Centric versus eccentric engine‐driven endodontic instrument design for microbial load reduction—A systematic review and meta‐analysis of randomised clinical trials

Abstract

This systematic review assessed the clinical influence of centric and eccentric engine‐driven instrument design for reduction in microbial load in infected root canal system. The literature search was conducted in electronic databases (PubMed, Cochrane Library, Scopus, Lilacs and Google Scholar) and grey literature till June 2022. The search strategy followed the PRISMA 2020 guidelines. Qualitative and quantitative synthesis was conducted based on the guidelines of the Cochrane Handbook. The risk of bias was assessed using the revised Cochrane criteria and quality of evidence was conducted using the Grading of Recommendation Assessment, Development and Evaluation tool. Out of 28 papers, only five papers met the inclusion criteria of this review. Studies showed reduction in microbial load after instrumentation using centric or eccentric instruments with no statistically significant difference in the meta‐analysis. In conclusion, there is low‐grade evidence suggesting that microbial reduction is similar using centric and eccentric instruments.

Instrumentation time and effectiveness of hand and rotary files in a prototyped second mandibular primary molar: A micro‐CT study

“…8,9 In fact, eccentric, or offset, instruments do not follow a centralized rotational axis, thus acting not only in the center of the canal but also in the sideward. 10 The ProTaper Next® system (Dentsply Sirona Endodontics, Ballaigues, Switzerland) is a multi-file system produced with an M-wire alloy and an off-centered rectangular cross section, rendering the file a "snakelike" movement as it moves through the root canal. 11 XP-endo® Shaper (XPS-FKG, La Chaux-de-Fonds, Switzerland) is also an eccentric instrument produced with the highly flexible Max-wire alloy with the ability to expand when exposed to the body temperature, resulting in further surface contact between the instrument and the root canal walls.…”

“…Recently, eccentric rotary instruments have been given special attention in permanent teeth due to alleged, improved shaping ability and less canal transportation due to better adaptation into the root canal 8,9 . In fact, eccentric, or offset, instruments do not follow a centralized rotational axis, thus acting not only in the center of the canal but also in the sideward 10 …”