Teething is one of the characteristics of living organisms, related to the formation, arrangement and number of teeth inside the mouth within a certain age. Animals are divided according to the shapes of their teeth into:
Homodent animals: This category includes every animal that has one type of tooth that is identical in shape, and this category includes in particular non-mammalian vertebrates.
Heterodents: Animals with different teeth.
It is divided according to the number of times it replaces the teeth into:
Monophydont: Animals whose teeth remain for life without alteration.
Diphydont animals: They replace their permanent teeth with primary teeth.
Polyphodont: Animals that lose and replace their teeth throughout their lives.
Humans are multi-toothed (different shapes) and bi-dental.[7]
