Influence of incorporation of antibacterial monomer on curing behavior of a dental composite.

A newly developed monomer, methacryloyloxdodecylpyridinium bromide (MDPB), has an antibacterial activity against oral streptococci, and this monomer can be active even after being immobilized as one component of a cured composite. The purpose of this study was to investigate the influence of incorporation of MDPB on the curing behavior of Bis-GMA-based composites. Depth of cure, degree of cure, light-attenuating effect, and surface hardness of composites incorporating 0.4 or 0.5% MDPB were measured and compared with those of a control material without MDPB. Depth of cure of composites with MDPB, measured by means of a penetrometer, was greater than for the control (p < 0.05). Differential thermal analysis showed that composites with MDPB had a significantly greater degree of cure than the control (p < 0.05). The light-attenuating effect of MDPB composites was less than for the control (p < 0.05). No significant difference between experimental and control was obtained with respect to Vickers hardness after both one day's and seven days' storage in water. These results indicate that the incorporation of small quantities of MDPB into Bis-GMA-based composites did not adversely affect the cure performance. On the contrary, a significant, though small, improvement was observed.