On several occasions, I've heard Charles refering to a retainer when giving Brett a hard time. Did she wear a retainer or was this part of an inside joke that spilled into the show?

I really think she did wear a retainer. If you listen to her speak sometimes, you can hear that she kind of lisps becuase of it. Well, it's not really lisping, but you get what I mean. I used to wear one and it's harder to talk with it in.