The clinic was clear that the goal of the case was a straight replacement of both arches. No change in vertical dimension of occlusion. No change in tooth shade. No change in tooth arrangement unless we flagged a specific problem.
A few extra notes from the prescription that we had to design around:
- The patient's gag reflex was noted as mild but real. The posterior palatal area on the maxillary base had to stop short of the vibrating line, not run past it.
- The lower ridge had resorbed since the previous build. The muscle attachments sat closer to the crest than they used to.
- The patient was a known light bruxer at night. The dentist did not prescribe a night guard but asked us to pick posterior teeth that would not chew through within a year.
What the clinician asked for
The dentist's prescription came with five specific asks. Each one changed something we had to do on the bench.
1. Keep the old vertical dimension of occlusion. The patient had adapted to the current VDO over years. The dentist did not want us to raise it, lower it, or "ideal-ize" it. Our job was to measure it from the old set, confirm it on the wax rim bite record, and build to it. VDO is a clinical determination, not a laboratory decision, and the ACP Parameters of Care are explicit about that.
2. Copy the tooth arrangement that already worked. Midline, incisal edge position, lip support, and the arch form had to come from the old upper denture. Only the posterior cusp anatomy needed to be rebuilt, because the old posteriors were worn flat and were giving the patient nothing to grind with.
3. Match the shade on the day of the scan. The clinic sent a shade photo in daylight next to a VITA shade tab. We used the photo, not a verbal shade note, as the primary reference.
4. Make the lower arch tighter than the old one. The old lower had been getting looser between relines. The dentist asked us to improve retention within the available ridge, without extending the border beyond what the clinician had captured in the border molding.
5. Keep the posterior palatal seal (PPS) light and placed where the dentist marked it. The intake notes carried a hand-drawn line on the maxillary cast photo showing where the PPS should sit. The dentist did not want it any deeper than drawn. The literature backs this up — a well-placed PPS is one of the main contributors to maxillary retention, and the design and depth are a clinical call rather than a technical preference. See this literature review on posterior palatal seal design and this in-vivo comparison of PPS types and retention.
The constraint — why this case was not just "make a new set"
The constraint that shaped this build was simple to say and hard to do: the only valid reference for the new upper and lower dentures was the old upper and lower dentures the patient had already adapted to. And the old set was partly unreliable. The lower base had a repair line through it, which meant the lower base was no longer a stable reference for vertical height or arch form. The upper was still stable, but its posterior anatomy was flat.
A worn and partly repaired set can still be useful as a reference if you know which parts of it you are allowed to copy and which parts you have to replace. We treat that choice as a decision matrix, not a judgement call.
What the old set gave us | What we kept | What we rebuilt |
|---|---|---|
Maxillary tooth position, midline, lip support | Kept — the patient had adapted to it | — |
Maxillary posterior cusp anatomy | — | Rebuilt — the old teeth were worn flat |
Maxillary base intaglio | Scanned, not poured — kept the shape, used it to confirm the dentist's border capture | — |
Mandibular tooth position | Kept the midline and anterior position | Posterior position re-evaluated against the shrunken ridge |
Mandibular base | — | Rebuilt — the repair line meant the old base was no longer a stable reference |
Occlusal vertical dimension | Kept — read from the old set and confirmed on the wax rim | — |
Occlusal plane | Kept — face-bow transfer confirmed it | — |
The one line in that table that matters most is "scanned, not poured." If an old denture base has flex or a repair line in it, pouring a stone cast from it reproduces whatever distortion is in the base, and every occlusal decision after that inherits the distortion. We scan it instead, use the shape as reference only, and leave the dimensional measurements to the fresh impression and the wax rim.
How we met those requirements
Step 1 — Checking the records before any design work
Every denture case we take in goes through a records check on arrival. For this one we looked at four things:
- The impressions. Both arches had a complete peripheral roll, no voids over the ridge crest, no pulled borders. The lower had been border-molded in function, which matched the dentist's note about preserving the muscle attachments.
- The wax rim bite record. The record was stable — meaning when the two rims were seated together twice in a row, they met in the same place. An unstable bite record is returned for a re-take, not averaged. On this case the record was stable, so it went through.
