title: Gross, computed tomographic and histological findings in mandibular cheek teeth extracted from horses with clinical signs of pulpitis due to apical infection.
abstract: BACKGROUND
  The most prevalent type of equine dental pulpitis due to apical infection is not associated with coronal fractures or periodontal disease. The pathogenesis of this type of pulpitis is not fully understood. Computed tomography (CT) is increasingly used to investigate equine dental disorders. However, gross, tomographic and histopathological changes in equine dental pulpitis have not been compared previously.
  
  
  OBJECTIVE
  To compare gross, CT and histological appearances of sectioned mandibular cheek teeth extracted from horses with clinical signs of pulpitis without coronal fractures or periodontal disease. To contribute to understanding the pathogenesis of equine dental pulpitis.
  
  
  METHODS
  Descriptive study using diseased and healthy teeth.
  
  
  METHODS
  Mandibular cheek teeth extracted from horses with clinical signs of pulpitis (cases), and from cadavers with no history of dental disease (controls), were compared using CT in the transverse plane at 1 mm intervals. Teeth were then sectioned transversely, photographed and processed for histopathological examination. Tomographs were compared with corresponding gross and histological sections.
  
  
  RESULTS
  Cement, dentine and bone had similar ranges of attenuation (550-2000 Hounsfield Units, HU) in tomographs but could be differentiated from pulp (-400 to 500 HU) and enamel (> 2500 HU). Twelve discrete dental lesions were identified grossly, 10 of which were characterised histologically. Reactive and reparative dentinogenesis and extensive pulpar mineralisation, previously undescribed, were identified. Pulpar oedema, neutrophilic inflammation, cement and enamel defects, and reactive cemental deposition were also observed. The CT and pathological findings corresponded well where there was mineralised tissue deposited, defects in mineralised tissue, or food material in the pulpar area. Pulpar and dentinal necrosis and cement destruction, evident grossly and histologically, did not correspond to CT changes.
  
  
  CONCLUSIONS
  Computed tomography is useful for identifying deposition and defects of mineralised material but less useful for identifying inflammation and tissue destruction. The equine dentine-pulp complex responds to insult with reactive and reparative changes.
authors: Department of Clinical Veterinary Science, University of Bristol, UK.
authors: M B
authors: MB
authors: Casey
authors: Department of Clinical Veterinary Science, University of Bristol, UK.
authors: G R
authors: GR
authors: Pearson
authors: Department of Veterinary Clinical Sciences, Royal Veterinary College, London, UK.
authors: J D
authors: JD
authors: Perkins
authors: Department of Clinical Veterinary Science, University of Bristol, UK.
authors: W H
authors: WH
authors: Tremaine
mesh_terms: D000818:Animals; D016022:Case-Control Studies; D006734:Horse Diseases / Q000473:pathology*; D006736:Horses; D011671:Pulpitis / Q000473:pathology / Q000662:veterinary*; D014057:Tomography, X-Ray Computed; D014070:Tooth / Q000000981:diagnostic imaging / Q000473:pathology*; D014081:Tooth Extraction / Q000662:veterinary*
keywords: apical infection; computed tomography; dentistry; horse; pulpitis