I think that your introduction can play with the concept of being an orthodontist in some rather interesting manners. The idea of "making straight" that which is crooked, righting what was wrong, being able to rectify that which is the past into what can be the present and future is fairly powerful. The power in making childhood teeth straight to help provide a better today and tomorrow is something that can be introduced in an almost "superhero" manner. The appliances that are used to help in this process could be the superhero's "tools." I almost see this emerging as the narrative of a "Dark Knight" type of figure. Focus on how the attempts of the orthodontist fighting teeth crookedness are akin to the superhero who fights crime, and this introduction is both "tongue and cheek" (no pun intended) and insightful about the career choice.