You have two options:
First to get a Removable complete denture. But it requires removal of all the teeth. So, if there are only few teeth left then you can get it removed and after that opt of complete dentures. To know more about complete dentures visi the link....http://www.identalhub.com/articlecategory-dentures-50.aspx
Another option is to get the conservative treatment for the left out teeth and then go for implants.
For more info on implants you can visit the link..... http://www.identalhub.com/articlecategory-dental-implants-25.aspx