Presence of the fourth molar. Literature review

Resumen

Fourth molars, also called distomolars, are a variant in shape and number appearing as alterations during odontogenesis. They can be eumorphic or dismorphic, single or multiple, erupted or impacted, unilateral or bilateral, and can appear in both jaws. They are of unknown etiology, but there are several theories to justify these tooth alterations such as dental lamina duplication, its horizontal proliferation or its hyperactivity. Other factors can be hereditary factors, full division of tooth bud or phylogenetic regression. Fourth molars are found in a very important space, and when their own existence or the suitable extraction techniques are unknown, severe complications can frequently occur during and after surgery. A literature review was undertaken, examining different articles and texts of different years, in order to better determine the origins and formation of this supernumerary tooth.