What to Send for an RPD Design Case: Scans, Survey and Prescription

Most delays in outsourced RPD design are not design problems. They are intake problems: a scan that cannot show an undercut, a missing antagonist, a prescription that says "partial upper" and nothing else. This is the checklist we work from, and why each item matters.

The short version

• Arch to be restored — intraoral scan or digitized model, undercuts readable.
• Antagonist arch.
• Bite relation.
• Kennedy classification, or simply which teeth are missing.
• Which teeth you intend to use as abutments, if you have a preference.
• Clasp preference per abutment, or permission for us to choose and report.
• Anything already planned in the case: crowns, rest seats prepared, guide planes, attachments, telescopic copings.
• Your production route: SLM printing, milling, or PROCA printing it in titanium.

If you send those, the case usually runs without a single round trip.

The scan: what "readable undercuts" means

A framework's retention comes from engaging a measured undercut. If the scan stops above the survey line, or the gingival third is smeared or trimmed away, that undercut does not exist in the data — and no amount of design skill invents it.

Capture the abutment teeth fully, including the gingival third and the interproximal areas, and do not trim the soft tissue back on a distal extension case: the tissue that will carry the base has to be in the file. Model scans work as well as intraoral scans; the requirement is coverage, not the device.

The antagonist and the bite: not optional on removable

It is tempting to skip the opposing arch on a partial. Don't. Occlusion determines where a rest can sit without interference, whether an occlusal rest seat has clearance, and how much vertical space the framework and the teeth actually have. Without it, a designer is guessing at exactly the dimension that causes chairside adjustment.

The prescription: five lines that prevent two days of delay

A useful RPD prescription is short and specific. Something like:

Upper Kennedy Class II mod 1. Abutments 4, 6, 11. Cast circumferential on 4 and 11, RPI on 6. Palatal strap, standard relief. Rest seats already prepared on 4 and 11. Printing in titanium, we finish here.

That is enough to design without asking anything. If you don't want to specify clasps, say so — we will select and tell you what we chose, which is a decision you can review rather than a surprise you discover.

If you survey your own cases

Send the survey and we design to it. If you don't survey, we establish the path of insertion ourselves and report it with the design. What we would rather avoid is the middle case — an implied path that nobody stated — because that is where a framework gets designed to one assumption and evaluated against another.

Tell us what already happened in the mouth

Frameworks are frequently designed against work that is already done or already planned: crowns being made in parallel, rest seats prepared at the last appointment, guide planes cut, attachments selected, telescopic copings in progress. Anything the framework has to mate with changes the design.

The same applies to a redesign: if a framework came back from the mouth, tell us what happened — where it rocked, where it wouldn't seat, where the patient complained. A returned case with a description gets a different design. A returned case with no description gets the same design again.

House preferences, set once

Clasp type by default, connector dimensions, relief values, finish line placement, mesh style, export format and file naming. We record these per account and repeat them, so the tenth case looks like the first one you approved. If your preferences change, they change once, not per case.

What we send back

A framework file in a standard mesh format that opens in your workflow and is validated for printing — watertight, correct thicknesses, sane orientation — plus the decisions written down: path of insertion, undercut engaged per clasp, relief applied, connector dimensions. The step-by-step behind those decisions is in digital RPD framework design.

One thing not to send

Patient identifiers. We design from geometry and a prescription; we do not need names, dates of birth or chart numbers, and we would rather not receive them. Send the case, not the record.

Frequently asked questions

Do you need a physical model?

No. Digital files are enough for design. Physical models only enter the picture if you ask us to produce the framework and want it fitted here before shipping.

What if my scan is incomplete?

We tell you before designing, and we tell you what specifically is missing and why it matters. A framework designed on data that cannot support it is worse than a delayed case.

Can you work from a scanned stone model?

Yes. A well-scanned model is often better than a rushed intraoral scan, particularly for capturing the gingival third and tissue on extension cases.

Which file formats do you accept?

Standard mesh exports from the systems U.S. labs run — exocad and 3Shape workflows included. If your route requires a specific export convention, we set it up once for your account.

Ready to run one? Start at RPD design services for U.S. dental labs.