Introduction: Dental materials are frequently used to restore teeth defects in human oral cavity[1]. Teeth and dental materials are in continuous contact with the oral microbial community offering appropriate surfaces to the adhesion of microbes including pathogen species such as S. mutans, P. gingivalis and C. albicans[2]. Correlations between bacterial adhesion and various surface characteristics were reported to reduce bacterial adhesion through surface modification[3]. Other initiatives were undertaken to prevent microorganism adhesion and growth and biofilm formation, including the incorporation of antimicrobial molecules[4] such as fluoride into restorative materials[5]. As an example Glass-ionomer, a restorative material containing fluoride, was shown to decrease bacterial adhesion and thus infections[6]. Furthermore, the denture acrylic material supplementation with histatin-5 showed reduced Candida biofilm formations[7]; such effect may also be achieved using fluoride-rich dental materials.
Objectives: To design restorative dental materials containing fluoride. To investigate the interaction of C. ablicans with fluoride-rich materials. To study the interaction between fluoride-rich dental materials, human gingival fibroblasts and C. albicans.
Materials and Methods: To perform this study we used two fluoride free materials which are composite resin (Filtek ™ Supreme Plus) and acrylic resins (Diamond D, Ivocap). As a control, we used fluoride-rich glass-ionomer (GC Fuji II LC capsule) martial. Composite and acrylic resins were enriched or not with sodium fluoride (NaF) at 2ml per 30 ml of Methyl methacrylate monomer for Ivocap. For fluoride-rich Diamond D, we mixed 2ml of NaF with 10 ml of the monomer. Designed materials were then subjected to surface analyses by mean of SEM, FTIR and XPS. Furthermore, materials were put in contact with C. albicans (SC 5314) to investigate the yeast adhesion (at 8 and 24 h) and growth (at 3 and 5 days). The interaction of NaF-rich dental material with human gingival fibroblasts in the presence and absence of C. albicans was also investigated.
Results and Discussion: Resin composites are frequently used for tooth cavity restorations[8]. However, these resins do not have antimicrobial activities that may favor bacterial adhesion, the formation of biofilm contributing oral infections. We designed fluoride-rich dental material and showed by SEM analyses smooth surface of the material. The FTIR analyses revealed fluoride spectra characterized by bands at 3,750 to 3,250 cm-1, as previously reported[9]. XPS analyses confirmed the presence of fluoride within the samples showing specific pics at 682 eV (Fig.1a). C. albicans adhesion and growth were decreased with fluoride-rich materials at 8 and 24 h (Fig 1b) and also biofilm formation after 3 and 5 days of contacts. The designed fluoride-rich materials were not toxic to human gingival fibroblasts as shown by cell adhesion and growth (Fig. 1c).
Conclusion: This is the first study demonstrating the possibility supplementing restorative dental materials with fluoride to controlling C. albicans growth and biofilm formation. Such study may open new insight preventing microbial infections in the human oral cavity. (This project was supported by the research group program (number RGP-VPP-260) in the Kingdom of Saudi Arabia and by a grant from the Fonds Émile-Beaulieu (Laval University Foundation).).
Study Supported by the King Saudi University; Study supported by the Fonds Émile-Beaulieu , Laval University
References:
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