Flexible partial dentures.
Valplast and comparable nylon thermoplastics produce a metal-free partial with no visible clasps. They solve a real aesthetic problem and they carry genuine limitations. Tick Valplast on the Rx.
What they do well
The retentive elements are tooth-coloured or gingival-shaded extensions of the base material, engaging undercuts without a visible metal clasp. For a patient who has refused a partial on the appearance of clasps, that is frequently the difference between wearing something and wearing nothing.
The material is resilient rather than rigid, which makes them comfortable and difficult to fracture — they flex rather than snapping. They are also thin and light compared with acrylic.
They contain no metal, which resolves the question for a patient with a documented alloy sensitivity.
What they do not do
They are not rigid, so they cannot provide tooth support in the way a cast framework does. Load is transmitted to the mucosa rather than along the long axes of the abutments, and the ridge resorbs beneath them over time.
They cannot be relined or adjusted with the ease of acrylic — the material does not bond to conventional acrylic repair materials, so relines, additions and repairs require the same thermoplastic and specific technique.
That combination means a flexible partial worn long term in a free-end saddle case tends to sink, and the resorption it causes is not easily compensated for.
Where they are the right choice
Short bounded saddles, unilateral cases, and situations where the surrounding teeth provide genuine bracing. Transitional use while a definitive plan proceeds. Patients with a metal sensitivity. And patients whose objection to a cast partial is specifically the visible clasp.
Where they are a poor choice: long free-end saddles, cases needing definitive tooth support, patients with limited remaining dentition, and any situation where the prosthesis will be the long-term definitive solution.
Set expectations accordingly. A flexible partial presented as equivalent to a cast framework will disappoint; presented as an aesthetic solution with a defined role, it performs well.
Preparation and records
Minimal preparation is one of the attractions, though a small amount of recontouring can improve the path of insertion and the way the retentive extensions sit.
The impression needs to capture the full sulcus depth and the denture-bearing areas as well as the teeth, and the undercuts that will provide retention have to be recorded accurately — the material engages them directly.
An accurate opposing arch and jaw relation are needed as for any partial.
Maintenance and patient instructions
Cleaning is different from acrylic. The material should not be brushed aggressively or cleaned with hot water, which distorts it, and some denture cleansers are unsuitable.
Give the patient specific instructions rather than assuming they will treat it like a conventional denture. A distorted flexible partial cannot be reshaped chairside.
See appliance care for patient guidance.
Adding to a flexible partial
Where a further tooth is lost, adding to an existing flexible partial is possible but not straightforward — the material does not accept conventional acrylic additions, so the work has to be done in the same thermoplastic.
For a patient whose remaining dentition is deteriorating, that is worth weighing at the outset. A cast framework designed with future additions in mind is easier to modify over time.
Send the prosthesis with an accurate impression of the current situation and describe exactly what is being added.
What to put on the prescription
Tick Valplast under Type of Denture. Mark the saddles and the teeth being engaged for retention on the design chart.
Give the teeth shade and mould, and note whether the case is transitional or intended as definitive — it changes how the prosthesis is designed and what should be said to the patient.
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Digital scans and conventional impressions are both accepted. Cases move by UPS and Purolator, and Fairmont works with practices throughout British Columbia and across Canada.