Felis ISSN 2398-2950

Dental trauma: tooth discoloration

Contributor(s): Alex Smithson, Peter Southerden

Introduction

  • Trauma commonly affects the oral cavity, this may be specific, eg animal 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.
  • 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 Dental trauma: tooth luxation/avulsion, soft tissue laceration, jaw fracture Mandible: fracture, symphyseal separation, temporomandibular joint displacement, oronasal communication, pulpal bleed (resulting in tooth discoloration), and pulpitis leading to pulpal necrosis also potentially causing tooth discoloration.
  • Tooth discoloration: the result of a pulpal hemorrhage, pulpitis and pulpal necrosis secondary to tooth trauma. Other causes include hematogenous infection of the pulp, excessive orthodontic or occlusal forces or any event causing long term disruption to the blood supply to the tooth.
  • Most commonly seen with canine teeth.

Pathogenesis

Etiology

  • Blunt dental trauma.

Predisposing factors

General

  • Traumatic incident.
  • Reduced alveolar support, eg pre-existing periodontitis Periodontal disease.

Pathophysiology

  • A blow to a tooth may cause trauma to the pulp, with resultant hemorrhage from pulpal vessels or pulpitis which may be reversible or if irreversible eventually progressing to pulpal necrosis. The blood hemoglobin breakdown products enter the dentinal tubules within the dentine of the crown and stain the dentine. This often begins as a pink discoloration several days after the trauma (this may return to normal if the initial discoloration is due to a reversible pulpitis), gradually changing to purple. A non-vital pulp will often lead to reduced translucency of the tooth, while a black necrotic pulp gives a gray appearance to the tooth. The majority of pulps become non-vital (94% reported as suffering irreversible pulpitis). Pulpitis produces toothache. Should non-vital pulps become infected, abscessation may occur. Bacteria colonizing a necrotic pulp may combine with iron from hemoglobin producing iron sulphide which may further darken the tooth.

Timecourse

  • Acute incident however may not be noted for some time (many animals will continue to eat).
  • Discoloration may alter over time, usually darkening as time from injury increases, but is usually permanent.

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

  • 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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