Inflammatory cell population and bacterial contamination of membranes used for guided tissue regenerative procedures.

The purpose of this study was to determine the types of inflammatory cells 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 the flap procedure, which included the use of an ePTFE membrane. Twelve months after the second surgery, the defect sites were re-evaluated for changes in probing depth and clinical attachment level. The ePTFE membranes were retrieved after 4 to 6 weeks of healing and sectioned serially at 3 microm in a coronal-apical plane. The ePTFE membrane was divided into 3 portions: cervical, middle, and apical, each of which was subdivided into outer, central, and inner segments, providing a total of 9 fields. Cells and bacteria were analyzed by light microscopy for their types: mononuclear cell, erythrocyte, fibroblast, neutrophil, plasma cell, T lymphocyte, B lymphocyte, macrophage, and oral bacteria. Both 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 observed in almost the same number in the outer and inner parts. The results indicate that numerous inflammatory cells adhered to and invaded the ePTFE membranes accompanied by bacterial contamination and that there was a tendency for a negative correlation between the increment number of bacteria and the gain of clinical attachment level.

Effect of repeated local minocycline administration on periodontal healing following guided tissue regeneration.

BACKGROUND: Infection after a periodontal surgical site has been prepared for guided tissue regeneration (GTR) is one of the common complications that can compromise healing. The purpose of this study was to assess the effect of repeated local antimicrobial therapy following GTR for improving clinical attachment gains, and to histologically evaluate the various cell populations and bacterial contamination of the retrieved expanded polytetrafluoroethylene membrane (ePTFE). METHODS: Forty periodontal intrabony defects in 40 patients were treated by a flap procedure that included the use of ePTFE membranes to allow GTR. Patients were randomly assigned to 2 treatment groups: 20 patients were treated with the ePTFE alone (control group), and the other 20 were treated with the ePTFE combined with the administration of a weekly repeated local application of minocycline ointment for 8 weeks after membrane placement (test group). The membranes were retrieved 6 weeks after the initial surgery and sectioned serially in a coronal-apical plane. The sections were then divided into 9 fields and examined by light microscopy for the presence of inflammatory cells and oral bacteria. Clinical measurements were taken at the time of baseline examination and at a 6-month follow-up examination after removal of the ePTFE. RESULTS: At the 6-month follow-up examination, control and test groups showed significant improvement; i.e., reduction in the probing depth and increased clinical attachment gain compared with the values at the baseline examination. However, the mean clinical attachment gain of the test group (3.0+/-0.3 mm) was significantly (P = 0.03) greater than that of the control group (2.0+/-0.5 mm). Histologically, the total number of the cells of both groups was similar. In both groups, mononuclear cells were dominant and fibroblasts, neutrophils, and plasma cells were rarely encountered. There was a tendency for the number of macrophages to be somewhat higher in the control group. The total number of bacteria in the test group was significantly less than that in the control group. The number of bacteria in both control and test groups decreased toward the apical portion. CONCLUSIONS: In the present study, clinical attachment gain of intrabony defects following GTR was favorable with repeated local administration of minocycline ointment. However, a complete microbial eradication was not achieved.