What defines dilaceration in dental terminology?

Dilaceration in dental terminology refers specifically to an abnormal curvature or bend in the root of a tooth, which can occur during development. This characteristic often arises due to trauma or a developmental anomaly, leading to a persistent, abnormal root curvature that affects the tooth's shape and alignment. Understanding this definition is crucial, particularly in diagnosing and managing dental issues related to tooth form and positioning.

The other options, while related to dental anomalies, do not accurately depict what dilaceration means. Fusion of two teeth pertains to a different phenomenon where two adjacent teeth merge during development. Enamel persistence on primary teeth relates to the retention of enamel on baby teeth, and extra roots on molars describe a condition where additional roots develop, neither of which captures the specific definition of dilaceration. Thus, the focus on root curvature as the defining trait of dilaceration makes that choice the correct one.