title: Photodynamic Inactivation of Actinomyces naeslundii in Comparison With Chlorhexidine and Polyhexanide--A New Approach for Antiseptic Treatment of Medication-Related Osteonecrosis of the Jaw?
abstract: OBJECTIVE
  Local antimicrobial therapy is a fundamental principle in the treatment of lesions of medication-related osteonecrosis of the jaw. Antimicrobial photodynamic therapy (aPDT) as a local application for the treatment of microbial infections has become more widely used in recent years. In the mouth, the bone surface is in constant contact with saliva and thus cannot be kept sterile, making the development of strategies for disinfection even more important. Different methods currently in use include local rinses with chlorhexidine (CHX), polyhexanide (PHX), or aPDT. This study compared the efficiency of these 3 methods.
  
  
  METHODS
  The in vitro activity of 3 different agents against slowly growing Actinomyces naeslundii isolated from a patient with osteonecrosis was evaluated. PHX 0.04% solution, CHX 0.12% solution, and methylene blue (MB) based dye with a laser light of 660-nm wavelength (aPDT) were compared.
  
  
  RESULTS
  The decrease in colony-forming units by each method was measured using an in vitro killing assay based on a water-exposed surface in a well plate. MB dye with laser (10 seconds) decreased the bacterial load by more than 4 orders of magnitude and was superior to PHX and CHX exposure for 60 seconds.
  
  
  CONCLUSIONS
  Laser exposure alone and MB dye exposure alone decreased bacterial loads slightly, but less efficiently than 60-second exposure to PHX or CHX. The most effective means of decreasing colony-forming units was achieved by a combination of laser light and dye, which also can be used clinically.
authors.affiliation: Senior Resident, Department of Oral and Maxillofacial Surgery, University of Munich (LMU), Munich, Germany.
authors.forename: Sigurd
authors.initials: S
authors.lastname: Hafner
authors.affiliation: Professor and Department Head, Department of Oral and Maxillofacial Surgery, University of Munich (LMU), Munich, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Ehrenfeld
authors.affiliation: Scientific Assistant, Department of Bacteriology, Max von Pettenkofer Institute (LMU), Munich, Germany.
authors.forename: Enno
authors.initials: E
authors.lastname: Storz
authors.affiliation: Senior Resident, Division of Infectious Diseases and Tropical Medicine, Medical Center of the University of Munich (LMU), Munich; Department of Bacteriology, Max von Pettenkofer Institute (LMU), Munich; German Center for Infection Research (DZIF), Munich, Germany; College of Public Health and Medical Science, Jimma University, Jimma, Ethiopia. Electronic address: wieser@mvp.uni-muenchen.de.
authors.forename: Andreas
authors.initials: A
authors.lastname: Wieser
mesh_terms: D000190:Actinomyces / Q000187:drug effects*; D000891:Anti-Infective Agents, Local / Q000494:pharmacology*; D058491:Bacterial Load / Q000187:drug effects; D001645:Biguanides / Q000494:pharmacology*; D059266:Bisphosphonate-Associated Osteonecrosis of the Jaw / Q000382:microbiology*; D002710:Chlorhexidine / Q000494:pharmacology*; D005456:Fluorescent Dyes; D006801:Humans; D054023:Lasers, Semiconductor / Q000627:therapeutic use; D008751:Methylene Blue / Q000627:therapeutic use; D050296:Microbial Viability / Q000187:drug effects; D010778:Photochemotherapy / Q000379:methods*; D017319:Photosensitizing Agents / Q000627:therapeutic use
chemical_list: D000891:Anti-Infective Agents, Local; D001645:Biguanides; D005456:Fluorescent Dyes; D017319:Photosensitizing Agents; C031233:polihexanide; D002710:Chlorhexidine; D008751:Methylene Blue