Possibly surprising teeth

I had mentioned last week how I avoid places that may not allow me to pay for parking by cash. It is thus agreeable that my dentist is but a ten-minute walk from my workplace, the last part being to ascend a stone spiral staircase. This afternoon's check-up included an interesting element: in doing the normal survey of teeth and reporting to the assistant, for my bottom teeth on both sides the dentist reported no number six and the first time he had to confirm because the assistant was so surprised, piquing my curiosity. I have not knowingly lost any adult teeth so I had previously assumed that I have them all.

Britain is unusual in using Palmer notation for navigation around one's teeth. It fits with that and with where the dentist seemed to be investigating at those moments for this number six to refer to my mandibular first molars. Some initial searching online suggests that never having had them has an incidence of the order of one in ten thousand or so, even less when not associated with many other teeth being missing. Perhaps rather more likely is that the dentist is somehow mistaken about which pair of molars is missing or I am misintepreting either the original statement or the research literature.