Keystone Tray, Retainer and Spacer Sheets: A Thickness and Material Guide

Keystone tray, retainer and spacer sheets cover the most common thermoformed lab work: Tray Material at .125 or .150 for custom impression trays, Retainer Material at .030 for clear retainers, and reusable Spacer Foam to create relief. Chase Dental Supply carries the full range of Keystone Industries 5×5 sheets, and this guide matches each thickness and material to the appliance it is made for.

Key Takeaways

• Tray Material is pure, high impact styrene in .125 or .150 for custom impression trays, with spacer foam included.
• Retainer Material is a stiff, clear .030 sheet in Clear or Super Clear, and acrylic sticks to it.
• Spacer Foam makes the cast easier to remove, works with all materials and is reusable.
• Base Plate Material comes in .060, .080 and .100 with a low melt temperature for denture bases and wax bite plates.
• Bleaching Laminates and Crown and Bridge Material are both .020 but serve very different jobs.

What Are Keystone Tray, Retainer and Spacer Sheets?

Keystone tray, retainer and spacer sheets are 5×5 thermoplastic and foam sheets that labs and practices form over stone models on a vacuum former. Each material is engineered for a specific appliance, so the right choice depends on rigidity, clarity and whether acrylic needs to bond.

High impact styrene is a rigid thermoplastic used for custom impression trays and base plates because it holds its shape under impression loads. Clear retainer materials are stiffer, transparent sheets designed to stay discreet in the mouth.

Every sheet performs better on a clean, accurately trimmed model. For model base formers, trimmers and dowel pins, see our model prep essentials guide.

Which Keystone Sheet Thickness Should I Choose?

Choose the thickness the appliance calls for: .125 or .150 for impression trays, .030 for retainers, .060 to .100 for base plates, and .020 for bleaching trays or temporary bridges. The table below summarizes Keystone’s published options.

How Do You Make Custom Impression Trays with Keystone Tray Material?

You make a vacuum formed custom tray by placing spacer foam over the model, forming Tray Material over it, then trimming the borders and removing the spacer. The finished tray leaves room for impression material and fits the patient’s arch.

Keystone Tray Material

Keystone Tray Material is pure, high impact styrene in .125 or .150 thickness, supplied as 5×5 sheets in packages of 100 or 625. Spacer foam is included, so a new package is ready for custom impression tray work.

Keystone Spacer Foam

Keystone Spacer Foam is a 5×5 sheet used as a spacer material that makes the cast easier to remove. One size works with all materials, the foam is reusable, and it comes 25 per pack.

Some labs prefer light-cure tray resin over thermoformed trays. Our guide to the Keystone Procure 300 light oven explains how light-cured trays are processed.

What Is the Best Keystone Material for Clear Retainers?

Keystone Retainer Material is the sheet made for invisible orthodontic retainers. It is a stiff, clear .030 sheet in Clear or Super Clear.

Because acrylic sticks to Keystone Retainer Material, ortho labs can add acrylic components when a case calls for them. It comes in 5×5 sheets in packs of 25, 50 or 625.

Base Plate, Bleaching and Crown and Bridge Sheets: What’s the Difference?

These three sheets solve different problems: base plates for denture work, bleaching laminates for whitening trays, and crown and bridge material for temporaries. Picking the wrong one usually shows up as a tray that is too thin or a matrix that sticks to acrylic.

Keystone Base Plate Material

Keystone Base Plate Material is pure, high impact styrene in .060, .080 or .100 thickness with a low melt temperature. It is used for denture bases and wax bite plates.

Keystone Bleaching Laminates

Keystone Bleaching Laminates are only .020 inches thick once formed over the model and include a foam liner that absorbs the bleach. Keystone calls it its biggest-selling item for bleaching, packed 50 per box.

Keystone Crown and Bridge Material

Keystone Crown and Bridge Material is a thin, clear, rigid .020 (.50mm) sheet for temporary bridges. Acrylic does not bond to it, so it works as a clean matrix.

Keystone Soft EVA Material

For soft appliances, Keystone Soft EVA Material is a clear, easily trimmed sheet used for bleaching trays, soft bruxing appliances, custom fluoride trays and model duplication. For harder-wearing guards, see our night guard and splint materials guide.

Form any of these sheets on a Keystone unit such as the Keystone Machine III Vacuum Former, and compare all three machines in our Keystone vacuum former buyer's guide.

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Frequently Asked Questions

What thickness is Keystone Tray Material?

Keystone Tray Material comes in two thicknesses, .125 and .150. It is pure, high impact styrene in 5×5 sheets, made for custom impression trays, and sold in packages of 100 or 625 sheets with spacer foam included.

What is Keystone Retainer Material used for?

Keystone Retainer Material is a stiff, clear .030 sheet used for invisible orthodontic retainers. It comes in Clear or Super Clear, 5×5 sheets in packs of 25, 50 or 625, and Keystone notes that acrylic sticks to the material.

What does spacer foam do in a custom tray?

Spacer foam creates room between the model and the tray material so the finished impression tray leaves space for impression material. Keystone Spacer Foam is a 5×5 sheet that makes the cast easier to remove, works with all materials, is reusable, and comes 25 per pack.

Which Keystone sheet should I use for bleaching trays?

Keystone Bleaching Laminates are made for bleaching trays. They are .020 (.5mm) thick once formed and include a foam liner that absorbs the bleach. Keystone also lists bleaching trays among the uses for its Soft EVA Material.

Does acrylic bond to Keystone Crown and Bridge Material?

No. Keystone Crown and Bridge Material is a thin, clear, rigid .020 (.50mm) sheet that acrylic does not bond to, which makes it useful as a matrix for temporary bridges. If you need acrylic to stick to the sheet, Keystone Retainer Material is the option that accepts acrylic.

Browse every brand we stock in our dental lab and office supply brands guide. Chase Dental Supply carries Keystone Industries sheet materials in the thicknesses and bulk pack sizes labs and practices rely on. For help choosing a thickness or ordering in volume, email sales@chasedentalsupply.com.