Three-dimensional study of human dental fissure enamel by synchrotron X-ray microtomography

Abstract

The three-dimensional morphology of human tooth fissures and the quantification of mineral distribution in fissure enamel are pertinent to the development and diagnosis of caries. Synchrotron X-ray microtomography was used to measure linear attenuation coefficients (at 25 keV) at high spatial resolution with a volume-imaging element (cubic voxel) of 4.9 × 4.9 × 4.9 μm3 in a block from a human premolar that included part of a stained fissure. From the linear attenuation coefficient, the mineral concentration, expressed as gHAp cm-3 (where HAp is stoichiometric hydroxyapatite), was calculated. The mean mineral concentration in bulk enamel was 2.84 gHAp cm-3. Well-defined regions (1.5-2.6 gHAp cm-3), extending up to ∼130 μm from the base of some narrower lengths of the fissure and up to ∼50 μm deep from the fissure surface, were attributed to hypomineralization. Other regions of low mineral concentration, some (1.4-2.3 gHAp cm-3) lying within the expected course of the fissure base and some (2.2-2.7 g HAp cm-3) deep to the pit, were also considered to be of developmental origin. However, a diffuse distribution of low mineral concentrations (2.2-2.7 gHAp cm-3) in the pit walls was attributed primarily to demineralization from caries. The fissure contained heterogeneous material (≤ 0.5 gHAp cm-3) exhibiting partial mineralization. © Eur J Oral Sci, 2006.