Simple breaks to acrylic dentures can be done in less that two hours.
More complex repairs such as where a metal casting has broken will take about 24 hours.
Teeth can be added to existing partial dentures on the same day.
If you have an existing denture, in good condition, but it is a bit loose, it might need a reline. This is done by taking a fresh impression of your mouth and re-fitting the denture to the new impression.
This is an all day procedure.