Aluminum concentrations in human deciduous enamel and dentin related to dental caries

The aluminum (Al) concentrations in the enamel and dentin of 314 human deciduous teeth were determined in order to examine the relationship between Al and dental caries. The sample teeth were divided into three groups: the sound tooth group, carious tooth group and filled tooth group. The teeth of the carious tooth group were further classified into three groups depending on the stage of caries. The Al content was determined using graphite furnace atomic absorption spectrometry. In both the enamel and dentin, the Al concentrations were unaffected by sex, but did depend on tooth type. In enamel, the Al concentration was significantly higher in the sound tooth group (42.8±37.3 μg/g) than in the three carious groups (20.7±17.1–24.9±22.0 μg/g) and the filled tooth group (27.3±25.5 μg/g). As for dentin, the Al concentration was also significantly higher in the sound tooth group (36.2±35.1 μg/g) than in the three carious groups (15.1±13.3–24.5±23.4 μg/g) and the filled tooth group (17.2±20.6 μg/g). Even when analyzing incisors alone, the Al concentrations were significantly higher in the sound tooth group than in the other groups, for both enamel and dentin. Furthermore, the Al levels in carious enamel and dentin did not decrease with the advance of caries. These findings indicated that the deciduous teeth containing higher Al concentrations on average had less caries than the teeth with lower Al concentrations, and suggest that Al acts as a possible cariostatic agent by itself.