At fifteen she had taken a bad fall at school — nothing dramatic in retrospect, but hard enough to damage her two upper central incisors beyond saving. At the time she was told implants were not an option: her jaw was still developing, and the clinic she went to wanted to wait. She wore a provisional that nobody loved, got on with high school, got on with college, and eventually started a work year abroad in Seoul.
By the time she walked into the dentist's office in Seoul, three things had changed and one had not. She was an adult now, so growth was finished. She had health insurance in two countries, which complicated who would pay for what. She had a flight home in roughly three months. And the bone in her upper front, where the two central incisors used to be, was described in the chart as small, rigid, and fragile — the kind of ridge that resists drilling without flexing, and that an experienced surgeon will not place implants into without a longer graft-and-wait cycle than her window allowed.
A few other details from her intake that mattered to the design:
- She has a high smile line. A relaxed smile shows about half the length of her upper front teeth. A full laugh shows a visible band of gum above them. Any mistake in the shape of the incisal edge, the midline, or the margin where the pontic meets the ridge is going to be on view every time she smiles.
- She grinds her teeth at night, occasionally. Not a diagnosed bruxist, but she is aware of it. The dentist did not want this restoration carrying any lateral load.
- She drinks coffee, and sometimes smokes. Both pick up on provisional resin fast, which affected the shade decision.
- The previous temporary she had been wearing was unusable. Her own description: "Too thick, too long, the two sides are at obviously different heights, and the shade is way yellower than my own teeth. I feel awful. I'm scared the final one will come out the same."
That last line is the one that mattered most for the brief. A temporary bridge for front teeth is not supposed to be invisible — it is supposed to be the design document the dentist and the patient both approve, with enough resemblance to the final restoration that approving the temporary approves the final. The previous one she was wearing could not do that job because it got the four basic things wrong: length, symmetry, shade, and bulk. If we built the next one with the same mistakes, the dentist would copy them into the final, and she would wear those mistakes for ten years.
So we built against the four things the previous temporary got wrong, and against the six items her dentist specified. In that order.
What the dentist asked us to do
The Rx arrived in one document with photographs attached. We write it out here more or less the way it came in. These six items are what we built against.
1. Design and position. Three-unit bridge, teeth #8 and #9 as the pontics, #7 and #10 as the abutments. Minimal preparation has already been done chairside on #7 and #10 — do not expect to remove more tooth structure in the design.
2. Material. Milled PMMA. Not chairside bis-acryl. The patient will be in Korea for about three months and then on a plane, and the restoration has to hold up through that.
3. Shade. Not a tab number alone. Three reference photographs, each taken in daylight with a Vita 3D-Master tab held against the adjacent tooth at a specific height — one at the incisal third of #11, one at the middle third, one at the cervical third of #6. The dentist wanted a gradient, not a flat color.
4. Incisal reference. Match the incisal edge of #10 exactly. Do not average between #7 and #10. The patient's smile line is high — any asymmetry at the incisal edge will show up as asymmetry across the gumline too.
5. Pontic contact. Pinpoint contact only — one defined point of touch on each pontic, placed slightly labial, with the lingual side kept clear for cleaning. This is a fresh socket; the ridge is still settling, and the pontic is not here to shape tissue, only to hold the space.
6. Occlusion. Light centric only. Zero contact in protrusive. Zero contact in either lateral excursion. The patient's night-time grinding history goes with the restoration, not just with the Rx.
The dentist added one line that was not a numbered item but changed the whole design before we started: "This has to be adjustable at the chair. If I can't shorten it or round the corners without going through the surface, I'll ask you to remake it." That rules out a thin surface stain layer. The characterization had to go deeper than that.
How we built it, step by step
Our standard anterior workflow runs through our own facility end-to-end. No outsourcing to third-party labs. For this case the sequence was the same one we use for every three-unit anterior restoration, with the material path adapted for PMMA. Nine steps.
