In order to deliver the most high-quality prosthetic solutions, trueness, precision, and accuracy are essential. Advanced digital solutions are now becoming available in the dental setting. As such, it’s important that we consider the meaning of accuracy when it comes to dentistry, how accurate prostheses can be achieved in the lab, and the potential barriers and benefits of a digital approach.
Trueness, precision, and accuracy
Although there is a range of acceptable error when it comes to dental restorations known as ‘biological tolerance’, clinicians and dental technicians should aim to achieve the most accurate prosthesis possible. This is true across all types of restorative treatment, in particular implant-supported prostheses as they require higher levels of accuracy.[i]
As such, it’s important to understand what is meant when we discuss trueness, precision, and accuracy. Trueness represents how close a measurement is to the true or accepted reference value. This would mean that a dental scanner with high trueness delivers results that are very close to the actual dimensions of the scanned object. As such, trueness is a reflection of how correct a scan is compared to the actual dimensions. Precision on the other hand describes how repeatable or reproduceable measurements are. Therefore a dental scanner with high precision will provide consistently similar scans when scanning is repeated. Accuracy is the combination of both trueness and precision. Therefore, a high-quality scanner is accurate and repeatable, and should be seen as a measure of how good the scan is overall.[ii]
Use of accurate 3D object scanners
A coordinate measuring machine (CMM) has traditionally been used as a benchmark for accuracy in measuring the geometry of a solid object. As such, CMMs have been used in studies which evaluate the accuracy of digital impressions.[iii] However, CMMs lack scan speed and have their limitations when compared to industrial 3D scanners, in addition to their inability to detect small features such as fissure lines and gingival margins.
Industrial 3D scanners are able to produce scans which are sufficiently accurate in a dental setting. They are smaller, more affordable, and can capture complex surface features – able to display deviations within a few micrometres.[iv] Dental laboratory scanners are used to scan cast models produced by conventional dental impressions in order to export the scan into CAD software for a digital design workflow. The accuracy of industrial scanners and dental laboratory scanners is comparable, ranging from 1 to 10 μm and 2 to 10 μm, respectively.
Impact of introducing digital tech in the lab
Digital dentistry provides dental labs with a wide range of benefits when it comes to quality, time savings, and increased productivity. Digital solutions are becoming more commonplace, resulting in innovative workflows, more consistent outcomes, and high-quality solutions. Whilst new equipment will inevitably require an initial investment, digital solutions are thought to improve quality by 40%, reducing the need to re-work, and saving time, resulting in increased capacity by up to 50%.
When selecting digital equipment to incorporate into their workflows, dental labs should consider the limitations and potential barriers for some team members. These might include the initial cost of purchasing the equipment, the learning curve associated with using some new tools (which may require additional training and time), as well as concerns around data security and privacy. Dental professionals must also consider the areas in which conventional processes remain more appropriate than digital technologies, and the ways in which they can be used alongside each other.
The new digital scanning solution from Mimetrik, Cubit360, enables dental labs to achieve highly accurate scans in no time and without the learning curve. Cubit360 breaks down the barriers usually associated with incorporating new technology into your workflow. It’s intuitive, space saving, and doesn’t require clamping of the scan object, allowing the user to simply hold the object and scan instantly. Continuous, real-time scanning with no mechanical delays allow for the fastest scanning on the market and, as the world’s only six degrees of freedom scanner, it gives dental technicians full 360 degree scanning with no gaps for accurate, high-quality scans.
When it comes to levelling up workflows in the dental lab, digital solutions offer a range of fantastic benefits. However, when considering which individual piece of equipment to invest in, it’s important to choose solutions with limited barrier to entry and which will enable your lab to boost productivity and produce excellent outcomes.
Author: Alyn Morgan
[i] Sanda M, Miyoshi K, Baba K. Trueness and precision of digital implant impressions by intraoral scanners: a literature review. Int J Implant Dent. 2021 Jul 27;7(1):97. doi: 10.1186/s40729-021-00352-9. PMID: 34312701; PMCID: PMC8313656.
[ii] Mehl, A., Reich, S., Beuer, F. and Güth, J.F., 2021. Accuracy, trueness, and precision-a guideline for the evaluation of these basic values in digital dentistry. International Journal of Computerized Dentistry, 24(4).
[iii] Revilla-León, M., Att, W., Özcan, M. and Rubenstein, J., 2021. Comparison of conventional, photogrammetry, and intraoral scanning accuracy of complete-arch implant impression procedures evaluated with a coordinate measuring machine. The Journal of prosthetic dentistry, 125(3), pp.470-478.
[iv] Sanda M, Miyoshi K, Baba K. Trueness and precision of digital implant impressions by intraoral scanners: a literature review. Int J Implant Dent. 2021 Jul 27;7(1):97. doi: 10.1186/s40729-021-00352-9. PMID: 34312701; PMCID: PMC8313656.