Dentinogenesis Imperfecta also known as (hereditary) opalescent dentin is a congenital disorder affecting the dentin of both primary and permanent dentitions (Figure 1 & 2).
Before we begin, lets first have a quick look at our tooth structures.
Our teeth are made from Enamel which is the visible part in our mouth and is the hardest tissue in the human body. Beneath it, is the dentin which is less harder than enamel and it provides support for the Enamel and the tooth. Dentin is composed of tubules called Dentinal Tubules which connect to the pulp, the soft tissue containing nerves, vessels and lymphatics. Any defect to both enamel and dentin may lead to irritation of the pulp and consequently causing pain (Figure 3).
Dentinogenesis Imperfecta has been divided into three types:
- Type I or syndrome associated in which the dentin abnormality occurs in patients with concurrent osteogenesis imperfecta & the primary teeth are more severely affected than permanent dentition.
Briefly, Osteogenesis Imperfecta (OI) also known as brittle bone disease or Lobstein syndrome, is a congenital bone disorder characterized by brittle bones that are prone to fracture and the patients are often associated with blue eyes (Figure 4).
- In type II, patients have only dentin abnormalities and no bone disease.
- In type III, or the Brandywine type, only dental defects occur. Its similar to type II but has some clinical and radiographic variations.
Features of type III that are not seen in type I and type II include multiple pulp exposures, periapical radiolucencies (in which a radiolucency is seen in the area around the root of the tooth radiographically), and a variable radiographic appearance.
Clinically, all three types share numerous features. In both dentitions, the teeth exhibit an unusual translucent, opalescent appearance, with color variation from yellow-brown to gray. The entire crown appears discolored because of the abnormal underlying dentin. Although the enamel is structurally and chemically normal, it fractures easily, resulting in rapid wear. The enamel fracturing is believed to be due to the poor support provided by the abnormal dentin, and possibly in part to the absence of the microscopic scalloping normally seen between dentin and enamel, which is believed to help mechanically lock the two hard tissues together. Overall tooth morphology is unusual for its excessive constriction at the cementoenamel junction (Figure 5), giving the crowns a tulip or bell shape. Roots are shortened and blunted. These teeth do not exhibit any greater susceptibility to caries, and they may in fact show some resistance because of the rapid wear and absence of interdental contacts.
Radiographically, types I and II exhibit identical changes. Opacification of dental pulp occurs as the result of continued deposition of abnormal dentin. The short roots and bell shaped crowns are also obvious on radiographic examination. In type III, the dentin appears thin and the pulp chambers and root canals extremely large, giving the appearance of thin dental shells.
Microscopically, the dentin of teeth in dentinogenesis imperfecta contains fewer, but larger and irregular, dentinal tubules. The pulpal space is nearly completely replaced over time by irregular dentin. Enamel appears normal, but the dentinoenamel junction is smooth instead of scalloped.
Treatment is directed toward the protecting the tooth tissue from wear and toward, thereby improving the esthetic appearance of the teeth. Generally fitting with full crowns at an early age is the treatment of choice. Despite the qualitatively poor dentin, support for the crowns is adequate. These teeth should not be used as abutments (for braces as an example) because the roots are prone to fracture under stress.
- Affects all teeth and both dentitions.
- Tooth color may be yellow.
- Tooth shape may show extreme occlusal wear.
- X-ray findings will show obliterated pulps, short roots, and bell crowns.
- Systemic manifestations is that it may be associated with osteogenesis imperfecta.
- Treatment involves full crowns.
Reference: Oral Pathology, Sixth Edition. By Regezi, Sciubba, & Jordan.
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