Fillings are a hard material used to replace natural tooth lost due to decay. A dentist will removed the decay (bone that has become soft due to bacteria) and replace it with a composite material that will harden an fill in the missing tooth structure. It will then be shaped to fit your natural tooth and bite pattern.
A dental restoration or dental filling is a treatment to restore the function, integrity, and morphology of missing tooth structure resulting from caries or external trauma as well as to the replacement of such structure supported by dental implants. They are of two broad types— direct and indirect— and are further classified by location and size. A root canal filling, for example, is a restorative technique used to fill the space where the dental pulp normally resides.