The dentin formation and mineralization proceeds in the defined, matrix-mediated manner. It begins from the secretion of the organic matrix and ends with the complete mineral deposition. The dentin apposition takes place when odontoblasts begin the secretion of type I collagen into the extracel- lular compartment. Type I collagen is the main component of the dentin extracellular organic matrix and forms the specific scaffold for the deposition of dentin hydroxyapatite crystals. The dentin minera- lization begins from the secretion of noncollagenous proteins directly at the mineralization front. These noncollagenous, strongly acidic proteins are able to bind covalently to type I collagen fibrils. Concurrently they have the strong affinity to calcium ions. The available data confirm that the right interaction between collagen and noncollagenous proteins secretion as well as mineral deposition is the prerequisite for the complete dentin mineralization. The fluoride hypersupplementation when provided internally can alter this coordination. The mechanism of the formation of dentin extracellular matrix has been described. We focused our attention on the metabolism of the most important dentin matrix protein and emphasized the stages in the proteins metabolism which can be adversely affected by fluoride leading to the subsequent disturbances in the proper mineralization of dentin.