"...There is a fluid flow from the pulp chamber, through the dentin, through the enamel and into the mouth in people who have no dental decay. Thyroid is part of the endocrine function that controls the direction of this fluid flow. Low thyroid hormone production allows this fluid flow to run in the opposite direction--from the mouth, into the enamel, dentin, and pulp chamber. This fluid brings bacteria and debris from the mouth with it, leading to dental decay. When the teeth are susceptible to decay, the whole body is susceptible to degenerative disease...."
One theory might be that with OP, for people who have this "reverse flow" through the teeth, that the presence of the oil for so long effectively stops the reverse flow, and enables that flow to reverse again, in the right direction. Just a theory. Teeth are very much alive.