Elastomeric impression materials used in modern orthopedic dentistry

Abstract

This article presents a review of elastomeric impression materials currently used in orthopedic dentistry. The elastomer group is divided into silicone, polyester, and thiocol (polysulfide) materials. Silicone impression materials are widely used in orthopedic dentistry. Their structural basis is polymethylsiloxane with active terminal hydroxyl groups. Polyester materials consist of the main and catalyst components (pastes). The main component contains a polymer with imine groups, fillers, and plasticizers. Sulfonic acid ester is present in the catalyst paste. When these two components are mixed, ionic (cationic) polymerization occurs. Polysulfide materials are produced as base and catalyst pastes. The structural unit of the main paste is polysulfide or mercaptan rubber, and the catalyst paste acts as an oxidizer. Lead dioxide is often used as an oxidizer. The resulting polymer does not have a stereoregular structure, which causes its stickiness. It is technologically challenging to obtain a polymer with a stereoregular structure.
 When theoretically comparing the listed types of elastomeric impression materials, according to their properties, chemical composition, advantages, and disadvantages, polyester and polysulfide impression materials can be distinguished as more advanced. Silicone materials have disadvantages; however, they are often used for domestic dentistry owing to the presence of domestic manufacturers and relatively low cost.