Felis ISSN 2398-2950

Dental trauma: tooth luxation/avulsion

Contributor(s): Alex Smithson, Peter Southerden

Introduction

  • Trauma commonly affects the oral cavity, this may be specific, eg fracturing a tooth or as part of a greater trauma syndrome, eg maxillofacial trauma from high rise or road traffic accidents.
  • 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 each insult accurately triaged Triage.
  • Dental, oral and maxillofacial trauma often exists in combination; if one injury is found there are frequently other injuries which may be less obvious.
  • Examples include: tooth fracture (crown or root Dental fracture  Dental trauma: root fracture  ), tooth luxation, soft tissue laceration, jaw fracture Mandible: fracture, symphyseal separation, temporomandibular joint displacement, oronasal communication, pulpal bleed (resulting in tooth discoloration Dental trauma: tooth discoloration).
  • Tooth luxation: the tooth is dislocated within its socket but maintains some attachement.
  • Tooth avulsion: the tooth is exarticulated with the entire periodontal ligament being severed as is the vascular and neural supply to the pulp of the tooth.
  • The tooth trauma causes loss of integrity of all or part of the periodontal ligament fibers, vascular and neural supply and/ or alveolar (socket) bone. The result is loosening of the tooth from the alveolus/ socket rather than tooth fracture.
  • Most commonly seen with single rooted teeth, especially the canines.
  • Several types exist and an injury may involve a combination of several of these:
    • Subluxation.
    • Lateral luxation.
    • Intrusive luxation.
    • Extrusive luxation.
    • Avulsion.
    • Concussion.

Pathogenesis

Etiology

  • The tooth trauma causes loss of integrity to the periodontal ligament fibers and/ or alveolar (socket) bone.
  • The result is loosening of the tooth from the alveolus/ socket rather than tooth fracture (however luxation type injuries are often accompanied by additional tooth fracture).
  • Tooth trauma may be by a force directed along axis of tooth or at an angle to the long axis.

Predisposing factors

General

  • Traumatic incident.
  • Reduced alveolar support, eg pre-existing periodontitis.
  • Single rooted teeth.

Pathophysiology

  • The trauma suffered by apical nerves, lymphatics and blood vessels which supply the tooth pulp with vital nutrients, oxygen and waste removal will dictate the likelihood of the tooth remaining viable.
  • Where irreversible damage occurs the pulp will die resulting in a non-viable tooth.
  • Non-viable teeth require treatment!
  • Likely pathological changes vary with the type of luxation:
    • Subluxation: loosening without displacement of a tooth within its alveolus/socket by traumatic periodontal ligament damage. The blow to the tooths crown causes compression and crushing of periodontal ligament fibers opposite the point of injury and stretching and tearing of those fibers closest to the point of impact. This effect will be produced, in reverse manner, at the root when tipping action is involved or by animal pulling on the wires of its cage. Apical vessels may be damaged but are likely to recover. Subluxation may occur in a mesio-distal, labial or palatal direction.
    • Lateral luxation  Tooth luxation: lateral movement - diagram   Tooth: lateral luxation : displacement of a tooth within its alveolus/socket by horizontal trauma. Usually accompanied by alveolar bone fracture. The blow to the crown produces a tipping action of the tooth with compression and crushing of periodontal ligament fibers furthest from the point of impact with the crown and stretching and tearing of those fibers closest to the point of impact. This pattern is reversed at the root apex as it tips in the opposite direction to the crown. This effect may be produced, in reverse manner, by animal pulling on the wires of its cage. Apical vessels may be damaged; if crushed or torn they may not recover. Luxation may occur in a mesio-distal, labial or palatal direction.
    • Intrusion  Tooth luxation: intrusion - diagram an end-on (ie inwardly directed) blow to the tooth causes stretching and tearing of the less apical fibers and compression and crushing of periodontal ligament fibers around the root apex as the tooth is pushed further into the bone. Usually accompanied by alveolar bone fracture. The apical vessels are crushed and unlikely to recover.
    • Concussion: a blow to the tooth causes momentary tooth movement and thus trauma to the supporting periodontal tissues, however the tooth is not displaced. This may thus go un-noted but would cause temporary discomfort where tissues remain viable. Discoloration Dental trauma: tooth discoloration  of the tooth may follow due to pulpal hemorrhage usually resulting in pulpal necrosis.
    • Extrusion  Tooth luxation: extrusion - diagram  : an outward force is applied to the tooth resulting in tearing of ligament fibers and outward tooth movement. Apical vessels may recover if stretched, but not if torn.
    • Avulsion: the injury to the periodontal ligament fibers is sufficient to result in complete loss of the tooth from its socket ie exarticulation of the tooth. Apical vessels torn permanently thus pulp will become non-viable.

Timecourse

  • Acute incident however may not be noted for some time (many animals will continue to eat).
  • If periodontitis is a pre-existing condition, the time course of loss of bony support is often years.
  • Loss of tooth viability may be rapid (eg avulsion, intrusion) or more protracted (eg eventual non-viability in lateral luxation case).

Diagnosis

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Treatment

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Outcomes

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Further Reading

Publications

Refereed papers

Other sources of information

  • Gorrel C (2004) Veterinary Dentistry for the General Practitioner. Saunders, Elsevier Science.
  • Gorrel C, Penman S, Emily P (1993) Small Animal Oral Emergencies. Pergamon Press.

Organisation(s)


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