title: Thermoplastic properties of endodontic gutta-percha: a thermographic in vitro study.
abstract: BACKGROUND
  Endodontic gutta-percha undergoes deformation at temperatures above 65°C. The temperature influence of heat carriers on gutta-percha cones was investigated in vitro.
  
  
  METHODS
  Six single-rooted extracted teeth were embedded in resin and fixed. The root canals were prepared (ProFile; Dentsply Maillefer, Ballaiques, Switzerland) to different tapers and bisected. Thermographic images when heating the gutta-percha cones (Roeko, Langenau, Germany) with a heat carrier (ML .12; SybronEndo, Orange, CA) at 1 and 5 mm from the working length were made with an infrared thermal imaging camera (ThermaCam P640; Flir Systems, Täby, Sweden). The device temperature was preset at 200°C. The pixel temperature registered at the contact lines between the heat carriers and gutta-percha cones in the thermographic images was recorded and statistically described.
  
  
  RESULTS
  A mean temperature (°C) instability in the heat carrier (324.96 ± 46.10, minimum = 147.35, maximum = 474.13), a temperature drop of the gutta-percha cones (159.52, ± 37.57, min 67.64, max 259.04) at the measuring level, and a mean temperature penetration depth (mm) equal or to higher than 65°C (1.05 ± 0.28, minimum = 0.20, maximum = 1.30) were recorded. No correlation between the penetration depth into the gutta-percha cones and applied temperatures, regardless of the size and/or taper, could be established.
  
  
  CONCLUSIONS
  Temperature discrepancies between the device preset and achieved ones of the heat carriers was observed. Gutta-percha is a poor thermal conductor, transports heat irregularly, and should be heated 1-2 mm from the target area.
authors.affiliation: Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany.
authors.forename: Benjamín
authors.initials: B
authors.lastname: Briseño Marroquín
authors.affiliation: Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany. Electronic address: thomaswolf@uni-mainz.de.
authors.forename: Thomas Gerhard
authors.initials: TG
authors.lastname: Wolf
authors.affiliation: Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany.
authors.forename: Dennis
authors.initials: D
authors.lastname: Schürger
authors.affiliation: Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany.
authors.forename: Brita
authors.initials: B
authors.lastname: Willershausen
mesh_terms: D006171:Gutta-Percha / Q000737:chemistry*; D006358:Hot Temperature; D006801:Humans; D066298:In Vitro Techniques; D007180:Incisor; D008422:Materials Testing; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation; D013499:Surface Properties; D013814:Thermal Conductivity; D013817:Thermography / Q000379:methods*; D014092:Tooth Root
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha
keywords: Gutta-percha; infrared thermography; material property; thermoplastic