duval

I have a fair overbite and I realised a few days ago (after 10 years of playing) that as I go up the register my front teeth seem to protrude more so that when I get to about fourth space Eb my top teeth are touching my bottom lip. I feel this is stopping everything from working... sound, range, articulation. With a push, I can take myself up to the D above high C but it is with a pinched sound and is not particulary comfortable. Have you any advice on how I might correct this?

Thanks very much,
David