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The most acknowledged theory for supernumerary teeth is hyperactivity of dental lamina. [6] On completion of the dentition, the dental lamina is usually destroyed and reabsorbed, but when remnants fail to resorb, it can continue to proliferate abnormally. This abnormal proliferation can form the extra tooth bud leading to supernumerary teeth ...
The vestibular lamina forms shortly after the dental lamina and is positioned right in front of it. The vestibule is formed by the proliferation of the vestibular lamina into the ectomesenchyme. [1] The vestibular lamina is usually contrasted with the dental lamina, which develops concurrently and is involved with developing teeth.
[2] The word Trimorphodon is a combination of three Greek words, 'tri' - three, 'morph' - shape, and 'odon' - teeth, which refers to the three distinct kinds of teeth that lyre snakes have: recurved anterior teeth; shorter middle teeth, and large grooved fangs at the rear of the jaw.
It was theorized that positive selection for shovel-shaped incisors over the spatulate incisors is more commonly found within cultures that used their teeth as tools due to a greater structural strength in increased shovel-shaped incisors. [2] In some instances, incisors can present a more pronounced version of this called double shovel-shaped.
The primary teeth typically erupt in the following order: (1) central incisor, (2) lateral incisor, (3) first molar, (4) canine, and (5) second molar. [45] 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. [46]
An intact lamina dura is seen as a sign of healthy periodontium. Lamina dura, along with the periodontal ligament, plays an important role in bone remodeling and thus in orthodontic tooth movement. Under the lamina dura is the less bright cancellous bone. Trabeculae are the tiny spicules of bone crisscrossing the cancellous bone that make it ...
New, permanent teeth grow in the jaws, usually under or just behind the old tooth, from stem cells in the dental lamina. [5] Young animals typically have a full set of teeth when they hatch; there is no tooth change in the egg. Within days, tooth replacement begins, usually in the back of the jaw continuing forward like a wave.
As their teeth wear down, older tuatara have to switch to softer prey, such as earthworms, larvae, and slugs, and eventually have to chew their food between smooth jaw bones. [56] The tuatara possesses palatal dentition (teeth growing from the bones of the roof of the mouth), which is ancestrally present in reptiles (and tetrapods generally). [57]