Fig. 7
From: Investigation on the Gradient Nanomechanical Behavior of Dental Fluorosis Enamel
SEM image of normal and abnormal enamel rods in the outer layer of the dental fluorosis enamel. The microstructure is viewed under × 20,000 magnification after etching with 37% phosphoric acid for 30 s. Green arrows show the broadened gaps between the enamel rods, while white circles show the pores. Red arrows indicate loosely arranged crystals in the enamel rods with increasing crystal clearance and micropores