5.5. Dentine minerals

Only groups fed on the standard diet (the 6 week"s experiments) were included in the mineral element analyses in order to avoid caries induced demineralization zones. Ca/P ratio was the same (1.8) in all the groups in dentine formed both before and after the onset of the experimental period. Also, no differences were found between the groups in any of the measured mineral elements of dentine formed before the experiment.

The amount of calcium in dentine formed before the experiment was higher than that formed during the experiment in all the groups, except in the group 2 (metabolic acidosis), in which it was lower (Table 7). In addition to this, in group 4 (metabolic alkalosis) the amount of fluoride increased and the amount of phosphorus and total mineral contents decreased during the experiment. In the group 6 (respiratory alkalosis) the amount of magnesium decreased and in the group 8 (controls) sodium, phosphorus and total minerals decreased during the experiment.

When the change in mineral values (dentine formed during the experiment - dentine formed before the experiment) of the groups 2, 4 and 6 were compared (Table 7) to those of the control group 8, the group 2 (metabolic acidosis) differed most: the values of Ca, Mg, Na and total minerals were higher in the group 2. The amount of fluoride was lower, but not significantly. When the "opposite" groups 2 (metabolic acidosis) and 4 (metabolic alkalosis) were compared, the amounts of Ca (p=0.008, Mann-Whitney U -test), Mg (p=0.03), P (p=0.005) and total minerals (p=0.007) were higher in group 2, but the amount of fluoride was lower (p=0.027).