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For human teeth to have a healthy oral environment, all parts of the tooth must develop during appropriate stages of fetal development. Primary (baby) teeth start to form between the sixth and eighth week of prenatal development, and permanent teeth begin to form in the twentieth week. [1]
Primary teeth start to form in the development of the embryo between the sixth and eighth weeks, and permanent teeth begin to form in the twentieth week. [25] If teeth do not start to develop at or near these times, they will not develop at all. A significant amount of research has focused on determining the processes that initiate tooth ...
There are 20 primary teeth and they typically erupt in the following order: (1) central incisor, (2) lateral incisor, (3) first molar, (4) canine, and (5) second molar. [13] As a general rule, four teeth erupt for every six months of life, mandibular teeth erupt before maxillary teeth, and teeth erupt sooner in females than males. [14]
Primary (baby) teeth start to form between the sixth and eighth weeks in utero, and permanent teeth begin to form in the twentieth week in utero. [1] If teeth do not start to develop at or near these times, they will not develop at all. A significant amount of research has focused on determining the processes that initiate tooth development.
The maxillary central incisors contact each other at the midline of the face. The mandibular central incisors are the only other type of teeth to do so. The position of these teeth may determine the existence of an open bite or diastema. As with all teeth, variations of size, shape, and color exist among people.
An alternative way to develop two openings from the blastopore during gastrulation, called amphistomy, appears to exist in some animals, such as nematodes. [3] [4] In humans, the perforation of the mouth and anus happen at four weeks and eight weeks respectively. [5]
The formative role of the dental follicle starts when the crown of the tooth is fully developed and just before tooth eruption into the oral cavity. [2]Although tooth eruption mechanisms have yet to be understood entirely, generally it can be agreed that many factors, together, affect the tooth eruption process which is why it is very difficult to differentiate the causes and effects. [3]
More teeth appear, often in the order of two lower incisors then two upper incisors followed by four more incisors and two lower molars but some babies may still be waiting for their first. Arm and hands are more developed than feet and legs (cephalocaudal development); hands appear large in proportion to other body parts.