Inlays and Onlays are two types of filling used to repair a damaged tooth or to prevent the further spread of the decay. An inlay is one kind of filling material that is used to place inside the cavity of the tooth. It may seem similar to that of a normal amalgam or a composite white filling. Onlay filling is inserted not only into the cavity, but also over the surface of the tooth. Inlays and Onlays are also known as 'indirect filling'. Because, they are produced in a dental laboratory before being applied on the patient's teeth. Usually, back teeth require these fillings because, we use back teeth most and they are difficult to clean also. So, tooth decay is most prone in these areas. There are two types of inlays and onlays. They are: 1. All ceramic inlays and onlays and 2. Composite inlays and onlays. These inlays and onlays are strong and durable. They can last up to 30 years. They can enhance your appearance because they are natural looking.