IADR Abstract Archives
Variations in Prenatal and Postnatal Primary Tooth Enamel
Objectives: The neonatal line in dental enamel is a manifestation of birth, and is found in most primary teeth when microscopically studied. The neonatal line defines enamel being formed before and after birth. In prenatal enamel, amelogenesis progresses during normally stable intrauterine conditions. In postnatal enamel, amelogenesis is subjected to possible outer influences. The aim of this study was to compare prenatal and postnatal primary tooth enamel, by means of polarization microscopy patterns and micro X-ray analysis.
Methods: Eight exfoliated primary molars or incisors were acquired from a biobank. The teeth were embedded in methylmetacrylate and ground-cut into 120 um vertical sections. Sections with visible neonatal lines in the enamel were selected for polarization microscopy. All sections were photographed in white light and polarized light, in a light microscope and were analyzed dry and after water imbibition. Sections from six of the teeth were subjected to soft micro X-ray analysis. The microradiographs were photographed in white light.
Results: Polarization microscopy birefringence did not change after water imbibition, indicating a low degree of enamel porosity. In 63% of the samples, there was a difference in the refringence pattern between prenatal and postnatal enamel (Chi2, p=0.03). Variations, revealed as polarization microscopy color changes and/or non-refringent areas, were in most cases, observed in the postnatal portion of the enamel. Microradiography did not reveal further information.
Conclusions: Postnatal primary tooth enamel was affected with varying degrees of changes in polarized light color and the presence of non-refringent areas. It is suggested that primary tooth enamel aberrations emanate from circumstances during and after birth.
Methods: Eight exfoliated primary molars or incisors were acquired from a biobank. The teeth were embedded in methylmetacrylate and ground-cut into 120 um vertical sections. Sections with visible neonatal lines in the enamel were selected for polarization microscopy. All sections were photographed in white light and polarized light, in a light microscope and were analyzed dry and after water imbibition. Sections from six of the teeth were subjected to soft micro X-ray analysis. The microradiographs were photographed in white light.
Results: Polarization microscopy birefringence did not change after water imbibition, indicating a low degree of enamel porosity. In 63% of the samples, there was a difference in the refringence pattern between prenatal and postnatal enamel (Chi2, p=0.03). Variations, revealed as polarization microscopy color changes and/or non-refringent areas, were in most cases, observed in the postnatal portion of the enamel. Microradiography did not reveal further information.
Conclusions: Postnatal primary tooth enamel was affected with varying degrees of changes in polarized light color and the presence of non-refringent areas. It is suggested that primary tooth enamel aberrations emanate from circumstances during and after birth.