Evaluation of the imaging accuracy of different desktop scanners, with different restorations designs

Abstract

This vitro study was designed to evaluate the accuracy of 3 desktop scanners with reference scanner regarding different designs. The accuracy of desktop scanners is described according to ISO 5725-1 as trueness and precision. The deviation of measurements between the reference scanner and the other scanners is termed "trueness", and the deviation of measurements between the same scanner termed "precision".

The aim of the study was to evaluate different scanner's accuracy by the effect of convergence angle of axial walls in single crown preparation, divergence angle in onlay preparation, and on bridge design, also a full model that have a large area and continues several arch curvature. These preparations were already done on a typodont model.

Four desktop scanners took part in our study: InEosX5, Kavo Arctica, Identica Hybrid and 3Shape D850. We subdivided our groups according to the type of the scanned object into five scans of full coverage central, five scans of onlay preparation, five scans of a bridge and five scans of a full model. For the trueness measurements, all the different designs are scanned with the reference scanner InEosX5 to get a reference STL file. With the help of 3D analysis software used to superimpose the STL files of the reference with the other scanners to calculate the amount of deviation between them. For the precision measurements, the calculation is performed in each scanner which means every scan was considered the reference file once and all the remaining scans were superimposed on it.