IRM Temporary Filling Material

Sometimes we use this stuff called IRM, that stands for Intermediate Restorative Material. It was developed as a temporary filling material; used to buy time till the patient could have a proper, more permanent restoration. Of course, there really is no restoration that is truly permanent. A variation of this material is simply called Zinc Oxide and Eugenol or "ZOE". The stuff consists of a powder of Zinc Oxide and a liquid Eugenol which is basically oil of cloves. Yes, it smells like cloves. The clove oil sort of numbs the tooth (thus a sedative effect). IRM is the same as ZOE but has a reinforcing material added to make it more resistant to wear.

If you have a rather large cavity, you can remove the bulk of the decay and place an "IRM" filling, also known as a sedative filling. This will often slow or stop the progression of decay and help the patient feel better. It also may allow the tooth time to recover and lay down secondary dentin (sort of a second layer of scar tissue), sometimes eliminating the need for pulpal treatment like a root canal. Once the tooth is recovered and less inflamed, any remaining decay is removed and the final restoration (filling or crown) is placed. You mix the powder and the liquid together to make a kind of play dough material which is placed in the tooth. It hardens up in a few minutes. It usually lasts a pretty long time, but still will eventually wash out due to the biting forces and wear. I have seen them last anywhere from a month to more than a year.

In pediatric dentistry we use IRM it for temporary sedative fillings and to seal pulpotomies. ZOE can be used too seal pulpotomies and baby tooth root canals. You can actually buy a variation of this stuff in your local CVS or drug store. It often comes under the name, "Dent-Temp".

Here is a little video showing kind of how it looks:

IRM Video: