Specific Binding and Mineralization of Calcified Surfaces by Small Peptides

Several small (<25aa) peptides have been designed based on the sequence of the dentin phosphoprotein, one of the major noncollagenous proteins thought to be involved in the mineralization of the dentin extracellular matrix during tooth development. These peptides, consisting of multiple repeats of the tripeptide aspartate-serine-serine (DSS), bind with high affinity to calcium phosphate compounds and, when immobilized, can recruit calcium phosphate to peptide-derivatized polystyrene beads or to demineralized human dentin surfaces. The affinity of binding to hydroxyapatite surfaces increases with the number of (DSS)n repeats, and though similar repeated sequences—(NTT)n, (DTT)n, (ETT)n, (NSS)n, (ESS)n, (DAA)n, (ASS)n, and (NAA)n—also showed HA binding activity, it was generally not at the same level as the natural sequence. Binding of the (DSS)n peptides to sectioned human teeth was shown to be tissue-specific, with high levels of binding to the mantle dentin, lower levels of binding to the circumpulpal dentin, and little or no binding to healthy enamel. Phosphorylation of the serines of these peptides was found to affect the avidity, but not the affinity, of binding. The potential utility of these peptides in the detection of carious lesions, the delivery of therapeutic compounds to mineralized tissues, and the modulation of remineralization is discussed

Fundamental Structure and Properties of Enamel, Dentin and Cementum

In this chapter, the fundamental structure of dental tissue at different scale levels and its concurrent role in determining the mechanical properties of the tooth are discussed. The main emphasis is on the role of the organic phase in determining the mechanical properties of enamel and dentin. In this regard, the results of nanoindentation experiments following different treatments of enamel and dentin are presented. These treatments include selective removal of matrix proteins and water of enamel and dentin tissue. The findings indicate that peptides and organic remnants not only play a significant role in the formation and structure of enamel and dentin, but also they regulate the mechanical response and functional integrity of the tooth tissue. In addition, these findings provide a basis for further investigation of the adverse effect of some current clinical treatments, such as bleaching, on the health and properties of dental tissue