Everything wears out at some point.
After getting a knee replaced the Dr. will typically say,
"that should last you about 15 years."
I got Lasik done and the Dr, told me that I would
have to come back in to get it touched up over time.
The same can be said for metal fillings.
Over time, they will break down and need to be replaced.
Just beware of a few scams out there.
#1 All of you metal fillings need to be replaced at one time.
#2 The metal is bad for you and will cause a disease so they need to come out.
Neither of these are true.
If all of your metal was placed at the same time then perhaps a few of them
are going bad together but MANY factors dictate rate of decay.
Where the filling is on the tooth.
Where the tooth is in the mouth.
Etc.
Also, it has been proven over and over again that the contents
of metal fillings (in the state they are in in your mouth) do
not cause diseases.
Here is an example of a filling that was going bad.
It's pretty plain to see that there is decay around the
edges of the filling.
We then put a white one in.
The effects are fairly dramatic.
The patient was very pleased.