When more than a third of a tooth’s biting surface is damage, at Dr. Ehab Dental Clinic will often use onlay or inlay. Large fillings on back teeth often require stronger and properly contoured restoration such as porcelain inlays or onlays.The onlay allows for conservation of tooth structure when the only other alternative is to totally eliminate cusps and perimeter walls for restoration with a crown. Dental inlays and onlays are restorations used to repair rear teeth that have a mild to moderate amount of decay. They can also be used to restore teeth that are cracked or fractured if the damage is not severe enough to require a dental crown. Inlays and onlays are usually made from porcelain, composite resin, and sometimes even from gold. Because they can be created from tooth-colored materials, inlays and onlays are often used to replace metal fillings for patients who desire a more natural looking smile