Can Dental Fillings Shrink?

Posted on: 28 February 2022

As the years go by, people will literally shrink. Not by much, and it's largely due to the way in which your bones connect together, but adults in their golden years may lose a tiny amount of their overall height. Shrinkage can occur elsewhere in the body, and it can even affect parts of your body that you weren't in fact born with. How is it possible for your dental fillings to shrink?

Composite Resin and Amalgam 

The two primary types of material for a dental filling are composite resin (tooth-colored) and amalgam (metallic), although the latter isn't as widely used as it once was. While composite resin fillings may shrink as they dry (immediately after application), this effect is accounted for in the amount of the material that's applied to the tooth. So this minor shrinkage won't prevent the filling from covering the cavity. The composite resin has adhesive qualities, so it's intended to hug the cavity as tightly as possible, for many years to come.

Amalgam Shrinkage

Amalgam fillings are also a long-term solution, but shrinkage is a way in which amalgam shows its age. The temperature and moisture fluctuations in your mouth (over the course of many years), in addition to the considerable bite forces the tooth (and its filling) are subjected to each day, means that the amalgam filling may contract, and will begin to pull away from the edges of the cavity. This can lead to an unfortunate consequence known as microleakage.

Microleakage and Your Filling

Microleakage creates a miniscule entryway into the tooth's internal structure. This allows bacteria (and even microscopic fragments of food) to enter the tooth. It can conceivably begin to affect the pulp (nerve) at the center of the tooth. Irritated dental pulp will quickly lead to toothache, and a root canal may prove to be necessary if infection should overwhelm the pulp. Replacing the filling should prevent this from happening. But how do you know when this has become urgent?

Solutions and Prevention

Any irritation to a tooth fitted with a filling must be assessed by your dentist. Minor toothache that has just begun to be noticeable doesn't mean that your dental pulp has been irreversibly infected, but it's important to have your aging filling assessed and replaced. Fillings are checked as part of your regular dental checkups, so your dentist should be able to spot the early signs of microleakage before it becomes significant. Of course, this identification method is only going to work if you attend your regular dental checkups.

Fillings can in fact shrink and leak, which is simply the filling showing its age, and demonstrating that it needs to be replaced as soon as possible.