Quantitative assessment of collagen crosslinks in dissected predentin and dentin.

Dentinogenesis offers a unique system for the study of changes in collagen structure occurring simultaneously with mineralization. Bovine dentin was found to contain about one reducible crosslink per collagen molecule; rat dentin contained twice this amount. In contrast, bovine dentin contained twice as much pyridinium crosslink as did rat dentin collagen. These results indicate that the collagen in rat teeth is less mature and again emphasize the difference in composition between the organic matrices of rat and bovine dentin. In dissected bovine predentin, the unmineralized precursor of dentin, the content of reducible crosslinks was almost double that of dentin. Only minute amounts of non-reducible crosslinks were found in predentin, whereas both pyridinoline and deoxy-pyridinoline were present in collagen from mineralized dentin. The observed differences in crosslinking between predentin and dentin of the same teeth may indicate some alterations within the area of mineralization.