This study grew out of the need to remove adventitious pellicle that formed on some enamel specimens during exposure in the oral cavity. Objective: To find a way to remove the pellicle without altering the surface of the enamel beneath. Method: Enamel cores with various kinds of artificial surface defects, were covered with a growth of pellicle by exposure for one month in the human oral cavity. They were examined by SEM, and then treated by potential pellicle hydrolysis agents such as sodium hydroxide (NaOH) under various conditions of time and temperature. Results: Overnight exposure to 1 M sodium hydroxide at room temperature was found to remove the bulk of pellicle without appreciable alteration of the enamel surface; in some cases, an extra overnight exposure was required to remove all. The treatment with sodium hydroxide caused severe damage to nail varnish used to occlude cut enamel faces, but this could be prevented by coating it with a clear epoxy finish. Prior to treatment, secondary electron SEM (SEI) showed smoothed surfaces due, in many cases, to accumulated pellicle; after depelliclization the sharpness of the image was restored. Backscattered electron SEM images (BEI) made before and after depelliclization tend to show about the same surface, as opposed to SEI, which tends to “see” pellicle more than BEI. Conclusions: Enamel specimens can be cleaned of adventitious pellicle by 1 M NaOH without alteration of the enamel surface if other vulnerable surfaces are coated with epoxy first.

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