title: Temperature change within gutta-percha induced by the System-B Heat Source.
abstract: OBJECTIVE
  This study evaluated the temperature change within gutta-percha during the vertical compaction technique performed with a System-B Heat Source.
  
  
  METHODS
  Extracted human teeth were prepared and divided in two equal groups depending on the apex diameter (group 1: 0.20-0.25 mm and group 2: 0.30-0.35 mm). Teeth were root treated with a combination of step-back and coronal flaring instrumentation using Gates Glidden burs and hand stainless steel K- and H-files. Two thermocouples were connected to the outer surface of the root: the first one was placed 2 mm apically from cement-enamel junction (CEJ) (point C); and the second one 1.5 mm from the apex (point A). The instrumented canals were filled with size F gutta-percha cones. All teeth were then immersed in a thermostatic bath at a constant temperature of 37 degrees C and warm vertical compaction was performed using a System-B Heat Source. delta T values were recorded by means of a digital thermometer connected to the thermocouples.
  
  
  RESULTS
  Increments of temperature (delta T) recorded in point A revealed a mean value of 0.5 +/- 0.5 degree C for group 1 and 0.9 +/- 1.1 degrees C for group 2; delta T values recorded at point C gave a mean value of 4.1 +/- 1.7 degrees C for group 1 and 3.9 +/- 1.81 degrees C in group 2. No statistical difference was found between the groups, whilst a difference was present between the measurements at points A and C (P < 0.01).
  
  
  CONCLUSIONS
  The use of the System-B Heat Source on root canals maintained at a constant body temperature by a thermostatic bath revealed that the increase of temperature of the gutta-percha at the apical third of the canal was negligible and that the compaction of the mass of the gutta-percha close to the apex was performed at body temperature. Minor changes in temperature of the outer surface of the root canals occurred, suggesting no danger for the periradicular tissues.
authors.affiliation: Private Practice, Bologna, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Venturi
authors.forename: G
authors.initials: G
authors.lastname: Pasquantonio
authors.forename: M
authors.initials: M
authors.lastname: Falconi
authors.forename: L
authors.initials: L
authors.lastname: Breschi
mesh_terms: D000704:Analysis of Variance; D003786:Dental Pulp Cavity / Q000473:pathology; D006171:Gutta-Percha / Q000737:chemistry*; D006801:Humans; D012387:Root Canal Filling Materials / Q000737:chemistry*; D012389:Root Canal Obturation / Q000295:instrumentation / Q000379:methods*; D018915:Root Canal Preparation / Q000295:instrumentation / Q000379:methods; D018709:Statistics, Nonparametric; D013696:Temperature; D013821:Thermometers; D019227:Tooth Apex / Q000473:pathology
chemical_list: D012387:Root Canal Filling Materials; D006171:Gutta-Percha