In an alginate impression material, tri sodium phosphate is the:
- A- filler.
- B- reactor.
- C- retarder.
- D- accelerator.
The correct answer for the role of tri sodium phosphate (TSP) in an alginate impression material is: C. Retarder
Here's why the other options are incorrect:
A. Filler:
TSP doesn't function as a filler in alginate impression materials. Fillers like diatomaceous earth are added to provide bulk and improve handling characteristics.
B. Reactor:
While TSP interacts with calcium sulfate to initiate the cross-linking reaction, it isn't considered the primary reactor. Calcium sulfate itself drives the setting reaction in alginates.
D. Accelerator:
TSP actually slows down the setting reaction by binding to calcium ions that would otherwise participate in the cross-linking process. Therefore, it acts as a retarder, allowing more working time for manipulating the impression before it sets.
In summary, tri sodium phosphate plays a crucial role in extending the working time of alginate impression materials, making them easier to handle and ensuring accurate impressions.
