SEM analyses of bacterial contamination of e-PTFE membranes and GTR clinical results

The aim of the present study was to determine whether bacterial contamination of expanded polytetrafluoroethylene (e-PTFE) membranes and the degree of membrane exposure could affect the clinical results of guided tissue regeneration (GTR). Seven patients (aged 42 to 58 years) presented with twenty intrabony defects that were treated by GTR + DFDBA (decalcified freeze-dried bone allograft). Gingival recession, probing depths, and clinical attachment levels were recorded before surgery and 10 months subsequently. Exposure of the membrane was recorded at the moment of removal. The membranes were analyzed in three distinct regions by scanning electron microscopy (SEM): collar, medial and apical regions. The presence of host cells adhering to the e-PTFE membrane was determined and bacterial contamination was quantified as per Simion et al. (1994). Statistical analysis did not show significant differences for bacterial contamination or for the presence of host cells on the membrane surface at different levels of exposure (up to 30%, from 31% to 60%, and from 61% to 75%). Results were considered statistically significant at p < 0.05, according to the Kruskal-Wallis rank sum test. Exposure of the membrane and bacterial contamination did not modify the levels recorded. Bacterial contamination had an adverse effect on bone defect filling.