What X-ray feature is noted in cases of dentinogenesis imperfecta?

In cases of dentinogenesis imperfecta, the X-ray feature that is typically observed is the presence of bulbous crowns. This condition is characterized by abnormal dentin formation, leading to distinctive morphological changes in the teeth. The crowns of the teeth appear bulbous or enlarged, often giving them a constricted appearance at the neck or cervix. This morphological change is a direct result of the underlying dentin defects, which affect both the structure and appearance of the crowns.

The other options present different dental conditions or observations. A ground-glass appearance is more commonly associated with conditions such as fibrous dysplasia. Prominent pulp chambers would indicate a different form of dental anomaly or trauma, while narrowed roots may suggest root resorption or other dental issues unrelated to dentinogenesis imperfecta. Thus, the bulbous crowns are a hallmark radiographic feature in individuals with this specific condition.