In vitro evaluation of N-acetylcysteine, calcium hydroxide, chlorhexidine digluconate and their combinations effect against five dental obligate anaerobic bacteria
Lara Steffany de Carvalho, Júlia Andrade de Oliveira, Gabriel Manente Cezarino, Luiz Augusto Rodrigues dos Santos, Gustavo Guimarães Guerrero, Mauro Felipe Rios do Nascimento, Marcia Carneiro Valera, Luciane Dias de Oliveira, Amjad Abu HasnaBackground
This study aimed to evaluate the antibacterial action of N-acetylcysteine (NAC), calcium hydroxide Ca(OH) 2 , chlorhexidine digluconate (CHX), and their combinations against five obligate anaerobic bacteria including Fusobacterium nucleatum, Porphyromonas endodontalis, Porphyromonas gingivalis, Prevotella intermedia , and Parvimonas micra in planktonic and biofilm forms.
Methods
Eight experimental groups were evaluated in this study including saline solution (SS) (control group), Ca(OH) 2 , CHX, NAC, NAC + Ca(OH) 2 , NAC + CHX, Ca(OH) 2 + CHX, and NAC + Ca(OH) 2 + CHX. The anti-planktonic evaluation was performed by determination of minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) following Clinical and Laboratory Standards Institute guidelines (CLSI M11). The antibiofilm was evaluated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and crystal violet (CV) assays. Data were analyzed statistically considering a significant level of ( α ≤ 0.05).
Results
It was found that the MIC and MBC values of the tested intracanal medications ranged from 1.95–500 mg/mL. MTT and CV assays showed significant, species-dependent antibiofilm activity. CHX was most effective against F. nucleatum ; NAC-based medications, especially combined with Ca(OH) 2 and/or CHX, were superior against P. endodontalis, P. intermedia , and P. micra . Ca(OH) 2 -containing groups were particularly effective against P. gingivalis . Therefore, NAC + Ca(OH) 2 and NAC + Ca(OH) 2 + CHX can be considered as effective combinations of intracanal medication against different obligate anaerobic bacteria.