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Deciduous neonatal line: Width is associated with duration of delivery
Jaana Hurnanen1, Vivian Visnapuu2, Matti Sillanpää3
1Department of Oral Pathology, Institute of Dentistry, Lemminkäisenkatu 2, FIN-20520 Turku, Finland.
Forensic Science International
|January 11, 2017
Summary
The neonatal line (NNL) in teeth, a live birth marker, appears narrower with longer vaginal deliveries. This suggests delivery stress may affect tooth enamel formation during development.
Area of Science:
- Developmental Biology
- Pediatric Dentistry
- Human Physiology
Background:
- The neonatal line (NNL) is an enamel marker of live birth, appearing in primary teeth and first permanent molars.
- NNL width and location vary, offering potential insights into gestation and birth processes.
- The specific factors triggering NNL formation at birth remain unclear.
Purpose of the Study:
- To investigate the impact of delivery duration and mode on the width of the neonatal line (NNL).
- To analyze the relationship between birth process parameters and NNL characteristics in deciduous teeth.
Main Methods:
- Analysis of 129 teeth from a prospective population cohort.
- Measurement of NNL width using light microscopy in 54 optimally sectioned teeth.
- Correlation analysis of NNL width with delivery duration and mode.
Main Results:
- NNL was detected in 98% of deciduous teeth, with a median width of 9.63μm.
- A prolonged duration of vaginal delivery showed a significant inverse association with NNL width (r=-0.41, p=0.0097).
- No significant association was found between NNL width and the mode of delivery (p=0.36).
Conclusions:
- Neonatal lines are consistently present in deciduous teeth.
- NNL width appears inversely proportional to the duration of vaginal delivery.
- Prolonged delivery stress may alter amelogenesis, leading to narrower NNLs, warranting further mechanistic research.
