The teeth of Tyrannosaurus rex displayed marked heterodonty (differences in shape).
The premaxillary teeth, four per side at the front of the upper jaw, were closely packed, D-shaped in cross-section, had reinforcing ridges on the rear surface, were incisiform (their tips were chisel-like blades) and curved backwards.
Tooth can differ in color from picture, a reconstruction.
The D-shaped cross-section, reinforcing ridges and backwards curve reduced the risk that the teeth would snap when Tyrannosaurus bit and pulled.
Paleontology is the study of ancient life.
People (geologists) have found fossil remains of living organisms since ancient times and studied them. But this is a complex process of searching, digging and structuring data.