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
Dental material deep undercuts). In order to obtain an accurate impression, a suitable property of impression material must be used. Impression materials are designed to be liquid or semi-solid when first mixed, then set hard in a few minutes, leaving imprints of oral structures. Common dental impression materials include: Historically these products were used as impression materials: Dental lining materials are used during restorations of large cavities, and are placed between the remaining tooth structure and the restoration material. The purpose of this is to protect the dentinal tubules and the sensitive pulp, forming a barrier-like structure. After drilling the caries out