Removal of dentin by fuchsin staining.

A 0.5% basic fuchsin-propylene glycol solution was applied to the carious dentin of extracted and vital human teeth, and the depths of the fuchsin-stained dentin and the bacterial invasion were compared on histological sections. Excavation guided by this staining method was always deeper than the bacterial invasion, with differences between the depths being greater in acute decay than in chronic decay. This staining is considered to be a reliable clinical guide for the complete removal of deteriorated dentin without causing failure to remove the infection completely. The depths of the images of dentin caries on the radiographs before treatment and after excavation guided by the fuchsin staining method were also compared. The image on the radiograph was always shallower than the excavated cavity. Dentists must expect to excavate caries cavities somewhat deeper than radiographic images.