Step 1 — Case receiving and review. The case coordinator opened the scan, cross-checked the Rx against the photographs, and flagged two things back to the dentist before anything else happened: whether the "match #10 exactly" instruction overrode the usual smile-arc curvature at #9 by any amount, and which philtrum landmark in his photos to use as the midline reference. He answered both the same day. We did not start CAD until that was in writing.
Step 2 — CAD design. The designer dropped a horizontal construction plane through the incisal edge of #10 and used that as the reference line for #8 and #9. #9 was built down to that plane with a 0.3 mm concession for a very slightly curved smile arc — the amount the dentist had approved in writing in Step 1. The midline came from his marked philtrum point, not from averaging #7 and #10. The pontic tissue surfaces were modeled as modified ridge-lap with a single defined contact point on each, placed slightly labial. The lingual stayed open for a floss threader and a water flosser.
Step 3 — Design preview and sign-off. The CAD file was exported to a design-approval PDF with the pontic contact point marked, the incisal reference plane visible, and the midline annotated. The dentist signed off before milling. If this step comes back with changes requested, nothing moves forward until the changes are reflected in CAD. On this case there were no changes.
Step 4 — 3D model print. The resin model was printed from the intraoral scan, with the opposing arch, so the ceramist and QC could physically verify occlusion later. The pontic sites were kept in print so the intaglio could be checked against the printed ridge.
Step 5 — CAM milling. A PMMA puck was loaded and the bridge was milled as a single unit. Separation and basic finishing were done before anything cosmetic began.
Step 6 — Characterization. We built the shade from the inside out. The body shade was set a quarter-step cooler than the dentist's target, because PMMA picks up warm tones in the mouth over the first few weeks — a case that comes out perfectly matched on day one tends to read warm by week four, especially with coffee and nicotine in the mix. Surface tints were then applied in two passes to pull the warmth back into the cervical third and leave the incisal third slightly more translucent, matching the gradient the dentist had shown in the three photographs. The published evidence on CAD/CAM and chairside provisional restorations is clear that color stability over service time varies between materials — building a one-step compensation into the body shade is cheaper than remaking the whole restoration at week five.
Step 7 — Occlusal verification. The restoration was tried on the printed model with the opposing arch. Centric contact was checked and set to a light, even touch across the three units. The mandible was walked through protrusive and lateral excursions on both the model and in CAD. All excursive contact on the bridge was removed before the restoration left this step. The articulating paper reading at the end of this step was recorded and sent to the clinic alongside the restoration. Connector cross-section was checked against the published parameters study for anterior resin-bonded fixed dental prostheses so that nothing on the bench ran thinner than the material allowed.
Step 8 — Polishing and finishing. The pontic tissue surfaces were polished to a mirror finish on the side that faces tissue. The reason is boring but matters: a rougher surface at the pontic grips plaque, and the patient was going to be living with this one for six weeks. The intaglio of the retainers was then checked for a passive fit against the printed model. The pontic itself was designed as a modified ridge-lap with a defined contact point, matching the digital workflow described in the pontic design literature — because horizontal ridge resorption after extraction runs to about 2.5–4.6 mm over six months, a pontic designed with a flat broad contact surface would be sitting in open space within weeks.
Step 9 — QC and dispatch. Final QC walked through four hard-stop checks: margin fit around the full periphery of the retainers, pontic contact at the designated single points only (not spread across a shelf), occlusal clearance confirmed again, and shade read under three different light conditions. If any of the four fails, the case goes back to the preceding step, not forward. On this case the first shade check at QC read a half-step too warm at the cervical and the restoration went back to Step 6 for a second pass before it was released. The restoration was then packaged with the design-approval PDF, the articulating paper reading, and a short note for the dentist listing the three questions he should ask the patient at the two-week review.
At try-in: feedback from the patient and the dentist
At the try-in appointment the restoration seated passively on the first attempt. The dentist walked through his standard chairside checks and recorded what he observed.
