Recently, every time I eat a carb like a potato chip or popcorn, it tastes and feels as if it is stale even if it is just opened. I feel the crunch but it tastes like a stale chip tastes. It sort of feels like the food is melting as soon as it comes in contact with my saliva. I feel like I have a faint strange taste in my mouth constantly but not soapy or metallic. I am an adult who had braces and now wear a plastic retainer (like a sports mouth guard) at all times, taking it out to eat, and I'm wondering if it has to do with that.