I agree that he may just not be a barker, and he is settling into his new home. Teddy wasn't a barker for the longest time, years. Now he is vocal.
Could also be the result of the dental/anesthesia intubation. My Max who is normally very vocal was quiet and a bit raspy for a week after a surgery. I was worried that his trachea was damaged, but it was just a bit sore.