Upper Denture Case Study: Gag Reflex, Suction, and a Border on the Vibrating Line

What this page is. A clinical case study of one upper complete denture, written for the dentists, clinics, and lab partners who already prescribe this kind of work every week. Names and identifiers are removed. The point is the prescription, the lab response, and what the patient ended up wearing.

Who it is for. Prescribing dentists and clinic teams who want to see what a useful upper denture work order looks like and what kind of follow-up a lab should send back with the case.

Patient situation

A long-standing edentulous maxilla, worn for years by a patient who had reached the point where the previous denture was, in the patient’s words, “strong suction” and “never needed adhesive.” The newer denture the patient had been given was the opposite: a noticeably smaller plate, a shorter posterior border, and a fit that failed on the first bite. The patient also had a sharp, immediate gag reflex, which the older plate had somehow never triggered. Upper anterior teeth, separately, looked shorter than the patient’s natural teeth ever had, and the patient wanted them longer.

Three things mattered to the prescription:

• The new denture was under-extended. It did not reach the area behind the last tooth and the posterior edge of the hard palate. Border seal depends on the border reaching the junction of the hard and soft palate; when the border stops short, suction collapses.
• The patient’s gag reflex would not tolerate a full-template border. Some practitioners handle this by trimming the back edge; that gains comfort but loses seal. The clinician in this case did not want either side fully satisfied at the expense of the other.
• The patient’s older denture was the reference the patient trusted. Anything further from that older form than the patient’s own notes could tolerate would be returned, not adapted to.

What the clinician asked for

The work order went to the lab in writing rather than by phone. Six items, each tied to a specific reason the previous denture had failed:

1. Posterior border on the vibrating line, with the hamular notch region captured. Not a generic “make the border shorter,” and not a template-driven “extend as far back as possible.” The border stops at the vibrating line because that is where the denture-bearing tissue transitions from firm to compressible; capture the hamular notch region because that is where the pterygoid plate gives the denture its posterior lateral seal.
2. A post-dam present, but kept to the minimum workable width and thickness. The post-dam is the small rim carved into the tissue surface along the posterior border that creates the negative pressure seal on a complete upper denture. Without it, a maxillary complete denture has no mechanical retention to speak of. With it too deep or too wide, the same denture will trigger a gag reflex on insertion. The prescription asked for the minimum width and thickness that would still produce seal, and asked the lab to record the actual measurement on the case sheet so any future reline could reproduce it.
3. Buccal frenum relief, with no border pressure across the frenum. The frenum is the small fold of tissue where the cheek meets the alveolar ridge; an unbuffered border running across it will cut on every facial movement and is one of the most common sources of a “sore spot that came back after every adjustment.”
4. Upper anteriors not lengthened. The incisal edge position is set by two things, esthetics and phonetics; lengthening the tooth moves it out of the phonetic zone and changes the /f/ and /v/ sounds. The prescription asked the lab to leave length alone and, if the patient wanted to see more tooth, to build that out of the labial flange thickness instead, by thickening the acrylic on the front of the denture so the upper lip rides slightly higher and exposes more of the tooth face.
5. Base form duplicated from the patient’s older denture. Where the older denture had worked, the newer denture should look like a refinement of it, not a redesign. The older denture’s base outline, posterior stop, and tooth arrangement were taken as the starting point, and only the changes the clinician had written in items 1 through 4 were applied on top.
6. Shade and tooth mould confirmed at the wax try-in, in writing. Mould reference, shade value, and the incisal edge position were written onto the wax try-in card so the patient could see and approve them before the case went into flask. Anything not written at try-in was not guaranteed at delivery.

The work order also asked for one follow-up item: an expectation sheet with the case, written for the patient, separating “this is normal during the first two weeks” from “this needs to come back to the clinic.” This is the part of the prescription the previous practice had skipped, and it was the part the patient had been most angry about.

How we made it

The denture was built inside our Removable Denture Department, which handles around 4,000 removable cases in a normal month and roughly 6,500 at peak. Every step that follows happened on one site, on one bench, by the same technician from start to finish, because the part of the case the patient was going to feel first (the border) and the part the patient was going to see first (the front teeth) needed to be the same person’s judgement.

Impression and border. A preliminary impression was taken in alginate for the study cast, then a custom tray was made on that study cast. Border molding was done on the custom tray using a heavy-body material, then a wash impression with a light-body material captured the mucosal detail inside the border. The border molding step is the part of an upper denture impression most practices skip, and it is also the part that determines whether the finished border sits where the prescription asked. Border molding here was done in two passes; a single pass tends to leave the distobuccal corner short, which is exactly the corner that fails on a maxillary denture first.

Record base and wax rim. A record base was processed on the master cast and a wax occlusion rim built on top of it. The vertical dimension of occlusion was set first, then the lip support, then the midline and the incisal edge position. The incisal edge position was set at the phonetic zone, not at the esthetic-only position the patient asked about at the consultation, and the patient was shown the result on the wax rim and asked to say “f” and “v” out loud so they could hear that the lip was still free to close around the teeth.

Tooth set-up. Anterior teeth were set to the patient’s older denture’s mould and arrangement as the starting point; the only change was a small build-out of the labial flange thickness so the upper lip would sit slightly higher and expose more of the tooth face. Posterior teeth were set to a balanced lingualized occlusion scheme, which keeps the working-side and non-working-side contacts on the upper lingual cusp during lateral excursions and reduces the lateral destabilising force on the upper denture base. This is the scheme most peer-reviewed sources on upper complete denture occlusion reach for, including the systematic review on maxillary overdentures cited in our reference list.

