Impact of scanning errors on the trueness of digital implant impressions

In dentistry, digital technologies have become firmly established in the field of oral implantology. The trueness of impressions taken using intraoral scanners as part of the digital workflow has a direct influence on the accuracy of fit of the subsequent restoration. Therefore, this in-vitro study investigates the influence of possible scanning errors on the trueness of digital implant impressions.

A standardized titanium model of a maxillary alveolar ridge with three bone-level implants was digitized with two different scan body systems (Medentika and NT-Training) using an industrial high-precision scanner to generate the virtual reference models. Subsequently, three different modifications, including two different gingival heights and artificially created defects, were each digitized 15 times using two different intraoral scanners (Primescan and Trios 4) with both scan body systems. The digitized scan bodies were then matched with the scan body analogs in the Exocad software to generate the virtual working models. Trueness was examined by superimposing the virtual working models with the corresponding virtual reference model.

All scanning errors evaluated resulted in significantly higher deviations. Across all groups, the trueness decreased with increasing gingival height. The best results (30 ± 15 μm) were attained when scanning at the lower gingival height. The largest discrepancy (178 ± 63 μm) was found when impressions of the higher gingival height were taken.

In the process of taking digital implant impressions, it is essential to maximize the exposure of the scan bodies. Furthermore, it is imperative to minimize defects in order to achieve optimal outcomes.