Home Dentistry Articles Dentition
Dentition is the development
of teeth and their arrangement in the mouth.
All mammals except the monotremes, the edentates,
the pangolins, and the cetaceans have up to four distinct types
of teeth, with a maximum number for each. These are the incisor,
the canine, the premolar, and the molar. Mammals that have distinct
types of teeth are heterodont; others are homodont.
The number of teeth of each type is written as a dental formula.
The human dental formula is:
Of cats it is:
The last upper premolar and first lower molar
of the cat, since it is a carnivore, are called carnassials
and are used to slice meat and skin. The armadillo, being homodont,
has a dental formula that is simply 7/7.
The maximum dental formula for heterodont mammals
which is approached most nearly by the opossum,
which has 3/3 premolars.
In many mammals the children have a set of
teeth that fall out and are replaced by adult teeth. These are
called deciduous teeth, baby teeth or milk
teeth. Animals that have two sets of teeth, one followed
by the other, are said to be diphyodont. Normally the
formula for milk teeth is the same as for adult teeth except
that the molars are missing.
The milk tooth formula for humans is:
The kitten has 26 teeth.
Teeth are numbered starting at 1 in each group,
except the premolars which end at 4. This means that the carnassials
are always the fourth upper premolar and the first lower molar.
Thus the human teeth are I1, I2, C1, P3, P4, M1, M2, and M3.