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In vertebrates, an odontoblast is a cell of neural crest origin that is part of the outer surface of the dental pulp, and whose biological function is dentinogenesis, which is the formation of dentin, the substance beneath the tooth enamel on the crown and the cementum on the root.
Enamel spindles are often confused with two other entities: enamel lamellae and enamel tufts. Lamellae are linear enamel defects that extend from the surface of the enamel towards the DEJ, or vice versa. Enamel tufts are "small, branching defects that are found only at the DEJ, protruding into the enamel towards the enamel surface.
After the formation of enamel matrix, mineralisation of enamel takes place which is known as maturation. During this stage, the ameloblasts are slightly reduced in length. The stratum intermedium cells lose their cuboidal shape and assumed to be as spindle shape. During this stage, ameloblasts also exhibit microvilli at their distal extremities.
Enamel tufts should also not be confused with the similar enamel spindles. Enamel spindles are also linear defects, similar to lamellae, but they too can be found only at the dentinoenamel junction, similar to enamel tufts. This is because they are formed by entrapment of odontoblast processes between ameloblasts prior to and during amelogenesis.
Enamel tufts are small branching defects that are found only at the DEJ, and so differ from lamellae which can be facing either direction and are strictly linear. Enamel spindles are also linear defects, but they too can be found only at the DEJ, because they are formed by entrapment of odontoblast processes between ameloblasts prior to and ...
In about 60–65% of teeth, the cementum overlaps the enamel at the CEJ, while in about 30% of teeth, the cementum and enamel abut each other with no overlap. In only 5–10% of teeth, there is a space between the enamel and the cementum at which the underlying dentin is exposed. [3]
Tomes's processes (also called Tomes processes) are a histologic landmark identified on an ameloblast, cells involved in the production of tooth enamel. During the synthesis of enamel, the ameloblast moves away from the enamel , forming a projection surrounded by the developing enamel.
Amelogenesis is the formation of enamel on teeth and begins when the crown is forming during the advanced bell stage of tooth development after dentinogenesis forms a first layer of dentin. Dentin must be present for enamel to be formed. Ameloblasts must also be present for dentinogenesis to continue.