J Adv Prosthodont.  2016 Oct;8(5):354-362. 10.4047/jap.2016.8.5.354.

Comparative analysis on reproducibility among 5 intraoral scanners: sectional analysis according to restoration type and preparation outline form

• Park JM

• KMID: 2355439
• DOI: http://doi.org/10.4047/jap.2016.8.5.354

Abstract

PURPOSE
The trueness and precision of acquired images of intraoral digital scanners could be influenced by restoration type, preparation outline form, scanning technology and the application of power. The aim of this study is to perform the comparative evaluation of the 3-dimensional reproducibility of intraoral scanners (IOSs).
MATERIALS AND METHODS
The phantom containing five prepared teeth was scanned by the reference scanner (Dental Wings) and 5 test IOSs (E4D dentist, Fastscan, iTero, Trios and Zfx Intrascan). The acquired images of the scanner groups were compared with the image from the reference scanner (trueness) and within each scanner groups (precision). Statistical analysis was performed using independent two-samples t-test and analysis of variance (α=.05).
RESULTS
The average deviations of trueness and precision of Fastscan, iTero and Trios were significantly lower than the other scanners. According to the restoration type, significantly higher trueness was observed in crown and inlay than in bridge. However, no significant difference was observed among four sites of preparation outline form. If compared by the characteristics of IOS, high trueness was observed in the group adopting the active triangulation and using powder. However, there was no significant difference between the still image acquisition and video acquisition groups.
CONCLUSION
Except for two intraoral scanners, Fastscan, iTero and Trios displayed comparable levels of trueness and precision values in tested phantom model. Difference in trueness was observed depending on the restoration type, the preparation outline form and characteristics of IOS, which should be taken into consideration when the intraoral scanning data are utilized.

Keyword

Intraoral scanner; Digital impression; Reproducibility of intraoral scanner; Trueness; Precision

MeSH Terms

Crowns
Dentists
Humans
Inlays
Jupiter
Tooth

Figure

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  Fig. 1 Dental models with various preparation designs. Right maxillary incisor and canine (#11, 13); 3-unit fixed dental prosthesis, right maxillary second molar (#17); MO inlay, and right mandibular second molar (#47); crown.

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  Fig. 2 Illustration of the sectioning of the superposed datasets and selected sites from preparation ouline form. (A) section lines of crown and bridge groups (sections 1, 3, 5, and 7 were investigated for the mesiodistal and buccolingual comparison). (B) measured sites for crown and bridge groups. (C) section line of inlay group (sections a and b were inspected for the box and non-box comparision). (D) sites from preparation outline form for inlay group.

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  Fig. 3 Number of polygons for selected maxillary incisor for the comparison of the each IOS's resolution.

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  Fig. 4 Illustration of absolute mean trueness and precision values of intraoral scanners. Same letters denote significant differences in between the groups at the 5% significance level.

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