Temporary cements are designed to keep the temporary crown or bridge in place and, at the same time, are easy to remove when it's time to place the permanent restoration. One of the most commonly used materials for the manufacture of temporary restorations of crowns and bridges is methyl methacrylate. This category is also called polymethylacrylic methacrylate (PMMA). The material is available in powder and liquid form and is self-healing.
The liquid is mainly composed of methyl methacrylate and small amounts of other chemicals, and the powder is predominantly a dibutyl or diethyl polymer and phthalate. These materials come in various tooth colors and also as transparent material that can be used for surgical stents or orthodontic retainers. Temporary methyl methacrylate materials can be added by adding more material; the best adhesion occurs to a clean surface that has been moistened by the monomeric liquid. The temporary crown is prepared by a dental technician in the laboratory based on the impression of the filed tooth.
The dental technician prepares the plaster model on which they produce a temporary crown in acrylic resin. When the crown is ready, the dentist fixes it to the tooth with temporary cement.