title: Evaluation of Cold Plasma Treatment and Safety in Disinfecting 3-week Root Canal Enterococcus faecalis Biofilm In Vitro.
abstract: BACKGROUND
  Although endodontic infection is caused by multi-bacteria species, Enterococcus faecalis is usually isolated in chronic apical periodontitis. The aim of this study was to evaluate the effectiveness and mechanical safety of cold plasma therapy in disinfecting 3-week E. faecalis biofilms.
  
  
  METHODS
  Teeth with 3-week E. faecalis biofilm were treated with AC argon/oxygen (Ar/O2) cold plasma for various treatment times and compared with those treated with Ca(OH)2, 2% chlorhexidine gel, and Ca(OH)2/chlorhexidine for a week. Antimicrobial efficacy was assessed by colony-forming unit method. Scanning electron microscopy was used to assess the morphologic changes of E. faecalis biofilm by plasma. Confocal laser scanning microscopy was used to confirm the viability of the biofilm after the plasma treatment. Microhardness and roughness changes of root canal dentin caused by plasma were verified with Vickers Hardness Tester and 3D Profile Measurement Laser Microscope, respectively.
  
  
  RESULTS
  There were no detectable live bacteria after 12 minutes of cold plasma treatment. This was further confirmed by scanning electron microscopy and confocal laser scanning microscopy results. Microhardness and roughness of root canal dentin showed no significant difference after plasma treatment.
  
  
  CONCLUSIONS
  Atmospheric pressure cold plasma is an effective therapy in endodontics for its strong sterilization effect on fully matured biofilm within a few minutes. Meanwhile, it has an accepted mechanical safety for its low temperature and not affecting the microhardness and roughness of root canal dentin significantly.
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Yinglong
authors.initials: Y
authors.lastname: Li
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Sun
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Guopin
authors.initials: G
authors.lastname: Ye
authors.affiliation: College of Engineering, Peking University, Beijing, China.
authors.forename: Yongdong
authors.initials: Y
authors.lastname: Liang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Pan
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China.
authors.forename: Guomin
authors.initials: G
authors.lastname: Wang
authors.affiliation: National Engineering Laboratory for Digital and Material Technology of Stomatology, Beijing, China.
authors.forename: Yijiao
authors.initials: Y
authors.lastname: Zhao
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; Department of General Dentistry, Peking University School and Hospital of Stomatology, Beijing, China. Electronic address: panjie72@sina.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Pan
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; College of Engineering, Peking University, Beijing, China.
authors.forename: Jue
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China; College of Engineering, Peking University, Beijing, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Fang
mesh_terms: D000900:Anti-Bacterial Agents / Q000009:adverse effects / Q000627:therapeutic use; D001128:Argon / Q000627:therapeutic use; D018441:Biofilms / Q000187:drug effects*; D003786:Dental Pulp Cavity / Q000382:microbiology* / Q000503:physiopathology / Q000648:ultrastructure; D003804:Dentin / Q000648:ultrastructure; D013293:Enterococcus faecalis / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure; D016908:Gram-Positive Bacterial Infections / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D006244:Hardness; D006801:Humans; D021621:Imaging, Three-Dimensional; D018613:Microscopy, Confocal; D008855:Microscopy, Electron, Scanning; D010100:Oxygen / Q000627:therapeutic use; D058626:Plasma Gases / Q000009:adverse effects / Q000627:therapeutic use*; D011671:Pulpitis / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D012390:Root Canal Therapy / Q000379:methods; D013997:Time Factors
chemical_list: D000900:Anti-Bacterial Agents; D058626:Plasma Gases; D001128:Argon; D010100:Oxygen
keywords: Cold plasma; Enterococcus faecalis biofilm; mechanical safety; microhardness; roughness