title: The dynamics of microbial colonization of barrier membranes for guided tissue regeneration.
abstract: The microbial colonization of expanded polytetrafluoroethylene membrane by putative periodontopathogens at 3 minutes of intraoral manipulation was determined in 42 patients with 42 mandibular posterior two- to three-wall defects. Twenty patients exhibited no periodontal pockets of > or = 5 mm, other than the study site, and low levels of pathogens (group A). Twenty-two patients revealed multiple periodontal pockets of 5 mm or more and numerous pathogens (group B). Within the preceding 3 months of regenerative surgery, group A patients had received apically positioned flap surgery with osseous recontouring (except for the study site), and group B patients had been enrolled in a non-surgical maintenance program. The subgingival microbiota was examined prior to regenerative therapy, and the membrane microbiota was examined at 3 minutes and at the time of removal at 6 weeks by culture, DNA probes, and phase-contrast microscopy. The mean initial defect depth was 7.4 mm for group A and 7.2 mm for group B. At 6 months, the difference in mean clinical attachment gain was statistically significant (P < 0.001; group A: 3.4 mm; group B: 1.4 mm). At 3 minutes, putative pathogens were detected in seven (16.7%) membranes in group B (group Binfected), and the associated sites gained only 0.6 mm in clinical attachment at 6 months. Clinical attachment gain was modeled as a linear function of the explanatory variables (r2 = 86%). The presence of Porphyromonas gingivalis detected by DNA probe at 3 minutes was associated with 1.5 mm less expected gain (P = 0.0002). Total microbial counts and the percentage of Peptostreptococcus micros and Capnocytophaga species at baseline, and of motile rods on the membrane surface facing the gingiva at 6 weeks, were statistically significant negative predictors of clinical attachment. For each week the membrane remained covered, an additional 0.5 mm gain could be expected (P = 0.002); and for every 10 sites that exhibited bleeding on probing, the clinical attachment gain was 0.6 mm less at the site of regeneration (P < 0.0001). The present results showed that putative pathogens may colonize membranes within 3 minutes of intraoral manipulation. The patient group treated with periodontal osseous surgery revealed the lowest levels of periodontal pathogens in the membranes and exhibited the most gain in clinical attachment.
authors.affiliation: School of Dentistry, Department of Periodontology, University of Southern California, Los Angeles, USA.
authors.forename: H
authors.initials: H
authors.lastname: Nowzari
authors.forename: E S
authors.initials: ES
authors.lastname: MacDonald
authors.forename: J
authors.initials: J
authors.lastname: Flynn
authors.forename: R M
authors.initials: RM
authors.lastname: London
authors.forename: J L
authors.initials: JL
authors.lastname: Morrison
authors.forename: J
authors.initials: J
authors.lastname: Slots
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001419:Bacteria / Q000302:isolation & purification; D018441:Biofilms / Q000254:growth & development*; D015169:Colony Count, Microbial; D004866:Equipment Contamination; D005260:Female; D016557:Guided Tissue Regeneration, Periodontal / Q000009:adverse effects*; D006801:Humans; D016014:Linear Models; D008297:Male; D008567:Membranes, Artificial; D008875:Middle Aged; D010510:Periodontal Diseases / Q000601:surgery; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000382:microbiology*; D011138:Polytetrafluoroethylene
chemical_list: D008567:Membranes, Artificial; D011138:Polytetrafluoroethylene