Backstage Wife (Dr. Lyons was one of the sponsors). Perfect choice: someone who is (a) on the radio and (b) backstage. So we have no idea what shape her teeth are in.
By the way, I love how it says, in parentheses, at the end of the incomplete verse, "rhyme with bright." That's because they do not think we are, very:
For beautiful teeth to shine bright
Use Dr. Lyon's morning and night
Your smile will be prouder
Because of this POWDER....
...But if it's still lame, that's all right.
...Even though it won't cure overbite.
...Although you still dress like a fright.
...We're begging you please to just try it.
You can try it, too, if you like. Although unlike Mary I don't have any nice cash prizes for you or anything. On the other hand, I won't insult your intelligence by saying, as the shop guy is in the bottom cartoon, "And all you do is just write a line to rhyme with 'BRIGHT.'" Yes, thank you. We get it!