BACKGROUND: Endodontic sealers are expected to provide a favorable adhesion for a successful seal. This study aimed to evaluate the effect of ethylenediaminetetraacetic acid (EDTA) and Hydroxyethylidene Diphosphonic acid (HEDP) on bond strength of AH Plus and EndoSequence BC HiFlow sealers to root canal walls. METHODS: This study utilized 144 mandibular human premolars. Root canals were shaped using ProTaper Next system. Teeth were divided into 4 groups of 36 according to final irrigation: Group 1: NaOCl, EDTA
Group 2: NaOCl, HEDP (mixed with distilled water)
Group 3: HEDP (mixed with NaOCl)
Group 4: NaOCl only. Teeth were then divided into 2 subgroups (n = 18) and filled by AH Plus or BC Sealer HiFlow using warm vertical compaction. Teeth were kept at 37 °C with 100% humidity for 7 days. Using the IsoMet device, horizontal sections with a thickness of approximately 1 mm were taken from each sample from the apical, middle and coronal third of the root. Bond strength was tested using an Instron universal testing device at a constant speed of 1 mm/min until failure. Statistical analysis was performed using Shapiro-Wilk normality test, one-way analysis of variance and Three-Way ANOVA for intergroup comparisons. RESULTS: Statistically significant differences were observed between all groups (p = 0,0001). Push-out averages of NaOCl, EDTA group were significantly higher than NaOCl, HEDP
HEDP (NaOCl) and NaOCl groups (p = 0,0001). Push-out averages of NaOCl group were significantly lower than NaOCl, HEDP and HEDP (NaOCl) groups (p = 0,0001). No significant difference was observed between AH Plus and BC Sealer HiFlow (p = 0,883). Push out averages of the apical region were significantly higher than others and those of middle region were significantly higher than coronal (p = 0,0001). Cohesive failure was prevalent in NaOCl, EDTA, NaOCl, HEDP and HEDP (NaOCl) groups and mixed failure was prevalent in NaOCl group. CONCLUSIONS: Irrigation using chelating agents such as EDTA and HEDP mixed with NaOCl gave higher adhesion compared to teeth where only NaOCl was used. EDTA and HEDP mixed with NaOCl can be advocated both for resin based and calcium silicate based sealers.