± 26 μm for P1, 46.8 ± 14.1 μm for P2, and 39.7 ± 9.1 μm for P3.

Conclusion: Two optical impression systems (TR and TD) were superior to the other tested systems in most of the measurements. However, none of the tested systems was clearly superior with respect to both trueness and precision.