title: Bactericidal Efficacy of Cold Plasma at Different Depths of Infected Root Canals In Vitro.
abstract: OBJECTIVE
  Cold plasma (CP) has been shown to be effective even against multiresistant microorganisms. As previous investigations on the effect of CP in root canals showed promising results, the aim of the present study was to analyze the bactericidal efficacy of CP in different depths of infected dentin.
  
  
  METHODS
  32 standardized root canals of human mandibular premolars were infected with Enterococcus faecalis and incubated for one week. Specimens were randomly selected for one of four disinfection methods: control (5mL NaCl), 5mL chlorhexidine (CHX), CP alone (CP), and a combination of 5mL CHX and cold plasma (CHX+CP). CHX was ultrasonically activated for 30s, while cold plasma was used for 60s in the root canals. Dentin samples at depths of 300, 500 and 800 µm were obtained and diluted serially. Colony forming units (CFUs) were counted on agar plates after 24h of incubation.
  
  
  RESULTS
  The highest overall logarithmic reduction factors (RF) were obtained from CHX+CP (log RF 3.56 p<0.01; Mann-Whitney U test), followed by CP (log RF 3.27 p<0.01) and CHX alone (log RF 2.65 p<0.01) related to the control. All disinfection methods showed significantly lower CFU counts compared to the control group in 300 µm and 800 µm (both p<0.01, Kruskal-Wallis test).
  
  
  CONCLUSIONS
  The adjuvant use of CP might be beneficial in highly infected root canals to improved disinfection. However, the disinfection effect against Enterococcus faecalis of CP is comparable to ultrasonically activated CHX.
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Sascha R
authors.initials: SR
authors.lastname: Herbst
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Oral Medicine, Dental Radiology and Oral Surgery, Germany.
authors.forename: Moritz
authors.initials: M
authors.lastname: Hertel
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Husam
authors.initials: H
authors.lastname: Ballout
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Philipp
authors.initials: P
authors.lastname: Pierdzioch
authors.affiliation: INP Greifswald, Leibniz Institute for Plasma Science and Technology, Greifswald, Germany.
authors.forename: Klaus-Dieter
authors.initials: KD
authors.lastname: Weltmann
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Henrik C
authors.initials: HC
authors.lastname: Wirtz
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Shady
authors.initials: S
authors.lastname: Abu-Sirhan
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Eckehard
authors.initials: E
authors.lastname: Kostka
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Sebastian
authors.initials: S
authors.lastname: Paris
authors.affiliation: Charité - Universitätsmedizin Berlin, Department of Operative and Preventive Dentistry, Germany.
authors.forename: Saskia
authors.initials: S
authors.lastname: Preissner
keywords: Cold plasma; Enterococcus faecalis; dentinal tubules; disinfection; penetration depth; tissue tolerable plasma.