Full or partial dentures consist of a gum-colored base made of plastic resin, which fits over the remaining alveolar (bone) ridge that formerly held the teeth. The prosthetic teeth projecting from the base are designed to look and function just like your natural teeth. Dentures are held in place primarily by the suctioning effect of their close fit against the alveolar ridges — that's why it's so important that they are fitted properly. The upper denture also gets extra support from the large surface area of the roof of the mouth (palate), which generally makes it extremely stable.