Upper Dentures Case Study: a Hybrid Flow Remake, Lucitone 199 Base, Two Post Dams on the Cast

Quick view

1. Patient background

Woman in her mid-60s, Caucasian. Edentulous upper for just over four years. Partially dentate lower, with four natural teeth remaining on the lower anterior region and a cast-metal removable partial on the lower that she wears daily — the partial stays. We are only working on the upper.

Her existing upper denture is her second one. The first was an immediate denture made right after her upper extractions four years ago; the current one replaced it about two and a half years ago. She has been in the same clinic the whole time, so there is a continuous chart and photo record. The clinic shared her "what I don't like about this denture" list in writing, which turned the subjective part of the case into something we could design against:

• The palate feels thick when she talks. She has mild lisping on "s" sounds, worst in the first hour of the day.
• A slight gag feeling at the back of the palate. Not food-triggered. Base-triggered.
• Retention drifts across the day. She started using denture adhesive once in the morning. By 3 PM she is reapplying.
• She likes the shade and the tooth setup of the existing denture — "don't change the look."

The lower partial is stable. Occlusion is maintained against the four natural lower anteriors and the partial. No implants on either arch. No bisphosphonate history, no uncontrolled systemic disease flagged by the clinic. The clinical scope here is a one-arch remake, upper only.

What this case is not: it is not an immediate case, not an implant overdenture, not a palateless design. The clinic ruled those out before the order ever reached us. Those are clinical calls, not lab calls, and we respect that boundary (see Section 9).

2. What the clinic prescribed

The written order came through our case-coordination team on day 0. One page, specific enough that every line could be checked on the finished appliance. For the geometry behind an order like this we work from a 2022 Dental Update technique note on the post dam, by Xavier and Beddis — it sets out, in order, how extension, fit and border seal feed into retention, and where the post dam sits in that chain. It is also the source for the depth figures used in Section 3.

2.1 Geometry

2.2 Material and setup

• Base: Lucitone 199, heat-cure. Our premium import base category, chosen by the clinic for a case where thin cross-sections and dimensional stability matter at the same time.
• Teeth: VITA MFT, shade A2. Setup to copy the existing denture's tooth position and length — the patient explicitly asked for that.
• Occlusion: Balanced occlusion against the lower anteriors and the lower partial. Articulator-verified before processing.
• Try-in: Wax try-in required. No fully digital shortcut on this case.

2.3 Items the clinic kept for itself

Our order sheet lists these as "clinician decides, lab executes":

• Palateless or full-palate design — this case: full palate.
• Implants — none for this case.
• Adhesive recommendation to the patient — clinic's call.
• Replacement timing after this denture starts to drift — the clinic uses the ACP position statement on frequency of denture replacement as its reference.

We did not touch any of those. On a remake, drawing clear lines early is how we avoid stepping into clinical territory later.

3. The technical problem

There is one real problem on this case, and it is the one that pulled in two directions.

Thin palate and good retention want opposite things. More palate thickness equals more rigidity and, in the small changes we are talking about here, slightly more base surface area contacting the mucosa, which contributes to the seal. Thinning the palate takes some of that away. For a patient who was already losing retention through the day on the old denture, we could not just thin the base and hope.

The clinic's answer, and the reason we agreed with the plan, is to pay back retention through the posterior border rather than through palate thickness. That means two things on the lab side:

1. The border has to go to the vibrating line. All the way. Not pre-shortened as a precaution.
2. The post dam has to be real — in the right anatomical position, with depth that follows the compressibility of the tissue, not a flat groove picked by the lab. The Dental Update note we cited above puts the typical depth around 1–1.5 mm over the compressible tissue either side of the midline, dropping to about 0.5 mm over the midline itself and over the hamular notches. Those are the numbers we design to.

The gag question is why Post Dam B exists. Patients who gag can refuse the border at the full anatomical extent at insertion. If the clinic has to trim back at the chair, a single post dam disappears with that trim and the seal goes with it. By marking a second dam further forward on the master cast — at the position the patient's current denture already lives in — the clinic has a known fallback with a seal that still works. The denture is built at A. B is the safety net.

4. How we built it

4.1 Day 0 intake

Clinic sent, by courier:

• Upper final impression (PVS wash in a custom tray), with a well-defined post dam area.
• A PVS bite record. We ask for PVS, not wax, on international courier cases — wax can shift in a long box.
• Facebow transfer with references.
• The old upper denture, boxed. The clinic sent it because the patient wanted the tooth position and shade copied.
• Full-face photos, intraoral photos with a shade tab, a smile photo with a reference ruler.
• The written order (Section 2).

