Here is just a little anecdote about the family and dentists: In Lost Splendor, Yussoupov said that their dentist, who was also the IF's dentist (must have been some special guy!) had been sent to take care of the IF's teeth while they were in captivity (I forgot if this was a Tsarskoe Selo or Tobolsk and can't find the exact page) Upon returning, Felix said the next time the dentist came to their place, he told his mother, Zenaida, that Nicholas had relayed a message through him to her, saying "tell Princess Yussoupov she was right", meaning about Rasputin, and that they should have listened to her.