Many accounts sat the in the UK in the early 20th century dentistry was still so expensive that some people chose to have all their teeth pulled to spare themselves a lifetime of pain. Having all your teeth removed was considered the perfect gift for a 21st birthday or a newly married bride. My mother-in-law had her teeth out under this practice.

The foundation of the NHS in 1948 made dental care affordable for all and in the first nine months four million cavities were filled and queues formed outside surgeries.

see: https://bda.org/museum/exhibitions-and-events/nhs70-celebrat...

This would have been the early 1920s so the availability of dentistry out in the countryside would have been minimal. Instead of having a bunch of rotting and broken teeth (and the concomitant pain) it would h have been simpler to just get them all out.

The replacement plates can’t have been that comfortable either.

My English grandmother was the same, though I think it was closer to her 30s. My understanding is her dental hygiene was not the best (she grew up in WW2), and it was just “easier” to remove all of the teeth and use dentures.