Objectives: This study aims to evaluate the efficacy of the rotary instrument XP-endo Finisher for the removal of Ca(OH)2 aided by different irrigation regimens. Methods: Sixteen double-rooted upper premolar human teeth were selected for the study. Thirty-two canals were prepared using a ProTaper Next rotary system up to X3. Then, the canals were filled with Ca(OH)2. The volume of Ca(OH)2 inside the canals was measured by microcomputed tomography (micro-CT). After that, the teeth were randomly allocated into two experimental groups, i.e., A and B (n = 16 canals). In group A, Ca(OH)2 was removed using the master apical file (X3). In group B, Ca(OH)2 was removed using a XP-endo finisher. In half of both groups (n = 8), syringe irrigation (SI) was used, while passive ultrasonic irrigation (PUI) was used for the other half. After removal, the remaining volume of Ca(OH)2 was measured. All data were statistically analyzed using two-way ANOVA with Tukey’s post hoc test. Results: The percentages of remaining Ca(OH)2 in the apical thirds of all canals were significantly higher as compared with the middle and coronal thirds in all groups (p < 0.05). There was no significant difference between different files and techniques (p > 0.05). Clinical Significance: This study presents a new method for the removal of Ca(OH)2 from root canals.

The presence of blood contamination could affect the chemical characterization of mineral trioxide aggregates as endodontic repair material during surgical approach. The aim of this study was to assess and compare the chemical characterization of two white mineral trioxide aggregates (ProRoot and Angelus) mixed with blood versus water. ProRoot and Angelus were mixed with either distilled water, fresh human blood, or diluted blood and analyzed using Fourier transform infrared spectroscopy. The same materials were packed inside holes in dentin blocks for scanning electron microscopy with energy-dispersive X-ray. Gray Portland cement was used as a control. The infrared spectra of unhydrate powders showed an increase in alite in ProRoot and Angelus, belite in Portland cement, and calcium hydroxide in Angelus. Upon hydration, changes in these bands were detected. Energy-dispersive X-ray displayed significantly higher calcium, aluminum, and phosphorous in hydrated Angelus and silicon in hydrated ProRoot (p < 0.05). No phosphorous was detected in ProRoot. Traces of iron were detected in blood groups. A granular pattern was observed at the hydrated material of all tested groups. Definitive gaps were detected at certain areas within hydrated material and its dentin-interface, particularly in blood-contaminated groups. It was supported with the appearance of new bands assigned to Amide I and II of blood protein. It was concluded that the presence of blood during the hydration process of mineral trioxide aggregates produced small gaps of protein impurities within the hydrated material, affecting its chemical behavior and dentin=material-interface integrity.