Ideal Properties Of Impression Materials
Ideal Requirements of an Impression Material:
- Have a pleasant taste, odor, and aesthetic color.
- Not contain any toxic or irritating ingredients.
- Have an adequate shelf-life for storage and distribution.
- Be economic.
- Be easy to use with the minimum equipment.
- Have adequate setting characteristics that meet clinical requirements.
- Possess a satisfactory consistency and texture.
- Have an adequate strength so that it will not break or tear while removing from the mouth.
- Possess elastic properties with freedom from permanent deformation after strain.
- Exhibit dimensional stability.
- Be compatible with the die and cast materials.
Disinfection Of Impressions
Disinfection of impression is a concern because of viral diseases such as hepatitis B, AIDS, and herpes simplex.
The viruses can contaminate the gypsum mould and present a risk to dental laboratory and operating personnel. As impression is removed from the mouth, it is disinfected before pouring the cast to prevent cross-contamination.
- As per protocol of Centers for disease control and Prevention, hydrocolloid impressions should be immersed in household bleach, iodophors or synthetic phenols.
- As the impression is taken out from mouth, it is thoroughly rinsed and then disinfectant is sprayed over the impression.
- Now the impression is wrapped in a disinfectant-soaked towel, and is sealed for 10 minutes.
- As disinfection get complete impression is thoroughly rinsed with water to remove remnants of disinfectant which can affect surface of cast when gypsum is poured.
- For disinfecting the elastomeric impression materials recommended disinfectant solutions except for polyether are 2% glutaraldehyde, chlorine compounds, complex phenolic and phenolic glutaraldehyde compounds.
- As polyethers are hydrophilic their disinfectant protocol is same as hydrocolloids.
- Impressions are disinfected for 10 minutes in 2% glutaraldehyde and for 3 minutes in chlorine compounds.
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