I think the grinding is a possible cause for the sensitivity. I would consider seeing your dentist for a mouthguard to prevent any excessive wear on your teeth.
b12 deficiency,according to my knowledge, has nothing to do w sensitive teeth.
sounds like your problem may be due to grinding. let me tell you from a hardcore grinder, it can make your teeth sens. hurt and shift. talk to your dentist about this and if it is the problem a splint, or nightgaurd can help. bad thing is it is usually covered by medical ins, and hmo's dont cover it . but if you can get one it will save your teeth!
Ok, thanks for the info, appreciate it, I have a dentist appointment scheduled in about two weeks.