A filling is a way to restore a damaged tooth back to its normal function and shape. Different restorative, filling materials are used to restore the function, integrity and morphology of missing tooth structure. The structural loss typically results from caries or external trauma. When a dentist gives you a filling, first removes the decayed tooth material, cleans the affected area, and then fills the cleaned out cavity with a filling material. Composite (plastic) resins are matched to be the same color as your teeth and give an all natural appearance. The advantage of direct resin restorations is that they usually set quickly and can be placed in a single procedure.