You may understand the basic gist of an amalgam filling procedure: the dentist will remove the decay and restore the missing enamel with a silver restoration. However, if you are going in for an amalgam filling, you may wonder why this procedure may take half an hour or more. There are many important steps besides just placing the filling. Here are just a few steps you may encounter.

Dental Dam Placement

Dental dams are thin latex barriers that can isolate one or several teeth that need fillings. They isolate the area from debris and moisture—like saliva. Restorative materials can break down if exposed to moisture, so the dam is a great way to isolate the site. Plus, moisture can irritate exposed tooth pulp or the living portion of the tooth, so this is a great way to protect the pulp before the amalgam filling is placed.

Remember to breathe through your nose should your dentist use a dental dam. If you have a strong gag reflex, you can ask to be seated higher up instead of supine. 

Dental Matrix Placement

Do you need a filling on the side of a tooth? If so, your dentist will place a matrix band. These metal bands fit snugly around the tooth. Thankfully, you will be numb during this portion of the procedure, so it shouldn't be uncomfortable. If the dentist didn't use a matrix band, then the amalgam filling would seep out since there would be no enamel wall to hold in in place. Once the amalgam filling is seated and hardened, then the matrix band can be removed.

Dental Liner and Base Placement

When you have a deep cavity, the pulp may be exposed to the restoration. If your dentist just placed a filling straight on to this exposed surface, the dentin could become irritated and sensitive.

Before placing the silver amalgam, your dentist will use a liner, such as a cavity varnish or calcium hydroxide, to seal the dentinal tubules. Dentinal tubules are small channels in the enamel that also radiate to the pulp. When these are sealed, then the pulp will be insulated and protected. Some dentists use liners that contain fluoride, which provides extra strength to the tooth and helps with sensitivity.

If the cavity is very deep, your dentist may place a base along with the liner. Like a liner, bases are great at sealing the dentin and reducing irritation. They also are resistant to water and are insulating. As you can see, many important preparations need to be made before your amalgam filling is placed. Contact a dentist in your area for more information.