Fabrication and evaluation of polypropylene/natural rubber dental clamps: a model-based comparative study of isolation quality and user satisfaction

Conventional metal rubber dam clamps provide effective isolation but may be associated with gingival trauma, localized enamel stress concentration, and patient discomfort. Polypropylene/natural rubber (PP/NR, 90/10 wt%) blends have previously demonstrated favorable mechanical properties and resistance to repeated autoclave sterilization; however, the functional isolation performance of PP/NR clamps has not been established. This study evaluated the isolation quality and user satisfaction of a PP/NR rubber dam clamp compared with a commercial polymer clamp and a conventional metal clamp using a standardized dental simulator. Three clamp systems were evaluated: an experimental PP/NR clamp, a commercial polymer clamp (SoftClamp™), and a conventional metal clamp ( n = 10 clamps per group). Isolation quality, including sealing ability, retention efficacy, and linear slippage, was assessed on a simulated mandibular left first molar at baseline (T0) and after each of ten successive steam sterilization cycles (T1–T10). Differences among clamp types were analyzed using the Kruskal–Wallis test, whereas changes across sterilization cycles were evaluated using the Friedman test. User satisfaction was assessed by 12 dental specialists and analyzed using the Friedman test with post hoc pairwise comparisons. The PP/NR clamp showed sealing ability that was not statistically different from that of SoftClamp™ and the metal clamp at baseline ( p = 0.835) or after repeated sterilization ( p > 0.05). All clamp systems maintained four-point contact throughout the study. Linear slippage was significantly greater in the PP/NR clamp than in both comparator groups at all assessment intervals ( p < 0.001), with median displacement ranging from 0.10 to 0.16 mm. Repeated sterilization did not significantly affect sealing ability or slippage in any clamp system. No statistically significant differences were detected among the three clamp systems for most clinician-reported usability outcomes. However, the PP/NR clamp demonstrated greater linear displacement and required longer placement time than the conventional metal clamp. The novel PP/NR clamp demonstrated no statistically significant differences in sealing ability and four-point retention compared to both conventional metal and SoftClamp™ systems. However, the PP/NR clamp demonstrated greater slippage and longer placement times than the metal clamp.