title: Evaluation of triple antibiotic paste removal by different irrigation procedures.
abstract: BACKGROUND
  Regenerative endodontics aims to re-establish a functional pulp-dentin complex. First, the root canal system is disinfected primarily by irrigants and medicaments. Triple antibiotic paste (TAP), a commonly used intracanal medicament, has been shown to be directly toxic to stem cells at concentrations greater than 0.1 g/mL. Thus, its complete removal is a crucial step in regenerative endodontic procedures. We hypothesized that currently used irrigation techniques do not completely remove TAP from root canal system.
  
  
  METHODS
  TAP was radiolabeled by the incorporation of I(125), and calcium hydroxide (Ultracal; Ultradent, South Jordan, UT) was radiolabeled with Ca(45). The intracanal medicaments were placed into standardized human root segments and incubated for 28 days at 37°C. Then, canals were irrigated with EndoActivator (Dentsply, Tulsa, OK), passive ultrasonic irrigation, EndoVac (SybronEndo, Coppell, TX), or a syringe/Max-i-Probe needle (Dentsply Rinn, Elgin, IL) using a standardized irrigation protocol in a closed system. Radioactivity levels (counts per minute values) were measured for each tooth before and after the irrigation protocols. Furthermore, the canals were sequentially enlarged and dentin samples collected and evaluated for radioactivity. Data were analyzed with analysis of variance and Bonferroni post hoc testing (P < .05).
  
  
  RESULTS
  Approximately 88% of the TAP was retained in the root canal system regardless of the irrigation technique used (no difference among groups). Furthermore, approximately 50% of the radiolabeled TAP was present circumferentially up to 350 μm within the dentin. Conversely, up to 98% of the radiolabeled intracanal calcium hydroxide was removed, and most residual medicament was found present in the initial 50 μm of dentin.
  
  
  CONCLUSIONS
  Current irrigation techniques do not effectively remove TAP from root canal systems, possibly because of its penetration and binding into dentin. However, calcium hydroxide is effectively removed with significant less residual presence.
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors: Julie A
authors: JA
authors: Berkhoff
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors: Paul B
authors: PB
authors: Chen
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas.
authors: Fabricio B
authors: FB
authors: Teixeira
authors: Department of Endodontics, University of Texas Health Science Center at San Antonio, San Antonio, Texas. Electronic address: Diogenes@uthscsa.edu.
authors: Anibal
authors: A
authors: Diogenes
mesh_terms: D000900:Anti-Bacterial Agents / Q000737:chemistry*; D002126:Calcium Hydroxide / Q000737:chemistry; D002132:Calcium Radioisotopes; D002939:Ciprofloxacin / Q000737:chemistry; D003786:Dental Pulp Cavity / Q000033:anatomy & histology*; D003804:Dentin / Q000033:anatomy & histology; D004867:Equipment Design; D006801:Humans; D007457:Iodine Radioisotopes; D008795:Metronidazole / Q000737:chemistry; D008911:Minocycline / Q000737:chemistry; D009339:Needles; D012388:Root Canal Irrigants / Q000737:chemistry*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods*; D013594:Syringes; D007507:Therapeutic Irrigation / Q000295:instrumentation / Q000379:methods*; D019227:Tooth Apex / Q000033:anatomy & histology; D000069453:Ultrasonic Waves
chemical_list: D000900:Anti-Bacterial Agents; D002132:Calcium Radioisotopes; D007457:Iodine Radioisotopes; D012388:Root Canal Irrigants; D008795:Metronidazole; D002939:Ciprofloxacin; D008911:Minocycline; D002126:Calcium Hydroxide
keywords: Calcium hydroxide, Ca(OH)(2), endodontics, irrigation, isotope, regenerative, TAP, triple antibiotic paste