Deciduous teeth first teeth seen in the mouth are the mandibular centrals and the last are the maxillary second molars. The primary teeth are made up of central incisors, lateral incisors, canines, first molars, and secondary molars; there is one in each quadrant, making a total of four of each tooth. All of these are gradually replaced with a permanent counterpart except for the primary first and second molars; they are replaced by premolars. The replacement of primary teeth begins around age six, when the permanent teeth start to appear in the mouth, resulting in mixed dentition. The erupting permanent teeth cause
River of Teeth America’s history." In October 2017, Tor Books released "Taste of Marrow", which follows the characters of "River of Teeth" in the months following the events of that book. River of Teeth River of Teeth is a 2017 alternate history novella by Sarah Gailey. It was first published by Tor Books. In the 1850s, James Buchanan approved a plan to import hippopotamuses into the United States as livestock. Decades later, the lawless swamps of Louisiana are infested with murderous feral hippos, and Winslow Houndstooth and his band of misfits are hired to clear them out. "River of Teeth" was a finalist