Influence of extraoral scan body design on the accuracy of 3-dimensional patient representation across professional and smartphone-based facial scanning technologies: A clinical study.

STATEMENT OF PROBLEM Facial scans combined with intraoral scans using extraoral scan bodies as an aid to facilitate their digital integration enable the representation of 3-dimensional virtual patient models supporting virtual dentofacial analysis. However, the impact of extraoral scan body design on virtual patient representation compared with the conventional tooth-based approach remains unclear.

Purpose

The purpose of this observational clinical study was to evaluate the influence of extraoral scan body design on the accuracy (trueness and precision) of virtual patient representations by using professional and smartphone-based facial scanning technologies. MATERIAL AND

Methods

Ten participants were scanned using 1 professional (MetiSmile) and 3 smartphone-based (EM3D, Heges, Qlone) facial scanners. For each scanner, 6 subgroups were created: 1 tooth-based and 5 extraoral scan body-based groups, each using a different extraoral scan body design (single sphere, single cube, 3-sphere, 3-cube, and rectangular). Scanning was repeated 12 times for each combination of scanner and digital integration technique. Prior to facial scanning, 4 fiducial landmarks were placed on each participant's face. Each facial model was superimposed onto the corresponding intraoral scan to generate a virtual patient representation. Twenty linear distances between the predefined facial landmarks and tooth-based reference points were measured manually with digital calipers to serve as control data, and the same distances were measured digitally using a metrology software program. Statistical analysis was conducted using 2-way ANOVA for pairwise comparisons (α=.05).

Results

Tooth-based digital integration resulted in virtual patient representation with increased trueness compared with that of the extraoral scan body workflow for both the professional and the EM3D smartphone-based facial scanner, regardless of the extraoral scan body design. The ESB design significantly affected the trueness of virtual patient representation across all evaluated face scanners (P<.05). Metismile resulted in significantly better trueness of virtual patient representation compared with all other evaluated face scanners (P<.05). For the Qlone and Heges smartphone-based software programs, extraoral scan body-based integration led to increased trueness compared with that of tooth-based integration (P<.05).

Conclusions

To maximize the accuracy of virtual patient representations, clinicians should consider the impact of the digital integration technique, including the design of extraoral scan bodies in conjunction with facial scanning technology.