title: Effect of dentin conditioning with intracanal medicaments on survival of stem cells of apical papilla.
abstract: BACKGROUND
  Regenerative endodontics is a valuable treatment modality for immature teeth with pulpal necrosis. A common feature in regenerative cases is the use of intracanal medicaments. Although these medicaments are chosen because of their antibacterial properties, their enduring effect on dentin (conditioning) and the subsequent impact on stem cell survival has never been evaluated. In this study, we hypothesized that triple antibiotic paste (TAP), double antibiotic paste (DAP), or Ca(OH)2 has an indirect adverse effect on the survival of stem cells of apical papilla (SCAP) by dentin conditioning.
  
  
  METHODS
  Human dentin disks were created with a standardized root canal diameter of 3.2 mm. The disks were then exposed to either TAP or DAP (at concentrations of 1 mg/mL or 1000 mg/mL), Ca(OH)2 (Ultracal), or Hank's balanced salt solution for 7 or 28 days. Next, the medicaments were removed with copious irrigation, followed by placement of SCAP in a Matrigel scaffold in the lumen of the disks. The bioengineered constructs were cultured for 7 days, followed by determination of cellular viability by using the CellTiter-Glo luminescence assay. Data were analyzed using 1-way analysis of variance with Bonferroni post hoc test.
  
  
  RESULTS
  Exposure of dentin to TAP or DAP at 1000 mg/mL resulted in no viable SCAP, whereas the use of these medicaments at 1 mg/mL had no adverse effect on cell viability. In contrast, Ca(OH)2 treatment significantly increased SCAP survival and proliferation when compared with the control group.
  
  
  CONCLUSIONS
  Dentin conditioning with TAP and DAP at commonly used clinical concentration (approximately 1000 mg/mL) alters dentin in such a way as to prevent SCAP survival. This lethal indirect effect of both TAP and DAP can be largely avoided if these medicaments are used at the 1 mg/mL concentration. Conversely, dentin conditioning with Ca(OH)2 promotes SCAP survival and proliferation.
authors.affiliation: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Riyadh I
authors.initials: RI
authors.lastname: Althumairy
authors.affiliation: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors.forename: Fabricio B
authors.initials: FB
authors.lastname: Teixeira
authors.affiliation: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas. Electronic address: Diogenes@uthscsa.edu.
authors.forename: Anibal
authors.initials: A
authors.lastname: Diogenes
mesh_terms: D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001672:Biocompatible Materials / Q000737:chemistry; D002126:Calcium Hydroxide / Q000494:pharmacology; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D002939:Ciprofloxacin / Q000008:administration & dosage / Q000494:pharmacology; D003094:Collagen / Q000737:chemistry; D003804:Dentin / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D006801:Humans; D007552:Isotonic Solutions; D007797:Laminin / Q000737:chemistry; D008795:Metronidazole / Q000008:administration & dosage / Q000494:pharmacology; D008911:Minocycline / Q000008:administration & dosage / Q000494:pharmacology; D010486:Periapical Tissue / Q000166:cytology* / Q000187:drug effects; D011509:Proteoglycans / Q000737:chemistry; D012388:Root Canal Irrigants / Q000008:administration & dosage / Q000494:pharmacology*; D013234:Stem Cells / Q000187:drug effects*; D013997:Time Factors; D054457:Tissue Scaffolds / Q000737:chemistry
chemical_list: D000900:Anti-Bacterial Agents; D001672:Biocompatible Materials; D004338:Drug Combinations; C072670:Hanks Balanced Salt Solution; D007552:Isotonic Solutions; D007797:Laminin; D011509:Proteoglycans; D012388:Root Canal Irrigants; C059485:matrigel; D008795:Metronidazole; D002939:Ciprofloxacin; D003094:Collagen; D008911:Minocycline; D002126:Calcium Hydroxide
keywords: Dentin; double antibiotic paste; endodontics; regenerative; stem cells; toxicity; triple antibiotic paste