A polymer-mineral composite was prepared by solvent casting a mixture of chitosan, poly(vinyl alcohol), and Ag+-exchanged tobermorite in dilute acetic acid and characterised by scanning electron microscopy and Fourier transform infrared spectroscopy. The in vitro bioactivity of the CPTAg membrane was confirmed by the formation of hydroxyapatite on its surface in simulated body fluid. The alkaline dissolution products of the tobermorite lattice buffered the acidic breakdown products of the chitosan polymer and the presence of silver ions resulted in marked antimicrobial action against S. aureus, P. aeruginosa, and E. coli. The in vitro cytocompatibility of the CPTAg membrane was confirmed using MG63 osteosarcoma cells. The findings of this preliminary study have indicated that chitosan-poly(vinyl alcohol)-Ag+-tobermorite composites may be suitable materials for guided tissue regeneration applications. 1. Introduction Periodontitis is an infectious disease that destroys the tooth attachment apparatus. During the progression of the disease, the epithelial tissue detaches from the tooth, the periodontal ligament (PDL) disconnects, and the alveolar bone tissue is resorbed (as shown in Figure 1(a)) [1, 2]. Traditional treatment of periodontitis involves the debridement and cleaning of the root surface without the restoration of the tooth attachment apparatus. Rapidly migrating epithelial cells subsequently grow alongside the tooth root and prevent the reestablishment and reattachment of the PDL and alveolar bone at the defect site. The development of biocompatible membranes for the guided tissue regeneration (GTR) of the periodontal structures is an area of increasing interest in the treatment of periodontitis. GTR strategies involve the placement of a barrier to exclude the epithelial and gingival tissues from the exposed root surface to provide an opportunity for the more slow-growing bone and PDL tissues to regenerate (as shown in Figure 1(b)). Animal models have demonstrated that, in comparison with conventional treatment, resorbable chitosan-based GTR membranes promote the regeneration of the tooth attachment apparatus [3–5]. Improvements in the design of GTR membranes are now sought via the incorporation of bioactive and antimicrobial components that enhance tissue regeneration and reduce infection [2]. Figure 1: A sketch of (a) periodontal ligament (PDL) detachment and alveolar bone loss during periodontitis and (b) the placement of a GTR membrane (M) to prevent epithelial (E) migration and to stimulate the regeneration of lost bone. Chitosan is the
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