Filling enquiry

[Bee333]

Patient has a tiny distal filling on an upper 1st premolar that has come loose, needs a new filling, doesn’t want the hole drilling bigger but wants an amalgam filling, no decay. What would you advise?

 

[Dr M]

Why does the patient want an amalgam filling? Amalgam fillings need some sort of mechanical retention in order to stay in place. There is no chemical bond. If the initial cavity was not prepped according to the specifications for an amalgam filling, you will have to adjust the prep by drilling unfortunately, otherwise there is a chance that the amalgam filling can dislodge as well.

 

[MattKW]

If the filling has come loose, then it is either:

1. A white filling (composite resin) come loose due to failure of the bond or inadequate mechanical retention (grip).
2. A filling (composite or amalgam) that has leaked at the margins, and decay has restarted underneath.
3. A filling which has been undermined by new decay coming in from a new angle.

The dentist has to look at these factors and then advise you of the best path.

• If the filling has come loose (1), then the dentist will probably have to change the shape of the cavity to give it more grip.
• If there is decay underneath (2 & 3) then enlargement is going to be needed to get rid of the decay.

Either way, you are most likely to end up with a larger cavity.
When decay is removed, the clean cavity often has some undercuts for retention occur incidentally, and then amalgam is quite a valid choice. Composite can have poor bonding sometimes( e.g. goes under the gum level) and amalgam may be the only way. It will be a sad day when amalgam is no longer available for some difficult cases.