[Drying of root canals]

The dryness of root canals was checked using special paper points prepared with an indicator medium. In the presence of moisture these paper points promptly change from white to blue in color. In a two-step in vitro experiment, moisture was always demonstrated at the apical stop and in the apical third of the canal wall, although according to clinical criteria we believed the root canal to be dry. The results were not influenced by any previous manipulations of the prepared root canals. It may be recommended for routine root canal therapy to observe the following rules: 1. use alcohol for the last irrigation, 2. keep using larger paper points in between, 3. use 2 to 3 paper points more after you believe the root canal is dry, 4. remove the last paper point right before obturating the root canal.