A New Solution for the Removal of the Smear Layer

Abstract

Various organic acids, ultrasonic instruments, and lasers have been used to remove the smear layer from the surface of instrumented root canals. The purpose of this study was to investigate the effect of a mixture of a tetracycline isomer, an acid, and a detergent (MTAD) as a final rinse on the surface of instrumented root canals. Forty-eight extracted maxillary and mandibular single-rooted human teeth were prepared by using a combination of passive step-back and rotary 0.04 taper nickel-titanium files. Sterile distilled water or 5.25% sodium hypochlorite was used as intracanal irrigant. The canals were then treated with 5 ml of one of the following solutions as a final rinse: sterile distilled water, 5.25% sodium hypochlorite, 17% EDTA, or a new solution, MTAD. The presence or absence of smear layer and the amount of erosion on the surface of the root canal walls at the coronal, middle, and apical portion of each canal were examined under a scanning electron microscope. The results show that MTAD is an effective solution for the removal of the smear layer and does not significantly change the structure of the dentinal tubules when canals are irrigated with sodium hypochlorite and followed with a final rinse of MTAD.

Effect of final irrigation protocols on microhardness reduction and erosion of root canal dentin

“…Photomicrographs were taken at 2000× magnification. One blinded and calibrated observer (kappa=0.88) classified erosion in each image according to the following criteria, adapted from Torabinejad et al 14 score 0 = smear layer covering almost all dentin surface, with few or no opened tubules; score 1 = no erosion: all tubules looked normal in appearance and size; score 2 = moderate erosion: the peritubular dentin was eroded; score 3 = severe erosion: the intertubular dentin was destroyed and the tubules were connected to each other. The area to be analyzed was selected randomly, with a lower magnification (200×).…”

“…6,11 However, it is known that such chemical auxiliary substances are responsible for reaching the inorganic structure of dentin and thereby cause changes in dentin microhardness 8,12,13 and erosion. 12,14,15,16 Some studies have suggested that these changes could increase the susceptibility to tooth fracture. 17 A solution known as QMiX has been suggested in the literature.…”

Endodontic Irrigation Solutions: A Review

“…A combination of CHX with an added surfactant and EDTA is used to increase penetration to the dentinal tubules (4,49).…”

“…This mixture acts as a chelator and has antimicrobial activity. As it has no organic tissue-dissolving effect, its use after NaOCl at the end of chemomechanical preparation is recommended (49).…”

“…The concentration of antibiotic (doxycycline-50 mg / ml) and the type of detergent (propylene glycol) differ from those in MTAD. Tetraclean does not dissolve organic tissue, and its use after NaOCl at the end of chemomechanical preparation is recommended (49,55).…”