title: Lesion progression in post-treatment persistent endodontic lesions.
abstract: BACKGROUND
  Radiographic lesions related to root-filled teeth may persist for long periods after treatment and are considered to indicate failure of initial treatment. Persistent lesions are found in a proportion of cases, but information on lesion progression is lacking. This study examined the incidence of lesion improvement, remaining unchanged, and deterioration among persistent lesions in a group of patients recruited from a university-based clinic and identified potential predictors for lesion progression.
  
  
  METHODS
  Patients of a university clinic with persistent endodontic lesions at least 4 years since treatment and with original treatment radiographs available were recruited with informed consent. Data were obtained by interview and from dental records and clinical and radiographic examinations. Univariate and multivariate statistical analyses were carried out by using SPSS (version 19).
  
  
  RESULTS
  One hundred fifty-one persistent lesions were identified in 114 patients. A majority of the lesions (107, 70.9%) received treatment between 4 and 5 years prior. Eighty-six lesions (57.0%) improved, 18 (11.9%) remained unchanged, and 47 (31.1%) deteriorated since treatment. Potential predictors for lesions that did not improve included recall lesion size, pain on biting at recall examination, history of a postobturation flare-up, and a non-ideal root-filling length (P < .05). Lesions that had persisted for a longer period appeared less likely to be improving (relative risk, 1.038; 95% confidence interval, 1.000-1.077).
  
  
  CONCLUSIONS
  A specific time interval alone should not be used to conclude that a lesion will not resolve without intervention. This study identified several clinical factors that are associated with deteriorating persistent lesions, which should aid in identifying lesions that require further intervention.
authors.affiliation: National University of Singapore, Singapore. denyshv@nus.edu.sg
authors.forename: Victoria Soo Hoon
authors.initials: VS
authors.lastname: Yu
authors.forename: Harold Henry
authors.initials: HH
authors.lastname: Messer
authors.forename: Liang
authors.initials: L
authors.lastname: Shen
authors.forename: Robert
authors.initials: R
authors.lastname: Yee
authors.forename: Chin-ying Stephen
authors.initials: CY
authors.lastname: Hsu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016009:Chi-Square Distribution; D002908:Chronic Disease; D018450:Disease Progression; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010485:Periapical Periodontitis / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000628:therapy; D011859:Radiography; D012044:Regression Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D012390:Root Canal Therapy / Q000009:adverse effects*; D018709:Statistics, Nonparametric; D017211:Treatment Failure; D057832:Watchful Waiting; D055815:Young Adult