There are a few different types of lining used in an orthopedic dog bed. The two main ones are memory foam and egg crate or convoluted foam. From the names alone, can you guess which one is used in a human orthopedic mattress? Memory foam is the one that is used in orthopedic mattresses for humans. Its quality of molding to your body while maximizing comfort and releasing pressure points on your body has long been recognized and praised. Egg crate foam is not very strong. As such, you do not notice a human orthopedic mattress made from egg crate foam. It is only used for mattress toppers and mattress pads. But dog beds are made from it. So you should know that a large dog can wear it out relatively fast. You may not wish to consider purchasing it, unless you have a small dog.