title: Bimix antimicrobial scaffolds for regenerative endodontics.
abstract: BACKGROUND
  Eliminating and/or inhibiting bacterial growth within the root canal system has been shown to play a key role in the regenerative outcome. The aim of this study was to synthesize and determine in vitro both the antimicrobial effectiveness and cytocompatibility of bimix antibiotic-containing polydioxanone-based polymer scaffolds.
  
  
  METHODS
  Antibiotic-containing (metronidazole [MET] and ciprofloxacin [CIP]) polymer solutions (distinct antibiotic weight ratios) were spun into fibers as a potential mimic to the double antibiotic paste (DAP, a MET/CIP mixture). Fiber morphology, chemical characteristics, and tensile strength were evaluated by scanning electron microscopy, Fourier transform infrared spectroscopy, and tensile testing, respectively. Antimicrobial efficacy was tested over time (aliquot collection) against Enterococcus faecalis (Ef), Porphyromonas gingivalis (Pg), and Fusobacterium nucleatum (Fn). Similarly, cytotoxicity was evaluated in human dental pulp stem cells. Data were statistically analyzed (P < .05).
  
  
  RESULTS
  Scanning electron microscopy and Fourier transform infrared spectroscopy confirmed that electrospinning was able to produce antibiotic-containing fibers with a diameter mostly in the nanoscale. The tensile strength of 1:1MET/CIP scaffolds was significantly (P < .05) higher than pure polydioxanone (control). Meanwhile, all other groups presented similar strength as the control. Aliquots obtained from antibiotic-containing scaffolds inhibited the growth of Ef, Pg, and Fn, except pure MET, which did not show an inhibitory action toward Pg or Fn. Antibiotic-containing aliquots promoted slight human dental pulp stem cell viability reduction, but none of them were considered to be cytotoxic.
  
  
  CONCLUSIONS
  Our data suggest that the incorporation of multiple antibiotics within a nanofibrous scaffold holds great potential toward the development of a drug delivery system for regenerative endodontics.
authors.affiliation: Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana; Department of Endodontics Indiana University School of Dentistry (IUSD), Indianapolis, Indiana.
authors.forename: Jadesada
authors.initials: J
authors.lastname: Palasuk
authors.affiliation: Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana.
authors.forename: Krzysztof
authors.initials: K
authors.lastname: Kamocki
authors.affiliation: Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana.
authors.forename: Lauren
authors.initials: L
authors.lastname: Hippenmeyer
authors.affiliation: Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana.
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Platt
authors.affiliation: Department of Oral Biology, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana.
authors.forename: Kenneth J
authors.initials: KJ
authors.lastname: Spolnik
authors.affiliation: Department of Restorative Dentistry, Faculty of Dentistry, Naresuan University, Phitsanulok, Thailand.
authors.forename: Richard L
authors.initials: RL
authors.lastname: Gregory
authors.affiliation: Department of Restorative Dentistry, Division of Dental Biomaterials, Indiana University School of Dentistry (IUSD), Indianapolis, Indiana. Electronic address: mbottino@iu.edu.
authors.forename: Marco C
authors.initials: MC
authors.lastname: Bottino
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology; D002470:Cell Survival / Q000187:drug effects; D002939:Ciprofloxacin / Q000737:chemistry / Q000494:pharmacology; D003782:Dental Pulp / Q000166:cytology / Q000187:drug effects; D055664:Electrochemical Techniques; D013293:Enterococcus faecalis / Q000187:drug effects; D016967:Fusobacterium nucleatum / Q000187:drug effects; D006801:Humans; D008422:Materials Testing; D008795:Metronidazole / Q000737:chemistry / Q000494:pharmacology; D008855:Microscopy, Electron, Scanning; D057139:Nanofibers / Q000737:chemistry; D016687:Polydioxanone / Q000737:chemistry*; D016966:Porphyromonas gingivalis / Q000187:drug effects; D012038:Regeneration; D012390:Root Canal Therapy / Q000295:instrumentation*; D017550:Spectroscopy, Fourier Transform Infrared; D013234:Stem Cells / Q000187:drug effects; D013499:Surface Properties; D013718:Tensile Strength; D023822:Tissue Engineering / Q000379:methods; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D000900:Anti-Bacterial Agents; D008795:Metronidazole; D016687:Polydioxanone; D002939:Ciprofloxacin
keywords: Antibiotic; bacteria; disinfection; electrospinning; nanofibers; pulp; regeneration; root canal; scaffold; stem cells