The options
Which applies depends on how many teeth are involved and what is left to anchor to.
Full dentures
A complete arch, upper or lower. Held by suction and the shape of the ridge, so the accuracy of the impression does most of the work.
Partial dentures
For an arch that still has sound teeth. The partial clasps to them and fills the gaps, which also stops the remaining teeth drifting into the space.
Implant-secured dentures
A small number of implants can hold a denture firmly, which largely removes the movement people dislike most. Often far less costly than replacing every tooth. More on implants.
Repairs and relines
Ridges change shape over the years and a denture that fit perfectly will eventually not. A reline re-fits the base to the ridge rather than replacing the whole thing.