Evaluation of the effect of different final irrigation activation systems on dentin tubule penetration of intracanal medicaments with A confocal laser microscope

Aim of this thesis is to investigate the effects of 4 irrigation activation systems on the depth of dentin tubule penetration of 2 intra-canal medications. Root lengths of 96 human mandibular premolar teeth used in the study were standardized to be 12 mm. Roots were shaped until X3 with the Protaper Next rotary system, and at each file change, the root canals were irrigated with 2 mL of 5.25% NaOCl solution. The shaped roots were divided into four groups according to the final irrigation activation systems: Group 1;EndoActivator, Group 2;XP-endo Finisher, Group 3;passive ultrasonic irrigation Group 4;conventional needle irrigation. Final irrigation for each group was achieved by activating 5 mL 5.25% NaOCl and 17% EDTA solution with activation systems for 1 minute. The roots, whose final irrigation was finished, were divided into two subgroups according to the intracanal medicament; Sub-GroupA;Ca(OH)2 and Sub-Group B;mTAP. Root canal medicaments were labeled with 0.1% Rhodamine B and applied into the canals using a Lentulo spiral and then the access cavity were closed with temporary filling material. The roots were kept at 100% humidity for 24 hours. Each root was embedded in an acrylic resin block. Transverse sections were made with a slow-speed, water-cooled diamond disc at 2 mm, 5 mm and 8 mm levels from the root apex. Images from 288 sections were taken with a confocal laser microscope at 4x magnification and transferred to Zeiss LSM Image Browser v.4.2.0 program. The dentinal tubule penetration percentage and maximum penetration depth were calculated using the program's image tools. For statistical analysis, we used three-way analysis of variance(ANOVA). Statistical analysis revealed that: all of the EndoActivator, XP-endo Finisher and PUI activation methods significantly increased the dentin tubule penetration of the intracanal medicaments compared to conventional needle irrigation (p<0,05); Irrigation activation with XP-endo Finisher was determined to show the highest dentin tubule penetration percentage and maximum penetration depth for both intracanal medicaments. It was also found that dentinal tubule penetration percentage and maximum penetration depth of intracanal medicaments in the coronal region were significantly higher than the apical region (p<0,05). While mTAP shows higher dentinal tubule penetration percentage than Ca(OH)2 (p<0,05), no significant difference was found between intracanal medicaments in terms of maximum depth of penetration (p=0,948). Here we found that no final irrigation system provided 100% dentinal tubule penetration of the intracanal medicaments, but the XP-endo Finisher file achieved the highest dentin tubule penetration among the groups tested here. Keywords: Confocal laser microscope, EndoActivator, Final irrigation activation, Intracanal medicament, Passive ultrasonic irrigation, XP-endo Finisher.