My previous dentist somewhat arbitrarily replaced a silver filling with porcelain. He gave two reasons, cosmetics, and silver was supposedly bad for you long term. He wanted to replace them all. The real reason was probably that I had the insurance to cover it. lol Well, the one filling he got to replace cracked not too long after and it ended up splitting the tooth in half! My current dentist said not only is porcelain fragile compared to silver, but the old dentist did a crap job installing it. I've had my silver fillings for over 30 years and never had a problem with them. If I ever need another one, I'm going to demand silver.