An inlay or onlay is a solution between the filling and the crown. It is an aesthetical treatment method that is used when there is no sufficient dental tissue for filling, or for the teeth that are not too damaged for veneering.
What are the differences between inlays and onlays?
The difference between them is the area they cover. An inlay is more similar to a filling, but between the tubercles on the chewing surface of teeth. An onlay is done to cover one or more tubercles.