Fillings no longer have to be the old-fashioned grey/black metal amalgam ones which look and feel unnatural. There is also a concern about the potential toxicity of the 50% mercury component of amalgams.
The traditional alternative of “white fillings” were typically composite resins, a type of plastic. Composite resins are characteristically softer than natural enamel and would wear quickly (within 3-7 years) if used to repair large fillings on back teeth.
Ceramic or porcelain materials provide the best solution for modern dentistry. They were developed to closely mimic natural tooth enamel, both in wear rate, feel and aesthetics. The durability of ceramics is far greater than plastic composite resins and designed to last for 10-15 years or longer.