Effect of Novel Antibacterial Composites on Bacterial Biofilms

Abstract

Continuing cariogenic bacterial growth demineralizing dentine beneath a composite filling is the most common cause of tooth restoration failure. Novel composites with antibacterial polylysine (PLS) (0, 4, 6, or 8 wt%) in its filler phase were therefore produced. Remineralising monocalcium phosphate was also included at double the PLS weight. Antibacterial studies involved set composite disc placement in 1% sucrose-supplemented broth containing Streptococcus mutans (UA159). Relative surface bacterial biofilm mass (n = 4) after 24 h was determined by crystal violet-binding. Live/dead bacteria and biofilm thickness (n = 3) were assessed using confocal laser scanning microscopy (CLSM). To understand results and model possible in vivo benefits, cumulative PLS release from discs into water (n = 3) was determined by a ninhydrin assay. Results showed biofilm mass and thickness decreased linearly by 28% and 33%, respectively, upon increasing PLS from 0% to 8%. With 4, 6, and 8 wt% PLS, respectively, biofilm dead bacterial percentages and PLS release at 24 h were 20%, 60%, and 80% and 85, 163, and 241 μg/disc. Furthermore, initial PLS release was proportional to the square root of time and levelled after 1, 2, and 3 months at 13%, 28%, and 42%. This suggested diffusion controlled release from water-exposed composite surface layers of 65, 140, and 210 μm thickness, respectively. In conclusion, increasing PLS release initially in any gaps under the restoration to kill residual bacteria or longer-term following composite/tooth interface damage might help prevent recurrent caries.

Varying 10-methacryloyloxydecyl dihydrogen phosphate (10-MDP) level improves polymerisation kinetics and flexural strength in self-adhesive, remineralising composites

“…Previously, 4-META was included in the UDMA/PPGDMA to further improve adhesion promotion in dentine. It was also proposed it might provide a bond between the monomer and these hydrophilic particles [32,43]. The increase in strength seen above with 4-META addition provides evidence that this interface bonding might be occurring.…”

“…to have antibacterial action in cariogenic-relevant bacteria [32,42]. To achieve remineralising properties, monocalcium phosphate particles were added.…”

“…To this, 8 wt% monocalcium phosphate monohydrate and 4 wt% polylysine particles were added. These may promote remineralising, self-sealing and antibacterial features in resin-dentin interfaces [32,33]. Powders were mixed at 1000 rpm for 30 s using a Speedmixer (DAC600.…”

Antibacterial and Antibiofilm Properties of Three Resin-Based Dental Composites against Streptococcus mutans

“…All composite disk specimens were placed in 96-well polystyrene microtiter plates and sterilized through top and bottom surface exposure to ultraviolet UV light for 40 min [ 29 ]. Then, the sterile specimens were inoculated for 2 h in saliva at 37 °C in a shaking incubator with slight agitation to form the protein pellicle layer on the surface and to provide bacterial adhesion.…”

Bacterial Interactions with Dental and Medical Materials

“…As cariogenic bacterial grows inside the mouth due to lack of caries disease management, the tooth-material interface continues to degrade by bacterial acids leading to increasing premature failure of tooth filling. Bienek et al [1], Mena Silva et al [2], Yaghmoor et al [3], Lu and Jin [4], Lygidakis et al [5], and Mitwalli et al [6] investigated the application of polymerizable antibacterial monomers based on di-imidazolium or quaternary ammonium compounds as an antibacterial strategy for resin-based materials in efforts toward caries-related biofilm control.…”