I personally believe that since the oil is absorbing toxins it may also absorb some vitamins and minerals that are present in the saliva, one of the reasons it may not be advisable to do OP close to meal times. I experienced teeth sensitivity when I did OP at the same time as a liver flush, and I believe it had to do with the reduction of calcium from the magnesium of the flush, and the absorption of the calcium from the OP. This of course is just a theory, but it seems logical.
I must say however, that I don't believe that OP will CAUSE a mineral imbalance, but I do believe that it will exacerbate an existing imbalance. The sensitivity you feel may be your body communicating with you thru OP to let you know that you do not have enough Calcium or that it is not adequately balanced with your magnesium. After I increased my calcium intake, the tooth sensitivity went away, and I didn't stop OP so it can be reversed without stopping OP.