Because amalgam fillings are made of metal, they often expand and change shape over time. This can sometimes cause a rough feeling in patients' mouths. On the other hand, white fillings won't expand or contract, and they'll typically retain their smooth comfortable feeling for a lifetime. It's also been reported by some patients that having amalgam fillings replaced with white fillings causes a feeling of overall wellness. Patients have claimed to feel the health difference in having silver fillings vs. white fillings. While the claim hasn't been researched enough to be validated, the idea makes sense. Because amalgam has mercury in it, it can be a serious detriment to a person's health. It's no wonder then that replacing them has made certain patients feel more healthy.