title: Periapical health and treatment quality assessment of root-filled teeth in two Canadian populations.
abstract: OBJECTIVE
  The prevalence of apical periodontitis (AP) and the quality of root fillings and restorations were determined in two Canadian populations differing in avail-ability of endodontists.
  
  
  METHODS
  Radiographs of first-time university patients aged 25-40 years in Toronto and Saskatoon were examined for missing teeth, presence and standard of root fillings, standard of restoration, and AP according to the Periapical Index. Patients with root-filled teeth were invited for clinical examination and interview to inspect the restorations, and to reveal the providers of endodontic treatment and reasons for extractions of missing teeth. Chi-square and independent t-tests interpreted at the 5% significance level were used to examine associations between the prevalence of AP in root-filled teeth and the standard of the root filling, restoration, and providers of treatment.
  
  
  RESULTS
  Proportion of patients with root-filled teeth was significantly higher (P < 0.001) in Toronto than in Saskatoon (39 and 26%, respectively). Presence of AP about root-filled teeth (44% in Toronto, 51% in Saskatoon) was significantly associated with poor density (OR = 2.7) short (OR = 2.4) and long (OR = 2.8) root fillings, and with poor radiographic quality of the restoration (OR = 1.7) Prevalence of AP did not differ significantly between teeth treated by generalists and endodontists.
  
  
  CONCLUSIONS
  The prevalence of AP in root-filled and untreated teeth was comparable to that reported in previous methodologically compatible studies. The quality of both the root filling and the restoration were found to impact on the periapical health of root-filled teeth, with the impact of the restoration being most critical when the quality of the root filling was adequate.
authors.affiliation: Department of Endodontics, Faculty of Dentistry, University of Toronto, 124 Edward Street, Toronto, Ontario, Canada M5G 1G6.
authors.forename: N N
authors.initials: NN
authors.lastname: Dugas
authors.forename: H P
authors.initials: HP
authors.lastname: Lawrence
authors.forename: P E
authors.initials: PE
authors.lastname: Teplitsky
authors.forename: M J
authors.initials: MJ
authors.lastname: Pharoah
authors.forename: S
authors.initials: S
authors.lastname: Friedman
mesh_terms: D000328:Adult; D016009:Chi-Square Distribution; D003430:Cross-Sectional Studies; D019232:Dental Restoration Failure; D003815:Dentists / Q000600:supply & distribution; D004708:Endodontics / Q000193:education; D005260:Female; D006801:Humans; D008297:Male; D016017:Odds Ratio; D009864:Ontario / Q000453:epidemiology; D010485:Periapical Periodontitis / Q000000981:diagnostic imaging / Q000453:epidemiology* / Q000209:etiology*; D015995:Prevalence; D011785:Quality Assurance, Health Care; D011859:Radiography; D012390:Root Canal Therapy / Q000009:adverse effects / Q000592:standards / Q000706:statistics & numerical data*; D012525:Saskatchewan / Q000453:epidemiology; D018709:Statistics, Nonparametric; D011795:Surveys and Questionnaires; D000078329:Workforce