Stem Durability Testing of Interdental Brush

The purpose of the present study was to determine the ability of interdental brush to withstand repeated use and to relate this property to clinically observed fractures of such brushes. The stem durability test was conducted according to ISO (International Standards Organization) standard by using a bending at 90 degrees under a 500-g controlled load (ISO/TC106/SC7/ WG3). Two sizes (ss, m) of each of the five commercially available interdental brushes (D, B, P, I, S) were used. The cycle number at the time of fracture was noted for all interdental brushes. The fractured surfaces of the stem wire following the stem durability test were also observed under a scanning electron microscope. The specimens, when ranked in decreasing order of the number of cycles at which fracture occurred, were D-m, D-ss, B-ss, B-m > P-m, P-ss, I-ss, I-m, S-m, S-ss (P < 0.05). L-type interdental brushes (P-m, P-ss, I-ss, I-m, S-m, and S-ss) showed significantly decreased fracture resistance when compared with straight-type interdental brushes (D-m, D-ss, B-ss, B-m). In all cases, the fracture was found to be of ductile nature.