Effect of water storage of E-glass fiber-reinforced composite on adhesion of Streptococcus mutans

This study investigated the effect of water storage of fiber-reinforced com posite on the adhesion of Streptococcus mutans (S. mutans) and its ability to stay adhered and multiply on the FRC. The materials (E-glass fibers and denture base polymer) were stored in water for 14 or 30 days or left dry. W ater contact angles of the materials before and after water storage were de termined. Test specimens, with or without parotid saliva or serum pellicle, were incubated in a suspension of S. mutans allowing initial adhesion to o ccur. Bacterial adhesion and multiplication was studied using scanning elec tron microscopy. Contact angles of both materials were significantly reduce d after water storage indicating an increase in surface free energy. When s tudied without a surface pellicle, water storage significantly increased ad hesion of S. mutans to both glass and polymer. Saliva coating of the materi als resulted in higher degree of adhesion to glass fibers in comparison wit h polymer and after 14 days water storage glass bound over twice as much S. mutans cells than the polymer matrix. Bacterial growth and biofilm formati on occurred equally on both materials. The results of this in vitro study s uggest that in order to avoid the possible increase in S. mutans adhesion, the reinforcing glass fibers should be covered with the matrix polymer of t he composite. (C) 2001 Elsevier Science Ltd. All rights reserved.