- The scans of the old dentures. We scanned both the upper and the lower rather than pouring them, for the reason above. The lower scan was for shape reference only, not for measurement.
- The face-bow transfer. The clinician sent one, which let us mount the case on a semi-adjustable articulator at the same occlusal plane the patient had been using. For a full upper and lower dentures rebuild where the existing VDO has to be preserved, a face-bow transfer carries real weight.
Step 2 — Design and setup
Our denture team runs a hybrid workflow — digital design and setup where that is faster and more consistent, physical processing where that still beats the digital route. For this case the setup was done digitally so the dentist could see a 3D proof before any wax was carved.
What our designer worked on:
- Maxillary tooth position was duplicated from the scan of the old upper. The midline sat on the mid-palatal raphe, confirmed against the clinical photos.
- Mandibular tooth position had to be re-thought. The ridge had resorbed since the last build, which meant the old lower tooth position was now sitting labial to the crest. If we had copied it exactly, the patient's tongue would have been fighting the teeth. We moved the lower posteriors onto the ridge crest, keeping the arch form that the patient was used to.
- Posterior palatal seal. We transferred the dentist's hand-drawn PPS line onto the digital design — the depth and shape stayed exactly as marked. No deeper, no wider.
- Base thickness. Minimum 2 mm over the ridge, verified at the thinnest point. Thin bases on acrylic dentures tend to flex, and flex ends in a repair line like the one we were replacing.
- Occlusal scheme. The dentist had not asked for a specific scheme (lingualised, bilateral balanced, or monoplane), so we built to a balanced occlusion that matched the old set's contact pattern. The research on this is clear — there is no single occlusal scheme that outperforms the others across the board, so we match what the patient has already adapted to. See the systematic review of occlusal schemes and the systematic review on occlusal designs and masticatory ability.
Step 3 — Material picks and why
Component | Material | Why we picked it |
|---|---|---|
Denture base | Lucitone 199 heat-cure acrylic | A high-impact base acrylic in the range that meets ISO 20795-1:2013 for denture base polymers. Chosen because the old lower had failed at a stress point and the patient's bruxing history argued for the tougher option. |
Posterior teeth | VITA acrylic teeth | Cross-linked acrylic teeth specified under ISO 22112:2017. We matched acrylic to acrylic so the two arches wear at a similar rate. Wear rates for modern denture teeth sit in a wide range depending on material and antagonist — see this systematic review on denture tooth wear — so pairing matters more than picking the hardest option. |
Anterior teeth | VITA acrylic teeth, shade matched to the day-of-scan photo | Pulled from the daylight photo rather than a verbal shade note, because photos capture value and translucency the way a shade tab chip does not. |
A quick note on something we did not do: we did not switch the patient to a milled or printed base, even though those routes are faster. Milled bases are strong and dimensionally very stable, but their intaglio surface detail is not as fine as a well-run heat-cured base, and this patient's lower ridge needed every bit of intaglio detail we could give it. Printed resin bases are improving quickly, but a 2025 systematic review and meta-analysis comparing milled vs printed denture bases is a useful read on where each sits today. For this case the call was heat-cured. The lab makes the material pick with the dentist's scope in mind, not against it.
Step 4 — Our build process, from wax try-in to finished pair
With the design signed off, the case moved into the bench. We split the build in two — a wax try-in sent to the clinic first, then processing and finishing once the dentist approved what the patient had seen.
The wax try-in. Before anything was processed, we shipped a wax try-in to the clinic for the dentist to seat on the patient. Our standard try-in checklist matches what we ask the dentist to look at:
- Esthetics, midline, tooth shape
- Occlusion in centric and in excursion
- Vertical dimension — same as the old set, which is what the dentist asked for
- Speech, especially sibilants, which show up fast if the maxillary anterior teeth sit too far lingual or labial
- Base stability on the ridge
- Lip support and the smile line
The dentist seated the try-in, pulled us into a video session, and signed off on it with one small change — a slightly flatter curve on the lower incisal edge. We adjusted it the same day.
Once a wax try-in is approved, the colour, surface finish, small shape details, and contact relationships can still be adjusted during processing. The tooth position and the occlusion cannot — those get locked in as the sign-off reference.
