Human tooth missing or diminished enamel on a permanent tooth usually from a prior infection of a nearby primary tooth. Hypoplasia may also result from antineoplastic therapy. Tooth destruction from processes other than dental caries is considered a normal physiologic process but may become severe enough to become a pathologic condition. Attrition is the loss of tooth structure by mechanical forces from opposing teeth. Attrition initially affects the enamel and, if unchecked, may proceed to the underlying dentin. Abrasion is the loss of tooth structure by mechanical forces from a foreign element. If this force begins at the cementoenamel junction, then progression
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