Polyethers And Polysulfides

Polyethers And Polysulfides

“What are polyethers and polysulfides? A detailed question and answers guide”

Polysulphide Rubber-base Impression Material:

• This was the first elastomeric impression material.
• It is also known as “Mercaptan” and “Thioko”

Composition of Polysulphide Rubber-base Impression Material:

• Base Paste
  • Liquid polysulphide polymer    –    80 – 85%
  • Inert filer (titanium dioxide, zinc sulphate, copper carbonate, and silica)  -16 – 18%
• Reactor Paste
• • Lead oxide –  60 – 68%
  • Dibutyl phthalate – 30 – 35%
  • Sulfur –  03%
  • Other substances like (magnesium stearate (retarder) and deodorants) – 02%

“Understanding polyethers and polysulfides through FAQs: Composition, properties, and uses explained”

“Importance of studying polyethers and polysulfides for dental professionals: Questions explained”

Manipulation Polysulphide Rubber-base Impression Material:

• High viscosity material, i.e. Put is usually supplied in small tubs with different colored scoops for identification and dispensing.
• Equal quantities of both the pastes are taken. Mixing is done by hand by kneading the material together to obtain a uniform mix without any streaks.
• Manufacturers also supply base and catalyst in separate tubes with a much smaller diameter opening for a catalyst to enable dispensing equal lengths of base and catalyst, though the volume is different.
• For polysulphide, mixing of low viscosity material is accomplished by taking equal lengths of base and catalyst on a paper pad and manipulating by stiff bladed spatula
  in a circular motion for 45 seconds till the mix is free from streaks.
• Mixing is done in a large area to dissipate the heat.

Advantages of Polysulphide

• Excellent reproduction of surface detail as fie as 0.025 mm wide
• Polysulphide can be electroplated more with silver than copper
• The shelf-life is good (2 years)
• Polysulphide has good flexibility (7%)
• Polysulphide has high tear strength (4,000 g/cm) thus making it more resistant to tearing even when the impression is in thin section.

“Common challenges in mastering impression material knowledge effectively: FAQs provided”

Disadvantages of Polysulphide:

• Unpleasant odor and color.
• These materials are extremely viscous and sticky. Mixing is difficult.
• Polysulphide has long setting time which adds to the patient discomfort.
• Dimensional unstability: It has high permanent deformation. The curing shrinkage is high, and loss of byproduct (water) also causes shrinkage.
• Staining is present due to lead dioxide.