The effectiveness of reciprocating instruments in the removal of root filling materials: A systematic review

Introduction: Re‑establishing the health of the periapical tissues is considered to be the main objective of
nonsurgical root canal retreatment in cases with posttreatment disease. Removal of filling material from
the canal space is the most difficult and challenging step during retreatment, regardless of the technique/
instrument used. The aim of this study was to determine the effectiveness of nickel–titanium reciprocating
instruments in the removal of root canal filling material in comparison with continuous rotary shaping and
retreatment instruments.
Materials and Methods: Four electronic databases were used (PubMed, Google Scholar, ScienceDirect, and
Scopus) as information sources. Articles describing in vitro studies carried out on extracted human teeth
were included in this systematic review, while narrative, systematic review, in vivo studies, animal studies,
studies published in languages other than English, and studies that used methods other than micro‑computed
tomography to detect root filling material were excluded from this systematic review. The studies were
assessed for eligibility according to inclusion criteria by two independent reviewers; the opinion of the
third reviewer was requested when one of the reviewers did not accept the study to be included.
Results: Forty‑one studies of 560 titles and abstracts screened were selected for full‑text analysis; 26 studies
were excluded, and 15 studies were included in this systematic review. Eleven studies (73%) showed a
nonsignificant difference between reciprocating and rotary instruments.
Conclusions: The collected studies showed no effect of motion (either reciprocation or full rotary motion)
on the remnant of root canal filling materials.
Keywords: Reciprocating, retreatment, root canal filling, rotary nickel–titanium