How Many Teeth Do People Normally Have In Their Mouths?

Children under the age of six usually have twenty primary teeth, ten on the top and ten on the bottom. Adults usually have thirty-two permanent teeth. In my practice there are many adults who either don't have their third molars (wisdom teeth) erupted into the mouth or didn't develop them to begin with (congenitally missing teeth, or hypodontia or partial anodontia).

I also have patients with congenitally missing teeth other than the third molars; however, most of them are in the permanent set. If a primary tooth in the back of the mouth doesn't have a permanent one (bicuspid) under it, that primary tooth just may stay in the mouth for a while... sometimes a long while. I see evidence of congenitally missing lateral incisors in the top front of the mouth next to the two middle front teeth (central incisors) with some frequency.

Another anomaly seen in the mouth is extra teeth, or supernumerary teeth (hyperdontia), of which there is no specific cause that we can pin down (this condition may genetically run in families). The most common supernumerary tooth seen is called a mesiodens, which is seen located on or near the midline of the upper jaw, and can deflect the directional growth or even block the permanent incisors from erupting.

I have even seen multiple mesiondens in one patient and have noticed them in all the siblings of the same family I treated. This lets me know that there is likely a familial (hereditary or genetics-based) component involved, but it is said that a simple Mendelian pattern is not followed.

Supernumerary teeth have different shapes and are seen in otherwise normal, healthy people, and may be “accidentally” discovered with a routine set of x-rays. Multiple supernumeraries have been observed in people with serious disorders like Gardner's syndrome (which may also manifest itself with multiple polyps inside and outside the colon) and cleidocranial dysostosis (a general skeletal condition).

Unerupted supernumerary teeth are generally asymptomatic. Identalhub.com relates that in the permanent set of teeth, the incidence of supernumerary teeth seen in males is twice that seen in females.  The occurrence of supernumeraries can be single or multiple, erupted (25%) or unerupted (75%), in the upper (95%), lower (5%) or both jaws, in the front or back of the mouth, and unilateral or bilateral. Extra teeth have been diagnosed more in permanent dentitions than in primary dentitions.

Extraction of supernumeraries may be necessary if they are in the way of other erupting teeth or look "uncosmetic” (if they are erupted).

In some cases involving extra teeth, “the more, the merrier,” may not necessarily apply. Check with your dentist to see if you have something “extra” about your teeth!

May you have many…full blown, extra and special, count with my fingers, toes, and teeth… smiles!