The presence of bulbous crowns and narrow roots, relatively normal density of any remaining enamel, and the obliteration of pulp chambers and root canals in the absence of marked attrition, are characteristic of dentinogenesis imperfecta. These findings distinguish this condition from amelogenesis imperfecta.
In patients with dentin dysplasia, the crowns are usually of normal shape, size, and proportion, in contrast to those of the patient with dentinogenesis imperfecta, whose crowns are typically bell-shaped with a constriction in the cervical region. If the roots are short and narrow, the condition is likely to be dentinogenesis imperfecta. Normal-appearing roots, or no roots at all, suggests dentin dysplasia.
Tetracycline stains are not hereditary, and this patient's history did not suggest the intake of this medication. Enamel formation is normal with this condition except for intrinsic staining.
Dentinogenesis imperfecta may have been first recognized by Barret in 1882. The first published report describing the disorder as an enamel defect was by Talbot, as quoted by Witkop. Dentinogenesis imperfecta has been reported using several different names, the most common of which are called hereditary opalescent dentin (owing to the refractory property of the dentin) and odontogenesis imperfecta.[2,3,4] The term hereditary opalescent dentin was first used by Skillen,Finn, and Hodges to describe the brown translucent teeth that have an opalescent sheen and lack pulp chambers.
Inheritance. Dentinogenesis imperfecta is a localized mesodermal dysplasia, affecting both the primary and permanent dentitions. The disease is inherited in an autosomal dominant fashion, with high penetrance and a low mutation rate. It is the most common dental genetic disease, affecting approximately 1 in 6000 to 8000 births.[7,8]
Clinical features. Clinically, both primary and permanent dentitions are affected. The color of the teeth varies from brown to blue, and is sometimes described as amber or gray. In one-third of patients, the enamel may show hypoplastic or hypocalcified defects, and the enamel tends to break at the dentinoenamel junction. The exposed dentin may then undergo severe and rapid attrition.
Radiographic features. Affected teeth have bulbous crowns and constricted, short roots. Initially, the pulp chambers may be abnormally wide, giving the appearance of "shell teeth," but they become progressively obliterated.
Histology. Histologically, the dentin is composed of irregular tubules, often with large areas of uncalcified matrix. The tubules tend to be larger in diameter and less numerous in a given volume of dentin than in normal teeth.
Medscape Dental & Oral Health © 2011
Cite this: Smita Kamtane. A Family With Malformed and Discolored Dentition - Medscape - Sep 26, 2011.