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. Continue reading
Many manufacturers tout the trueness, or accuracy, of a digital intraoral scanner in the same breath as precision. While both are important features of any scanner, the two concepts are not interchangeable. According to a recent study1 published in PLOS ONE, an online scientific journal, “an intraoral scanner should possess high trueness…but also high precision.” Let’s take a look at the difference between the terms and why both are vital for the best digital impressions.
First, trueness is a scanner’s ability to scan an object and replicate it as closely as possible to the original item—in this case, teeth, gingiva, abutments, etc. The more accurate the scanner, the more likely the digital impression on the screen will mirror the patient’s actual teeth. Precision, on the other hand, is a scanner’s ability to produce the same results consistently. If you picture a target, an accurate shot would mean the arrow hit the bullseye; or at least came incredibly close. Precise shooting would result in a grouping of several arrows close together, though not necessarily near the bullseye.