Adult Komodo teeth are similar to those of theropod dinosaurs: new research
phys.org
phys.org
The theropod dinosaurs and the varanids a.k.a. monitor lizards have a so-called ziphodont dentition, i.e. teeth that have sharp edges that are serrated, like a bread knife. This is an obvious adaptation to cut easily the flesh and skin of the prey by biting, then pulling.
Among the living vertebrates, such serrated teeth are also typical for sharks and piranhas, however there the teeth have a different form, i.e. triangular, because their movement is different, they cut during the bite, not during the pulling motion that follows the bite.
While among the living tetrapods only the varanids have such serrated teeth, in the past there have been many other animals with similar serrated teeth. Besides the theropod dinosaurs there have been some extinct crocodilians, some mosasaurs, some pliosaurs, some phytosaurs, a few ichthyosaurs, some rauisuchians (these are triassic predators) and also a few saber-toothed synapsids that belong to the ancestors of mammals.
Such teeth are necessary for a predator whose prey is big, so it is necessary to be able to cut pieces of it in order to eat it.
Most living reptiles eat their prey whole, so they do not need such teeth. The modern crocodilians have another method of cutting, by biting then shaking, presumably because in water and with a short neck it would be difficult to pull backwards strongly enough the flesh of the prey, while the mammals have differentiated dentition, with some teeth specialized for cutting, which leaves the varanids as the only predators of large prey that cut it in the same manner as the carnivorous dinosaurs, by biting and pulling back.