Figure 1. Representative confocal laser scanning microscopic images. Only stained irrigant can be seen with this technique. (a) The image shows fluorescence around the canal walls without penetration into dentinal tubules; (b) Deep penetration is shown in part of the canal wall. The green line was used to mark and to measure the percentage of canal wall showing dentinal tubule penetration; (c) An intense irrigant-labelled penetration is shown. The maximum penetration into dentinal tubules was measured in each case (green line).