Elastomers (polysiloxanes) :Used to identify materials with a particular structure. Are organic materials consisting of polymer molecules with the ability to "stretch", "develop," compressed "ultimately bear to tensions mouth.
Chemically there are four types ofelastomeric impression materials used as: 1.Polisulfure2. Silicone condensation polymerization 3. Addition polymerization silicone 4.Polyether
According to the reaction to which they are subject to change to a plastic state Those who change their status in a physical reaction, it is to say, which do not change their properties, only its consistency when subjected to heat. . Wax printing . Model compounds or Godivas .reversible hydrocolloid
Classification according to theirbehavior during setting, hardening or curing. elastic:. Mercaptans.. Elastomers silicones.. Polyethers. rigid: Model compounds or góbidas. Waxes. Casts.
characteristics to be met by printing materials to be considered optimal for management Easy to handle. . Compatibility with oral tissues. . There are irritating. . Not allergic. . Taste and look nice mix. low cost. . that when subjected to disinfecting solutions preventing alterations. Hydrophilic Where possible, that does not affect the presence of moisture
Use of elastomers in odontology : 1 PLAY STRUCTURES WITH HIGH FIDELITY MOUTH. Fig#5
2. OCCLUSAL RECORDS MAKE OR BITE, ACCURATE . http://expodenta l.wordpress.com Fig#63 OTHER USES : MISMATCH INDICATOR OFRESTAURATIONS Fig#7 http://www.slideshare.net/yuritek/elasto m2005-presentation
- PRINTING MATERIAL FOR DUPLICATE MODELS http://www.slideshare.net/yu ritek/elastom2005- presentation Fig#8
Silicones: Elastic materials are based impressions polydimet hyl siloxanes orpolyvinyl siloxanhttp://www.dentald es. They owe their name toeml.com/catalogo/c the presence of silica andubetadealuminio.ht oxygen in its compositionmFIG#9
Uses: prints are used for crowns and fixed bridges For bite registration and laboratory procedures for the process of partial and full dentures. Fig#17 Fig#18
Condensation silicone compositionpolydimethylsiloxaneEthyl ortho silicateSilica fillerCATALYST : Tin octoateTin octoateSilicone Rubberethyl alcohol. The chemical reaction of a condensation silicone is as follows silicate ortoalquílico polydimethylsiloxane+ silicate ortoalquilico ---- polydimethyl siloxane + Alcohol
PROPERTIES: . The working time of the silicones is 2- 4 minutes less than the mercaptans Polymerization time: 6- 3 minutes is comparatively less than the mercaptans, the polymerization time can be changed with temperature temp. High polymerization acce lerates Dimensional Stability: Like other print materials, condensationsilicones contract. . Can be reduced using well adapted trays with a thickness of 3 to 4mm.
. Elastic recovery: the recovery is approximately 100% higher than virtually all other elastic materials. Fluency: compared with the mercaptans, these materials are morerigid and therefore have better flow. Flexibility: inflexible compared to the mercaptans and more flexible than the polyesters Toxicity of silicones are not toxic, however it is recommended not to touch his hands and not take material improperly mixedimpressions.
easy handling .Sensitive to high .It is stable over temperatures short periods of time .Evaporation of alcohol .Have different elastic .Short working properties time for multiple prints .Can be prepared .Greater contraction of with different polysulfides viscosity resists .Short life displacement of the gingival tissues .It has pleasant taste and odor