Evolution and developmental diversity of tooth regeneration

• Tooth replacement is a highly conserved process among vertebrates, from fish to mammals.
• Evolution of development over time has produced highly diverse vertebrate dentitions.
• The dental lamina, a dynamic epithelial structure, is related to both continuous and reduced tooth replacement in vertebrates.
• We discuss how this ancient system of tooth regeneration has been modified and conserved over 500 million years of evolution.

This review considers the diversity observed during both the development and evolution of tooth replacement throughout the vertebrates in a phylogenetic framework from basal extant chondrichthyan fish and more derived teleost fish to mammals. We illustrate the conservation of the tooth regeneration process among vertebrate clades, where tooth regeneration refers to multiple tooth successors formed de novo for each tooth position in the jaws from a common set of retained dental progenitor cells. We discuss the conserved genetic mechanisms that might be modified to promote morphological diversity in replacement dentitions. We review current research and recent progress in this field during the last decade that have promoted our understanding of tooth diversity in an evolutionary developmental context, and show how tooth replacement and dental regeneration have impacted the evolution of the tooth-jaw module in vertebrates.