title: Re-establishing apical patency after obturation with Gutta-percha and two novel calcium silicate-based sealers.
abstract: OBJECTIVE
  Aim of the present study was to evaluate the retreatability and reestablishment of apical patency of two calcium silicate-based sealers, TotalFill BC Sealer (BCS) and mineral trioxide aggregate Fillapex (MTA F), versus AH Plus, when used in combination with Gutta-percha (GP).
  
  
  METHODS
  The canals of 54 single-rooted anterior teeth were instrumented and filled with GP/AH Plus (Group A), GP/MTA F (Group B), or GP/BCS (Group C) using continuous wave obturation technique. The groups were subdivided into subgroups with the master-GP cone placed to the working length (WL) or intentionally 2 mm short. The retreatment procedures were performed using ultrasonics, chloroform, rotary, and hand files. The ability to establish the patency and reach WL was determined as well as the time taken to reach WL was calculated in minutes. Furthermore, the samples were observed under a dental, optical microscope, after vertically splitting them.
  
  
  RESULTS
  The WL and patency were reestablished in 100% of specimens in all groups. The Mann-Whitney U-test indicated that there was a significant difference in the amount of time required to reach WL between the groups (P < 0.05) with group GP/BCS short of the WL showing the most amount of time to be retreated.
  
  
  CONCLUSIONS
  The novel calcium silicate-based sealers are negotiable under simple root canal anatomy. However, the conventional retreatment techniques are not able to fully remove them.
authors.affiliation: Department of Endodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Agrafioti
authors.affiliation: Department of Endodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Anastasios D
authors.initials: AD
authors.lastname: Koursoumis
authors.affiliation: Department of Endodontics, School of Dentistry, National and Kapodistrian University of Athens, Athens, Greece.
authors.forename: Evangelos G
authors.initials: EG
authors.lastname: Kontakiotis
keywords: Bioceramics; calcium silicate; mineral trioxide aggregate; retreatment; root canal sealer