|An image from my private collection|
Like most myths there is a germ of truth lurking within. There exists a rare tumour called a teratoma. Teratomas contain highly differentiated tissue and are capable of forming fully formed dentition, and even hair. It is not inconceivable that a woman could be afflicted with a vaginal teratoma. This lamentable malignancy, if not excised, could result in the development of teeth.
On two occasions, I have dissected teratomas as part of my professional duties, and can vouch personally that teratomas contain teeth. They are perfect in every regard and resemble a child's first dentition. The teeth make an exotic addition to my rare artefact collection and reside on my mantelpiece as if in repose.