Intake QC on day 0:

• Impression check: no voids over the post dam area, no drag across the vibrating line, borders captured.
• Bite check: contact pattern consistent across both sides of the PVS record.
• Old denture: tooth positions, midline, incisal edge length, and shade all photographed and measured. These become the "do not change" reference.
• Order cross-check: shade, tooth brand and mould, thickness ceiling, border targets, both dam positions, try-in step — all present on the written order.

Everything cleared. The case opened under its unique ID, which from this point tracks the responsible technician, the equipment, the material lot, and every QC check through to shipment.

4.2 Design (digital)

• Master cast poured from the final impression, trimmed, scanned.
• Old denture scanned separately. Its tooth setup was overlaid onto the digital model as the aesthetic reference the patient asked for.
• Both post dam positions transferred to the digital model.
• Palate planned at 1.8 mm nominal. That gives 0.2 mm of headroom so the finished base, after flasking and finishing, still clears the 2.0 mm ceiling at every one of the three measurement points.
• Midline aligned to the facial midline from the smile photo, not to the cast midline alone.
• Design file sent to the clinic for approval before any physical work started on the base. Design approval is a separate gate from try-in in our workflow — it catches tooth-position questions before wax is poured.

4.3 Wax try-in

Why keep a wax try-in on a case that already has a digital design? Because a screen preview shows how the teeth look. A wax try-in shows how the base behaves on the patient's own tissue, how the lip is supported, and whether the "s" sounds she complained about actually improve with the 1.8 mm palate. On a remake case with a geometry change at the back, we do not skip it.

Try-in built on a rigid light-cured base so the post dam area was already carved and could be judged for retention at the appointment. Shipped to the clinic. Clinic feedback came back the same week:

• Shift upper incisal edge up 0.5 mm — the previous denture had them a hair too long and the patient had always meant to say so but never had.
• Slight relief on the left bicuspid centric contact.
• Everything else approved. Phonetics improved. Lip support unchanged, which is what she wanted.

Both revisions were applied and photo-confirmed back to the clinic before processing. Our order sheet also spells out what stays open after try-in approval — shade, surface effect, light morphology, contact relationships — and what does not, so the clinic knows the limit of late changes before the base goes into the flask.

4.4 Processing (heat cure)

• Flasking with controlled packing pressure.
• Heat cure with a stepped water-bath ramp. Mixing follows the manufacturer's powder-liquid ratio exactly, packed in the dough stage.
• Slow cool to room temperature before deflasking. We do not fast-cool. Fast cooling drives bubbles, polymerization shrinkage, and base warpage — and a warped base loses the fit that was measured on the cast.
• Deflask. Trim. Polish.
• Polishing on the polished surfaces only. The intaglio surface is cleaned and deburred, nothing more. Protective material isolates the tissue-contact surface during polishing so neither the border nor the fit surface gets accidentally altered.

4.5 Final lab QC

Every reading went onto the case card that ships with the denture.

Three palate readings and four post dam readings. Not one of each. A single caliper reading in the middle of the palate would have missed drift at the posterior third — the zone the patient complained about on the old denture. Two midline readings on the post dam separately from the two lateral readings catch the places where the seal is thinnest.

5. Timeline

7–8 working days of lab time end to end, plus the courier time the wax try-in spends in transit. A fully digital case on simpler geometry runs 1–2 working days faster, because the model does not need to make the round trip. The clinic kept the wax step on this one, and we agreed — the geometry change at the back of the palate on a gagging patient is exactly the kind of case where one more physical check saves a remake later.

6. Design goals the finished denture is built to hit

Written down so there is nothing fuzzy at insertion:

• Keep the palate at or under 2.0 mm across three measured points.
• Hold retention. Not by making the palate thick, but by extending the border to the vibrating line and sealing it with a post dam shaped to tissue compressibility, not to an arbitrary groove.
• Keep a safety net. If Post Dam A proves intolerant at insertion, the clinic trims back to Post Dam B and still has a working seal.
• Preserve the tooth position and shade of the old denture. The patient explicitly asked for that, and the smile photo record proves we did it.
• Protect the lower anteriors with balanced occlusion verified on an articulator.
• Hand the clinic a QC card with every reading, so chair-side adjustment at insertion starts from measurements, not from guesses.

