Confocal laser scanning, scanning electron, and transmission electron microscopy investigation of Enterococcus faecalis biofilm degradation using passive and active sodium hypochlorite irrigation within a simulated root canal model

• Published in: MicrobiologyOpen (Weinheim) Vol. 6; no. 4
• Main Authors: Mohmmed, Saifalarab A., Vianna, Morgana E., Penny, Matthew R., Hilton, Stephen T., Mordan, Nicola, Knowles, Jonathan C.
• Format: Journal Article
• Language: English
• Published: England John Wiley & Sons, Inc 01-08-2017; John Wiley and Sons Inc
• Subjects: Agitation; Biodegradation; biofilm resistance; Biofilms; Biofilms - drug effects; Biofilms - growth & development; cell wall; Computer simulation; Data processing; Degradation; Dental Pulp Cavity - microbiology; Electron microscopy; Endodontics; Enterococcus faecalis - drug effects; Enterococcus faecalis - growth & development; Enterococcus faecalis - physiology; Image Processing, Computer-Assisted; Infections; Lasers; Lavage; Microorganisms; Microscopy, Confocal; Microscopy, Electron, Scanning; Microscopy, Electron, Transmission; Models, Theoretical; Original Research; Printing; Root Canal Irrigants - administration & dosage; Root canals; Scanning electron microscopy; Sodium; Sodium hypochlorite; Sodium Hypochlorite - administration & dosage; Therapeutic Irrigation; Three dimensional models; Three dimensional printing; Transmission electron microscopy; Treatment Outcome; Ultrasonic testing; Variance analysis; Biodegradation; cell wall; biofilm resistance
• ISSN: 2045-8827; 2045-8827
• DOI: 10.1002/mbo3.455

Root canal irrigation is an important adjunct to control microbial infection. The aim of this study was to investigate the effect of 2.5% (wt/vol) sodium hypochlorite (NaOCl) agitation on the removal, killing, and degradation of Enterococcus faecalis biofilm. A total of 45 root canal models were manufactured using 3D printing with each model comprising an 18 mm length simulated root canal of apical size 30 and taper 0.06. E. faecalis biofilms were grown on the apical 3 mm of the models for 10 days. A total of 60 s of 9 ml of 2.5% NaOCl irrigation using syringe and needle was performed, the irrigant was either left stagnant in the canal or agitated using manual (Gutta‐percha), sonic, and ultrasonic methods for 30 s. Following irrigation, the residual biofilms were observed using confocal laser scanning, scanning electron, and transmission electron microscopy. The data were analyzed using one‐way ANOVA with Dunnett post hoc tests at a level of significance p ≤ .05. Consequence of root canal irrigation indicate that the reduction in the amount of biofilm achieved with the active irrigation groups (manual, sonic, and ultrasonic) was significantly greater when compared with the passive and untreated groups (p < .05). Collectively, finding indicate that passive irrigation exhibited more residual biofilm on the model surface than irrigant agitated by manual or automated (sonic, ultrasonic) methods. Total biofilm degradation and nonviable cells were associated with the ultrasonic group.
The article investigated the efficacy of sodium hypochlorite irrigant on enterococcus faecalis biofilm within the root canal system. This is particularly important to study root canal irrigation and its mechanics to remove and degrade single species biofilms.