Accuracy of Mobile Device–Compatible 3D Scanners for Facial Digitization: Systematic Review and Meta-Analysis

Abstract

Background The accurate assessment and acquisition of facial anatomical information significantly contributes to enhancing the reliability of treatments in dental and medical fields, and has applications in fields such as craniomaxillofacial surgery, orthodontics, prosthodontics, orthopedics, and forensic medicine. Mobile device–compatible 3D facial scanners have been reported to be an effective tool for clinical use, but the accuracy of digital facial impressions obtained with the scanners has not been explored. Objective We aimed to review comparisons of the accuracy of mobile device–compatible face scanners for facial digitization with that of systems for professional 3D facial scanning. Methods Individual search strategies were employed in PubMed (MEDLINE), Scopus, Science Direct, and Cochrane Library databases to search for articles published up to May 27, 2020. Peer-reviewed journal articles evaluating the accuracy of 3D facial models generated by mobile device–compatible face scanners were included. Cohen d effect size estimates and confidence intervals of standardized mean difference (SMD) data sets were used for meta-analysis. Results By automatic database searching, 3942 articles were identified, of which 11 articles were considered eligible for narrative review, with 6 studies included in the meta-analysis. Overall, the accuracy of face models obtained using mobile device–compatible face scanners was significantly lower than that of face models obtained using professional 3D facial scanners (SMD 3.96 mm, 95% CI 2.81-5.10 mm; z=6.78; P<.001). The difference between face scanning when performed on inanimate facial models was significantly higher (SMD 10.53 mm, 95% CI 6.29-14.77 mm) than that when performed on living participants (SMD 2.58 mm, 95% CI 1.70-3.47 mm, P<.001, df=12.94). Conclusions Overall, mobile device–compatible face scanners did not perform as well as professional scanning systems in 3D facial acquisition, but the deviations were within the clinically acceptable range of <1.5 mm. Significant differences between results when 3D facial scans were performed on inanimate facial objects and when performed on the faces of living participants were found; thus, caution should be exercised when interpreting results from studies conducted on inanimate objects.

Accuracy of Portable Face-Scanning Devices for Obtaining Three-Dimensional Face Models: A Systematic Review and Meta-Analysis

“…Separately, automatic landmark localization obtained by curvature analysis was introduced to eliminate the subjective errors made by the manual landmark marking process [ 37 ]. For facial volume analysis and surface-to-surface distance, the accuracy in different facial regions was found to be inconsistent for 3D facial models, particularly for the face with deformities [ 1 , 12 , 18 , 52 , 53 ]. A smaller discrepancy was found in the frontal parts of the face, whereas a greater discrepancy was found in the lateral parts of the face, sides of the nose, and around the facial deformities [ 12 , 18 ].…”

The Effect of Perioral Scan and Artificial Skin Markers on the Accuracy of Virtual Dentofacial Integration: Stereophotogrammetry Versus Smartphone Three-Dimensional Face-Scanning

“…Thus, when only the teeth area was used for image matching between the face scan and intraoral scan images, the matching could be prone to error because of the image deformations of the 3D facial model at the mouth region owing to the difficulties in capturing the complex structures of the teeth and the gingiva [ 12 ]. In the smartphone 3D depth camera face scan, the teeth scan quality could be inferior to that of the stereophotogrammetry because of the high sensitivity to the depth of the smartphone face scan [ 31 ]. The smartphone-base facial models are reconstructed by compiling the 3D facial images to create a depth map of the object and the surroundings [ 32 ].…”

Age- and Sex-Related Changes in Labial Dimensions of Sudanese Youngs of Arab Descent: A Three-Dimensional Cross-Sectional Study

“…From a technical point of view, a hand-held laser scanner was used for data collection: facial scanning needs approximately 20–30 sec and motion artifacts may be possible [ 26 ]. Indeed, this is a limitation common to most of the hand-held instruments, especially when a laser beam is used [ 28 ]. Nonetheless, the instrument and the data collection protocol have been reported to be clinically acceptable [ 32 , 43 , 49 , 50 ].…”

“…Currently, investigations may be performed using two-dimensional photographs, but methods to solve scale and calibration issues are required, as well as rigorous standardization of photographic procedure [ 23 ]. Optical image analysis systems working in three-dimensional (3D) space allow us to overcome that limitation; among them, stereophotogrammetry, laser scanning and structured light cameras are probably the most used worldwide, coupling minimal or null patient discomfort with a fast data collection [ 2 , 8 , 10 , 11 , 12 , 18 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 ]. In addition, intraoral dental scanners have been recently successfully proposed for the digitization of the superficial soft tissues of the nasolabial area [ 4 ].…”