Microorganisms in polytetrafluoroethylene barrier membranes for guided tissue regeneration

This study examined the microflora in 11 barrier membranes around teeth with furcation involvement or 2 to 3 wall intrabony defects and in 16 membranes around implants with various types of bony defects. Total viable counts and the occurrence of selected microbial species were determined by non-selective and selective culture and by DNA probes. Study sites were examined for probing pocket depth and attachment level. All tooth-associated membranes yielded high levels of microorganisms. 4 of 5 teeth with membranes harboring less than 10(8) organisms gained 3 mm or more in probing attachment, whereas 6 teeth with membranes with more than 10(8) organisms exhibited loss or only small gains in attachment. 3 membranes with high levels of black-pigmented anaerobic rods lost 1 to 2 mm of attachment. Ten implant-associated membranes with no cultivable microorganisms demonstrated a mean probing gain of 4.9 mm. 6 implants with infected membranes only gained an average of 2.0 mm of supportive bone. The present findings underscore the importance of controlling or eliminating periodontal pathogens on barrier membranes in order to gain new attachment.