Gelatinase A in human dentin as a new biochemical marker for age estimation

Dentin proteins from 24 individual permanent molars from patients aged 15 t o 73 years were sequentially extracted, with guanidinium chloride (G1-extra ct) and then with EDTA; after demineralization, the material was again extr acted with guanidinium chloride (G2-extract). Extracts were analyzed by SDS -PAGE electrophoresis and the gels were processed for zymography to detect gelatinolytic activities. The patterns of gelatinase A distribution differe d in the different dentin protein fractions, and the changes varied with ag e. Significant differences were detected in gelatinase A in G2-extracts bet ween individual younger than 20 years old and the rest of the sample (chi(e xp)(2) = 19.429; 1 d.f.; p less than or equal to 0.001). The incidence of t rue and false positives and negatives, and sensitivity and specificity for the presence of gelatinase A in dentin extracts, were calculated. Determina tion of gelatinase A in human dentin may be a useful marker to estimate age , especially when other morphological methods are of limited usefulness.