Benjamín Briseño Marroquín1, Thomas Gerhard Wolf2, Dennis Schürger1, Brita Willershausen1. 1. Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany. 2. Department of Operative Dentistry, Johannes Gutenberg University Medical Center, Mainz, Germany. Electronic address: thomaswolf@uni-mainz.de.
Abstract
INTRODUCTION: 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.
INTRODUCTION: 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.