Manufacturers of intraoral scanners often use the terms “true,” “precise” and “accurate” interchangeably to describe their scanners, but what role do these concepts play in digital impressions and the final restoration or appliance? In fact, according to a recent study, “Accuracy of four intraoral scanners in oral implantology: a comparative in vitro study,”1 published by the scientific journal BMC Oral Health, for an intraoral scanner to be considered accurate it needs both trueness and precision.
Trueness refers to whether a measurement matches the actual quantity being measured, while precision indicates the ability of that measurement to be consistently repeated. Therefore, for a scanner to be called accurate it must deliver consistent results, even when it is used to obtain different measurements of the same object. In this way, an intraoral scanner should detect all impression details and generate a virtual 3D model that is as close to the initial rendering as possible.
The aforementioned study evaluated the trueness and precision of four intraoral scanners by scanning two stone models—one partially edentulous and one completely edentulous, including three and six implant analogues respectively—to measure trueness and precision. It found the CS 3600 intraoral scanner was “significantly better” than the three other intraoral scanners in terms of its trueness—a fact that “may have important clinical implications.” In addition, “no statistically significant differences” in terms of precision between the four intraoral scanners were found.
In conclusion, the study determined “the use of the most accurate IOS [intraoral scanner] would seem preferable, in order to improve the quality of fit and marginal adaptation of the implant-supported prosthetic restorations.” Furthermore, because the “CS 3600 gave the best trueness results,” it recommends its use in “similar clinical settings.” Ultimately, the study reinforces the importance of choosing an intraoral scanner that features a high degree of trueness to ensure detailed scans, as well as a high rate of precision to ensure consistency. Using an intraoral scanner with high accuracy ensures better fitting restorations and/or appliances.
More findings from the study can be read here.
1Imburgia M, Logozzo S, Hauschild U, Veronesi G, Mangano G, Mangano FG. June 2, 2017. Accuracy of Four Intraoral Scanners in Oral Implantology: A Comparative In-Vitro Study. BMC Oral Health. 17(92): DOI 10.1186/s12903-017-0383-4