ABSTRACT
Introduction: Coronal leakage and reinfection after root canal therapy is an important reason for endodontic failure. Zinc oxide-eugenol (ZOE) -based materials are often used as a coronal seal to prevent secondary infection. The antibacterial effect of ZOE cement is mainly due to leaching of eugenol from the material, but the effect is reported to decrease over time. Chitosan (CH) is a natural polymer with antibacterial properties. The aim of the study was to investigate if incorporation of (CH) and chitosan oligosaccharide (COS) in a ZOE-based material improved both the immediate and sustained antibacterial properties of the material. Methods: Enterococcus faecalis, Streptococcus mutans and Staphylococcus epidermidis was used to investigate the antibacterial effect of the materials in a modified direct contact test (MDCT) immediately after setting and after storage for 18 weeks in water. Leaching per week of eugenol from the materials was quantified using gas chromatography-mass spectrometry (GC-MS). The effect of eugenol on growth of bacteria was measured by reading of optical density at 600 nm after 18 h growth. Mechanical properties were investigated in a compressive strength test according to ISO 3107. Results: The present study showed that a ZOE-based material has antibacterial activity both as freshly prepared and after immersion in water for 18 weeks. Incorporating CH or COS may increase the antibacterial effect depending on the bacterial species investigated. The amount of leached eugenol did not differ between materials or during or after storage. S. mutans showed the highest susceptibility to eugenol of the three species investigated. Modification of the materials with CH or COS reduced the compressive strength, but the requirements in ISO 3017 were still met.
ABSTRACT
Aim. The aim of this study was to investigate the antibacterial and antibiofilm properties of low viscosity chitosan on S. epidermidis growth and biofilm formation. Methods and Results. The antibacterial and antibiofilm properties were investigated, during both planktonic growth and biofilm formation. This was performed using different concentrations in media and by coating on polystyrene surfaces. In addition, the bactericidal effect was investigated using a modified direct contact test. The results showed that low viscosity chitosan in media had both a bacteriostatic and bactericidal effect on planktonic growth and biofilm formation of S. epidermidis in a concentration dependent manner. Polystyrene discs coated with chitosan reduced both early biofilm formation (6 h) and late biofilm formation (18 h), as confirmed by scanning electron microscopy. The modified direct contact test showed a bactericidal effect. Conclusion. This study demonstrated that low viscosity chitosan has a bacteriostatic and bactericidal activity against S. epidermidis and that the activity is dependent on the amount of chitosan added. In addition, low viscosity chitosan reduced biofilm formation both when added to media and when coated on polystyrene surfaces. Significance and Impact of Study. Low viscosity chitosan could be a contribution to new treatment approaches of biofilm-related infections of S. epidermidis.
