Tooth whitening the human eye and brain. Teeth are composed of a surface enamel layer, which is whiter and semitransparent, and an underlying dentin layer, which is darker and less transparent. These are calcified, hard tissues comparable to bone. The natural shade of teeth is best considered as such; an off-white, bone-color rather than pure white. Public opinion of what is normal tooth shade tends to be distorted. Portrayals of cosmetically enhanced teeth are common in the media. In one report, the most common tooth shade in the general population ranged from A1 to A3 on the VITA classical A1-D4 shade guide.
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