Accuracy of virtual mounting at centric relation using personalized 3D-printed transfer key: a clinical in vivo study

Abstract

Aim: Previously, we developed a 3D-printed customized transfer key for virtual mounting of the face and maxillomandibular relationship at centric occlusion. The accuracy was evaluated in vitro using a phantom head model with simulated soft tissue. In the present study, we aimed to investigate the effect of the transfer key in humans with clinical situations.

Methods: In the cross-sectional study, twenty volunteers with class I Angle occlusion were clinically registered for centric relation using a personal 3D-printed transfer key. The facial and intraoral (IOS) scans were recorded and integrated to build a virtual model patient via the transfer key. Large-view CBCT images were obtained and then segmented for 3D reconstruction as a reference. The deviation between the virtual model and the reference was evaluated using 3D superimposition, with min, max, mean, and root mean square (RMS) deviations calculated. We also calculated the difference between the virtual model and the reference at the upper and lower occlusal planes.

Results: Superimposition demonstrated high deviations in the total head and face areas, especially on the chin and submandible sides, with mean and RMS deviations of 0.05 and 0.88 mm for the head and 0.17 and 1.26 mm for the face only. Significant differences were found between the head and face, with high agreements in the upper and lower arches, as indicated by the mean and RMS deviations of 0.008 and 0.34 mm for the upper arches, and 0.1 and 0.61 mm for the lower arches. Upper arches were mounted accurately in all teeth, while lower arches were more rotated at the incisors. The lower arches showed a higher deviation than the upper arches, with an occlusal plane discrepancy of 0.66° for the lower and 1.6° for the upper arches, respectively.

Conclusions: The dental arches achieved the highest agreement, while deviations were noted in the facial regions. The 3D-printed customized transfer key effectively enhanced the virtual class I patient's accuracy. This novel approach offers a streamlined, patient-friendly solution for digital dental workflows.