Inlays and onlays are forms of restorative dentistry. Unlike fillings, inlays and onlays are bonded to the outside of a tooth and are therefore classed as indirect forms of dental restoration.
Sometimes a tooth may be damaged or decayed beyond the point of needing a filling. Inlays and onlays are ideal for repairing larger cavities that might otherwise progress to the point of needing a crown if left untreated.
Where an inlay is a single piece of solid material that is bonded to the outside of a damaged tooth, an onlay covers more of the tooth including the cusp. Onlays are thus larger than inlays, covering a greater surface area.
Where fillings are insufficient for repairing a cavity, but teeth are not yet at the point of requiring a crown, inlays and onlays may be used. Your dentist may suggest this course of action if they feel there is enough of the damaged tooth or teeth to be preserved.
A key benefit of both inlays and onlays is their durability. These treatments are a non-invasive way of restoring function to damaged teeth and can last anywhere between 5 and 30 years.