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
Deciduous teeth important for the development of the child's speech, for the child's smile and play a role in chewing of food, although children who have had their primary teeth removed (usually as a result of Dental caries) can still eat and chew to a certain extent. In almost all European languages the primary teeth are called "baby teeth" or "milk teeth". In the United States and Canada, the term "baby teeth" is common. In some Asian countries they are referred to as "fall teeth" since they will eventually fall out. Various cultures have customs relating to the loss of deciduous teeth.