Has this ever happened to anyone or do any of you know if it's true?!

Has this ever happened to anyone or do any of you know if it's true?

I have been reading a lot online about fillings and the silver ones versus the tooth colored. Something I read, was that there are a lot of claims that silver fillings are not as durable and that they leak, and expand and can cause the tooth to crack over time. For this reason many people are opting to replace their silver fillings with the tooth colored ones. When I read this it kind of alarmed me because I have silver fillings on most of my teeth in the back or on the sides. If they are known to cause the teeth to crack then I was thinking about getting them replaced with the tooth colored ones. I wonder is this true and have any of your teeth cracked because of a silver filling? Of course I will ask my dentist first, but I just don't want to have to worry about my teeth cracking. I've had these fillings since I was a teen and i'm in my 20's now. So I don't know how much longer they'd last.

I am sure plenty of people will answer you this question but I will attempt it. Yes alloys (dental silver fillings) do expand and contract with temperature and (if they are big can cause a tooth to crack. They can leak sometimes as well...this is normally due to bad dentistry but it can happen. They can re-decay (meaning you would need a new filling.
Having said all this....the tooth colored fillings have these and problems as well... Number one is that they shrink when they turn hard...why is this important..because it will leave microscopic gaps much bigger than that of a silver filling. The greater the gap between filling and tooth the greater chance of more decay and failure.
As of today, the tooth colored fillings are lasting between 4-7 years...whereas the silver fillings are lasting between 10-15. You will have the risk of fracture with alloy but you will also have a much higher chance of not needing a new filling with alloy.
The bigger debate today is whether the mercury in the filling will kill you...some say it will...Myself and the American dental association say it won't. The state of California and Europe are trying to ban alloy. The rest of the world is not. It is a tough decision.
As a dentist though, If I needed a filling that was on two surfaces or less of the tooth...I would want alloy...except if it were up front :)
Good Luck
PS If a filling is large enough, fracture is likely for either filling material.