As a kid  my ear was practically glued to our Zenith .     Almost every station in Philadelphia carried a singing commercial by a dentist: Dr . Algase.     He must have been a pioneer since in those days it was not ethical for doctors and dentists, etc to advertise. After much searching I found on the sheet music the cover (right)  .  That song, Show a Sunny Smile,was composed by Dr. Algase himself and legend has it that he sang it as well!  He also founded a club  and even produced a radio wedding!  Attached is the cover of the music.   If by some miracle there as a recording of that singing commercial I would be surprised and delighted.  The singer (Dr. Algae?) was a tenor backed by a 1920s or 1930s type orchestra.  I know that they should be very rare especially those that were local. If you happen to have such a recordings, please reply below!
Old Time Radio Shows from the Golden Age of Radio