What are the elastomeric impression materials?
There are 4 groups of elastomers; polysulfide, condensation silicone, addition silicone and polyether; each differ in their setting mechanism and their physical and chemical properties.
Is alginate an elastomeric?
Hydrocolloid materials include agar, which is reversible, and alginate, which is irreversible. Elastomeric materials include polysulfide, polyether, condensation-cured silicone, and addition-cured silicone. Alginate is currently one of the most popular impression materials. It is supplied as dust-free powders.
How are elastomeric impression materials dispensed?
Manipulation of Impression Materials. Currently, elastomeric impression materials are supplied for three modes of mixing: hand mixing, static mixing, and dynamic mechanical mixing (Figure 8-8). A, Hand mixing. Two equal lengths of the material are dispensed on the mixing pad with the mixing spatula.
What is elastomeric material used for in dentistry?
Elastomeric impression materials (addition silicones and polyethers) offer high elastic recovery and acceptable flexibility on removal of the impression from the mouth. Recently, new elastomeric impression materials with very high elastic recovery and high tear strength have been introduced.
How are elastomeric impression materials mixed?
elastomeric materials use an Automix system. the extruder gun insert is a dual cartridge with a tube of catalyst and a tube of base. although technique may vary, when assisting a dentist in taking an elastomeric impression, mix the light-bodied material first.
How is the VPS impression materials supplied?
Polyether impression materials are supplied as a base (containing moderate length polyether macromonomer with terminal ethylene imine rings, silica filler and a plasticizer) and a catalyst (2,5 dichlorobenzene sulfonate, thickening agents and colorants).
Is VPS the same as PVS?
Polyvinyl siloxane (PVS), also called poly-vinyl siloxane, vinyl polysiloxane (VPS), or vinylpolysiloxane, is an addition-reaction silicone elastomer (an addition silicone). Polyvinyl siloxane is widely used in dentistry as an impression material.
What are the different types of elastomeric impression materials?
The impression taken should be highly precise, thus, requiring specific care when manipulatingthese materials. There are 4 groups of elastomers; polysulfide, condensation silicone, addition silicone and polyether; each differ in their setting mechanism and their physical and chemical properties.
When to pour elastomeric impressions on the mouth?
Rubber materials are viscoelastic, so impressions should be poured 30 min after removal from the patient mouth in order to get the whole elastic and delayed recovery of imp.mat. Comparative Properties 28. Chemical properties: 1. Dimensional changes…
What are the different types of elastomer materials?
There are 4 groups of elastomers; polysulfide, condensation silicone, addition silicone and polyether; each differ in their setting mechanism and their physical and chemical properties. This review elaborates the major properties of elastomers and its implications on their use.
Why are polyethers used as an impression material?
Polyethers have excellent dimensional stability. They also have excellent wettability, resulting in minimal voids and excellent reproduction of detail. Wettability An impression material should have intimate contact with the tooth and underlying soft tissues and should not form bubbles or voids.