RESUMO
Background: Any solution of chemical nature when combined will result in the formation of a precipitate, which in the root canal system will interfere with the hermetic seal. In clinical practice presence of any precipitate, especially carcinogenic in nature, should be eliminated. Aim: To evaluate whether final irrigation with different agitation protocols will remove the precipitate formed following lidocaine hydrochloride and sodium hypochlorite combination at the coronal, middle, and apical-root thirds. Materials and Methods: Forty-four uniradicular teeth were standardized at 17 mm. All specimens were injected with 2% lidocaine hydrochloride and 2.5% sodium hypochlorite, followed by mechanical instrumentation using rotary files. Further, specimens were arbitrarily divided into four groups (n = 11) based on the final irrigation protocol: Group 1: No irrigation; Group 2: Manual irrigation; Group 3: Mechanical irrigation; Group 4: Ultrasonic irrigation. Samples were sectioned and Field Field Emission Scanning Electron Microscopic (FESEM) analysis of the canal wall was done at coronal, middle, and apical thirds. Results: FESEM images revealed occluded dentinal tubules with the presence of precipitate seen in all-thirds of each specimen. Conclusion: No irrigation protocol was successful in removing the precipitate formed; but when compared ultrasonic irrigation had the least precipitate seen at-coronal,-middle and apical thirds.
