The Antibacterial Effects of Quaternary Ammonium Salts in the Simulated Presence of Inhibitors in Root Canals: A Preliminary In-Vitro Study

Sanjay Kumar Tiwari,Xuedong Zhou,Biao Ren,Xian Peng,Lei Cheng,Mingyun Li,Suping Wang,Hockin H K Xu,Michael D Weir,Yannan Huang

doi:10.3390/coatings10020181

Sanjay Kumar Tiwari, Xuedong Zhou + Show 8 more

Open Access

https://doi.org/10.3390/coatings10020181

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Abstract

To investigate the antibacterial effects of two newly developed quaternary ammonium salts (QAMs)-dimethylaminododecyl methacrylate (DMADDM) and dimethylaminohexadecyl methacrylate (DMAHDM), in the presence of various root canal inhibitors. Streptococcus gordonii, Enterococcus faecalis, Lactobacillus acidophilus and Actinomyces naeslundii were used. Dentine, dentine matrix and dead bacteria were selected as inhibitors. The antimicrobial efficacy of monomers of DMADDM and DMAHDM was tested against suspensions formed by mixtures of four bacterial species in or without the presence of inhibitors. The inhibition results were compared with chlorhexidine (CHX) and sodium hypochlorite (NaOCl). One-way analyses of variance (ANOVA) followed by Tukey’s multiple comparison test was performed to determine significant differences. The antibacterial effects of DMADDM and DMAHDM were variably inhibited dentine, dentine matrix and dead bacteria. CHX and NaOCl showed substantivity and they inhibited bacteria present in suspension. The concentration of compound decreased in the dentine block due to constant release. Bacterial colonies on the dentine surface and dentine tubules were significantly inhibited by DMADDM and DMAHDM. The antibacterial effects of DMADDM and DMAHDM could be inactivated by dentine, dentine matrix and dead bacteria, while DMADDM and DMAHDM could inhibit bacteria colonization on the dentine surface and kill bacteria present in dentinal tubules. The antibacterial effects of DMADDM and DMAHDM as free monomers in the presence of inhibitors was evaluated for the first time. They could help inhibit the residual bacteria on the dentine surface and in dentinal tubules that may cause persisting infection. Therefore the novel QAMs showed great potentials as root canal medication.

Highlights

The main goal of endodontic treatment is to eradicate pulp and periapical tissue infection and promote periapical tissue healing
3 min, the dimethylaminododecyl methacrylate (DMADDM) group and the dimethylaminohexadecyl methacrylate (DMAHDM) group were totally inactivated by the presence of dead bacteria, dentine or dentine to the
After 3 min, the DMADDM group and the DMAHDM group were totally inactivated by the presence of dead bacteria, dentine matrix or dentine powder, compared to the group without exposure to any inhibitor

Summary

Introduction

The main goal of endodontic treatment is to eradicate pulp and periapical tissue infection and promote periapical tissue healing. There still exists bacterial persistence within the root canal system even after cleaning and shaping procedures. It is important to eliminate the persisting biofilm inside the root canal system before root canal obturation [1]. A wide variety of antimicrobial, disinfecting or cleaning agents such as sodium hypochlorite (NaOCl), chlorhexidine (CHX), ethylenediaminetetraacetic acid (EDTA), citric acid, hydrogen peroxide, have been developed and investigated. Apart from conventional irrigants and intracanal medicaments [2], other measures such as nanoparticle–based disinfectants [3] and photodynamic therapies [4,5] have been reported. The effectiveness of these antimicrobial agents is compromised in the clinical conditions because of the complexity of the root canal anatomy system that permits the localization of bacteria in the inaccessible areas

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