When the dental caries/decay is in outer layers of teeth that is enamel and dentin and has not yet affected the inner layer that is pulp, then fillings are done in teeth to save them from further decay.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.
(1) preparing the tooth for placement of restorative material or materials.
(2) placement of these materials.
The process of preparation usually involves cutting the tooth with a rotary dental handpiece and dental burrs to make space for the planned restorative materials and to remove any dental decay or portions of the tooth that are structurally unsound. If permanent restoration cannot be carried out immediately after tooth preparation, temporary restoration may be performed.