Morphological aspects of dental hard tissues in primary teeth from preterm infants

Background. Preterm children with very low birth weight suffer from several neonatal and post-natal complications that may affect the mineralization of the teeth. Clinical studies have shown enamel aberrations in both dentitions. Aims. The aims of this study were to describe enamel histo-morphology in primary teeth, and investigate the relationship between medical history and morphological appearance. Design. Dental enamels in 44 exfoliated primary teeth, from 14 children with a gestational age below 29 weeks and with a very low birth weight, were investigated, using polarized light microscopy (POLMI) and under a scanning electron microscope (SEM). Results. The neonatal line was found in 1/3 of the sections located coronally of the crown. In the post-natal enamel, 31 teeth showed a degree of porosity higher than 5% with a varying extension. More than half of the teeth showed one or more increment lines. The SEM analysis confirmed the POLMI findings with irregular prisms covered with a structure-less film. Conclusions. Enamel from primary teeth of preterm children was found to have a high frequency of mineralization disturbances found in POLMI and SEM. The morphological features of the enamel from preterm children do not reflect the disturbances on general growth and development occurred during the neonatal period.