Trueness of full-arch IO scans estimated based on 3D translational and rotational deviations of single teeth-an in vitro study

Effect of substrate adjacent to the scan region on the trueness of four intraoral scanners: An in vitro study

OBJECTIVES

The purpose of this in vitro study was to evaluate the trueness of four commercially available intraoral scanners (IOSs) on scanning different substrates that existed in the adjacent proximal contact area.

METHODS

Four IOSs (TRIOS 4, TRIOS 3, Primescan, Omnicam) were used for scanning the intact enamel surface of a molar tooth, and six restorative materials (zirconia, lithium disilicate glass-ceramic, composite resin, hybrid ceramic, feldspathic ceramic, metal) that were located at the adjacent proximal contact area of the same tooth. Reference scans were obtained using an extraoral scanner (inEos X5). A 3-dimensional analyzing software (Geomagic Control X) was used to compare the reference and tested scans. The two-way analysis of variance (ANOVA) followed by Bonferroni correction was performed for statistical analyses (α=0.05).

RESULTS

TRIOS 3 and TRIOS 4 showed higher trueness than Primescan, and Primescan showed higher trueness than Omnicam (p<0.001), while there were no differences between TRIOS 3 and TRIOS 4. Metal showed significantly higher Root Mean Square values (0.273 ± 0.24 mm) than other substrates. No difference was found between the scanners' zirconia, lithium disilicate glass-ceramic, composite, and feldspathic ceramic scans (p > 0.05). For the metal, TRIOS 3 and TRIOS 4 showed higher trueness than Primescan and Omnicam, while Omnicam showed lower trueness among all scanners. For the hybrid ceramic, TRIOS 3 showed higher trueness than Omnicam (p<0.001). For the enamel, TRIOS 3 showed higher trueness than Primescan and Omnicam (p<0.001).

CONCLUSIONS

The trueness of IOSs can be affected by the substrates that exist in the proximal contact area. Amongst all, the metal substrate affected most the trueness of the IOSs.

CLINICAL SIGNIFICANCE

The clinician should decide on the impression system, taking into account that the IOS and the surfaces to be scanned affect the trueness of the digital data. The deviation of the digital impression would be high in the presence of a metal restoration on the adjacent proximal surface.

Factors Affecting Trueness of Intraoral Scans: An Update

Background: Intraoral scanning (IOS) technologies have been constantly developed and improved. This systematic review aimed at assessing studies in the recent literature describing factors that influence the trueness of intraoral scans. Methods: Comparative in vitro and in vivo (i.e., interventional and observational) studies that quantitatively assessed the trueness of intraoral scans and that identified factors significantly affecting IOS trueness values were considered eligible for inclusion. The PUBMED and EMBASE databases were searched for articles published in the last two years (from February 2020 to February 2022). Data assessment and extraction were performed according to the guidelines of the PRISMA statement. Results: The present search strategy yielded 13 publications. An initial screening of the publications was performed using abstracts and key words, and after application of exclusion criteria, a total of nine studies were finally identified as eligible to be discussed. Several factors significantly affecting IOS were identified. Conclusions: Studies using current IOS technologies revealed that the device, scanning distance, operator experience, rescanning and post-processing scans, conditions of the preparations and presence of adjacent teeth are factors significantly affecting IOS trueness.