Comparative Histopathological Evaluation of Gingival Tissue Reactions to Chlorhexidine-Coated and Uncoated Silk Sutures in Male Rats

Background: Surgical sutures play a crucial role in wound healing. Sutures coated with chlorhexidine are designed to provide secondary antimicrobial protection. However, the impact of these chlorhexidine-coated silk sutures on immediate tissue reactions, compared to ostensibly inert suture materials, has not been investigated. This study aims to compare tissue responses caused by the chlorhexidine coated silk sutures or uncoated silk suture in rats, as a guide to potential benefits clinically.Materials and Methods: In this study, 4-0 silk sutures were coated with 3% chlorhexidine using Eudragit RL polymer. Eighteen male Sprague-Dawley rats (10-wk-old, 200±20 gr) were randomly divided into three groups, with six in each group. Animals were anesthetized using ketamine hydrochloride and xylazine. A 5-mm incision was made on the keratinized gingiva between their right and left upper second premolars at both sides using a scalpel blade. The left flap was closed using chlorhexidine-coated sutures, while the right one was sutured with standard ones. On the 3rd, 5th, and 7th postoperative days biopsies from the suture sites were obtained for pathological examination after euthanasia. After determining normality and homogeneity of variance, inflammation was analyzed using the Kruskal-Wallis test for nonparametric data; formation of fibrous and granulation tissue was assessed with a chi-square test. A P-value < 0.05 was considered significant as recommended.Results: Histopathological evaluation of tissue extracted on the 3rd, 5th, and 7th days showed no statistically significant difference in tissue inflammation, granulation, or fibrous connective tissue accumulation between chlorhexidine-coated silk sutures and uncoated silk sutures.Conclusion: results indicated that chlorhexidine-coated silk sutures induced tissue responses comparable to those of uncoated silk control sutures. These data suggest that, although the release of chlorhexidine in oral solutions may be achieved with these sutures, potentially aiding in the effective inhibition of bacterial growth during wound healing, they do not demonstrate anti-inflammatory effects.