Wombat Teeth

The front teeth (incisors) of a Bare-nosed wombat are very strong (picture courtesy of Womland used with permission)
The teeth of the wombat are unlike any other marsupial but are extremely similar to that of rodents. The wombat has 24 rootless teeth that grow continuously to compensate for the wear caused by their diet of tough, fibrous grasses. Many plants that the wombat eats are high in silica which is quite abrasive to their teeth.
Wombats have a pair of large, robust incisors in both the upper and lower jaws (like a beaver) that are anchored deep in the jaw bone. They have no canines, and there is a wide gap between their incisors and premolars.
The grinding surface of their molars is like that of a rodent's. The way a wombat feeds and chews its food is also similar to a rodent.
The wombat's dentition is usually described as: Incisors=1/1 Canines=0/0 Premolars=1/1 Molars=4/4 Total=24 teeth.

Bare-nosed wombat skull shows the wombat's large incisors and the gap between the incisors and the premolars (picture courtesy of The Natural History Collections of the University of Edinburgh, used with permission)
This formula represents the teeth on one side of the mouth, upper teeth/ lower teeth. In total the Wombat has 4 incisors, 0 canines, 4 premolars, and 16 molars.
In the Hairy-nosed wombat, the incisors have enamel only on the front surface. The backsides are therefore much softer than the front, and as the softer back surface wears away more quickly than the front, the incisors are kept sharp with a chisel-like edge. This feature is more prominent on the upper incisors than the lower.
The Bare-nosed wombat on the other hand, doesn't have chisel-like incisors. Their incisors have a flatter surface and are similar to the incisors of a horse.
by Peter Marinacci