Quote Originally Posted by rowuk View Post
If you really believe what you just posted, you have your gap........

Seriously, all of those guys got to where they are, not by leveraging a gap, rather by not trying to conquer the upper register. All of them have a very low tension school of playing that is well documented. They teach the same process! They have earned the upper register by intelligent, result based practice. They are proof that it doesn't matter if you have thick or thin lips.
According to this, Jon Faddis' specific dental structure absolutely had an impact on his range and ability.

Music to My Mouth | Article About Greenwich Village Cosmetic Dentist Dr. Peter Silver | New York City, 10003

To quote from the article:

World-cIass jazz trumpet player Jon Faddis, leader of both the Chicago Jazz Ensemble and the Jon Faddis Jazz Orchestra of New York, grew up with a gap in his smile, the result of a rotated right maxillary central incisor with.a severely fractured mesial-incisal angle. As Faddis achieved professional success—and he became famous for his ability to play really, really high notes—he decided to get the tooth fixed. So he had his dentist place a big composite restoration. He took out his horn to play that night and immediately lost three octaves off his range. As the story goes, Faddis was back on the dentist’s doorstep the next morning, waiting for him to open the office. "Jon wanted to undo the repair,” a colleague explained, because he had lost his range and was limited to very low notes. The dentist removed Faddis’ composite, and the high notes came back.
It's been my observation, anecdotal as it may be, that most of the people I've known over the years who have that unreal, blistering high register, also have a pretty dorked up chompers. It's not an absolute, but it seems to me that it's a pretty danged high percentage.