Wax try-in. The wax try-in was the clinical checkpoint for items 5 and 6 in the prescription. Mould reference, shade value, and incisal edge position were written onto the try-in card and the card was photographed before the wax-up went back to the lab. The photograph was the artefact the clinician used later when checking the finished case against the prescription, and it was the artefact the lab used when confirming it had not drifted between try-in and flask.

Flask, pack, and cure. The case was flasked using a standard two-pour technique. The acrylic was a high-impact, heat-cured denture base; we use heat-cured rather than auto-polymerizing for upper complete dentures because the base is thicker and the polymerization shrinkage has to be controlled in a way that only a long, temperature-controlled cure gives. The post-dam was carved into the wax-up before flasking so it ended up as a feature of the acrylic surface rather than as a later addition to it; adding a post-dam with reline material after the fact is a common workaround, but it does not bond to the parent acrylic as a one-piece post-dam does.

Post-dam measurement. The post-dam was carved to the minimum workable width and thickness the prescription asked for. The actual width and depth were measured with a calibrated periodontal probe after carving, and the numbers were written onto the case sheet that travelled with the denture. This was the single item the prescription flagged for the future-relining clinician; a reline that does not reproduce the recorded post-dam is, functionally, a reline that has lost the seal.

Trim, polish, and fit check. The denture was trimmed to the border the wax-up had established, with the buccal frenum relief left clearly visible as a discontinuity in the polished surface, not as a feathered edge. The denture was then seated back on the master cast and a fit check was done against the master cast before the case left the lab. The fit check photo went into the delivery packet alongside the post-dam measurement, the try-in card photo, and the expectation sheet.

Final result

At delivery, the denture seated with positive border contact all the way around, including in the hamular notch region, and held without adhesive during speech and during moderate biting on a cotton roll. The patient’s own test, repeated before leaving the clinic, was to sip water and speak a short sentence with the denture in: it stayed. The patient reported the gag reflex as reduced, not absent, and as something they were willing to wear through, which was the result the prescription had asked for (the minimum workable border, not the maximum tolerable comfort).

The upper anteriors looked slightly fuller than the previous denture, but not because the teeth had been lengthened. The change was on the labial flange, which sat a fraction of a millimetre thicker than the patient’s older denture, lifting the upper lip a touch. The patient accepted this as the “longer teeth” they had asked for, which is the visual the prescription had predicted.

The case was delivered with the following items in the packet:

• The finished upper denture, in a labeled case.
• The master cast, for the clinic’s records.
• The wax try-in card with the photograph, the mould reference, the shade value, and the incisal edge position.
• The post-dam measurement recorded on the case sheet (width and depth, with the probe used).
• A fit-check photograph against the master cast.
• The expectation sheet for the patient, separating normal adaptation from “needs to come back.”
• A note for the clinic on what we would consider rework on our side (a border error, a missing post-dam, a mould mismatch) versus what we would treat as a clinical adjustment (a sore spot at the frenum relief, a phonetic complaint traceable to the incisal edge, a reline needed after healing).

The patient was followed up at one week and at four weeks. At one week, two small pressure spots on the alveolar ridge were relieved chair-side, which is normal for a first-week upper complete denture and was on the expectation sheet. At four weeks, no further adjustments were needed. The patient was placed on a standard six-month recall for a reline evaluation.

Why this case worked

Three things, in order:

1. The prescription was specific enough to act on. “Make it not gag the patient” is not a work order. “Posterior border on the vibrating line, hamular notch captured, post-dam at minimum workable width and thickness, buccal frenum relief, anteriors not lengthened” is. Every item on the work order is a separate clinical decision the lab can make or fail to make, and each one has a way of being checked when the case comes back.
2. The lab response was inside one workflow. Impressions, border molding, record base, set-up, try-in, flask, cure, and trim all sat in one department, on one bench, with one technician owning the case. The post-dam measurement, the try-in photo, and the fit-check photo are not extras; they are how the department documents that the work order has been read.
3. The follow-up was part of the case. The expectation sheet, the post-dam measurement, and the rework note are the parts of the case that age the best. Six months later, when the patient comes back for a reline, the reline technician has the original post-dam dimensions, the original mould and shade, and the patient’s own signed-off incisal edge position. The reline is faster, cheaper, and closer to the original prescription than it would have been without those artefacts.

Referenzen

• American Dental Association — Denture Care and Maintenance
• The number of implants required to support a maxillary overdenture: a systematic review and meta-analysis (ResearchGate)
• WebMD — Dentures: Types (Partial and Complete), Cost, Cleaning, and More
• Minnetonka Dental — Gag Reflex With Dentures: What Helps
• Acrylic vs Chrome vs Valplast Partial Denture (South Ken MD)
• Understanding Dental Code D5110 — Complete denture (DayDream Dental)
• Dentures Guide: Complete, Immediate, and Partial — Choosing What Fits Your Life (Panhandle DDS)
• How Much Do Full Dentures Cost? Complete Price Guide (Dental Team FL)
• FDA — OTC Denture Cushions, Pads, Reliners, Repair Kits, and Partially Fabricated Denture Kits
• International Journal of Science, Architecture, Technology, and Engineering (IJSATE)