Impression materials

Impression materials are used for the negative imprints (prints) with jaws. On the basis of impressions cast plaster models, which produce dentures (see).
Prints divided into anatomical and functional. The first is used in partial defects of dentitions; they are removed by means of the standard impression spoons (see Dental tools). Functional imprint resort in the absence of teeth, get it using individual spoons.
On the physical properties impression materials are divided into four main groups: 1) thermoplastic [wax (see Wax in dental practice), the gutta-percha (see), stent and other], 2) elastic (angelost, tomalin, calcinate, elastic and others), 3) crystallizing (eugenol-acticinbuy pasta, Repin, gypsum and other), 4) cured (AKR-100, stracel, duracryl, silicone mass). Impression materials of the first group when heated (55-60 degrees) are softened, but solidify when cooled.
O. M. the first group is used for taking impressions, often subsidiary, except gutta-percha.
O. M. the second group used primarily for the removal of prints in partial defects of dentitions.
Impression materials of the third group favorably differ from the others by its flexibility, fluidity; give a fairly accurate and smooth imprint prosthetic field. Use them mainly for prints with toothless jaws (especially the bottom). One of the main positive features of these pastes is their minimal shrinkage.
Widespread O. M. based on silicone polymers: plastic, elastic, select. Also used and tikalova mass. They consist of polysulfide rubber, zinc oxide, calcium sulfate. These masses are also used mainly for removal of prints of the edentulous jaw.
It is widely used dental impression materials include gypsum, which is used throughout the manufacturing process of the prosthesis.
The main requirements to the impression materials are accurate prints that weight easily deduced from the mouth and the resulting output is not deformed. The abundance of offered materials testifies to the incomplete conformity with the essential requirements.