Perikymata (

Greek Greek may refer to: Greece Anything of, from, or related to Greece, a country in Southern Europe: *Greeks, an ethnic group. *Greek language, a branch of the Indo-European language family. **Proto-Greek language, the assumed last common ancestor ...

plural of περικύμα, perikyma) are incremental growth lines that appear on the surface of

tooth enamel Tooth enamel is one of the four major Tissue (biology), tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the Crown (tooth), crown. The ...

as a series of linear grooves. In anatomically modern humans, each perikyma takes approximately 6–12 days to form. Thus, the count of perikymata may be used to assess how long a tooth crown took to form. They may disappear as the enamel wears over time after the tooth erupts. Perikymata are the expression of

striae of Retzius The striae of Retzius are incremental growth lines or bands seen in tooth enamel. They represent the incremental pattern of enamel, the successive apposition of different layers of enamel during crown formation. There are 3 types of incremental ...

at the surface of enamel. They can be found on all teeth, but are usually the easiest to notice on anterior teeth (incisors and canines).

References

{{reflist Parts of tooth