ABSTRACT
As described by Linde and Goldberg [1] and Butler and Ritchie [2], the composition of the dentin matrix and the process of dentinogenesis are highly complex. e organic phase of dentin is composed of proteins, proteoglycans, lipids, various growth factors, and water. Among the proteins, collagen is the most abundant and oers a brous matrix for the deposition of carbonate apatite crystals. e collagens found in dentin are primarily type I collagen with trace amounts of type V collagen and some type I collagen trimer. An important class of dentin matrix proteins is the noncollagenous proteins or NCPs [2]. e dentinspecic NCPs are dentin phosphoproteins (DPP) or phosphophoryns and dentin sialoprotein (DSP). Aer type I collagen, DPP is the most abundant of the dentin matrix proteins and represents almost 50% of the dentin extracellular matrix. DPP is a polyionic macromolecule rich in phosphoserine and aspartic acid. Its high anity for type I collagen as well as calcium makes it a strong candidate for the initiation of dentin mineralization. DSP accounts for 5-8% of the dentin matrix and has a relatively high sialic acid and carbohydrate content. Its role in dentin mineralization is presently unclear. For several years it was believed that DSP and DPP were two independent proteins encoded by individual genes. In fact DPP and DSP are specic cleavage products of a larger precursor protein that was translated from one large transcript [3]. is single gene encoding for DSP and DPP is named “dentin sialophosphoprotein” or Dspp [4].
