Originally Posted by sengsational
I'm in a similar spot, with my previous dentist being a "not broke, don't fix it" guy. But there have been a few failures that ended up with crowns, and I have some teeth that probably have significant cracks. The severity of the cracks apparently can't be determined without looking under the filling. But if there is a risk of a big failure, it would take a crown, not just a composite filling, to protect the natural tooth from failing.
Exactly! If the amalgam filling is too big, that means that the remaining tooth that supports it may be weak, and unable to withstand the forces applied to it. The tooth will develop cracks over time, or may just fracture cleanly away.
If the tooth is too weak to be adequately restored with an amalgam, it needs a crown, or some sort of restoration that wraps around the walls of the tooth, like a helmet, to protect it from fracturing.
Replacing that amalgam with a composite and saying it's stronger is sketchy at best.