Reduction of dual-species biofilm after sonic- or ultrasonic-activated irrigation protocols: A laboratory study

Daniela Hoedke*, Namira Kaulika, Henrik Dommisch, Sebastian Schlafer, Hagay Shemesh, Kerstin Bitter

*Corresponding author for this work

Research output: Contribution to JournalArticleAcademicpeer-review

Abstract

Aim: To evaluate the antibacterial effect of sonic- and ultrasonic-activated irrigation on bacterial reduction of a dual-species biofilm in root canals compared to nonactivated irrigation in a laboratory study. Methodology: Two hundred and forty extracted human single-rooted maxillary anterior teeth were divided into two main groups (G, n = 120) according to the initial preparation size of the root canal (G1: size 25, 0.06 taper, G2: size 40, 0.06 taper). Root canals were inoculated with Enterococcus faecalis and Streptococcus oralis. After 5 days, G1 received combined instrumentation (up to size 40, 0.06 taper) and irrigation/activation, whereas G2 received solely irrigation/activation protocols. In both groups, irrigation was performed with sodium hypochlorite (NaOCl 1%) or physiological saline (NaCl 0.9%), using nonactivated syringe irrigation, sonic activation (2 x 30 s) or ultrasonic activation (2 x 30 s). Logarithmic reduction factors (LRFs) of colony-forming units were analysed separately for dentine-adherent and planktonic bacteria immediately after irrigation/activation protocols (time-point 1) or after 5 days of further incubation (time-point 2) by analysis of variance (anova) and post hoc tests (Tukey's HSD, t-test). The significance level was set at 0.05. Results: In G1 subgroups (combined instrumentation with irrigation/activation), LRFs were significantly affected by the applied irrigation solution (p <.0001), but not by the activation method (p >.05; anova). In G2 subgroups (solely irrigation/activation), both, irrigant solution and activation, significantly affected LRFs (p <.0001, anova). Sonic activation resulted in significantly higher LRFs than ultrasonic activation (p <.0001) which had significantly greater reductions than nonactivated irrigation (p <.05; Tukey's HSD). At T2, strong bacterial regrowth was observed in all groups; however, a significant bacterial reduction was detected for factors instrumentation, irrigant solution and activation (p <.0001; anova). Similar LRFs were found for dentine-adherent and planktonic bacterial cells in all groups (r = 0.91 at T1, r = 0.8 at T2). Conclusions: In this laboratory study on extracted maxillary anterior teeth high-frequency sonic activation resulted in a greater bacterial reduction compared to ultrasonic activation in groups receiving solely irrigation/activation protocols; however, irrigation using NaOCl and ultrasonic activation also contributed significantly to bacterial reduction compared to the control groups.

Original languageEnglish
Pages (from-to)2219-2228
Number of pages10
JournalInternational Endodontic Journal
Volume54
Issue number12
Early online date21 Aug 2021
DOIs
Publication statusPublished - Dec 2021

Bibliographical note

Funding Information:
The authors thank Verena Kanitz (Department of Periodontology and Synoptic Dentistry, Charit? ? Universit?tsmedizin Berlin, Germany) and Lene Gr?nkj?r (Department of Dentistry and Oral Health, Aarhus University, Denmark) for her support in laboratory work as well as Dr. Konrad Neumann (Institute of Biometry and Clinical Epidemiology, Charit? ? Universit?tsmedizin Berlin, Germany) and Dr. Joachim Krois (Department of Oral Diagnostics, Digital Health and Health Services Research ? Universit?tsmedizin Berlin, Germany) for their statistical advice. The authors thank Verena Kanitz (Department of Periodontology and Synoptic Dentistry, Charit? ? Universit?tsmedizin Berlin, Germany) and Lene Gr?nkj?r (Department of Dentistry and Oral Health, Aarhus University, Denmark) for her support in laboratory work as well as Dr. Konrad Neumann (Institute of Biometry and Clinical Epidemiology, Charit? ? Universit?tsmedizin Berlin, Germany) and Dr. Joachim Krois (Department of Oral Diagnostics, Digital Health and Health Services Research ? Universit?tsmedizin Berlin, Germany) for their statistical advice.

Publisher Copyright:
© 2021 The Authors. International Endodontic Journal published by John Wiley & Sons Ltd on behalf of British Endodontic Society.

Keywords

  • antibacterial effectiveness
  • nonactivated irrigation
  • root canal disinfection
  • sonic activation
  • ultrasonic activation

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