Abstract:

Objective To investigate the Streptococcus mutans adhesion to polyurethane composites containing polyphosphazene. Methods Polyurethane composites containing 1% polyphosphazene (PZS-1% group), polyurethane composites containing 5% polyphosphazene (PZS-5% group) and silicone rubber soft liner (control group) were solidified under room temperature. These specimens were incubated with Streptococcus mutans suspension. Forty-eight hours after anaerobic culture, Streptococcus mutans adhesion to specimens was observed by light microscopy with Gram staining. Suspension with bacteria detached from specimens after ultrasound and vortex vibration was collected, and colonies of Streptococcus mutans were counted. Results Light microscopy revealed that the morphology of Streptococcus mutans adhered to specimens in three groups was similar, and exhibited typical chain arrangement of Gram positive coccus. The numbers of colonies of Streptococcus mutans adhered to specimens in three groups were well in line with corresponding absorbance. The numbers of colonies of Streptococcus mutans adhered to specimens in PZS-1% group, PZS-5% group and control group were (405.000±60.046), (253.000±62.946) and (1 008.000±119.955)(×10² CFU/m) accordingly, and the number of PZS-5% group was significantly lower than those of PZS-1% group and control group (P<0.001). Conclusion Relatively less Streptococcus mutans is adhered to polyurethane composites containing 5% polyphosphazene, which may be related to the addition of polyphosphazene.

Key words: polyurethane, polyphosphazene, soft liner, Streptococcus, adhesion