Animal and clinical studies have shown that sharp, unpolished toothbrush bristles can injure gingival tissues and that substantial variation exists in the degree of end-roundness of commercially available toothbrushes. In this study, eight brands of children's toothbrushes were assessed for their relative potential to cause oral tissue injury based upon the degree of end-roundness of their bristles. The brands studied were: Blend-a-dent Jr., Butler GUM Jr., Colgate Plus Jr., Johnson & Johnson Prevent Jr., Johnson & Johnson Reach Child, Lever Bros. Disney, Oral-B P20, and Sensodyne Jr. Brushes were ranked on the basis of three criteria: the percentage of bristles with sharp ends (89% roundness or less), the percentage of bristles with smooth edges (96% roundness or greater), and the average roundness of bristle ends. The Oral-B P20 brush had significantly more (p < 0.05) bristles with a roundness of 96% or greater; it also was in the group having the lowest number of bristles with sharp edges and had the highest average roundness. Based on these criteria, the Oral-B P20 showed the least potential for oral tissue damage, whereas the Johnson & Johnson Reach Child and Butler GUM Jr. showed the most potential for tissue injury. The other brands investigated were intermediate in end-rounding values and damage potential.