Millimetres, Not Metaphors: What a Digital Virtual Patient Workflow Actually Does to Your Patient's Lips
A pilot study by Guo et al. in the Journal of Prosthetic Dentistry quantifies the facial soft-tissue changes after full-arch implant-supported fixed prosthesis delivery using a digital virtual patient workflow, finding upper lip region change of 3.23 mm median RMS and a nasolabial angle reduction of 6.48 degrees.
Lip change: 3.23 mm median
Source Paper
Facial morphological changes following complete mouth rehabilitation with implant-supported fixed dental prostheses designed using digital virtual patients: A pilot study
Most of us, if we are being honest, have described perioral support to a full-arch implant patient using some variant of “the try-in looks right.” We have assessed lip fullness by eye, by reference planes, by the feel of a consultation that went well. The clinical literature on soft-tissue outcomes after complete-arch implant rehabilitation has, until recently, consisted largely of concepts, technique reports, and the occasional compelling case photograph. What it has not contained is numbers.
Facial morphological changes following complete mouth rehabilitation with implant-supported fixed dental prostheses designed using digital virtual patients: A pilot study, by Guo, Gao, Pan and Zhou from Peking University School and Hospital of Stomatology, sets out to supply them.
The Data Anchor
Eight completely edentulous patients (3 women, 5 men; mean age 50.8 years) received complete arch implant-supported fixed dental prostheses (ISFDPs). Seventy-six implants were placed using anchor pin-supported surgical templates (Straumann), and eleven ISFDPs were fabricated via a digital virtual patient (VP) workflow in exocad DentalCAD.
Facial scanning (FaceSCAN3D; 3D-Shape GmbH) was performed at three time points: initial examination (FS1), after jaw relationship recording (FS2), and after prosthesis delivery (FS3). FS1 and FS3 data were superimposed via an interactive closest point (ICP) algorithm and segmented into six perioral and buccal zones. Root mean square (RMS) deviation was recorded per region; labrale superius (Ls) linear deviation and nasolabial angle change were also measured. A Kruskal-Wallis H test assessed between-region differences (α = .05).
Overall facial RMS was a median of 2.04 mm. Upper lip change (3.23 mm, interquartile range (IQR) 2.62/3.86 mm) was significantly greater than all other regions (P = .012). Morphological divergence between VP design and delivered result was less than 2 mm across the full face; the authors cite this as evidence of VP predictive validity.
Key Findings
- The upper lip is where the story is. Median RMS 3.23 mm; significantly greater than buccal and paranasal regions (P = .012). Paranasal zones changed least.
- The lower third of the upper lip changed most (median RMS 3.40 mm, IQR 2.54/4.22 mm) versus the middle third (1.97 mm) and upper third (1.13 mm); highly significant intra-region differences (P < .001). The flange-free fixed prosthesis restores the vermilion border zone more than any other facial region.
- Labrale superius moved forward and inferiorly. Linear deviation 3.18 mm (IQR 2.53/3.60 mm); sagittal-forward and vertical components dominated; lateral deviation was minimal (0.07 mm).
- The nasolabial angle reduced by a median of 6.48 degrees (IQR 4.00/9.51 degrees). For reference, conventional complete denture wearers show reductions of approximately 18 degrees; the fixed prosthesis produces considerably less angular change, consistent with its reduced perioral bulk.
- Limitation: n = 8 is the study’s dominant constraint. Statistical power is limited, landmark measurement errors carry disproportionate weight, and findings apply only to patients without severe alveolar resorption. A larger cohort is needed.
💡 The Clinical Bottom Line
A clinician planning a maxillary ISFDP can now tell a patient that the lower third of their upper lip is likely to shift by around 3 mm following delivery. That belongs in the consent conversation.
The VP workflow also performed as a predictive tool. A sub-2 mm divergence between digital design and delivered outcome suggests the design is not merely aspirational — the face tends to go where the numbers say it will.
If fixed prostheses provide substantially less perioral support than overdentures — and these data suggest they do — the prosthesis choice is not only a biomechanical question. It is, millimetre by measurable millimetre, an aesthetic one.
The try-in has always looked right to someone. It is considerably more useful when we can also say by how much.
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.
Clinical Relevance
After complete mouth rehabilitation with a full-arch implant-supported fixed dental prosthesis (ISFDP) designed via a digital virtual patient workflow, the upper lip showed significantly greater 3D morphological change than all other facial regions (median RMS 3.23 mm). The lower third of the upper lip drove this change. The nasolabial angle reduced by a median of 6.48 degrees. Clinicians can now frame these expected changes in specific millimetre terms when gaining informed consent and planning prosthetic profiles.
Disclosure: The author has no financial conflicts of interest related to the products or topics discussed in this review. This is an independent summary prepared for educational purposes.
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