Photogrammetry for full-arch implants vs scan bodies
Photogrammetry for full-arch implants explained for labs: how it records implant positions, what studies report on accuracy and how the files reach the CAD.
Full-arch implant cases are where intraoral scanning is hardest. Long edentulous spans give the scanner little to stitch together, and small errors add up across the arch until a screw-retained framework no longer fits passively. Photogrammetry was developed for exactly this problem. This post explains photogrammetry for full-arch implants from the lab’s side: how it works, what the research says and how the data reaches the CAD.
Why full-arch scans drift
An intraoral scanner builds the arch from many small overlapping images. On natural teeth there are plenty of features to match, but in an edentulous arch with scan bodies the scanner relies on smooth mucosa and a few distant bodies. Each stitch adds a small error, and across a full arch those errors can sum to a misfit that the clinician feels when the framework is tried in.
Splinted scan bodies, auxiliary geometry and careful scanning strategies reduce the problem. Photogrammetry takes a different route.
How photogrammetry works
A photogrammetry system uses cameras to photograph special markers screwed onto the implants or multi-unit abutments. Because the camera sees several markers at once and calculates their positions from known geometry, it measures the relationship between implants directly instead of stitching it together. Systems differ in camera design, markers and software, and some are used outside the mouth and some intraorally.
The result is a set of implant positions. It does not include the soft tissue, the teeth of the opposing arch or the bite, which still come from an intraoral scan.
What the research says
In vitro studies have compared photogrammetry, intraoral scanning and conventional impressions for complete-arch implant cases. A study published in the Journal of Prosthetic Dentistry in 2025 compared intraoral and extraoral photogrammetry systems and found differences in trueness and precision between them, all small in absolute terms. Another in vitro study found photogrammetry systems more accurate than both conventional impressions and intraoral scanning, while noting that all methods stayed within clinically acceptable limits.
For a lab, the practical reading is that photogrammetry is a strong option for screw-retained full-arch frameworks, especially in long spans and with many implants. Results still depend on the system, the protocol and the operator, and in vitro results are not the same as clinical outcomes.
How the data reaches the CAD
The lab usually receives the implant position file from the photogrammetry software, together with intraoral scans of the soft tissue with scan bodies, the opposing arch, the bite and, in many cases, the provisional. In the CAD, the implant positions are aligned to the soft tissue scan with the library or workflow provided for that system, then the framework is designed as usual.
Before starting, check that the CAD has the library for the system and components used, that the files belong to the same patient and session, and that the provisional scan matches the planned vertical dimension. The design side of full-arch work is covered in exocad bar module and designing Toronto bridges with iBar, and fast provisionals in immediate loading rush cases.
Sources
- Journal of Prosthetic Dentistry, Accuracy of complete arch implant scans recorded by using intraoral and extraoral photogrammetry systems (2025)
- PubMed, Comparison of photogrammetric imaging, intraoral scanning and conventional impression accuracy of full-arch dental implant rehabilitation: an in vitro study
Frequently asked questions
Is photogrammetry more accurate than an intraoral scan for full-arch implants?
Several in vitro studies have found photogrammetry systems among the most accurate methods for recording complete-arch implant positions, often ahead of intraoral scanning. Differences between methods were often small, and results depend on the system, the scanner and the protocol.
Does photogrammetry replace the intraoral scanner?
No. Photogrammetry records the positions of the implants or multi-unit abutments. The soft tissue, the opposing arch, the bite and the existing provisional still come from an intraoral scan, and the lab combines both.
What does the lab receive from a photogrammetry system?
Usually a file with the implant positions and the related library data, plus the intraoral scans. The lab needs the matching library or workflow in its CAD to align the positions with the soft tissue scan.