Classification of impression materials in dentistry
What are the classification of impression materials?
Classification of Impression Materials
By their composition, the impression materials are divided into three major groups: nonaqueous elastomers, hydrocolloids, and inelastic materials. Elastomers include polysulfide, condensation and addition silicone, and polyether. Hydrocolloids are alginate and agar.
What are the three classifications of impressions used in dentistry?
There are three main types of dental impressions — preliminary, final, and bite registration.
What are dental impression materials?
Impression materials are used in dentistry to record the details of intraoral structures to fabricate a reproduction of teeth and soft tissues for the construction of dental prostheses.
What is impression tray classification?
Plastic impression trays are generally single use (disposable). Another special type of plastic impression tray is the “dual-arch” tray. Dual-arch trays consist of a handle, an external structure (vestibular and lingual) in rigid plastic in the shape of a “U” and a floor made from flexible plastic mesh.
What are the 3 types of impressions?
Impressions fall into three basic categories: patent, latent, and plastic. Plastic impressions are three-dimensional imprints. These impressions can be left in soft materials such as snow, mud, soil, or soap. Depending on how it is made, impression evidence may be either class evidence or trace evidence.
What types of impressions are there?
Types of Impression Material
- Light body-is the easiest-flowing material to flow.
- Regular body-is slightly thicker than the light body form.
- Heavy body –is the thickest of the three forms.
What are the two basic types of impression trays?
There are two kinds of full and partial denture trays: trays with perforations, for use with alginate impression materials, and solid, nonperforated trays for use with solid impression materials, such as red compound or fast-set impression plaster No.
What is special tray?
An individualized impression tray made from a cast recovered from primary impression. It is used in making a final impression. Special tray is constructed on the primary cast.
What are the three types of custom impression trays?
Impression trays are supplied as quadrant trays, which cover half of the arch; section trays, which are suited for the anterior teeth; and full arch trays, which cover the complete arch.
How are impressions used in dentistry?
Impression materials are used to copy the teeth and surrounding oral structures by creating a dental impression poured with dental plaster to fabricate a dental cast. This procedure provides a tridimensional and accurate mouth replica, allowing dental work even in the absence of the patient.
What are the three curing stages of impression materials?
Curing Stages of Elastomeric Materials
- Initial set.
- Final set.
- Final cure.
What is impression in dentistry?
Dental impressions are an impression of the teeth and the mouth to form shapes from which objects are formed. Dental impressions are used to create a close replica of either your set of teeth or your oral tissue or both.
What material is used for final impressions?
There are many materials for the final impression, such as gypsum, zinc oxide and eugenol (ZOE) paste, polysulfide rubber, polyether, polyvinyl siloxane, and alginate.
What are the four types of elastomeric 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.
What is PVS in dental?
[1] The most popular elastomer used in the dental practice today is the polyvinyl siloxane (PVS). PVS impression materials have low dimensional change, low creep, and relatively short setting time, have moderate to high tear resistance.
What is the best impression material?
The preferred elastomeric impression materials on the market are polyvinyl siloxanes (PVS) and polyethers (PE). Polyethers are known for their hydrophilic properties and good flowability. Polyvinyl siloxanes, on the other hand, are known for their excellent elasticity, high tear strength and stability.
What type of material is alginate?
Alginate is an elastic, irreversible hydrocolloid impression material. Irreversible hydrocolloid impressions form an inseparable part of indirect restorations.
What is putty impression material?
Silicone based dental putty as an impression material
Making dental impressions is a major part of dentistry. Therefore, there are different materials developed for the purpose suitable for the process of making crowns, bridges, braces and prosthesis.
How long is pvs stable for?
According to the manufacturers, both polyether and vinyl polysiloxane impressions may be stored for up to 14 days prior to pouring of the dies without compromising the accuracy of the material.
Why secondary impression is called wash impression?
“Wash impression” – this is a very thin layer of low viscosity impression material which is used to record fine details. Usually it is the second stage, where the runny impression material is used after an initial impression taken with a more viscous material.
What impression material is used for crown and bridge?
Vinyl polysiloxanes
The purpose of an impression material is to accurately reproduce the patient’s intraoral structures. Vinyl polysiloxanes (i.e., addition-cured silicones), a staple of most dental practices, are often used to capture these structures.
How do you store impressions?
Do not store polyether impressions in sealed plastic bags while still moist. Avoid direct sunlight expo- sure. Store in a dry place at room temperature 23 °C/73 °F. Polyether impressions can be poured anytime within 14 days after they have been made if stored properly.