Effect of Different Preparation Designs on the Trueness and Precision of Intraoral Digital Scanners

Abstract

his in-vitro study was designed to evaluate the accuracy of 2 intraoral scanners regarding different designs of preparation. Hence the accuracy of intraoral scanners are described according to ISO 12836 as trueness and precision. the deviation of measurements between the reference model and the intraoral scan model is termed the ‘trueness’ of impression technique, and the deviation of measurements between digital models of the same intraoral scanner is ‘precision ‘ of impression technique. The aim of the study was to evaluate the effect of different convergence angle of axial walls in single crown preparation and the different divergence angle in inlay preparation on the accuracy of both scanners, also the effect of arch contour on the accuracy of the scanners by comparing the results of anterior and posterior bridge and the effect of the complexity of the scan on the accuracy by comparing the results of single cown preparation with the posterior bridge. The preparation were done on a typodont acrylic model (Nissen, Kyoto, Japan), with the aid of computer numerical control machine (CNC machine).