My father, an old time country doctor, accidentally swallowed a dental appliance and resorted to the same technique to recover it. About two days later he recovered the dental appliance, carefully cleaned and autoclaved it and continued to use it for years.
On vacation with my family. We went to a restaurant. I accidentally left my retainer on the food tray. The contents of the food tray went into the garbage. We drove back to the restaurant and the waitress pointed me to the thing out back and I had to go through it. Luckily I found it quickly. The waitress gave me some bleach and I scrubbed my retainer with my toothbrush. Putting that in my mouth the first time was not fun.