Scan bodies.
A scan body is a precision measuring instrument that gets autoclaved, dropped and reused. The gap between how it is treated and what it does causes real clinical error.
Selecting the right one
The scan body must match the implant system, product line and platform exactly. Components that appear similar are frequently not interchangeable, and a mismatch produces a calculated position that is wrong.
The software matches the captured shape against a library file describing that specific component. Where the physical body differs from the library entry — different manufacturer, different generation, a compatible rather than original component — the match is against the wrong geometry.
The software will still produce a confident result, because it fits the closest match it can. It has no way of knowing the component differs. Record which scan body you used and tell the laboratory if it is not the original.
Seating is the first failure point
A scan body short of full seating reports an implant position that is too shallow, often rotated, and frequently by well under a millimetre — invisible on screen and clinically decisive.
Seat by hand until it stops, then confirm it cannot rock or rotate. Soft tissue offers enough resistance to feel like a positive stop when the component is still short of the connection, particularly on a deep implant or where the sulcus has tightened around a healing abutment.
Where access is limited, the implant is deep, or the fit felt uncertain, take a periapical radiograph before scanning. It takes a minute and removes the most consequential failure mode in the workflow.
They wear, and worn ones lie
Repeated autoclave cycles affect polymer components dimensionally. Handling scratches the flat reference surfaces the software matches against. A dropped component can deform at the connection without visible damage.
PEEK and other polymer bodies are convenient and light, and the most susceptible to cumulative dimensional change through sterilization. Titanium and hybrid designs are more stable but scratch, and a scratched scanning surface scatters light in ways that degrade the match.
Inspect under good light before use. Retire anything scratched, discoloured, deformed or of uncertain age. Manufacturers state reuse limits for a reason.
Capturing it properly
The scanner needs the full geometry of the body, including its flat reference surfaces and the transition to the tissue, plus enough surrounding dentition for the position to be located within the arch.
Capture the adjacent teeth completely. Where the implant sits at the end of the arch or beside an edentulous span, the available landmarks reduce and positional confidence with them.
Review before sending. Rotate the model and confirm the body has captured cleanly with no holes at the reference surfaces.
Multiple implants
Each additional implant adds its own potential seating error to the accumulated stitching error across the span, and the two are independent.
With splinted units the prosthesis is rigid and the implants are fixed in bone, so discrepancy becomes stress rather than a passive fit. That is the argument for verification on longer spans rather than trusting a scan that looked good.
Where a case involves several implants, seat and check each body individually before scanning any of them.
Conventional records remain available
Where a scan cannot be trusted — a deep implant, a tight sulcus, a long edentulous span, or a case where the record has to be certain — an impression coping and a conventional impression remain entirely viable.
Open-tray techniques, where the coping is splinted and stays in the impression, are generally regarded as more accurate for multiple implants than closed-tray approaches.
The choice exists. Persisting with a scan on a case the scanner is poorly suited to is a decision rather than an inevitability.
More in Implant Restorations
Send a case
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.