lost tooth device

A week ago Monday, my husband took the 28X  from Shady and Fifth to the airport.  Somewhere between there and arriving at his destination in another state, he lost a tooth device, quite costly, which helps to prevent snoring. (quite effectively, I must say!).  We have checked with airlines, airports, etc and so far have come up with nothing.  We walked along 5th Avenue between Denniston and Shady and wonder if it could have fallen there.  It would be in a hard plastic case similar to the one pictured.  If you have any idea of its whereabouts, please let us know, and THANKS in advance.Rita Nordquist