title: Incidence and factors related to flare-ups in a graduate endodontic programme.
abstract: OBJECTIVE
  To investigate the incidence and factors related to endodontic flare-ups in nonsurgical root canal treatment (NSRCT) cases completed by graduate endodontic residents at University of Pennsylvania, USA.
  
  
  METHODS
  Residents at University of Pennsylvania enter all clinical patient records into an electronic database called PennEndo database. Analysis of records of 6580 patients treated from September 2000 to July 2005 revealed a total of 26 patients with flare-ups (0.39%). Patients were categorized to have undergone flare-up when they attended for an unscheduled visit and active treatment, and when they suffered from severe pain and or swelling after initiation or continuation of NSRCT. SAS software was used to develop a logistic regression model with flare-up as a dependent variable. Independent variables included in the model were: history of previous pain, one vs. two visit NSRCT, periapical diagnosis, tooth type, rotary versus hand instrumentation, and lateral versus vertical compaction of gutta-percha.
  
  
  RESULTS
  The odds for developing a flare-up in teeth with a periapical radiolucency were 9.64 times greater than teeth without a periapical radiolucency (P = 0.0090). There was no statistically significant difference in flare-ups between one and two visits NSRCT. The odds of developing a flare-up increased 40 fold when NSRCT was completed in three or more visits. However, this result may have been confounded by addition of an unscheduled visit in patients suffering from flare-ups. Other independent variables did not have any statistically significant correlations.
  
  
  CONCLUSIONS
  A low percentage of patients experienced flare-ups during NSRCT procedures. The presence of a periapical lesion was the single most important predictor of flare-ups during NSRCT.
authors.affiliation: Department of Endodontics, University of Pennsylvania, School of Dental Medicine, Robert Schattner Centre, PA 19104-6030, USA. miqal@pobox.upenn.edu
authors.forename: M
authors.initials: M
authors.lastname: Iqbal
authors.forename: E
authors.initials: E
authors.lastname: Kurtz
authors.forename: M
authors.initials: M
authors.lastname: Kohli
mesh_terms: D015331:Cohort Studies; D003722:Dental Alloys; D004487:Edema / Q000209:etiology; D004499:Education, Dental, Graduate; D004708:Endodontics / Q000193:education*; D004867:Equipment Design; D006171:Gutta-Percha / Q000627:therapeutic use; D006801:Humans; D007396:Internship and Residency; D009532:Nickel; D010485:Periapical Periodontitis / Q000175:diagnosis / Q000628:therapy; D019233:Retreatment; D012189:Retrospective Studies; D012307:Risk Factors; D012387:Root Canal Filling Materials / Q000627:therapeutic use; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D012390:Root Canal Therapy / Q000009:adverse effects* / Q000706:statistics & numerical data; D013193:Stainless Steel; D013997:Time Factors; D014025:Titanium; D014098:Toothache / Q000209:etiology; D016896:Treatment Outcome
chemical_list: D003722:Dental Alloys; D012387:Root Canal Filling Materials; C040654:titanium nickelide; D013193:Stainless Steel; D009532:Nickel; D006171:Gutta-Percha; D014025:Titanium