I think everyone gets this once in a while, but for a few days now my two front upper and lower teeth and grinding against each other, the lower ones feel like they are pushing the upper ones forward from behind. I'm not in any great pain or anything, although I do think it's causing my upper two teeth to loosen a bit. I am going to see the dentist next week, in the meantime any idea what it might be and what they might do about it, if anything? Cheers.

They may just have to adjust your bite a bit. If this happens only at night, a night guard may help.