In vitro cleaning efficacy and resistance to insertion test of interdental brushes.

The aim of this study was to compare the resistance to insertion forces and cleaning efficacy values of triangular interdental brushes (TIB) and conventional round interdental brushes (RIB). Extracted human teeth were fixed in a socket and matched to pairs simulating interdental spaces. Before and after standardized cleaning of the proximal surfaces, the pre- and postbrushing situations were registered with a digital camera. The cleaning efficacy was quantified by digital image subtraction. The forces necessary for insertion were measured with a load cell. The ratio between the relative cleaning efficacy and the forces necessary for insertion was calculated. The results of our study revealed that the relative cleaning efficacies of round and TIB were equal. There were no statistically significant differences. TIB showed significantly lower resistance to insertion values. Consequently, at identical resistance to insertion the TIB cleaned more effectively compared with the RIB, which means that the same effectiveness was reached by significantly lower forces at insertion. TIB showed a more favorable ratio between relative cleaning efficacy and resistance to insertion than RIB.