The benefits for the oscillating-rotating brush over the sonic brush were 32.6 % for gingivitis , 35.4 % for gingival bleeding , 32 % for number of bleeding sites , 22 % for whole mouth plaque , 24.2 % for gingival margin plaque , and 33.3 % for approximal plaque ( p < or = 0.001 for all measures except gingival margin plaque , where p = 0.018 ) .