The effectiveness of five different irrigation protocols in elimination of bacteria colonizing in dentin tubules: A confocal laser study

The aim of this thesis study is to compare the effects of different irrigation activation systems (Standard needle irrigation (SNI), Endoactivator (EA), EDDY, Irriflex and Passive ultrasonic irrigation (PUI)) on bacteria colonizing dentinal tubules using Confocal Laser Scanning Microscope (CLSM) analysis. Sixty mandibular human teeth were included in the study. The teeth were divided into five experimental groups (n=10) and a control group (n=10). All tooth samples were equilibrated at 18 mm to ensure standardization. The teeth were shaped with T-endo Must rotary files up to a diameter of 40.04. The samples were sterilized by embedding in acrylic resin blocks. Then, planting with E.faecalis was completed and incubated for 21 days. Tooth samples were activated during the final irrigation using SNI, EA, EDDY, Irriflex and PUI (Irrisafe) methods. No irrigation was performed in the positive control group. Horizontal cross-sections of 1 ± 0.1 mm thickness were taken from the teeth at a distance of 2, 5, 8 mm, respectively, from the apical sections taken were stained using the LIVE/DEAD Baclight Vitality kit, then the samples were visualized with CLSM. The maximum penetration depth of dead bacteria colonizing the dentinal tubules was evaluated using the Leica Application Suite-Advanced Fluorescence software. Kruskal Wallis, Mann Whitney U test and Bonferroni correction were used for statistical analysis.The maximum penetration depth of dead bacteria in the control group was significantly lower than in all experimental groups in all three sections. SNI group in the coronal triad; EA showed significantly lower penetration depth than PUI, EDDY and Irriflex experimental groups (p<0.05). When the dead bacteria penetration depth in the coronal third of the EA and EDDY groups was compared, there was no significant difference between the groups (p>0.05); EA and EDDY groups showed higher values than Irriflex group (p<0.05). SNI group in the middle third; EA showed significantly lower penetration depth than PUI, EDDY and Irriflex experimental groups (p<0.05). While there was no significant difference between EA and PUI groups (p>0.05); EDDY and EA groups showed higher penetration depth than Irriflex group (p<0.05). SNI group in the apical third; EA showed significantly lower penetration depth than PUI, EDDY and Irriflex groups. The EA group showed significantly higher penetration depth than the Irriflex group (p<0.05). In group comparisons made according to cross-section levels; While the penetration depth in the coronal third was significantly higher than the apical third in the SNI and Irriflex groups (p<0.01) the penetration depth in the apical third in the PUI, EDDY and EA groups was found to be significantly lower than in the other sections (p<0.01). When we look at the results of our study, although a statistically significant E.faecalis decrease was observed in all groups except the positive control group in which we did not use irrigation solution, E.feacalis could not be eliminated %100 in any group. This indicated that the irrigation protocols used should be developed further and further research should be done.