Not much is known about the developmental mechanisms regulating diphyodont replacement. They lack incisors and canines, and have 20-22 teeth, which are evergrowing, unrooted, and diphyodont. "Ichthyolestes" exhibits heterodont and diphyodont dentition with cusped cheek teeth. Mammals, in general, are diphyodont, meaning that they develop two sets of teeth. Humans, like other mammals, are diphyodont, meaning that they develop two sets of teeth.