Processing and finishing. Once the try-in was signed off, the case went through the physical build. The denture department runs about 4,000 removable cases a month at Istar's facility, with capacity for up to 6,500 cases a month in peak season. The steps that mattered for this case:
- Flasking and packing. Powder-to-liquid ratio measured by weight, packing done in the dough stage, no shortcuts.
- Polymerisation. Stepped water-bath curing, not a straight boil. A fast polymerisation on acrylic creates porosity and shifts the tooth position. The ISO 20795-1:2013 limit for residual MMA in a Type 1 heat-cured base is 2.2% — well below that is where this family of resins should sit when cured properly.
- Cooling. Slow cool in the water bath, no quenching. Quenching warps bases, especially longer ones.
- Remount and occlusal adjustment. Both finished dentures were remounted on the articulator against the original jaw record and the occlusion was refined — centric first, then excursions, until the contact pattern matched the one the dentist had approved on the wax try-in.
- Finish and polish. The intaglio was left alone except for de-flashing. All polishing happens on the polished surface, with the intaglio and the borders protected. Polish the intaglio and you lose the fit the impression gave you.
Then the case was packaged and shipped. The infection control step before packaging is high-pressure wash and dry — the same step every case goes through before it goes near the shipping bench.
Feedback after the try-in and the delivery
We get our feedback the way any dental lab does — through the dentist, after the patient has been in the chair with the work in their mouth. Two check-ins came back on this case: one after the wax try-in, one after the finished upper and lower dentures were seated.
After the wax try-in. The dentist's note was short and specific. The vertical dimension felt right to the patient on the first bite. The midline and lip support looked the way the old set had on day one, years earlier. The patient flagged the lower anterior incisal edge as slightly sharper than they expected — hence the small flattening we did the same day. Nothing else needed changing. Speech was clean on sibilants. The dentist signed the try-in off.
After the finished pair was seated. The dentist's follow-up came back a few weeks later, after the patient had worn the new set long enough to form an opinion. The write-up stayed close to what the brief had asked for:
- The patient said the new pair felt like their old set, without the looseness on the lower or the flat chewing surfaces on the upper. That is the brief, in one sentence.
- The lower retention was reported as noticeably better than the old set at the end of its life. The dentist put that down to a fresh intaglio against the current ridge, not any one design choice on our side.
- Two small post-insertion adjustments were done chair-side — one pressure spot on the mandibular lingual flange, one minor contact refinement on the right side in lateral excursion. Both were in the range the dentist expected for a new full-arch build and did not come back to us as a remake.
- The patient's speech adaptation period was short, which the dentist linked to the fact that nothing about tooth position or VDO had changed from the old set.
That is the summary we were given. We are a denture lab, not the chair-side team, so we report what the dentist passed on. We do not have the patient's own words, and we do not try to speak for them. If you want to see what post-insertion review looks like from the clinical side, the ACP Parameters of Care and general denture guidance from the ADA both describe the kind of checks that normally follow delivery of a new set of upper and lower dentures.
What our denture department can supply, in one block
For planning purposes, so clinics running similar cases know what to expect from the bench side:
- Scope: full upper and lower dentures (acrylic), partial dentures (acrylic and metal frame, cobalt-chrome, Vitallium, titanium, PEEK), flexible partials, implant overdentures, denture repairs, relines, rebases, tooth addition.
- Bases: heat-cured, injection-moulded, milled PMMA, and 3D-printed — picked per case. Hybrid flows combining injection or heat-cured processing with a digitally designed setup are the default for complex ridges.
- Teeth: VITA, Ivoclar, Shofu, and compatible acrylic lines.
- Workflow: traditional, fully digital, or hybrid — chosen per case rather than per shop.
- Records we need with every upper and lower dentures case: upper and lower impressions or intra-oral scans, a stable interocclusal record (wax rim or bite registration), a face-bow transfer for cases where VDO or the occlusal plane matters, scans or photos of any existing prostheses, intra-oral and smile photos, shade reference, and a signed prescription.
- Try-in: offered as standard for full upper and lower dentures. Wax or 3D-printed try-in both available.
