A scanning electron microscope evaluation of smear layer removal from root canals prepared by manual or rotary instrumentation using three different irrigating systems: An in vitro study

Abstract

Introduction: Smear layer removal after root canal instrumentation requires the use of irrigating solutions, either alone or in combination. The mechanical debridement efficacy of an irrigation delivery/agitation system is dependent on its ability to deliver the irrigant to the apical and noninstrumented regions of the canal space and to create a strong enough current to carry the debris away from the canal walls. Materials and Methods: Ninety extracted single-rooted anterior teeth were included in the study and divided into two groups of 45 each. Biomechanical preparation was done with hand files in Group A and with rotary files in Group B. Three subgroups were further made from each group, wherein Max-I-Probe, Endosonic files, and EndoActivator irrigation systems were used in subgroups I, II, and III, respectively. After irrigation with 10% citric acid, specimens were split and the root surfaces were evaluated under scanning electron microscope at cervical, middle, and apical levels. Results: The removal of smear layer was more complete in coronal and middle thirds than in the apical third. No significant difference was found on the removal of smear layer in manually or rotary instrumented groups. When mean scores for all the groups were obtained, Max-I-Probe hand file (Group IA) was found to be most effective in cleaning smear layer in cervical third of root canals, whereas Endosonic rotary showed the best result in both middle and apical third. Conclusion: EndoActivator system did not enhance the removal of smear layer as compared with Endosonic system and the conventional Max-I-Probe irrigation with NaOCl and 10% citric acid. removal of smear layer was more complete in coronal and middle thirds than in the apical third.