title: Detection of Porphyromonas endodontalis, Porphyromonas gingivalis and Prevotella intermedia in primary endodontic infections in a Chinese population.
abstract: OBJECTIVE
  To assess the prevalence of three black-pigmented bacterial species (Porphyromonas endodontalis, Porphyromonas gingivalis and Prevotella intermedia) using microarray technology in root canals of teeth associated with primary endodontic infections in a Chinese population.
  
  
  METHODS
  Microbial samples were taken from root canals of 80 teeth with pulp necrosis and primary endodontic infections in a Chinese population. DNA extracted from the samples was amplified by PCR with universal bacterial primers based on 16S rRNA gene sequences, and the products hybridized with the microarrays in which the specific oligonucleotide probes were added. The results of hybridization were screened by a confocal laser scanner. Pearson chi-square test and the two-sided Fisher exact test were used to analyse whether a significant association existed between the species and symptoms as well as in co-existence of two target organisms by a statistical software package (SAS 8.02).
  
  
  RESULTS
  The 16S rRNA gene microarray detected at least one of the three test species in 76% of the study teeth. P. endodontalis, P. gingivalis and P. intermedia were found in 50%, 33% and 45%, respectively. A significant association was found in the presence of the pair P. endodontalis / P. gingivalis (P < 0.005). Both P. endodontalis (P <0.05) and P. gingivalis (P <0.005) had a statistically significant association with the presence of a sinus tract. The simultaneous presence of P. endodontalis and P. gingivalis was also associated with the presence of a sinus tract (P<0.005) and abscess formation (P<0.05).
  
  
  CONCLUSIONS
  The three black-pigmented bacteria were prevalent in teeth with pulp necrosis and primary endodontic infections in a Chinese population. P. gingivalis and P. endodontalis were associated with the presence of sinus tract and abscess formation.
authors.affiliation: Shanghai Institute of Microsystem and Information Technology, Chinese Academy of Sciences, State Key Lab of Transducer Technology, Shanghai, People's Republic China.
authors.forename: H
authors.initials: H
authors.lastname: Cao
authors.forename: Z
authors.initials: Z
authors.lastname: Qi
authors.forename: H
authors.initials: H
authors.lastname: Jiang
authors.forename: J
authors.initials: J
authors.lastname: Zhao
authors.forename: Z
authors.initials: Z
authors.lastname: Liu
authors.forename: Z
authors.initials: Z
authors.lastname: Tang
mesh_terms: D000038:Abscess / Q000382:microbiology; D000293:Adolescent; D000328:Adult; D000368:Aged; D016866:Bacteroidaceae Infections / Q000175:diagnosis*; D002681:China; D060085:Coinfection / Q000175:diagnosis; D004269:DNA, Bacterial / Q000032:analysis; D003751:Dental Fistula / Q000382:microbiology; D003786:Dental Pulp Cavity / Q000382:microbiology; D003788:Dental Pulp Diseases / Q000382:microbiology*; D003790:Dental Pulp Necrosis / Q000382:microbiology; D005260:Female; D006801:Humans; D008297:Male; D046228:Microarray Analysis; D008875:Middle Aged; D010483:Periapical Diseases / Q000382:microbiology; D016133:Polymerase Chain Reaction; D045202:Porphyromonas endodontalis / Q000302:isolation & purification*; D016966:Porphyromonas gingivalis / Q000302:isolation & purification*; D018713:Prevotella intermedia / Q000302:isolation & purification*; D012329:RNA, Bacterial / Q000032:analysis; D012336:RNA, Ribosomal, 16S / Q000032:analysis; D055815:Young Adult
chemical_list: D004269:DNA, Bacterial; D012329:RNA, Bacterial; D012336:RNA, Ribosomal, 16S