title: Correlation between Enterococcus faecalis and Persistent Intraradicular Infection Compared with Primary Intraradicular Infection: A Systematic Review.
abstract: BACKGROUND
  The relationship between Enterococcus faecalis and pulpal or periradicular diseases has been studied for many years; however, whether E. faecalis is correlated with persistent intraradicular infections (teeth after failed endodontic treatments) compared with primary intraradicular infections remains controversial. The objective of this systematic review was to compare the prevalence of E. faecalis in primary and persistent intraradicular infections.
  
  
  METHODS
  An exhaustive literature search combined with specified inclusion criteria was performed to collect all studies comparing the prevalence of E. faecalis in root canals with primary and persistent intraradicular infections. Descriptive statistics were applied first because of the high heterogeneity among studies. Subgroup analysis according to different detecting methods (culture and polymerase chain reaction) and sensitivity analysis was then applied. Meta-analysis was conducted with the help of Stata/SE 12.0 (StataCorp, College Station, TX) after excluding studies with uncertain forms of pulpal and periradicular lesions in their primary infection groups.
  
  
  RESULTS
  The systematic review included 10 studies covering 972 teeth. Among them, 2 studies used the culture technique, 6 studies used polymerase chain reaction, and the other 2 used both techniques. The detection rate of E. faecalis by both methods was higher in persistent infections compared with untreated chronic periapical periodontitis as primary infections. The difference was statistically significant (odds ratio = 7.247; 95% confidence interval, 4.039-13.002).
  
  
  CONCLUSIONS
  E. faecalis is more highly correlated with persistent intraradicular infections compared with untreated chronic periapical periodontitis.
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology, Institute of Stomatological Research, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China.
authors.forename: Chenjiao
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Department of Stomatology, Guangdong No. 2 Provincial People's Hospital, Guangdong, China.
authors.forename: Jianrong
authors.initials: J
authors.lastname: Du
authors.affiliation: Department of Operative Dentistry and Endodontics, Guanghua School and Hospital of Stomatology, Institute of Stomatological Research, Guangdong Provincial Key Laboratory of Stomatology, Sun Yat-sen University, Guangzhou, Guangdong, China. Electronic address: 13430371987@163.com.
authors.forename: Zhixiang
authors.initials: Z
authors.lastname: Peng
mesh_terms: D003786:Dental Pulp Cavity / Q000382:microbiology*; D013293:Enterococcus faecalis / Q000302:isolation & purification*; D016908:Gram-Positive Bacterial Infections / Q000150:complications / Q000453:epidemiology / Q000382:microbiology* / Q000628:therapy; D006801:Humans; D010485:Periapical Periodontitis / Q000150:complications / Q000453:epidemiology* / Q000382:microbiology* / Q000628:therapy
keywords: Enterococcus faecalis; persistent intraradicular infection; primary intraradicular infection; systematic review