Dental Materials

Polyethers as impression material



A. Development

Polyether impression material was developed in the late 1960s for use as
a dental impression material.

It was not borrowed from another industry.

Polyether impression material was significantly different from the other materials available at that time.

B. Chemistry-Optional

These materials have an ether group in the molecular structure.

An ether group is an oxygen atom that is bonded to two carbon atoms.

– Polyether impression materials set via a unique, ring-opening polymerization reaction that is thought to offset some polymerization shrinkage.

– The polymerization reaction is called cationic polymerization.

– Cationic polymerization is similar to addition polymerization except that instead of a free
radical, a cation (positive ion) is the reactive molecule.

– No reaction by-product is produced.

C. Properties and Use

The working and setting times are shorter than those for polysulfide materials; they are more like those of addition silicone materials.

– Polyether impression materials are very stiff compared with other materials and set quickly.

Polyether impression materials come in a single viscosity, much like the medium viscosity of other types of materials.

They are clean materials to use but have an unpleasant taste.

Polyether impression materials are very accurate and easy to pour with gypsum products.

These properties and the ease of use make polyethers popular.

The cost of polyether materials is similar to that of addition silicone materials.

They are very stiff, which makes them well suited for use with a disposable triple tray.

Impregum is the most popular polyether product.

The popularity of polyether impression materials has resulted in addition silicone
“Impregum clones.”

The addition silicone clones have the same viscosity, stiffness, and even the purple color as Impregum.

These clones are often called monophase impression materials.

– As with polyether materials, a single-viscosity addition silicone material is used in the syringe and the tray.

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