Root Fractures: Understanding the Injury and Its Classification

Dental trauma can range from relatively minor damage to serious injuries involving the entire tooth. Although crown fractures are more common, root fractures present a unique clinical challenge because they involve multiple tooth structures and can vary significantly depending on their location and direction. Understanding how root fractures occur and how they are classified is an important first step in their diagnosis and management.

Dental traumatic injuries account for up to 5% of all dental emergencies in children and young adults (IADT, 2012). A wide range of injuries can result from trauma, varying from a simple enamel infraction to complete tooth avulsion (IADT, 2012).

While crown fractures are more common, root fractures account for approximately 0.5–7% of all dental trauma involving permanent teeth and 2–4% of trauma affecting primary teeth (Poi et al., 2002). The lower percentage of dental trauma in the primary dentition may be due to the elasticity of the alveolar bone socket, which can absorb the impact by acting as a cushion (Andreasen et al., 2007). Moreover, because of a lower crown-to-root ratio, these teeth are more susceptible to luxation injuries than fractures (Glendor, 2008).

Root fractures specifically involve the dentin, cementum, and pulp (Castro et al., 2005). These fractures frequently occur between the ages of 2–6 years in the primary dentition and 11–20 years in the permanent dentition (Glendor, 2008).

In most cases, the aetiology of these fractures ranges from accidental falls, sports injuries, and traffic accidents to parafunctional habits, traumatic occlusion, or iatrogenic causes (Castro et al., 2005). Additionally, root fractures in anterior teeth usually occur as a result of direct traumatic impact, whereas fractures in posterior teeth are more commonly caused by indirect trauma (Popescu et al., 2017).

Classification of Root Fractures

Root fractures are classified according to the direction of the fracture line in relation to the axis of the tooth. They can generally be classified as either horizontal or vertical root fractures (Andreasen et al., 2007).

Horizontal Root Fractures

Horizontal root fractures can be further classified according to the position of the fracture line within the root. These include fractures located in the:

Apical third

Middle third

Cervical third

(Glendor, 2008).

They may also be classified as **partial or complete**, depending on the extent of the fracture, and as **simple or multiple**, depending on the number of fracture lines present (Glendor, 2008). In addition, the coronal segment of a horizontally fractured tooth may either be displaced or remain in its original position.

Vertical Root Fractures

Vertical root fractures extend along the length of the long axis of the tooth (Lertchirakarn et al., 2003). They can be further subdivided into **complete or incomplete fractures**, depending on the degree of fragment separation.

They may also be classified as **supra-osseous or intraosseous**, depending on the position of the fracture in relation to the surrounding bone (Lertchirakarn et al., 2003).

References

• Castro, J.C.M., Poi, W.R., Manfrin, T.M. and Zina, L.G., 2005. Analysis of the crown fractures and crown-root fractures due to dental trauma assisted by the Integrated Clinic from 1992 to 2002. *Dental Traumatology*, 21(3), pp.121–126.

• Glendor, U., 2008. Epidemiology of traumatic dental injuries – a 12-year review of the literature. *Dental Traumatology*, 24(6), pp.603–611.

• Lertchirakarn, V., Palamara, J.E. and Messer, H.H., 2003. Patterns of vertical root fracture: factors affecting stress distribution in the root canal. *Journal of Endodontics*, 29(8), pp.523–528.

• Poi, W.R., Manfrin, T.M., Holland, R. and Sonoda, C.K., 2002. Repair characteristics of horizontal root fracture: a case report. *Dental Traumatology*, 18, pp.98–102.

• Popescu, S.M., Diaconu, O.A., Scrieciu, M., Marinescu, I.R., Drăghici, E.C., Truşcă, A.G., Bănică, A.C., Vătu, M. and Mercuţ, V., 2017. Root fractures: epidemiological, clinical and radiographic aspects. *Romanian Journal of Morphology and Embryology*, 58(2), pp.501–506.