Mineral content in teeth with deciduous molar hypomineralisation (DMH)

We report the mineral (hydroxyapatite) density of sound and opaque areas in DMH molars with sound parts of (carious) deciduous teeth serving as controls.

Twenty-nine extracted second primary molars obtained from 15 children were studied. Thirteen of these molars were DMH molars with yellow opacities, seven were DMH molars with white opacities, three DMH molars with brown opacities and eleven were molars without DMH. Prior to microCT scanning, the teeth were mounted in impression material (Impregum(®)) and stored in water with a thymol crystal. Spot analysis and line scans were performed in areas with opacities and in sound areas. An ANOVA test and t-tests were used to test if there were significant differences between the groups.

The average densities of the hydroxyapatite in yellow and brown opacities (1368mg HA/cm(2) and 1407mg HA/cm(2), respectively) were significantly lower than in clinically unaffected enamel (1747mg HA/cm(2)) of DMH molars or of sound molars (1758mg HA/cm(2)). The mineral density in white opacities (1737mg HA/cm(2)) was not different from that in the enamel of sound molars. The mineral density values in yellow and brown enamel opacities were in between those of dentine (1018mg HA/cm(2)) and enamel.

DMH molars with yellow or brown opacities had a 20-22% lower mineral density in the hypomineralised enamel compared with sound molars. White opacities do not show a lower mineral content. The reduction in enamel mineral content in DMH molars stressed the need for a preventive approach in DMH.