Amalgam or silver fillings have been a staple for dentistry for many years. They have shown to be a very good restoration for cavities as they hold up well to the stresses of chewing and are fairly resistant to failure. Some of you have these fillings that have lasted even 30 plus years. But, there are many issues with these materials. Size is a big factor in longevity and what it does to the tooth long term. Small amalgams generally don’t cause cracks generally(although I’ve seem suprising cracks in very small fillings) and last a long time typically. Large amalgams generally cause cracks and the need for a crown at some point. This is inevitable. “White” fillings, called composites, bond to the tooth so they pull the tooth together and generally will not cause cracks to form. This is one of the primary benefits other than the obvious, they look like the tooth’s color!
Amalgams also have Mercury, a metal known to be toxic.