Tooth discoloration decomposed gradually and a blue-brown discoloration develops. Teeth may turn grey following trauma-induced pulp necrosis (death of the pulp). This discoloration typically develops weeks or months after the injury and is caused by incorporation of pigments released during the breakdown of the pulpal tissue and blood into the dentin. Yellow discoloration may occur following pulp canal obliteration, i.e., the sealing up of the pulp. Trauma to a developing adult tooth (e.g., intrusion of a baby tooth into the bone) may affect the enamel layer of the adult tooth. This becomes apparent when the adult tooth erupts into the mouth. Teeth
Human tooth development as reparative dentin, forms in reaction to stimuli, such as attrition or dental caries. Cementum formation is called cementogenesis and occurs late in the development of teeth. Cementoblasts are the cells responsible for cementogenesis. Two types of cementum form: cellular and acellular. Acellular cementum forms first. The cementoblasts differentiate from follicular cells, which can only reach the surface of the tooth's root once Hertwig's Epithelial Root Sheath (HERS) has begun to deteriorate. The cementoblasts secrete fine collagen fibrils along the root surface at right angles before migrating away from the tooth. As the cementoblasts move, more collagen is deposited to