Complete dentures are sets of artificial teeth intended to replace all of the natural teeth in the upper or lower jaw. The denture is made out of pink or gum-colored plastic with plastic or porcelain teeth. The shape of the jaw bone and fit of the denture affects the comfort and stability of the appliances. Often, the addition of dental implants can dramatically improve the comfort and stability. A partial denture is a removable appliance that replaces only a portion of the teeth. This type of replacement uses both the soft tissue ridge and the remaining natural teeth to secure it in place. It can be attached to the natural teeth with clasps or attached using crowns with hidden clasps. Dentures and partial dentures are necessary to keep facial muscles and lips from sagging, and to allow the patient to speak and eat normally.