Influence of virtual facebow designs on the accuracy of face scan-based virtual facebow records

To evaluate the accuracy of static maxillary-facial spatial registration obtained using different virtual facebow (VF) fork designs and two facial scanning systems. Accuracy was assessed in terms of trueness and precision of linear deviations at three maxillary point references and angular deviation of the occlusal plane. The findings are intended to inform the selection of VF fork designs for improved accuracy of static maxillary-facial spatial registration within a digital workflow.

A cone-beam computed tomography (CBCT) scan was performed on a phantom head to reconstruct a 3D facial model. The maxillary arch was separately scanned with the addition of 3 reference points: the left central incisor (#9), left first molar (#14), and right first molar (#3). This scan was aligned with the 3D facial model to create a control. Four distinct VF designs were fabricated using a 3D printer (Form 3+ 3D printer; Formlabs, Somerville, MA) with model resin (Model Resin V2; Formlabs) and sequentially attached to the phantom with blue bite material. Two scanning systems-an iPad-based scanner (IP) and an industrial-grade EinScan scanner (HX)-were used to obtain 3D scans of the phantom with each VF design. Each design was scanned 10 times per device, yielding 80 records. These were superimposed onto the baseline through superimpositions of common facial landmarks. The trueness and precision of linear deviations at the three reference points and the angular deviation of the occlusal plane were analyzed.

Overall, VF 1 demonstrated the highest average accuracy across all measured parameters, except for angular precision, whereas VF 2 exhibited the lowest accuracy among the four treatment groups evaluated.

VF 1 demonstrated the highest accuracy when used in conjunction with the IP scanner, whereas VF 4 provided the most accurate results when paired with the HX scanner.