Analysis of the calcium content in enamel surface layer of mandibular deciduous central incisor

Objective To study the content and distribution of calcium 50 μm inside down from the enamel surface of normal mandibular deciduous central incisor as well as its correlation with age and caries status in children. Methods Calcium content of 40 mandibular deciduous central incisors was measured at different depths 50 μm inside down from the enamel surface with the Electron Probe X-ray Microanalysis. The specimens were divided into groups according to their hosts' age and caries status respectively. The differences of calcium content at different depths and the correlation between calcium content and age as well as between calcium content and caries status were all analyzed statistically. Results Average calcium content of 40 mandibular deciduous central incisors 50 μm inside down from the enamel surface was 38. 39 ± 0. 92( wt%) and there was no statistical difference at different depths,among different age groups and caries status groups respectively. There was low negative correlation between decayed-filled tooth and the calcium content at 40 μm depth beneath enamel surface( r =- 0. 3573,P 0. 05),but no other correlations were discovered. Conclusions Calcium content 50 μm inside down from the enamel surface of normal mandibular deciduous central incisors is distributed homogeneously,which has no significant correlation with the age and cannot be used as the single indicator of caries status.