Effect of posterior span length on the trueness and precision of 3 intraoral digital scanners: A comparative 3-dimensional in vitro study

different span lengths. Materials and Methods: Three master casts were prepared to simulate 3 different span lengths (fixed partial dentures with 3, 4, and 5 units). Each master cast was scanned once with an E3 lab scanner and 10 times with each of the 3 intraoral scanners (Trios 3, Planmeca Emerald, and Primescan AC). Data were stored as Standard Tessellation Language (STL) files. The differences between measurements were compared 3-dimensionally using metrology software. Data were analyzed using 1-way analysis of variance with post hoc analysis by the Tukey honest significant difference test for trueness and precision. Statistical significance was set at P<0.05. Results: A statistically significant difference was found between the 3 intraoral scanners in trueness and precision (P<0.05). Primescan AC showed the lowest trueness and precision values (36.8 μm and 42.0 μm; (39.4 μm and 51.2 μm; and 54.9 μm and 52.7 μm) followed by Trios 3 (38.9 μm and 53.5 μm; 49.9 μm and 59.1 μm; and 58.1 μm and 64.5 μm) and Planmeca Emerald (60.4 μm and 63.6 μm; 61.3 μm and 69.0 μm; and 70.8 μm and 74.3 μm) for the 3-unit, 4-unit, and 5-unit fixed partial dentures, respectively. Conclusion: Primescan AC had the best trueness and precision, followed by Trios 3 and Planmeca Emerald. accepted successful ranges.