Patient Context
The patient was in their late forties, missing #8 and #9 — the two upper central incisors. The teeth were lost years ago in a bicycle fall and had since been covered by an acrylic flipper, which had cracked twice at the midline and was starting to show stress crazing again. Their chart was otherwise unremarkable:
- Periodontally stable. Adjacent abutments #7 and #10 fully erupted, no mobility, no bone loss on bite-wings.
- A Co-Cr sensitivity flagged in medical history — ruling out cast-metal framework as a direct swap.
- Overbite around 3 mm, no deep anterior guidance that would dislodge an upper anterior appliance in excursion.
- Mild gingival recession, roughly 1–1.5 mm on the labial of #7 and #10, left over from the trauma and years of flipper wear.
- Moderate smile line — gingival margin shows during a wide smile but not at rest.
- Tooth shade A2, gingival shade on the lighter side with slight translation into pink-brown at the recession line.
- No bruxism reported, no night-guard history.
What the patient wanted was straightforward and worth taking seriously:
- No metal visible at any angle, including at a wide smile. The flipper's labial wire had been the single thing they most disliked about it.
- Able to speak at work the same day. They present client workshops for a living.
- Something that would hold up to a sandwich at lunch, not a device they'd remove in the office bathroom.
Two things they did not want: a reduction or crown prep on #7 or #10, and a conversation about implants (previously declined on cost and surgery-aversion grounds).
The Clinician's Rx
The prescription came in clean and specific. Three things on it were worth more than one line:
- Code: D5225 — maxillary partial denture, flexible base. The dentist had already walked past D5284 (single-piece unilateral, per quadrant) because the two missing teeth sit on either side of the midline, in different quadrants. D5284 can't carry a cross-arch load; the dentist noted this on the Rx explicitly, which was helpful — we didn't have to call to confirm.
- Design request: cross-arch flexible base, bilateral embrasure clasps on #7 and #10, minimum palatal strap width. Specifically asked us to keep gingival margin coverage at the minimum consistent with retention because of the existing recession on the abutments. This is the kind of note we'd rather have on the Rx than figure out later.
- Shade: A2 for the pontics, two-tone pink for the base. Lighter pink across the body of the base, darker pink feathered into the labial margin to blend into the receded tissue line. A single-shade pink would read as a stripe against that recession.
The dentist also asked for a wax try-in before injection. On a two-upper-anterior case where the midline and the incisal edge position are both patient-visible every day, this adds a scheduled day to the workflow but removes two of the three most common complaints after delivery. We agreed.
Finally, the Rx carried a sensible after-care expectation: confirm up front that a tooth could be added or the base relined later if the ridge changed. Both are standard on a flexible base with the right protocol, and we confirmed before starting production.
How We Met These Requirements
The case was logged against a unique case ID and routed to our Removable Denture team (about 55 technicians inside Istar's roughly 460-person facility, operating out of Shenzhen and Huizhou). It went through the same six-stage flow every two-unit flexible case does — but the detail that matters is what we did at each stage for this case specifically.
1. Intake and design review
- Confirmed the Rx against the inbound data: a full-arch digital scan plus the patient's existing bite record. The flipper came with the case for shade and midline reference, which is useful on anterior work.
- Cross-checked the periodontal notes against the scan. Pocket depths on #7 and #10 were within normal range, so the embrasure clasps the Rx asked for were defensible.
- Verified the overbite and canine guidance on the mounted digital models. ~3 mm overbite, no deep anterior guidance — no need to flag back.
- Measured labial undercut depth on #7 and #10 for the flexible clasp arms.
2. CAD design
- A full-arch cross-arch flexible RPD (per D5225), not a unilateral.
- Thin palatal strap, kept well clear of the rugae ridges to minimize bulk at the roof of the mouth — the patient spoke for a living, and plate thickness is where speech lives or dies.
- Bilateral embrasure clasps on #7 and #10, engaging roughly 0.25 mm undercut on each — enough to retain, not enough to blanch gingiva.
- Gingival margin extension on the labial pulled back about 1 mm from the recession line, following the Rx. The retention loss was traded off against clasp depth, not against margin creep.
- Pontic ridge-lap designed with mechanical retention features for the acrylic teeth (small lab-cut retentions inside the thermoplastic), because a flexible base holds its teeth mechanically rather than through chemical bond.
- Sent the design file back to the clinician. Approved same day with no changes.
3. Wax try-in
- 3D-printed try-in base with denture teeth set.
- Patient and dentist checked midline (sat exactly on the facial midline, verified against the patient's upper lip philtrum), incisal edge length (1.5 mm display at rest, within what the patient wanted), and lip support (matched the pre-trauma reference photo the patient supplied).
- Dentist adjusted the pontic shade one step warmer. Try-in signed off.
4. Injection, finishing, polishing
- Thermoplastic nylon-type base injected under controlled pressure.
- Flange thickness kept even on the ridge-lap; palatal strap polished to a thin, continuous section without the thick-thin transitions patients feel with their tongue.
- Embrasure clasp terminals polished smooth. Both pontic ridge-laps re-checked for retention of the acrylic teeth before deflasking.
