Tucel Industries' patented fusing process was designed to help eliminate the build-up of bacteria in the drilled holes of most staple-set brushes. An NSF study concluded that fused filament brushes are easier to clean than staple-set brushes, resulting in 50% less bacteria. Tucel's "fused" filament eliminates "pathogenic pockets" whereby no bacteria, mildew or mold can be absorbed into the brush block. Unlike natural filaments or nylon, which are hydrophilic in nature,Tucel utilizes polypropylene filaments that do not absorb foreign materials. Fused filaments resist bacteria and are dishwasher safe.