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Dental trauma: root fracture

ISSN 2398-2942


Introduction

  • Trauma commonly affects the oral cavity and maxillofacial region. Common causes include extraction complication, hits, kicks, bites, falling from a height, road traffic accidents, burns and hit by projectiles. Oral injury also is common when chewing on very hard objects.
  • It is essential to fully assess the whole animal to ensure that life-threatening aspects such as shock, hemorrhage or internal injury are identified and dealt with appropriately.
  • Dental, oral and maxillofacial traumata often co-exist in combination; if one injury is found there may be other injuries that could be less obvious.
  • Examples include: tooth fracture (which may be limited to the crown or involve the root), tooth displacement injury (luxation and avulsion Dental trauma: tooth luxation/avulsion ), tooth discoloration Dental trauma: tooth discoloration (via extravasation of blood from pulpal vessel), soft tissue laceration, bone fracture, mandibular symphyseal separation, temporomandibular joint luxation Temporomandibular joint: luxation , and palate defect Cleft lip and palate.
  • Tooth fractures Dental fracture are classified based on location (crown, crown-root, or root) and pulp exposure (uncomplicated or complicated):
    • Crown fracture refers to fracture of a tooth involving the crown only.
    • Crown-root fracture refers to fracture of a tooth involving the crown and root.
    • Root fracture refers to fracture of a tooth involving the root only.
    • Uncomplicated fracture refers to fracture of a tooth without pulp exposure.
    • Complicated fracture refers to fracture of a tooth with pulp exposure.
  • The inciting trauma may result in loss of the coronal portion of a tooth (crown with or without a portion of the root), leaving behind a root remnant (or root remnants in the case of a multi-rooted tooth).
  • The coronal segment of a tooth with root fracture may be displaced to a varying degree. The apical segment is usually not displaced and the apical pulpal circulation not disrupted, thus pulp necrosis in the apical segment is rare.
  • If the trauma leads to fracture of the surrounding alveolar bone and/or rupture of periodontal ligament fibers, the remaining coronal segment usually becomes mobile.
  • The level (coronal root, midroot, apical root) and angle (horizontal, oblique) at which the root has fractured, and the degree of displacement of the coronal segment of the tooth, influence prognosis and prospective treatment type Tooth: root fracture - locations.
  • Root fracture is more likely to be seen in rostral teeth due to accidental trauma but may present in any tooth secondary to iatrogenic injury during attempted tooth extraction.
  • Root fracture during extraction is common and may lead to root remnant creation.
  • Root fracture may be seen in combination with other traumatic injuries including:
    • Concussion.
    • Subluxation.
    • Luxation.
    • Crown fracture.
    • Tooth discoloration.
    • Jaw fracture.

Presenting signs

  • Tooth appears missing.
  • Tooth appears mobile.
  • Tooth appears altered in size or position.
  • Bleeding from the mouth.
  • Pulp exposure.
  • Difficulty in chewing or closing mouth fully.
  • Oral discomfort/pain.
  • Facial swelling and lymphadenopathy (due to infection/inflammation).

Acute presentation

  • Tooth appears missing.
  • Tooth appears mobile.
  • Tooth appears altered in size or position/angulation.
  • Bleeding from the mouth.
  • Pulp exposure (with red, bleeding tissue visible at the fracture site).
  • Difficulty in chewing or closing mouth fully.
  • Oral discomfort/pain.

Age predisposition

  • In young to mid-aged animals where road traffic accidents, fights or playing with unsuitable objects are involved.
  • Animals of any age affected by iatrogenic injury during attempted tooth extraction.
  • Small dogs have relatively delicate teeth that may show pathology (eg tooth resorption, dentoalveolar ankylosis, periodontitis Periodontitis ) predisposing to root fracture.

Breed/Species predisposition

  • Dogs exhibiting keen catching and chasing habits (breeds such as Labradors and Border Collies) may be predisposed, particularly when inappropriate toys and treats are used (eg rocks, cricket balls, golf balls, tennis balls, ice cubes, cow hooves, nylon bones).

Cost considerations

  • Fracture of roots may go undetected and necessitate repeat examinations to identify.
  • Retained root remnants may lead to infection/inflammation of surrounding tissues (eg periapical granuloma or abscess Teeth: periapical abscess , osteitis, osteomyelitis), thus incurring further treatment costs.
  • Repeat costs may stem from iatrogenic injury during tooth extraction. Root remnant removal may increase anesthesia time and would thus create additional treatment costs.
  • Where stabilization and healing is attempted, costs of radiographic monitoring and removal of stabilization devices must be considered.
  • Endodontic therapy and crown restoration add cost when tooth preservation is elected.
  • Failure of healing would require salvage treatment (extraction).
  • Extraction of affected teeth is often the least expensive option.

Special risks

  • Ensure full assessment of all other injuries.
  • Increased intracranial pressure secondary to head trauma may increase the risk further insult during anesthesia.
  • Stabilize systemically first!

Pathogenesis

Etiology

  • Trauma either to:
    • The crown of a tooth, resulting in leverage forces and fracture of the root (via a blow or during tooth extraction).
    • The crown of a tooth (via impact with a hard object) resulting in a fracture extending from the crown into the root.
    • The alveolus and thus to the tooth that it contains, causing fracture of the root over the injured alveolar bone Tooth: root remnant - diagram 01.
    • The root, during extraction of a root remnant, resulting in fracture.
  • Tooth trauma may be by a force directed either towards or away from the tooth.
    • Force towards tooth (impact/blow), eg road traffic accidents, impact with hard objects which may have been thrown or have fallen from a height or excessive elevation forces during tooth extraction.
    • Force directed away from the tooth (pulling), eg pulling on the wires of cages or fences or fighting with other animals; also via incorrect use of extraction forceps.

Predisposing factors

General
  • Traumatic incident.
  • Poor extraction technique.
  • Reduced alveolar bone support, eg due to pre-existing periodontitis.
  • Weakening of tooth structure, eg via morphology, aging, resorption.

Specific

  • Iatrogenic - use of excessive force during tooth extraction, use of inappropriately sized dental elevators and luxators, use of extraction forceps on the crown/prior to adequate elevation.
  • Playing with or chewing of very hard objects (such as rocks, hard balls, metal items large ice cubes, cow hooves, nylon bones, and real bones).

Pathophysiology

  • Root fracture leading to pulp exposure within the alveolus or near the alveolar margin.
  • Infection being present depending on fracture location.
  • Pulpitis eventually leading to pulp necrosis Teeth pulpal necrosis 02.
  • Inflammation extending into periradicular tissues (periodontal ligament and alveolar bone).

Timecourse

  • Acute incident, however root fracture may not be noted for some time.
  • Loss of tooth vitaility may be rapid or more protracted.

Diagnosis

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Treatment

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Prevention

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Cohen S, Burns R (2006)Pathways of the Pulp. 9th edn. Mosby, St Louis.

Organisation(s)