title: Two subgingival plaque-sampling strategies used with RNA probes.
abstract: BACKGROUND
  The purpose of this study was to compare the results of microbiological RNA-probe analysis after subgingival plaque sampling applying two different strategies.
  
  
  METHODS
  In 220 patients, clinical examinations were obtained prior to commencement of therapy for aggressive or generalized severe chronic periodontitis (n = 113), after combined mechanical and antibiotic anti-infective periodontal therapy (n = 43), or because of periodontal pockets despite adequate therapy (n = 64). Subgingival plaque samples were obtained from the three pockets with the deepest probing depths. Two sterile paper points were inserted simultaneously into the periodontal pockets. One paper point from each pocket was put into a separate transport vial; the second paper point was pooled (multiple site test [MT3]) with paper points from each of the two other sampling sites from the respective patient into a transport vial. The content of each vial was analyzed separately for Actinobacillus actinomycetemcomitans, Tannerella forsythensis, Porphyromonas gingivalis, and Treponema denticola (Td) with a commercially available RNA-probe test.
  
  
  RESULTS
  For all tested pathogens, log-transformed numbers of bacteria were higher in pooled samples compared to the mean values for the separate samples (P < or =0.01). However, for Td only, statistically significant differences in frequency were seen between the separate samples and MT3. These findings were observed over all samples as well as after evaluation of subgroups separately.
  
  
  CONCLUSIONS
  Pooling of plaque samples increased the bacterial counts per analysis compared to separate samples and thus may increase the probability of detecting existing pathogens. However, this observation only was statistically significant for the frequency of Td.
authors.affiliation: Section of Periodontology, Department of Conservative Dentistry, Clinic for Oral, Dental, and Maxillofacial Diseases, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Diana-Maria
authors.initials: DM
authors.lastname: Krigar
authors.forename: Jens
authors.initials: J
authors.lastname: Kaltschmitt
authors.forename: Jörg K
authors.initials: JK
authors.lastname: Krieger
authors.forename: Peter
authors.initials: P
authors.lastname: Eickholz
mesh_terms: D016976:Aggregatibacter actinomycetemcomitans / Q000235:genetics / Q000302:isolation & purification; D000704:Analysis of Variance; D015373:Bacterial Typing Techniques; D001439:Bacteroides / Q000235:genetics / Q000302:isolation & purification; D002908:Chronic Disease; D015169:Colony Count, Microbial; D003773:Dental Plaque / Q000382:microbiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010514:Periodontal Pocket / Q000382:microbiology*; D016966:Porphyromonas gingivalis / Q000235:genetics / Q000302:isolation & purification; D015347:RNA Probes; D012329:RNA, Bacterial / Q000032:analysis; D013048:Specimen Handling / Q000379:methods; D018709:Statistics, Nonparametric; D048373:Treponema denticola / Q000235:genetics / Q000302:isolation & purification
chemical_list: D015347:RNA Probes; D012329:RNA, Bacterial