Intragroup comparison
Comparisons between mean percentage of isthmus cleanliness before and after different activation techniques (comparison within the same group): The mean of isthmus cleanliness (%) changed significantly from i1 (after chemomechanical preparation) to i2 (after final irrigation) at all measured levels (2 mm, 4 mm, and 6 mm) and as a total. Total isthmus cleanliness (%) changed significantly (sign. < 0.001*) from 54.72 to 60.15 in the final needle irrigation without activation (NA) group, from 53.95 to 79.42 in the Irrisafe group and from 42.22 to 76.53 in the EDDY group as revealed by paired samples t-test (Table Comparison between mean % of anastomosis cleanliness before (i1) and after (i2) different activation techniques*significant at Comparison of mean % of isthmus cleanliness between different levels (comparison within the same group): showed that the intragroup comparison showed that improvement in anastomosis cleanliness (i2-i1) in the needle irrigation without activation group (NA) was significantly higher in the apical 2 mm level compared to the 4 & 6 levels. The difference in cleanliness improvement in the Irrisafe and EDDY was insignificant between the three levels. (Table 