Comparative Evaluation of Smear Layer Removal Using Gutta Percha, Ultrasonic, Sonic, Plastic Finishing File and Canal Brush Methods: A Scanning Electron Microscope Study

Instrumentation of the root canal is associated with the formation of a smear layer. The presence of a smear layer prevents the penetration of intracanal disinfectant into the dentinal tubules and prevents complete adaptation of obturation materials to the dentinal walls. Additionally, bacteria remaining in dentinal tubules after root canal preparation may be sealed by the smear layer. The aim of the study was to compare the efficacy of gutta percha, ultrasonic, sonic, plastic finishing file and canal brush methods for the removal of the smear layer from the apical third of root canals. Sixty freshly extracted mandibular premolars were instrumented up to protaper file F3 and divided randomly into six groups (n = 10) according to the following final irrigation agitation techniques: group 1- no agitation (control), group 2- gutta percha, group 3- ultrasonic, group 4- sonic, group 5- plastic finishing file, group 6- canal brush. Specimens were then sectioned and observed under a scanning electron microscope and presence of smear layer was evaluated and scored. Under the testing condition it was concluded that the plastic finishing file method performed significantly better than the rest of the groups with respect to smear layer removal followed by the Canal Brush, sonic, gutta percha, ultrasonic methods.