Actually composites can hurt your health. Do not let some dds jam some unknown composite into your jaw without knowing how it works with your body. remember it will be in your body 24-7-365.
While I looked high and low I can only find one study that has shows metals in your jaw can lower your immune system-by half!
Bottom line there are several blood test you can do that will show you what dental materials work with your body-make your dds do this for you or get another dds.
FYI-this is the type of thing a biological dds would do-they can about how you body reacts to anything they place in your body-long term you will be healthier if you are careful about materials placed in your body