The Virtual Facebow Does Not Magically Behave
A clinical digital workflow study found that increasing occlusal vertical dimension changed the spatial position of occlusal contacts, while virtual facebow...
Dentistry has achieved a curious modern condition in which the word "virtual" can make a workflow sound more precise before anyone has checked where the contacts land. A digital facebow has a certain ceremonial glow. It feels like progress with a tablet attached. Biren and colleagues' Evaluation of relative deviations in virtual articulators for simulating occlusal contacts at increased vertical dimensions is therefore a useful interruption.
The study's uncomfortable little message is that counting occlusal contacts is not the same as knowing where those contacts have gone. The number may look reassuring while the geography has moved house with no forwarding address.
The Data Anchor
The researchers recruited 21 participants; 18 completed the study. Each received eight occlusal splint (OS) designs that varied by occlusal vertical dimension (OVD) increase, either 2 mm or 5 mm, by method, either intraoral or articulator-based, and by whether a virtual facebow was used.
Digital impressions, maximum intercuspal position (MIP) records, facial scans, scannable bite records, and three-dimensional superimposition were used to compare relative deviations in the X, Y, and Z directions. Group D, a 2 mm intraoral OVD increase without virtual facebow, was the reference. There were no significant differences in the number of occlusal contacts in centric relation (CR) or MIP among groups. But spatial deviation did change. X-direction differences were not significant, while Y-direction and Z-direction deviations differed in selected groups; the largest Z-direction shifts appeared in the 5 mm intraoral groups, with large effect sizes for Groups G and H.
Key Findings
Contact count was the reassuring decoy. The number of occlusal contacts did not differ significantly across groups, even when their positions shifted.
Bigger vertical changes moved contacts more. Z-direction deviations were more clinically relevant with 5 mm intraoral increases than with smaller or articulator-based changes.
The virtual facebow did not rescue the workflow. Within this study, virtual facebow use did not substantially reduce contact deviation.
The caveat matters. These were young dentate participants using splints and static digital records; the study did not test a completed full-mouth rehabilitation under function.
A contact mark is a dot. Occlusion is a relationship. The software may count the former while politely declining to understand the latter.
💡 The Clinical Bottom Line
For digital occlusal vertical dimension work, the gold standard remains clinical verification, not faith in the virtual articulator. The useful check asks where the contacts are after the vertical change, rather than merely how many dots the software can count.
This paper nudges digital dentistry back toward humility. The virtual facebow can help organise the room; it does not absolve the clinician from checking the furniture.
Dr Samuel Rosehill is a general dentist with a prosthodontic focus, practising at Ethical Dental in Coffs Harbour, NSW. He holds a BDSc (Hons) from the University of Queensland, an MBA, an MMktg, and an MClinDent in Fixed & Removable Prosthodontics (Distinction) from King's College London.
Reference: Biren et al. Evaluation of relative deviations in virtual articulators for simulating occlusal contacts at increased vertical dimensions. The Journal of Advanced Prosthodontics, 2025. DOI: 10.4047/jap.2025.17.6.339
This article was originally published on samrosehill.com.