title: Neonatal line on fetus and infant teeth: An indicator of live birth and mode of delivery.
abstract: BACKGROUND
  The neonatal line (NL) is an important issue in forensic odontology. It is the sign of a developmental birth defect, which is caused by the effect of metabolic stress on tooth structures when the fetus passes to extrauterine life.
  
  
  OBJECTIVE
  The aim of this research is to determine the existence and thickness of NL in teeth, as it is a legal necessity to indicate the signs of viability at birth in a forensic examination of a fetus or infant case.
  
  
  METHODS
  This research was conducted on 48 lower left and right lateral teeth, which were taken from 24 autopsy cases (46% female and 54% male). Left lateral teeth were sectioned in a vertical plane and right lateral teeth were sectioned in a horizontal plane. The NL thickness was measured with a scanning electron microscope (SEM). These cases comprised three conditions as: 70.3% normal birth, 16.7% caesarean sections, and 12.5% still birth cases under the legal and ethical permission.
  
  
  METHODS
  The mean NL thickness of normal birth cases was higher than caesarean cases as 7.7μm and 2.5μm, respectively.
  
  
  CONCLUSIONS
  The results showed a statistical significance between all birth conditions. NL does not exist in still birth cases (p<0.001). Not only is the presence of NL a sign of live birth, but also its thickness is an indicator of the delivery mode where NL thickness of normal birth was found thicker than the caesarean cases.
authors.affiliation: University of Ankara, Institute of Forensic Sciences, Department of Criminalistics, Ankara, Turkey. Electronic address: nergiscanturk@yahoo.com.
authors.forename: Nergis
authors.initials: N
authors.lastname: Canturk
authors.affiliation: University of Kirikkale, Faculty of Dentistry, Department of Prosthodontics, Kirikkale, Turkey.
authors.forename: Saadet Saglam
authors.initials: SS
authors.lastname: Atsu
authors.affiliation: University of Ankara, Faculty of Dentistry, Department of Prosthodontics and Unit of Forensic Odontology, Ankara, Turkey; Forensic Odontology Commission of Turkish Forensic Scientists Society, Ankara, Turkey.
authors.forename: P Sema
authors.initials: PS
authors.lastname: Aka
authors.affiliation: University of Ankara, Faculty of Science, Department of Statistics, Ankara, Turkey.
authors.forename: Rukiye
authors.initials: R
authors.lastname: Dagalp
mesh_terms: D002585:Cesarean Section; D036861:Delivery, Obstetric / Q000379:methods*; D003743:Dental Enamel / Q000033:anatomy & histology / Q000196:embryology*; D005260:Female; D006801:Humans; D007231:Infant, Newborn; D008297:Male; D008855:Microscopy, Electron, Scanning; D011247:Pregnancy; D050497:Stillbirth; D014094:Tooth, Deciduous / Q000033:anatomy & histology* / Q000196:embryology* / Q000648:ultrastructure
keywords: Fetus teeth; Forensic odontology; Infant teeth; Live birth; Neonatal line; Neonatology