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1.
A gnarly set of jacked up teeth.

Predominant in Kentucky, Northern GA, North and South Carolina. Rampant in the Appalachian region due to over indulgence in the sugar infested beverage.
Have you seen that girl from Appalachia?
She must have drank too much soda pop as a kid because she has Mountain Dew Mouth. Her teeth are gnarly dude.

Eeew. Man...when is the last time you went to the dentist?
Why?
Your teeth are jacked up dude. You have Mountain Dew Mouth.

by FergiFerg020608 February 16, 2009