It is a developmental disturbance in shape of teeth. It refers to an "angulation," or a sharp bend or curve, in the root or crown of a formed tooth.

The condition is thought to be due to trauma during the period in which tooth is forming, with the result that the position of the calcified portion of the tooth is changed and the remainder of the tooth is formed at an angle. The curve or bend may occur anywhere along the length of the tooth, sometimes at the cervical portion, at other times midway along the root or even just at the apex of the root, depending upon the amount of root formed when the injury occured. Such an injury to a permanent tooth, resulting in dilaceration, often follows traumatic injury to the deciduous predecessor in which that tooth is driven apically into the jaw.