title: Calculus-like deposit on the apical external root surface of teeth with post-treatment apical periodontitis: report of two cases.
abstract: OBJECTIVE
  To report two cases in which calculus-like material was found on external root surfaces of (i) an extracted root and (ii) an apicected part of a root, both of which were removed due to post-treatment refractory apical periodontitis.
  
  
  CONCLUSIONS
  In each case, there was a fistulous tract, which did not heal after conventional root canal treatment. The first case did not heal even after apical surgery, and subsequent tooth extraction revealed calculus-like material on a root surface of complex anatomy. The second case showed radiographic signs of healing after apicectomy. Histology of the apical biopsy revealed a calculus-like material on the external surface of the root apex. It is suggested that the presence of calculus on the root surfaces of teeth with periapical lesions may contribute towards the aetiology of failure.
  
  
  CONCLUSIONS
  Biofilm on the external root surface has been implicated in the failure of apical periodontitis to heal, despite adequate root canal treatment. Calculus-like material was found, in two cases, on the root surface of teeth with post-treatment apical periodontitis, where the only communication externally was a sinus tract.
authors.affiliation: dricucci@libero.it
authors.forename: D
authors.initials: D
authors.lastname: Ricucci
authors.forename: M
authors.initials: M
authors.lastname: Martorano
authors.forename: A L
authors.initials: AL
authors.lastname: Bate
authors.forename: E A
authors.initials: EA
authors.lastname: Pascon
mesh_terms: D000328:Adult; D001047:Apicoectomy; D003728:Dental Calculus / Q000382:microbiology / Q000473:pathology*; D003751:Dental Fistula / Q000150:complications*; D019232:Dental Restoration Failure; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000150:complications / Q000473:pathology* / Q000601:surgery; D012390:Root Canal Therapy; D019227:Tooth Apex / Q000473:pathology*; D014081:Tooth Extraction