A denture is a removable prosthesis made to replace missing teeth. Generally
dentures are made out of acrylic resin and can be combined with various metals.
Dentures improve chewing ability and speech, and provide support for facial
muscles. They are custom-made to be stable and look natural. They can be
removed easily at any time. There are three basic types of dentures:

• Full dentures, which are made when all natural teeth are missing or extracted;
• Partial dentures, which fill in the spaces created by missing teeth and prevent other teeth from shifting and changing position;
• Overdentures, which derive their support from abutment teeth by completely enveloping them beneath the fitting surface; and
• Implant supported denture, traditional denture that is held in place by
  dental implants

Dentures are normally clasped around existing teeth to give support and stability
while chewing. Existing teeth may need a small amount of preparation to help keep
the denture in position. If there are no existing teeth to hold the denture, it can be
made to fit directly on the gum or, for maximum stability, a denture can be supported by titanium implants.