After a clinical examination (defs/DMFS, initial caries lesions), an area of a deciduous tooth was etched in each of the 35 children (O=8.11+/-2.41 years) with 37% phosphoric acid gel for 1 min. Immediately after, this demineralization was stained with 2% aqueous methylene blue and the red/green/blue spectrum measured with a colorimeter. Twenty-four hours later, the remineralization of this area was measured following the same staining procedure.
Color measurements were clearly reduced after 24 h, indicating remineralization, and they correlated highly with the age of the children (Spearman correlation coefficient r=-0.48, p=0.004). Correlations between the number of initial caries lesions in the deciduous and permanent dentition and color measurements after demineralization were statistically significant (r=0.41 and 0.37, p=0.02 and 0.045, respectively).