Design non-goals — written here because they get overclaimed in this category

• The denture does not stop ridge resorption. It is a replacement, not a biological intervention. Following tooth removal and denture placement, significant resorption of the residual ridges typically happens over the first 3 to 12 months, and usually continues at a lower level for the rest of the patient's life, per the ACP evidence-based guideline on denture care.
• It is not a fix for a gag reflex. Thickness and border position are the two contributors a lab controls. The rest sits with physiology and with time.
• It is not a permanent appliance. It is a removable prosthesis with a defined service life, and the ACP replacement statement linked in Section 2.3 is what the clinic will apply when it is time for the next one.
• Adhesive is not a fit solution. The ADA's denture care guidance is direct on this: adhesives are not a remedy for ill-fitting dentures, and at best a temporary measure while the denture is relined or replaced. This case started from a patient reaching for adhesive mid-afternoon; the goal is to make the daily adhesive routine unnecessary at insertion, not to design a denture that depends on it.

7. What the finished denture turned out like

At insertion the clinic reported:

• Both post dam positions tried on the patient. Post Dam A was tolerated on the first appointment, which is the better of the two outcomes we had planned for. Dam B was documented in the case file as still-available geometry; it did not need to be trimmed to.
• Phonetics: "s" sounds clearer than on the old denture at the first appointment. The clinic flagged a very minor adjustment on the midpalate for tongue clearance, which was handled chair-side.
• Occlusion: balanced on insertion, light centric adjustment at the chair, no laboratory recall needed.
• Shade and tooth position matched the old denture per the smile photo. The patient's own words to the clinic, forwarded to us: "it looks like my denture, just thinner."

No lab-side rework was triggered on this case. Had any of our acceptance checks failed — bubbles in the base, honeycomb, poor seat on the cast, uneven occlusion — our internal standard is to rework at the lab before shipment, not after. On removable cases we run acceptance checks at four stages: model, wax-up, tooth arrangement, and final cured base. Any defect at any stage pulls the case back to that stage, not forward.

For record, our standard lab-side free-rework scope on removable work covers appliance-does-not-seat, base warpage, poorly placed clasps that affect oral aesthetics, inaccurate occlusion, and unsatisfactory base shade. Rework priority is above normal queue; typical rework turnaround is 3–5 working days. On this case we did not need to invoke any of that, but it is written here because it is the policy the clinic was ordering under.

8. What shipped to the clinic

Everything above sits under the case ID: scans, design file, cast, measurements, material lot, and the technician and equipment logs at every stage. If a reline evaluation comes up in 18–24 months, or a repair, or a full replacement later on, those records are the starting point.

Our removable department runs about 4,000 cases a month in normal season and up to 6,500 in peak, out of a team of about 55 technicians. The case-ID system is how a single case stays consistent across that volume, and how the clinic can walk in two years from now and get a reline that matches the base this denture was built on.

9. Working with us on upper dentures

• Direct manufacturing. Nine in-house departments across the two facilities, including a removable department of around 55 technicians. Cases stay in-house end to end, from case receiving through CAD, 3D model printing, setup, flasking, polishing, QC, and dispatch.
• Registrations. FDA establishment registration and device listing, EU MDR custom-device notification, UK MHRA, ISO 13485. Scope and limits documented, shareable on request.
• Try-in is standard. For a full upper dentures case, including a remake with a geometry change, wax or digital try-in is part of the normal flow, not an add-on charge. The clinic chooses which.
• Case tracking. Every case runs under a unique ID that logs the responsible technician, equipment, material lot, and QC results through to shipment.
• First case. We take a single trial case to let both sides calibrate on handoff, QC format, and response time. Sustained relationships work best on a steady shipping cadence with a shared clinician preference profile — tooth position, contact strength, shade conventions — kept in the case system so the second case is already configured for that clinic's taste.

10. Sourcing and compliance notes

• The FDA explainer and the Class II classification for relining, repairing and rebasing resin (21 CFR 872.3760) are linked in Section 9. A complete upper denture is a custom device, made per patient on a dentist's written prescription.
• Post dam depth ranges in Section 3 and Section 10 come from the Dental Update technique note linked in Section 2.
• The resorption statement in Section 6 comes from the ACP evidence-based denture care guideline linked in that bullet.
• The replacement timing reference in Section 2.3 is the ACP position statement linked at that point.
• The adhesive statement in Section 6 comes from the ADA denture care guidance linked in that bullet.