On fit. Margins closed cleanly around #7 and #10 with no visible gap on probing or in a photograph taken with a mirror. The pontic contact points at the ridge made light touch where they were designed to, with the lingual kept clear.
On occlusion. Articulating paper at centric left even, light marks across the three units — matching what we had sent in the Step 7 reading. In protrusive and in both lateral excursions there were no marks on the bridge at all. The dentist noted on the chart that he did not need to adjust the occlusal surfaces.
On the four things the previous temporary had got wrong.
- Length. The incisal edge of #8 and #9 sat at the same level as #10 within what the dentist described as "the thickness of the articulating paper." No chairside shortening was done.
- Symmetry. The incisal line read as a continuous curve across #7 through #10. Nothing visibly stepped.
- Shade. The dentist told the patient the color would warm slightly over the first month, which she already understood from the Rx explanation. In daylight at the chair the bridge read a quarter-step cool, as designed.
- Bulk. The labial surfaces had the depth the adjacent teeth had, no more. The patient's own description after seeing herself in the mirror: "It looks like a tooth, not a tooth-shaped block."
On the complaint she had come in with. The patient was asked the three review questions we had written on the dispatch note.
Review question | Her answer |
|---|---|
Is the incisal edge where you want it, or do you want it shorter? | "Leave it. This is where my own teeth were." |
Does the shade still feel right under indoor light? | "A little cool now. If it warms up like you said, that's fine." |
Any food catching under the pontic? | "No. I can get a floss threader through both sides." |
What the dentist decided. No adjustments at the chair. The design-approval PDF from Step 3 was filed as the reference geometry for the final restoration. The patient was booked for a two-week check and told to bring the three questions back answered.
A try-in where the dentist does not need to pick up a bur is the outcome a temporary bridge for front teeth is built to produce. It is not interesting. That is the point.
What a case like this proves a dental lab can do
A lab cannot decide whether a patient should get implants or a bridge. That is a clinical judgment, and in this patient's case the bone quality and the three-month window made it for the dentist. A lab cannot decide extraction timing, grafting materials, or the final occlusal scheme in the mouth. A lab also cannot promise service life — a temporary is defined by what the next appointment replaces it with, not by how long it lasts in isolation.
What a lab can do, and what we did here, is turn an Rx with six specific items into a restoration that lets a dentist test every one of those items in a six-week window with the actual patient in the chair. If any one of them is wrong — the incisal is a half-millimetre too long, the shade reads a shade too warm under office light, the pontic is contacting tissue where it should be clear — that mistake lives in the temporary, where it can be fixed, instead of in the final restoration, where it cannot.
That is the job of a temporary bridge for front teeth, and it is the one most of the work above is quietly aimed at.
Working with Istar on anterior temporaries
Istar Dental Lab has been running digital anterior cases through our own facilities in Shenzhen and Huizhou since 2012. All of the steps above — case review, CAD, model printing, milling, characterization, occlusal verification, finishing, QC, dispatch — happen under one roof with no outsourcing to third-party labs. The CAD department alone has around 100 designers; the ceramic and metal team is around 70. In normal production we run roughly 2,000 zirconia bridge cases a month, and anterior temporaries sit inside that same workflow with the same case-coordination and QC steps.
If you have an anterior temporary case with a hard date — a flight, a wedding, a long trip — send:
- An intraoral scan with the opposing arch
- Three shade photos with a tab in frame, taken in daylight if possible
- A photo marked with the philtrum landmark for the midline
- The target incisal reference (which adjacent tooth you want matched)
- The pontic contact level you want (passive, pinpoint, controlled pressure, or no contact)
- The occlusal scheme (and, if the patient grinds, whether the bridge should be fully out of all excursive contact)
- The date your patient has to be out of the chair with it in
If any of those is missing or ambiguous — the shade reads flat, the midline reference is unspecified, the pontic contact level is not stated — we hold the case and ask before milling. That is slower than guessing. It is also the only way the temporary gets to do what a temporary is actually for.