Verification jigs.
A verification jig checks that the recorded implant positions match the actual ones, before a definitive prosthesis is made to those positions. On multi-unit work it is the difference between passive fit and permanent stress.
The problem it solves
Implants do not move. A splinted prosthesis made to positions that are slightly wrong will not seat passively, and forcing it home loads the components permanently.
The consequences are delayed and expensive: screw loosening, screw fracture, component failure, and marginal bone loss — usually appearing months later when the cause is no longer obvious.
The discrepancy that produces this is frequently too small to see on a model or a screen, which is precisely why a physical check exists.
What a jig is
A rigid structure connecting components seated on each implant, made on the working cast and then tried in the mouth. If the recorded positions are accurate, it seats passively on all implants simultaneously.
If it does not — if it rocks, if one component lifts when another is tightened, or if a gap is visible — the record is wrong and the jig can be sectioned and rejoined in the mouth in the correct relationship.
That corrected jig then becomes the accurate record from which the definitive framework is made.
The one-screw test
The standard clinical assessment is to tighten a single terminal screw and check whether the opposite end lifts. Any movement indicates the structure is not passive.
A radiograph at each connection is the supporting check, since a gap at the interface is visible radiographically and not always visible directly.
Both are quick, and together they answer a question that no amount of inspecting the cast will settle.
Alternatives
A splinted conventional impression as a cross-check against a digital record. Sectioning and rejoining the framework itself at try-in. Photogrammetric methods where available, which capture implant positions optically without the accumulated stitching error of an intraoral scan.
Which is appropriate depends on the number of implants, the span, and the consequences of a misfit. For a two-implant overdenture the answer is different from a full-arch fixed prosthesis.
What matters is that verification is planned rather than skipped on the assumption that a record which looked good is accurate.
When it is worth the stage
Any splinted full-arch prosthesis. Multi-unit bridgework spanning an edentulous region with few landmarks. Cases where the consequences of a misfit are substantial — an expensive prosthesis, a patient who cannot easily return, or implants in compromised bone.
For a single implant it is unnecessary. For two splinted implants it is usually unnecessary. The threshold sits where the prosthesis becomes rigid across a span the record may not have captured accurately.
Discuss it at the planning stage so the appointment is built into the sequence rather than added when a problem appears.
Making the appointment worthwhile
A verification try-in is a short appointment and it needs to be used properly. Seat the jig, tighten one terminal screw only, and check whether the opposite end lifts. Then repeat from the other end.
Radiograph each connection where access allows. A gap at the interface is frequently visible radiographically and not visible directly, particularly on posterior implants.
If the jig does not seat passively, section it between the affected units and rejoin it in the mouth in the correct relationship, then return it with a note describing exactly what was found and where. That note is what makes the corrected jig usable.
What to send
The implant record, component detail for every implant, and a statement that verification is planned so the case is staged for it.
After try-in, return the jig with a note on what was found — whether it seated passively, where it did not, and whether it was sectioned and rejoined. That note is what makes the corrected jig usable as a record.
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Digital scans and conventional impressions are both accepted. Cases move by UPS and Purolator, and Fairmont works with practices throughout British Columbia and across Canada.