- Two-tone gingival staining applied along the labial margin as per the Rx: lighter body, darker feathered band blending into the recession zone.
5. QC — three gates
- Incoming: data and Rx check at log-in.
- In-process: mid-production spot check on tooth position and clasp geometry.
- Terminal: independent QC technician — seating on master model (no rocking), clasp retention and resilience, flange adaptation, occlusal contacts, midline, shade match against the shade tabs and the provided photo. 100% of removable cases pass through this final inspection; nothing ships without it.
6. Delivery
Shipped on day four from design approval (digital workflow, no inbound model to receive). Case packed with the design file, batch records, and the QC checklist signed off.
Try-In Day: Patient and Clinician Feedback
The appliance was tried in at the dentist's office the same afternoon it arrived. Both pieces of feedback are summarized here from the dentist's post-delivery note and the patient's follow-up at the two-week check.
From the clinician
- Seating. Dropped onto the ridge without force. No rocking on the master model matched the behaviour in the mouth.
- Retention. Both embrasure clasps engaged passively on first try. Pull-off resistance felt right for an upper anterior appliance — enough to resist speech dislodgement, not so much that daily removal would stress the abutments.
- Occlusion. Centric contacts even on both pontics. One light spot-grind on the lingual of #9 was the only chairside adjustment. No excursive interference.
- Aesthetics. The two-tone pink matched the recession line better than the dentist had expected from a single-step Rx — the darker feathered band did its job. Midline sat exactly on the facial midline, matching the wax try-in position.
- Clasps. Both labial clasp arms stayed hidden under lip at full smile. The dentist's one note: at a very wide forced smile the gingival clasp on #7 is just visible — expected for this clasp pattern, acceptable to the patient.
From the patient (two-week follow-up)
- Speech. Noticeable the first evening, back to normal by day three. Able to run a half-day client workshop by the end of week one with no self-reported awareness of the appliance.
- Eating. Soft foods immediately, bread and cold cuts by day two, apple slices and firmer textures by the end of week one. No episodes of the appliance unseating during meals.
- Comfort. No pressure sores at either abutment. The palatal strap "disappeared" after about 48 hours — their own phrasing.
- Confidence. Smiled in front of a mirror on day one and in front of other people on day two. The flipper, by comparison, had taken them months.
No lab-side rework required. No reline requested at the two-week check. Follow-up at three months was booked for a routine recall rather than for an adjustment.
What This Case Shows
A two-tooth flexible partial, done well, is not a flipper upgrade and not a stopgap. On a cross-midline anterior case, three decisions carry most of the result: the choice of D5225 over D5284 (which the Rx should drive, not the lab), the clasp pattern and its termination depth, and whether the base extension respects an already-receded gingival margin. The rest is finishing and QC.
If any of the following matches a case on your bench right now — two adjacent upper anteriors, a trauma or long-standing extraction history, a patient who won't accept visible metal, a dentist who wants the margin pulled back — this is the workflow it goes through.
Codes, Scope, and Where to Verify
- D5225 / D5226 — maxillary / mandibular partial denture, flexible base (cross-arch). Standard code for the case above.
- D5284 — single-piece unilateral partial denture, one-piece flexible base, per quadrant. Appropriate when the two missing teeth sit within one quadrant.
- D5650 — add tooth to existing partial denture, per tooth. Supported on flexible bases with the right protocol.
- D5720 / D5721 — rebase a maxillary / mandibular partial denture.
Scope and classification of removable partial dentures sit under 21 CFR §872.3760; the FDA product code for finished partial dentures is NSK. Istar maintains active FDA establishment registration — verifiable in the FDA registration lookup — along with EU MDR custom-device notification, UK MHRA registration, and ISO 13485 on the lab side. For the current US position on direct-to-consumer denture services, see the ADA's reaffirmation policy.
FAQ — Flexible Denture 2 Teeth
Which code applies to two front teeth across the midline? D5225 (maxillary) or D5226 (mandibular). D5284 is for a single-piece unilateral appliance confined to one quadrant.
Can a tooth be added to a flexible partial later? Yes. Send the appliance with an impression and a bite record; we use a compatible resin and controlled heating.
Can it be relined? Yes, within the limits of the material. A reline is often the better option when a posterior ridge has resorbed under a saddle.
Turnaround time for a case like the one above? On a clean digital case with a wax try-in: roughly 4–5 working days plus try-in scheduling. Without a try-in, 2–3 working days. A physical-model workflow adds about 1–2 days for inbound shipping and model handling.
What if the appliance comes back for lab-side rework? Remakes for seating issues, clasp design, lab-side shade errors, or occlusal discrepancies from the lab are at our cost. Case changes after design approval, and unusable incoming data, are the two situations we quote separately.
How do I send a case in? A digital scan or physical model with a bite, the Rx with tooth numbers and arch, periodontal notes, tooth and gingival shade, and any smile-line photographs on anterior work.
Have a two-upper-anterior or same-side mandibular case to send? Reach the Removable Denture team or book a video audit of either facility — arrange a case consult.