How long do amalgam fillings last approximately ? what is the longest time that youve seen them on a someone ?

Amalgam fillings are quite durable and can last for many years. I've seen some that can be 25+ years old. But in general, all dental restorations are considered "durable" and if you get ten years out of them you should not be disappointed. Very few if any will last a lifetime.

Amalgam fillings can last up to 20 or more years, if there is no leakage to cause decay under the filling. Also if the bite is not high causing stress on the material than the filling will last a long time. Remember nothing lasts for ever and a replacement of the filling should be done at your dentists discretion.