title: Effectiveness of different irrigation techniques on smear layer removal in apical thirds of mesial root canals of permanent mandibular first molar: A scanning electron microscopic study.
abstract: OBJECTIVE
  The aim of this study was to compare smear layer removal after final irrigant activation with sonic irrigation (SI), manual dynamic agitation (MDA), passive ultrasonic irrigation (PUI), and conventional syringe irrigation (CI).
  
  
  METHODS
  Forty mesial canals of mandibular first molars (mesial roots) were cleaned and shaped by using ProTaper system to size F1 and sodium hypochlorite 3% and 17% ethylenediaminetetraacetic acid. The specimens were divided into 4 equal groups (n = 10) according to the final irrigation activation technique: Group 1, PUI; group 2, manual dynamic activation (MDA); group 3, SI; and group 4, control group (simple irrigation). Samples were split longitudinally and examined under scanning electron microscope for smear layer presence.
  
  
  RESULTS
  Control groups had the highest smear scores, which showed the statistically significant highest mean score at P < 0.05. This was followed by ultrasonic, MDA, and finally sonic, with no significant differences between them.
  
  
  CONCLUSIONS
  Final irrigant activation with sonic and MDA resulted in the better removal of the smear layer than with CI.
authors.affiliation: Department of Conservative Dentistry and Endodontics, College of Dental Sciences, Amargadh, Bhavnagar, Gujarat, India.
authors.forename: Pranav
authors.initials: P
authors.lastname: Khaord
authors.affiliation: Department of Conservative Dentistry and Endodontics, Karnavati School of Dentistry, Gandhinagar, Gujarat, India.
authors.forename: Aesha
authors.initials: A
authors.lastname: Amin
authors.affiliation: Department of Conservative Dentistry and Endodontics, Karnavati School of Dentistry, Gandhinagar, Gujarat, India.
authors.forename: Manish B
authors.initials: MB
authors.lastname: Shah
authors.affiliation: Department of Conservative Dentistry and Endodontics, College of Dental Sciences, Amargadh, Bhavnagar, Gujarat, India.
authors.forename: Roshan
authors.initials: R
authors.lastname: Uthappa
authors.affiliation: Department of Conservative Dentistry and Endodontics, Karnavati School of Dentistry, Gandhinagar, Gujarat, India.
authors.forename: Nirmal
authors.initials: N
authors.lastname: Raj
authors.affiliation: Department of Conservative Dentistry and Endodontics, Karnavati School of Dentistry, Gandhinagar, Gujarat, India.
authors.forename: Tejal
authors.initials: T
authors.lastname: Kachalia
authors.affiliation: Department of Prosthodontics, College of Dental Sciences, Amargadh, Bhavnagar, Gujarat, India.
authors.forename: Hiral
authors.initials: H
authors.lastname: Kharod
keywords: Manual dynamic agitation; passive ultrasonic irrigation; scanning electron microscopy; smear layer