- Turnaround: production times quoted on a per-case basis, counted in laboratory working days from records-complete to dispatch. Door-to-door time depends on the shipping lane.
FAQ
Can you make upper and lower dentures without changing a patient's current vertical dimension of occlusion? Yes. If the clinician asks us to copy the current VDO, we measure it off the old set, confirm it on the wax rim bite record and the face-bow transfer, and build to it. The final VDO is a clinical determination, so we work to the value on the prescription.
What if one of the old dentures is still fine and only one arch needs replacing? We can do a single-arch replacement. The new arch has to be designed against the surviving opposing arch, which sets the VDO, the occlusal plane and the tooth position. If the surviving arch has lost dimensional stability (flex, a repair line through it, or clear base distortion), we will flag it and talk through whether a full pair is the safer brief.
Which base material do you default to for a full set of upper and lower dentures? It depends on the case. For a patient with a bruxing history or a prior fracture, Lucitone 199 heat-cure is a safe default. For a patient with a clean history and a stable ridge, injection-moulded or milled PMMA are both reasonable. Material picks are per-case, not per-lab.
Do you offer a wax try-in on upper and lower dentures? Yes, as standard. The wax try-in is where the dentist signs off on tooth position, occlusion, VDO, and esthetics before anything is processed. 3D-printed try-ins are also available where a digital setup is in use.
Does your laboratory decide the posterior palatal seal design? No. The PPS is a clinical determination. If the dentist marks it on the cast or on the digital design, we transfer the exact position and depth onto the final denture. We do not add to it or deepen it.
What happens if a case comes in with records we can't work from? We call the clinic. An unstable bite record, a short-captured border, or a scan with a missing posterior section all get flagged before we start cutting wax. The faster that conversation happens, the less time the case loses.
Send us a case
If you are running a similar upper and lower dentures case and want a second set of eyes on the records before you commit to the build, send us the scans or impressions, the wax rim, and the prescription. We will give you a scope read and a target production window within one working day. You can also book a video walk-through of our denture department in Shenzhen or Huizhou — the full build happens in-house, no outsourcing, which is how we keep a case consistent from the first scan to the last polish.
Sources cited on this page
- American College of Prosthodontists — Dental Laboratory and Dentist Relationship. https://www.prosthodontics.org/about-acp/position-statement-dental-laboratory-and-dentist-relationship/
- American College of Prosthodontists — Parameters of Care for the Specialty of Prosthodontics (2020). https://www.prosthodontics.org/assets/1/7/ACP_Parameters_of_Care_2020.pdf
- ISO 20795-1:2013 — Dentistry — Base polymers (specimen limits). https://cdn.standards.iteh.ai/samples/62277/9509975bfa1d4ecd9515da579f4c6288/ISO-20795-1-2013.pdf
- ISO 22112:2017 — Dentistry — Artificial teeth for dental prostheses. https://www.iso.org/standard/70086.html
- American Dental Association — Dentures (oral health topic). https://www.ada.org/resources/ada-library/oral-health-topics/dentures
- Cleveland Clinic — Dentures. https://my.clevelandclinic.org/health/treatments/10900-dentures
- Posterior Palatal Seal: A Literature Review — Int J Oral Implantol Prosthodontic Res. https://www.ijoprd.com/doi/10.5005/jp-journals-10019-1020
- A comparative study of retention of complete denture base with different PPS types (in-vivo). https://www.dovepress.com/a-comparative-study-of-retention-of-complete-denture-base-with-differe-peer-reviewed-fulltext-article-CCIDE
- Occlusal schemes: systematic review of systematic reviews — J Prosthet Dent. https://www.thejpd.org/article/S0022-3913(21)00591-6/abstract
- Occlusal designs, masticatory ability and satisfaction: systematic review. https://www.sciencedirect.com/science/article/abs/pii/S0300571213001899
- Wear of Modern Denture Teeth — Systematic Review. https://www.mdpi.com/2673-6373/2/1/11
- Milled vs printed denture bases — systematic review and meta-analysis, Sci Rep 2025. https://www.nature.com/articles/s41598-025-14288-2