title: Prevalence of internal inflammatory root resorption.
abstract: BACKGROUND
  Internal inflammatory root resorption is regarded as rare because it is only occasionally detected in clinical or radiographic examination of teeth. However, inflammation is supposedly an important etiologic factor of internal resorption. Therefore, we tested the hypothesis that there is no difference in the presence of internal resorption between teeth with vital, healthy pulp and teeth with a history of pulp inflammation.
  
  
  METHODS
  Thirty teeth with no previous root canal treatment that were to be sequentially extracted from adult patients were diagnosed for their pulpal status (ie, healthy, pulpitis, or necrosis). After extraction, the teeth were split buccolingually, and both halves were exposed to 6% sodium hypochlorite for 10 minutes under constant shaking to remove all organic debris covering the root canal walls. The specimens were washed in water and prepared for scanning electron microscopy to examine the root canals for the presence of internal resorption.
  
  
  RESULTS
  The null hypothesis of this study was rejected. None of the 9 teeth with healthy pulps revealed signs of internal resorption. Four of the 8 teeth with pulpitis (50%) and 10 of the 13 teeth with necrotic pulps (77%) had internal resorption (P < .01). The average number of resorptive lesions in the affected necrotic teeth was 2.4, whereas in teeth with pulpitis and internal resorption, the average number of lesions was 1.25. The amount of resorption was always <100-μm deep; the length of the lesions varied from 200 μm to >1 mm. Most lesions (15) were detected in the middle third of the root, followed by the apical third (13). Only 1 internal resorptive lesion was detected in the coronal third of the root canal.
  
  
  CONCLUSIONS
  Internal resorption was a frequent finding in teeth with pulp inflammation or necrosis.
authors.affiliation: Division of Endodontics, Department of Oral Biological and Medical Sciences, Faculty of Dentistry, University of British Columbia, Vancouver, Canada.
authors.forename: Cornel
authors.initials: C
authors.lastname: Gabor
authors.forename: Esther
authors.initials: E
authors.lastname: Tam
authors.forename: Ya
authors.initials: Y
authors.lastname: Shen
authors.forename: Markus
authors.initials: M
authors.lastname: Haapasalo
mesh_terms: D000293:Adolescent; D000328:Adult; D003782:Dental Pulp / Q000648:ultrastructure; D003786:Dental Pulp Cavity / Q000648:ultrastructure; D003790:Dental Pulp Necrosis / Q000473:pathology; D005260:Female; D006801:Humans; D008297:Male; D008855:Microscopy, Electron, Scanning; D008875:Middle Aged; D011671:Pulpitis / Q000473:pathology; D012391:Root Resorption / Q000473:pathology*; D019227:Tooth Apex / Q000648:ultrastructure; D055815:Young Adult