Antimicrobial and Mechanical Properties of Resin-Based Dental Composites with Didodecyldimethylammonium Bromide (DDAB) as a Biocidal Additive

<p>Composite materials are among the most used in dentistry. Despite their many ad-vantages, they also have disadvantages. The aim of the study is to develop and character-ise an experimental composite for use in dentistry and caries prevention. In addition to the composite, didodecyldimethylammonium bromide (DDAB) was used as a biocide. DDAB was added in various concentrations (0-3 wt%) to the experimental dental composite. Hardness (HV), flexural strength (FS), and modulus of elasticity, as well as diametral ten-sile strength (DTS) of composites, were examined. Additionally, shrinkage stress, surface free energy (SFE), water sorption (Wsp), and solubility (Wsl) were determined. Antibacte-rial activity was assessed by cytometric analysis, including biocidal surface testing and susceptibility to colonisation by Streptococcus mutans, Escherichia coli, and Candida albicans. HV of RBCs varied from 27.2±1.5 to 31.5±1.8 depending on DDAB amount, FS - 67.0±16.1 MPa for control composite and 79.2±14.5 MPa for modified composite. All DTS values ex-ceed 24 MPa. Shrinkage stress is highest for the composite with 0.25 wt% DDAB - 18.5±1.9 MPa and lowest for the composite with 1 wt% DDAB - 15.0±2.5 MPa. Wsp is the lowest for control group - 37.19 ± 1.69 µg/mm3, the highest for 3 wt% of the modifier (3.47 ± 0.90 µg/mm3). Wsl was the lowest in control group (1.98 ± 1.58 µg/mm3), and highest for modi-fication wit 3 wt% (3.47 ± 0.90 µg/mm3). For RBCs modified with 3 wt% DDAB after 60 min the increase of dead cell is observed – 51% for E. coli, 71% for S. mutans and 24% for C. albicans. The modification with DDAB reduced the presence of the tested pathogens, still without compromising the mechanical properties of the composites. DDAB can be an innovative modifier that provides biocidal properties, allowing for the reduction of caries formation and hence improving the durability of restorations.</p>