title: A scanning electron microscopy study of idiopathic external tooth resorption in the cat.
abstract: BACKGROUND
  Multiple idiopathic root resorption (MIRR) is a rare condition in man characterized by cervical resorption leading to significant tooth loss. A similar condition, feline osteoclastic resorptive lesions (FORL), affects up to 70% of domestic cats and thus provides a valuable model for investigating the etiopathogenesis of MIRR. The aim of the present study was to establish changes in the surface microanatomy of the tooth in late stage FORL and to identify whether its location has a surface bias.
  
  
  METHODS
  Scanning electron microscopy (SEM) was used to analyze the surface features of enamel and cementum of feline teeth affected with advanced FORL.
  
  
  RESULTS
  Resorption involved the coronal root at the cementoenamel junction (CEJ) in 95% of teeth and focal resorption of intact enamel was observed in 14% of teeth. In 55% of teeth, the main lesion was on the buccal surface and a distinct circumferential resorption "front" was present at the apical margin of resorption. The root surfaces of most affected teeth either lacked extrinsic fibers or cellular lacunae or featured evidence of cementum remodeling. Woven bone-like tissue was found within lesions, on resorbed dentin, or on the root surface in 27% of teeth.
  
  
  CONCLUSIONS
  This study demonstrates that most FORL involve the CEJ, and the presence of focal lesions at this site suggests that this is where resorption is initiated. This implies that local factors in the oral microenvironment play a role in the etiopathogenesis of this condition. The study also shows that FORL are more likely to occur on buccal surfaces and are associated with changes in the microarchitecture of the root surface consistent with destruction of the normal periodontal attachment and stimulation of a reparative response. These findings may be relevant to understanding the etiopathogenesis of multiple idiopathic resorption areas in man.
authors: Bone and Mineral Centre, Department of Medicine, University College London, London, U.K. adelaur@nimr.mrc.ac.uk
authors: April
authors: A
authors: DeLaurier
authors: Alan
authors: A
authors: Boyde
authors: Michael A
authors: MA
authors: Horton
authors: Joanna S
authors: JS
authors: Price
mesh_terms: D000818:Animals; D002371:Cat Diseases / Q000473:pathology*; D002415:Cats; D003739:Dental Cementum / Q000473:pathology; D003743:Dental Enamel / Q000473:pathology; D008855:Microscopy, Electron, Scanning; D010010:Osteoclasts; D012391:Root Resorption / Q000473:pathology / Q000662:veterinary*; D019237:Tooth Cervix