Notation for the number of
incisors (I),
canines (C),
premolars (P), and
molars (M) in the upper and lower
dentition of a
species of
heterodont mammal, I:C:P:M. In
humans, the
adult dental formula is usually:
2.1.2.3/2.1.2.3. Since mammalian
teeth are usually symmetrical, the total number of
teeth is equal to the sum of the upper and lower
quadrants, times two; in
humans, for example, (8 816) 2 yields a modal number of 32
teeth. The
aye-aye has a
formula of 1.0.1.3/1.0.0.3, illustrating the need for both upper and lower
quadrant counts. Its
deciduous dental formula (dI:dC:dM) is 2.1.2/2.1.2. Both the
deciduous and
adult dental formulas are identical in all
extant hominoids.