November 24, 2021
Dilaceration refers to a dental anomaly that affects the root of the tooth. A dilacerated tooth has a characteristic appearance, where the lower third of the roots deviate more than 90 degrees from the long axis of the tooth. The shape that a dilacerated tooth acquires has led researchers to give it multiple names. A dilacerated tooth, first reported in 1848, has been called a sickle, a scorpion and also the hand of a traffic policeman in the past
Dilaceration can be a result of a traumatic injury or a disturbance in the developmental process. Understanding these two mechanisms can help us in getting a clearer idea of the condition. Dilaceration is more commonly seen in permanent teeth compared to deciduous teeth. The most commonly affected teeth are the upper front teeth.
The permanent maxillary incisor's eruption path is such, that it finds its position in the oral cavity by erupting behind the deciduous maxillary incisor. At the age of approximately 4 years, the permanent tooth's crown formation is already underway, but its roots are yet to form. During this period, the crown of the permanent tooth are in close approximation to the roots of the deciduous tooth. If a child suffers an injury on the upper deciduous incisor, the direction of the impact can travel from its crown to the root, to the developing tooth bud of the permanent incisor. This leads to a shift in the direction of the permanent tooth bud. However, there is no change in the direction in which its root is forming and hence the growth of the root occurs at an angle to the crown of the permanent incisor.
The above-mentioned mechanism is not the only means by which dilaceration occurs. Developmental disorders affecting the tooth bud, presence of cysts or tumours, traumatic extraction of primary teeth are some other reasons that can cause a shift in the direction of the developing tooth bud. There are certain syndromes like Smith-Magenis, Ehlers-Danlos, Axenfeld-Reiger and congenital icthyosis, along with whom, dilaceration has often been associated.
Dilaceration can occur at any area of the tooth's root. It can affect any teeth depending on the direction of trauma. As a result, the crown of the tooth may stay unerupted or might erupt abnormally in a different direction. The dilacerated tooth might cause an inflammatory bulge in the soft tissues which may or may not be painful.
Apart from palpation of the areas surrounding the dilacerated tooth and observing the position of the affected tooth, dilaceration can be suspected. However, it is only after a radiographic investigation of the roots that its presence is confirmed.
On the radiograph, a dilaceration can be detected by a characteristic Bull's eye appearance. Since the radiograph is a two-dimensional image, the bend of the dilacerated tooth appears as a small black spot like a halo. The bony ligament surrounding the affected tooth appears greyish because of the increased density of the x-ray beams at the area of the dilaceration.
Cone Beam Computed Tomography (CBCT) has become a more reliable radiographic investigation to confirm the presence of dilaceration. Since it gives a three-dimensional view of the tooth, diagnosis is much more accurate. Moreover, it has added benefits of less radiation exposure, better contrast and high resolution of the tooth of concern.
Management of a dilacerated tooth depends on the severity of the dilaceration, its position, amount of root formed and amount of space around the impacted tooth. Depending on these factors, it is decided whether to reposition the tooth or remove it altogether.
Orthodontic traction is one method where tooth with a favorable prognosis can be repositioned in the arch. However, this is a time consuming approach and warrants much patience. Moreover, it is a multidisciplinary approach, meaning, that dentists of multiple specialities (orthodontics, pedodontics, oral surgeons and periodontics) need to work together to maintain the health of the surrounding structures as well.
In case an extraction is planned, the treatment should also involve how to close the space created following the extraction of the dilacerated tooth. Moving the adjacent tooth to the extraction space or autotransplantation of another tooth in the extraction space are some of the methodologies. Other methods include restoring the space by means of implants, bridges and partial dentures.