Dentures can be made out of a variety of materials, such as acrylic which is plastic in nature or a metal framework denture made from chrome.
The type of denture you need, will depend on the number of teeth to be replaced, the strength of the denture needed and the condition of your remaining teeth. If you have a very strong bite a metal denture may be more suitable for you but if your teeth are missing at the front of your mouth you may prefer not to have any metal showing when you smile and so an acrylic denture may be a better solution.