Tissue reactions to sutures in the presence and absence of anti-infective therapy

Background: In the oral cavity, sutures are placed within tissues of high vascularity in a moist environment with infectious potential. The objective of this study was to evaluate tissue reactions at silk and expanded polytetrafluoroethylene (ePTFE) sutures in the presence and absence of anti-infective therapy (AT). Methods: Thirty-six sutures were placed within the mandibular keratinized gingiva in six Beagle dogs. Each animal received one braided silk (4-0) and one ePTFE (CV-5) suture in contra-lateral jaw quadrants at 14, 7, and 3 days prior to biopsy. Three animals received daily AT including topical 2% chlorhexidine solution and a systemic broad-spectrum antibiotic. Biopsy specimens allowed histometric analysis of tissue reactions along the central part of the suture loop including the area of perisutural epithelium, ratio inflammatory cells (ICs)/epithelial cells and IC/fibroblasts, and presence/absence of bacterial plaque in the suture track. Results: A perisutural epithelial sheath was forming within 3 days. The cross-sectional area of the epithelium increased with time for both suture materials (p = 0.003) but was particularly pronounced for the silk sutures in the absence of AT. Clusters of IC were present in the perisutural connective tissue and epithelium. Over time, a more prominent increase in IC/fibroblasts was evident for the silk sutures in the absence of AT. The pooled material revealed a significantly higher IC/fibroblast ratio for silk compared with ePTFE sutures (p = 0.017). Bacterial plaque influx was detected in 6/9 silk and 0/9 ePTFE suture channels in the presence, and 6/6 and 3/6 suture channels, respectively, in the absence of AT. Conclusions: AT may reduce biofilm formation and inflammation along the suture track. Braided silk, however, elicits more severe tissue reactions than ePTFE regardless of infection control.