Analysis of the impact of the facial scanning method on the precision of a virtual facebow record technique: An in vivo study

Abstract

Statement of problem. Virtual facebow record techniques typically record the relationship of a maxillary digital scan to facial landmarks by aligning it to a 3-dimensional face scan. Three-dimensional face scans can be acquired with different facial scanning methods, but the impact of the facial scanning method on the accuracy (trueness and precision) of a virtual facebow record technique remains unclear.Purpose. The purpose of this in vivo study was to assess the impact of the facial scanning method on the precision under the repeatability conditions (repeatability) of a virtual facebow record technique.Material and methods. Repeatability of the virtual facebow record technique with the following 3 clinical-grade facial scanning methods was determined and compared: a professional handheld scanner based on structured blue light scanning technology (PHS method); an attachment-type 3-dimensional sensor camera connected to a tablet and controlled with a mobile application (3DSC-T method); and a smartphone with an integrated 3-dimensional sensor camera controlled with a mobile application (3DSC-S method). To determine the repeatability of the virtual facebow record technique with each facial scanning method, 8 virtual facebow records of a completely dentate adult with class I occlusion and mesoprosopic facial form were obtained (8×3=24 in total); with these, 8 locations of a maxillary digital scan with respect to a common 3-dimensional face scan were obtained. Repeatability was determined in terms of deviations between located maxillary digital scans, determined, in turn, by calculating the distances between corresponding vertices for each of the possible nonrepeating combinations of pairs of located maxillary digital scans ( 8 C 2 =28). Finally, the repeatability of the virtual facebow record technique with the different facial scanning methods was compared by using the Welch ANOVA test and the post hoc Games-Howell test (both a=.05).Results. The repeatability of the virtual facebow record technique with PHS, 3DSC-T, and 3DSC-S facial scanning methods resulted in 0.243 ±0.094 mm, 0.437 ±0.171 mm, and 1.023 ±0.399 mm, respectively. Comparison of these results revealed that the facial scanning method had a statistically significant effect on the repeatability of the virtual facebow record technique (P<.001) and that its repeatability was statistically significantly greater with the PHS facial scanning method than with the 3DSC-T and 3DSC-S facial scanning methods and greater with the 3DSC-T facial scanning method than with the 3DSC-S facial scanning method (P<.001 for all pairwise comparisons).Conclusions. This study found that the facial scanning method had a great impact on the repeatability of the virtual facebow record technique and that the virtual facebow record technique was more repeatable with more accurate facial scanning methods.

Facial scanning technologies in the era of digital workflow: A systematic review and network meta-analysis

“…It has already been noted how facial scans with intraoral and extraoral matching tools can operate as digital facebow [60]. It was also seen that scanning technology had a huge influence on the repeatability of scans, with a mean variability of 0.2 mm for SL and 0.4 to 1.02 mm for ISL [61].…”

Superimposing Intraoral and Facial Digital Scan: A Novel Technique for Accurate Spatial Alignment of Dental Arches

“…Facial scanning, in comparison to the 2D photography, offers greater accuracy [14], and by incorporating 3D restorations design onto the 3D facial file, it is possible to assess the shapes of the teeth on the x-y-z axis and evaluate their aesthetic outcome before testing it on the patient with interim restorations or resin mock-up. Both facial scanning and its superimposition with intraoral scanning must be accurate to perform these assessments [15]. Conversely to a smartphone-specific application that uses a 3D sensor camera [10,12,16] or industrial scanners adapted for medical use [17,18] the advantage of using a static face scanner (Rayface 100,200; Ray Co., Ltd) is that the patient remains still and in 0,5 seconds the scanner scans patient's face, reducing the risk of inaccurate scans due to movements by the patient, scanner or operator [19,20].…”

Creating three-dimensional virtual patients by superimposing intraoral and facial digital scans guided with an aligner system: A dental technique

“…Although most aligner systems can be used to superimpose intraoral digital scans with facial digital scans acquired with any FSM, the accuracy of a 3DVP is greatly influenced by which FSM is used, being more accurate when using more accurate FSMs. 12,13 Most accurate FSMs, such as stationary facial scanners or professional handheld scanners, however, may be unsuitable for many dental clinics, principally because of their high cost. 14,15 Therefore, alternative FSMs have been proposed, with mobile device-compatible 3D sensor cameras attracting the most interest, principally because of their low cost and ease of use.…”