Effect of repeated autoclave on hardness and tensile strength of polypropylene/natural rubber developed for rubber dam clamp

Abstract

Abstract Background To explore the feasibility of utilizing polypropylene (PP) and natural rubber (NR) blends as alternative material for rubber dam clamps in dentistry.Methods The hardness of various PP/NR blend ratios compared to the commercial product, SoftClamp™. Selected blend ratios exhibiting hardness values resembling rigid plastic were further evaluated for hardness and tensile strength after undergoing 1, 5, and 10 autoclave cycles.Results One-way ANOVA test results found that PP/NR blends exhibit significantly lower hardness (p < 0.001) than the commercial SoftClamp™. PP/NR ratios of 100/0, 90/10, and 80/20 exhibited hardness levels equivalent to 82%, 80%, and 75% of SoftClamp™, respectively. Two-way ANOVA revealed significant reductions in hardness (p < 0.001) and tensile strength (p < 0.001) with increasing NR content across all autoclave cycles. However, post-autoclave assessments at 1, 5, and 10 cycles demonstrated no statistically significant differences in tensile strength (p = 0.058) and hardness (p = 0.52) for PP/NR ratios of 100/0, 90/10, and 80/20 compared to their pre-autoclave states.Conclusions The reduction of the NR content within PP/NR blends decreases hardness and tensile strength while autoclaving did not significantly affect the hardness and tensile strength of PP/NR blends.