Bacterial Colonization of the External and Internal Sulci and of Cellulose Membranes at Time of Retrieval

Membrane exposure with bacterial contamination is often considered one of the main reasons for the lack of predictability in achieving complete regeneration of periodontal defects. Ten cellulose membranes, retrieved from 7 patients treated for Class II furcation lesions in lower molars with at least 4 mm of exposure at time of retrieval were studied. Contamination of exposed membranes was studied using SEM analysis of four surfaces of the membrane, upper external, lower external, upper internal, and lower internal surfaces. DNA probe analysis of three periodontopathic bacteria, Porphyromonas gingivalis, Prevotella intermedia, and Actinobacillus actinmycetemcomitans, was carried out for specimens collected from the external and internal sulci. The results suggest that bacterial contamination of the membranes could be controlled if proper pre- and postoperative care is followed, since significant amounts of any of the three periodontopathogenic bacteria studied were not found. The SEM analysis corroborated the DNA probe analysis since the predominant morphotypes detected were not suggestive of periodontopathogenic bacteria. The importance of membrane contamination and of root concavities in the lack of predictability of the GTR procedure is discussed.