It belongs to a series of a growth lines in tooth enamel known as the Striae of Retzius denoting the prolonged rest period of enamel formation that occurs at the time of birth.
The neonatal line is darker and larger than the rest of the striae of retzius.
[3] Specific factors underlying its formation and width still remain unclear.
In forensic dentistry, the neonatal line can be used to distinguish matters such as if a child died before or after birth and approximately how long a child lived after birth.
The neonatal line can be used as a marker for the exact period of survival of an infant through the measurement of the amount of postnatal hard tissue formation [4] and examination of the thickness of the neonatal line.