There is little information in the endodontic litera­ ture regarding the effects of surface tension on the penetration of irrigating solutions into the canals. Sur­ face tension pertains to the spread of solutions and must be considered important in root canal therapy.

The irrigating solution must be brought into intirnate contact with the dentin wall and the debris. The intimacy of this contact depends on the wettability of  the solutions on  the solid dentin