Why Do We Do Inlays And Onlays? (processed white restorations by our lab) A dental restoration is any material that restores a tooth back to full form and function. Most patients think of restorations as either fillings or crowns. A filling is placed directly and requires support from from an adequate amount of tooth structure for retention. A crown is made indirectly in a laboratory from a mold taken from an impression. A crown provides complete support for the tooth. Resto