Deciduous teeth Middle Eastern countries (including Iraq, Jordan, Egypt and Sudan). It may originate in a pre-Islamic offering and certainly dates back to at least the 13th century, when Izz bin Hibat Allah Al Hadid mentions it. In premodern Britain, lost teeth were commonly burnt to destroy them. This was partly for religious reasons connected with the Last Judgement and partly for fear of what might happen if an animal got them. A rhyme might be said as a blessing: <poem style="margin-left:2em"> "Old tooth, new tooth" "Pray God send me a new tooth" </poem> Deciduous teeth Deciduous teeth, commonly known as milk
Dentition animals with two successions of teeth (deciduous, permanent) is referred to as "diphyodont", while the dentition of animals with only one set of teeth throughout life is "monophyodont". The dentition of animals in which the teeth are continuously discarded and replaced throughout life is termed "polyphyodont". The evolutionary origin of the vertebrate dentition remains contentious. Current theories suggest either an "outside-in" or "inside-out" evolutionary origin to teeth, with the dentition arising from odontodes on the skin surface moving into the mouth, or vice versa. Despite this debate, it is accepted that vertebrate teeth are homologous to the dermal denticles found