Welcome. The front teeth is where the measurement is taken. The therabite people have a nice gauge that comes with their device. Best of luck with the mouthpiece and the rad treatments.

11/1999 SCC tongue - surgery
1/2000 Met(s) in lymph nodes - modRND
2/2000-4/2000 RT ~6 weeks
end of 2006 SCC tongue - surgery
1/2008 SCC BOT - surgery / PEG installed
2/2008 chemo & RT
4/2008 last time I consumed solid food by mouth