Clinical Comparative Study for Validation of Digital Impression Reliability with the Gypsum Check: A Simple and Fast Way to Evaluate the Trueness and Accuracy of Implant-Supported Rehabilitation

Abstract

Despite many advantages, digital impressions, when compared to the conventional one, produce contrasting results and their complete substitution is still under debate. This comparative study aims to test a way to perform a clinical evaluation of digital impression Accuracy and Trueness with a gypsum check. After calculating the Trueness, Precision, and Accuracy of the digital impressions, a gypsum check was fabricated and screwed on implant abutments. The impression was not considered reliable if the gypsum check fractured during the insertion. The gypsum check test was correlated to a cut-off of 100 µm Trueness. Mean Trueness was 151.19 ± 37.23 µm of the first optical impression and 125.47 ± 41.90 µm of the second optical impression. The Precision mean was 39.76 ± 10.89 µm. The mean Accuracy percentage was 98.69 ± 0.29%. The gypsum checks fractured 10 times on 42 tests, and in any case, the Trueness value was above the 100 µm cut off, with a p = 0.001. A gypsum check screwed onto an implant abutment could be considered a way to perform clinical measurement of Trueness, allowing the clinician to understand if the Trueness value is higher or lower than 100 µm and reflecting the reliability of digital impressions.