The neonatal line is a particular band of incremental growth lines seen in histologic sections of both enamel and dentin of primary teeth. 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. The neonatal line is the demarcation between the enamel formation before birth and after birth i.e., prenatal and postnatal enamel respectively.[1] It is caused by the different physiologic changes at birth and is used to identify enamel formation before and after birth. The position of the neonatal line differs from tooth to tooth [2]

Formation

The formation of the neonatal line is caused by changes in the direction and degree of tooth mineralization caused by the biological stress from passing into extra uterine life.[3] Specific factors underlying its formation and width still remain unclear.

Forensic Dentistry

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.[5]

References

  1. ^ "BHDtwo.html". 2015-10-30. Archived from the original on 2015-10-30. Retrieved 2021-11-30.
  2. ^ Schour, Isaac (1936-10-01). "The Neonatal Line in the Enamel and Dentin of the Human Deciduous Teeth and First Permanent Molar*, *, **From the Department of Histology, College of Dentistry, University of Illinois.*Presented in the form of a discussion and demonstration before the Ninth International Dental Congress of the F.D.I., Vienna, Aug. 3, 1936.*This investigation has been aided by a grant from the Graduate School Research Board of the University of Illinois and from Mead Johnson and Company". The Journal of the American Dental Association. 23 (10): 1946–1955. doi:10.14219/jada.archive.1936.0277. ISSN 1048-6364.
  3. ^ Sabel, Nina; Johansson, Carina; Kühnisch, Jan; Robertson, Agneta; Steiniger, Frank; Norén, Jörgen G.; Klingberg, Gunilla; Nietzsche, Sandor (October 2008). "Neonatal lines in the enamel of primary teeth--a morphological and scanning electron microscopic investigation". Archives of Oral Biology. 53 (10): 954–963. doi:10.1016/j.archoralbio.2008.05.003. ISSN 1879-1506. PMID 18589400.
  4. ^ Janardhanan, Mahija; Umadethan, B; Biniraj, KR; Kumar, RB Vinod; Rakesh, S (2011). "Neonatal line as a linear evidence of live birth: Estimation of postnatal survival of a new born from primary tooth germs". Journal of Forensic Dental Sciences. 3 (1): 8–13. doi:10.4103/0975-1475.85284. ISSN 0975-1475. PMC 3190441. PMID 22022132.
  5. ^ Canturk, Nergis; Atsu, Saadet Saglam; Aka, P. Sema; Dagalp, Rukiye (August 2014). "Neonatal line on fetus and infant teeth: An indicator of live birth and mode of delivery". Early Human Development. 90 (8): 393–397. doi:10.1016/j.earlhumdev.2014.05.002. ISSN 1872-6232. PMID 24951074.
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