INFLAMMATORY CELL-POPULATION AND BACTERIAL-CONTAMINATION OF MEMBRANESUSED FOR GUIDED TISSUE REGENERATIVE PROCEDURES

THE PURPOSE OF THIS STUDY was to determine the types of inflammatory c ells and bacterial contamination on expanded polytetrafluoroethylene ( ePTFE) membranes which might affect new tissue formed by guided tissue regeneration (GTR). Forty periodontal bony defects were treated by th e flap procedure, which included the use of an ePTFE membrane. Twelve months after the second surgery, the defect sites were re-evaluated fo r changes in probing depth and clinical attachment level. The ePTFE me mbranes were retrieved after 4 to 6 weeks of healing and sectioned ser ially at 3 mu m in a coronal-apical plane. The ePTFE membrane was divi ded into 3 portions: cervical, middle, and epical, each of which was s ubdivided into outer, central, and inner segments, providing a total o f 9 fields. Cells and bacteria were analyzed by light microscopy for t heir types: mononuclear cell, erythrocyte, fibroblast, neutrophil, pla sma cell, T lymphocyte, B lymphocyte, macrophage, and oral bacteria. B oth cells and bacteria decreased in number towards the apical portion and were present even in the central part. Most cells were mononuclear cells. Erythrocytes, fibroblasts, neutrophils, and plasma cells were rarely encountered. Bacteria, most of which were Gram-positive, were o bserved in almost the same number in the outer and inner parts. The re sults indicate that numerous inflammatory cells adhered to and invaded the ePTFE membranes accompanied by bacterial contamination and that t here was a tendency for a negative correlation between the increment n umber of bacteria and the gain of clinical attachment level.