Trueness and precision of an intraoral scanner in digitally copying complete dentures

The ability to save a digital copy of a fabricated denture is poignant for large dental institutions. The purpose of this study was to evaluate the trueness and precision of an intraoral scanner (IOS) in its ability to digitally duplicate a complete denture (CD) and evaluate the possible effects of file resolution reduction on different exported media types. A desktop scanner was used to scan a complete mandibular denture and utilized as the control file. An IOS was used to scan the same denture and exported into both standard triangular language (STL) and polygon (PLY) file types and stored for additional analysis. The different file types at original resolution were compared to the desktop scan (DS100) to evaluate the accuracy of the IOS. Then the STL (Groups S100, S75, S50, S25) and PLY (Groups P100, P75, P50, P25) files were reduced in their resolutions to evaluate any statistical discrepancies in the volumetric analysis of the scan using the Hausdorff distance (HD) and dice similarity coefficient (DSC). When compared to the desktop scan (14888.40 mm3), the measured volume of the exported STL (Group S100: 15236.45 ± 114.67 mm3) and PLY (Group P100: 15231.71 ± 97.12 mm3) files from the IOS produced a similarity of 98.34% and 98.39% respectively. The similarity of the IOS files at different resolutions ranged from 99.99% to 99.96%. We conclude that the IOS used in this study demonstrates very high trueness and precision when digitally duplicating complete dentures.