No, it's not Bobby Bumps who needs a dentist's services. He and Fido are sitting on the porch, sharing a lollipop, when Fido comes down with a toothache. When the dentist gives the poor dog gas for anaesthesia, he has a very peculiar dream in this cartoon.
Looking at this short cartoon, you may be struck, as I was, at the use of word balloons. Director Earl Hurd and most animation cartoonists came out of the world of newspaper cartooning, and they simply adopted the technique for simple exclamations. For longer sentences, of course, there was always the title cards.