A filling is a way of restoring a tooth damaged by decay back to its normal shape and function. Your dentist will remove the decay, clean out the cavity and then fill and shape the tooth with filling material.
There are different materials that can be used.
Composite which is a tooth colour filling bonded to existing tooth and set using an ultra violet light. The dentist will colour match the filling however it can stain over time. Composite fillings are strong but may not be as hard wearing as amalgam.
Amalgam which is a silver filling are resistant to wear and relatively inexpensive. However, due to their dark color, they are more noticeable than composite restorations and are not usually used in very visible areas, such as front teeth.