Hypoplasia: A condition of arrested development in which an organ or part of an organ remains below the normal size or in an immature state.
Inherited dentin defects include Dentinogenesis Imperfecta which vary in phenotypic expression and are usually inherited in an autosomal dominant manner. DI can be a clinical feature of Osteogenesis Imperfecta. Teeth appear blue-gray or yellow-brown because the abnormal dentin shines through the enamel. Teeth have increased susceptibility to fracture and spontaneous abscess.
Dentin: A calcareous material similar to bone but harder and denser that composes the principal mass of a tooth; consists of a matrix containing minute parallel tubules which open into the pulp cavity and during life contain processes of the cells of the pulp.