Reliability of a face scanner in measuring the vertical dimension of occlusion.

OBJECTIVE: This study evaluated the reliability of a face scanner in measuring the vertical dimension of occlusion (VDO).

METHODS: Fully dentate volunteers (n=20; mean-age=30.0±10.7 years) were recruited. Clinical facial measurements were obtained using a digital caliper and a face scanner (Class 1 LASER, Obiscanner, Fifthingenium, Italy). The scans were imported into a mesh-processing software, and the distances were measured digitally. Measurements were obtained for each participant with the jaws positioned in maximal intercuspation (MI) and with increased vertical distances of 2, 4, and 6 mm. Vertical and horizontal measures were obtained using facial anatomical landmarks: Glabella (GL), Pronasale (PrN), Subnasale (SbN), inferior border of the right and left Alare, Labiale superius (Ls), right and left Cheilion (Ch), Soft Pogonion (SPg), right and left Tragus of the ear (Tr), for all selected vertical positions. Data analysis included intra-class correlation coefficient (ICC), pairwise comparison tests, Bland-Altman plots, and Passing-Bablok regression.

RESULTS: 120 VDO measurements (clinical=60, digital=60) were recorded by two independent evaluators. Mean differences between digital and clinical measurements ranged from 0.054±0.14mm to 0.203±0.13mm. All parameters were strongly correlated (r>0.93; p<0.001). ICC estimates revealed excellent reliability, and the measuring procedure yields the same results on repeated trials irrespective of the raters and measurement methods. Bland-Altman plots revealed a difference between digital and clinical measurements of 1.7% for the vertical measurements. Regression analysis revealed no significant proportional difference between the two methods, so both can be used interchangeably.

CONCLUSIONS: The findings of this study demonstrate that VDO can be measured accurately from face scans using 3D mesh-processing software and that even small changes in the VDO could be detected using the digital methods.

CLINICAL SIGNIFICANCE: Findings provide evidence about the reliability of a digital method for jaw relation registrations and may be applied towards incorporating this method into clinical workflows for CAD-CAM dentures.