Dentin anomalies

Dentinogenesis imperfecta is caused by a mutation in the DSPP gene. Clinically, the color of the teeth range from yellow to blue/grey. They are translucent and the crowns are bulb-shaped. The roots are short and the pulp chambers can be completely obliterated over time. The enamel is normal. Deciduous teeth are more affected than permanent teeth.

There are two types of dentin dysplasia. Type 1 is more frequent than type 2 and is also called rootless teeth since the roots are very short which leads to premature tooth loss. The enamel and the dentin in the crown are normal, only the dentin in the root is abnormal. There are multiple peri-apical lesions. Deciduous dentition is affected more severely than permanent dentition.

Type 2 appears clinically similar to dentinogenesis imperfecta. In deciduous dentition, the crown is amber and bulb-shaped and the pulp chamber disappears post-eruption. However, unlike dentinogenesis imperfecta, the roots are not affected. In permanent dentition, the teeth appear clinically normal but there are anomalies of the pulp chamber, it is flame shaped with pulp stones. There are no peri-apical lesions.

Osteogenesis imperfecta is one of the most common genetic bone disorders. It is caused by a mutation in the genes (COL1A1 and COL1A2) that code for type 1 collagen, an important constituant of bones, dentin, ligaments etc. The most common signs of this condition are fragile bones, hearing loss, looseness in the joints and a blue sclera. Patients with osteogenesis imperfecta can also have dental symptoms similar to dentinogenesis imperfecta. Patients also have maxillary hypoplasia which is responsible for a class 3 malocclusion (underbite).