The most common technique to get dentures "done in one day" is to do an immediate denture, where a denture is fabricated prior to removing teeth, and placed on the same day that teeth are removed. Immediate dentures (sometimes called "healing dentures") will loosen as your body heals, and are usually either replaced with another denture, or are relined to fit your mouth as your body heals. An immediate denture appointment usually involves several steps, and several appointments prior to the surgical date.
Over the past 10 years, there have been many innovations in immediate denture fabrication. However the final result is very much dependent on both the condition of the patient's mouth going into the procedure, the patient's healing ability, as well as the skill of the dentists and laboratory technicians involved.