Fig. 3From: Nanotribological and Nanomechanical Properties Changes of Tooth After Bleaching and Remineralization in Wet EnvironmentScratches observed by SPM and the residual traversal profiles of scratch tests. The small pictures in the left corner are the scratches observed by SPM. The red line shows where the traversal profiles of the scratch tests were got. a Control group. b 12HP group. c 35CP group. d 15CP groupBack to article page