Shree Ranjan, Manish Ranjan. Antibacterial Effectiveness Of Rotary And Reciprocating Systems On Microbial Load Reduction In Retreatment Cases- A Systematic Review. Int J Dentistry Oral Sci. 2021;8(8):3710-3717. 3710 OPEN ACCESS https://scidoc.org/IJDOS.php Antibacterial Effectiveness Of Rotary And Reciprocating Systems On Microbial Load Reduction In Retreatment Cases- A Systematic Review Review Article International Journal of Dentistry and Oral Science (IJDOS) ISSN: 2377-8075 *Corresponding Author: Dr. Manish Ranjan, Associate Professor, Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SI- MATS), Chennai-600077, India. Tel: +91-9543445029 E-mail: manish@saveetha.com Received: May 09, 2021 Accepted: August 5, 2021 Published: August 14, 2021 Citation: Shree Ranjan, Manish Ranjan. Antibacterial Effectiveness Of Rotary And Reciprocating Systems On Microbial Load Reduction In Retreatment Cases- A Systematic Review. Int J Dentistry Oral Sci. 2021;8(8):3710-3717. doi: http://dx.doi.org/10.19070/2377-8075-21000761 Copyright: Dr. Manish Ranjan © 2021. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution and reproduction in any medium, provided the original author and source are credited. Shree Ranjan 1 , Manish Ranjan 2* 1 Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai-600077, India. 2 Associate Professor, Department of Conservative Dentistry and Endodontics, Saveetha Dental College and Hospitals, Saveetha Institute of Medical and Technical Sciences (SIMATS), Chennai-600077, India. Abstract Introduction: One of the signifcant endodontic challenges is to control the microbial infection after a successful endodon- tic treatment has been administered. The failure of an endodontic treatment occurs due to post operative microbial leakage causing the reinfection to occur. The remedy to such cases is to perform the endodontic retreatment. One of the com- monest retreatment endodontic fle system is Protaper Universal retreatment fle(DentsplyTulsa,Tulsa) , D-Race retreatment system(FKG Dentaire, Switzerland) , Mtwo retreatment fle system(VDW,Munich Germany), R-Endo fle system(MicroMega, Besancon , France) or GPR mani fles for the retreatment cases. These systems are based on continuous rotary motion. The modern endodontic instruments which focus on the reciprocation method of functioning involve the following systems - Re- ciproc fle system(VDW,Munich Germany), reciproc blue fle system(VDW,Munich Germany) , Waveone fle system(Dentsply Maillefer,Switzerland) , Waveone Gold fle system(DentsplyMaillefer,Switzerland). The current systematic review analyses the effectiveness of Rotary and Reciprocating systems on microbial load reduction in endodontic retreatment cases. Aim: To assess the reduction in microbial load in cases of endodontic retreatment after the use of common rotary endodontic fles and reciprocation based fle systems Search Strategy: A search was performed in electronic database (i.e. PUBMED CENTRAL, Google , Scopus and Hand Search) using following search terms alone and in combination by means of PUBMED search builder from Jan 1980 till Jan 2021. Selection Criteria: All in vitro studies that involved the criteria of reduction in microbial load in retreatment cases which compared the antibacterial effectiveness following the use of rotary and reciprocating systems. Data Collection and Analysis: All the studies were based on the data extraction and analysis of the studies for quality. The outcome measure was to evaluate the antibacterial effectiveness when the rotary and reciprocation systems were used in the retreatment cases. Results: Two studies included for this review had high risk of bias. Of the 2 studies included for this review, both the study involved the use of modern reciprocating fling systems in comparison to continuous rotation, the reduction in the bacterial load was assessed by assessing the CFU units. Conclusion: This review concludes that the studies reviewed here have a high risk of quality bias. However, Reciprocating retreatment fling systems yielded better results compared to conventional retreatment fling systems. The included studies regarding the bacterial load reduction in retreatment cases were not designed properly with respect to randomization sample size calculation, blinding. Hence further clinical trials need to be conducted with proper sample size calculation, blinding and randomization to obtain accurate results. Keywords: Reciprocation; Retreatment Files; Systematic Review; D-Race; M-Two; Reciproc; WaveOne Gold; Protaper Uni- versal.