The response of dual‐species bacterial biofilm to 2% and 5% NaOCl mixed with etidronic acid: A laboratory real‐time evaluation using optical coherence tomography

Abstract

Aim:The addition of etidronic acid (HEDP) to sodium hypochlorite (NaOCl) could increase the antibiofilm potency of the irrigant, whilst maintaining the benefits of continuous chelation. Studies conducted so far have shown that mixing HEDP with NaOCl solutions of relatively low concentration does not compromise the antibiofilm efficacy of the irrigant. However, the working lifespan of NaOCl may decrease resulting in a reduction of its antibiofilm efficacy over time (efficiency). In this regard, continuous irrigant replenishment needs to be examined. This study investigated the response of a dual-species biofilm when challenged with 2% and 5% NaOCl mixed with HEDP for a prolonged timespan and under steady laminar flow. Methodology: Dual-species biofilms comprised of Streptococcus oralis J22 andActinomyces naeslundii T14V-J1 were grown on human dentine discs in a constant depth film fermenter (CDFF) for 96 h. Biofilms were treated with 2% and 5% NaOCl, alone or mixed with HEDP. Irrigants were applied under steady laminar flow for 8 min. Biofilm response was evaluated by means of optical coherence tomography (OCT). Biofilm removal, biofilm disruption, rate of biofilm loss and disruption as well as bubble formation were assessed. One-way anova, Wilcoxon's signed-rank test and Kruskal-Wallis H test were performed for statistical analysis of the data. The level of significance was set at a ≤.05. Results:Increasing NaOCl concentration resulted in increased biofilm removal and disruption, higher rate of biofilm loss and disruption and increased bubble formation. Mixing HEDP with NaOCl caused a delay in the antibiofilm action of the latter, without compromising its antibiofilm efficacy.Conclusions: NaOCl concentration dictates the biofilm response irrespective of the presence of HEDP. The addition of HEDP resulted in a delay in the antibiofilm action of NaOCl. This delay affects the efficiency, but not the efficacy of the irrigant over time.

Effectiveness of continuous chelation irrigation protocol in endodontics: a scoping review of laboratory studies

“…Table 2 reports the details of the ten studies identified for the antimicrobial activity outcome. Two blinded, randomized studies on extracted human teeth [ 25 , 37 ], seven randomized with no reporting on blinding procedures [ 27 , 38 – 43 ] and one with no information on randomization and blinding [ 44 ] were retrieved. All studies tested HEBP (5–18%) combined with different NaOCl concentrations (1–6%).…”

“…Antimicrobial activity was principally assessed by confocal laser scanning microscopy [ 27 , 37 – 39 , 41 – 43 ]. Other testing methods include optical coherence tomography [ 44 ], quantitative real-time polymerase chain reaction [ 40 ], SEM and atomic absorption spectrometry [ 25 ].…”

“…[ 43 ] reported that NaOCl + EDTA-T (i.e., EDTA plus sodium lauryl ether sulfate) showed the best intratubular antibacterial activity. Furthermore, the addition of HEBP delayed the anti-biofilm action of NaOCl but did not compromise its antimicrobial efficacy [ 44 ]. However, none of the solutions were able to completely eliminate bacteria from the root canals.…”

“…Although differences in the methodology, substrate and volumes of NaOCl make comparison difficult, all included studies demonstrated that HEBP did not interfere with the antimicrobial ability of NaOCl [ 25 , 38 , 39 , 42 , 44 ] and under certain circumstances, may significantly increase the bacterial reduction [ 27 , 37 , 40 , 41 ]. Indeed, the continuous chelation protocol penetrated deeper into the bacterial biofilm matrix, disrupting it and exposing the bacteria to NaOCl action [ 42 ].…”

The Effect of Different Compositions and Concentrations of Etidronate-Containing Irrigants on the Antibacterial Activity of Sodium Hypochlorite against Enterococcus faecalis and Candida albicans

“…In endodontics, etidronate is used in the form of tetrasodium salt (Na4etidronate). The effect of etidronate on the antimicrobial activity of SH has been investigated in a number of studies [ 34 , 35 , 36 , 37 ]. According to earlier investigations, despite the fact that mixing SH with HEDP resulted in a reduction in free available chlorine after one hour, its antibacterial effects were preserved, making this mixture theoretically suitable for chemomechanical preparation [ 23 , 31 , 37 , 38 ].…”