Introduction
Phosphate cement is a material that has been used in dentistry for over a hundred years. It has a white color. Phosphate cement can be mixed together from a powder and a liquid and is often used as a luting cement for the definitive placement of metal crowns or veneer crowns and bridges. It can also be used as an underfilling.
Composition of phosphate cement
Phosphate cement consists of cement powder and liquid. The liquid consists of 45-64% phosphoric acid and zinc and aluminum buffers to reduce the setting time.
- 80% zinc oxide (ZnO),
- 10% magnesium oxide (MgO),
- 5% calcium fluoride (CaF2),
- 4% silicon dioxide (SiO2),
- 1% aluminium oxide (Al2O3).
- Filling materials
- Tooth filling with cement
What is phosphate cement used for?
Phosphate cement is very often used in the dental surgery. It is used for the permanent cementation of metal crowns and bridges and can also be used as an underfill. It has high compressive strength and minimal setting shrinkage.
In contrast to other luting materials such as glass ionomer cement or composites, phosphate cement is less sensitive to moisture and easy to process.
- Temporary filling
- Dentures
- Bridge
- Crown
Phosphate cement used to be very often used as an underfilling before placing an amalgam filling. It can also be used as underfilling after a root canal treatment.
However, since it has a low bending strength and does not adhere to dentin, it can break off or crumble away quickly. In order to use phosphate cement as an underfilling, it should be mixed to a solid consistency and inserted into the previously dried tooth with a suitable metallic stopper, such as a plane stopper or a small ball stopper or Heidemann spatula. The working time after mixing is about two minutes. The phosphate cement should have hardened before the next definitive filling. This is the case after 7-8 minutes, but depends on the mixing consistency.
