Inlays and onlays are ways of repairing relatively extensive tooth decay or damage without having to replace the whole outer portion of the tooth. An inlay is done when the tooth structure replaced is within the cusp tips of the tooth. If the damage is more extensive and the new structure covers the entire chewing surface including one or more tooth cusps, the procedure is called an onlay.

Unlike fillings, inlays and onlays do not weaken the tooth structure, but actually strengthens it. After the procedure the tooth can bear up to 50 – 75% more chewing force. They also tend to last longer than a filling.

Most commonly used inlay and onlay materials are porcelain, ceramic or gold.