Effect of Different Irrigation Activation Techniques on Smear Layer Removal in Root Canal Treatment

An effective procedure to disinfect root canals and seal them involves the removal of a smear layer. Different irrigation activating methods are established to ameliorate the effectiveness of smear layer removal, but their efficiency in comparison is problematic.

To compare and assess the efficacy of three methods of irrigation activation, which included manual dynamic agitation (MDA), sonic activation (EndoActivator), and passive ultrasonic irrigation (PUI) in the removal of the smear layer on root canal walls.

Sixty extracted human mandibular single-rooted premolars were decoronated and prepared to F3 using the rotary ProTaper universal system. Each sample was randomly allocated into four groups (n = 15): group I (control, syringe irrigation), group II (MDA), group III (EndoActivator), and group IV (PUI). The last wash had 5 mL of 17% EDTA, 8 and 5 mL of 3* NaOCl. The degree of smear layer removal in coronal, middle, and apical areas was evaluated and calculated by utilizing scanning electron microscopy (SEM) and given a positive score depending on a 5-point scale. Analysis of data was done through ANOVA combined with Tukey post-hoc (P < 0.05).

PUI (Group IV) excelled especially in the smear layer removal in all the thirds (mean: score 1.4 + 0.5), followed by EndoActivator (1.8 + 0.6), MDA (2.3 + 0.7) and syringe irrigation (3.6 + 0.4). The results provided significant differences between PUI and other groups (P < 0.001).

Passive ultrasonic irrigation proved to be the most efficient procedure used in removal of smear layer, especially in the apical third, and therefore, it can be utilized in order to enhance results in endodontics.