title: Intracanal temperature rise evaluation during the usage of the System B: replication of intracanal anatomy.
abstract: OBJECTIVE
  To evaluate and determine intracanal temperature rises at 2 and 4 mm from the working length (WL) necessary to obtain proper replication of intracanal anatomy with gutta-percha (GP) using the System B heat source during vertical condensation.
  
  
  METHODS
  A split-tooth model was prepared and artificial shallow depressions were cut in the buccal canal wall 2 and 4 mm from the WL. At the same level on the palatal wall holes were drilled to adapt two thermocouples. The canal was filled using GP in a vertical condensation technique by placing the System B plugger at 2 and 4 mm from the WL in groups A and B, respectively. Two control groups in which no GP was used were carried out placing the plugger 2 and 4 mm from the WL (groups A.c and B.c, respectively) and activating the heat source. Recording of temperature rise was carried out during the filling procedure for groups A and B and during activation for control groups A.c and B.c; the highest temperatures were recorded. After each filling was completed, 3 min were allowed for the GP to cool and the model divided to reveal the filling. Images of the GP were taken with a CCD camera to evaluate the presence of replication of artificial round depressions. In control groups, the temperature was recorded for 20 s after a 3 s activation of the heat source. The rise in temperature was compared between the groups individually at each level (2 or 4 mm) and statistically analysed using one-way anova and Fisher PLSD tests at 5% of significance level (P < 0.05).
  
  
  RESULTS
  Mean temperature rises of 14 +/- 3 and 12 +/- 2 degrees C at 2 and 4 mm from the WL, respectively, were observed in group A fillings, and 4 +/- 1 and 6 +/- 1 degrees C at 2 and 4 mm, respectively, in group B fillings. Recordings at 2 mm showed significantly (P < 0.05) higher temperature rises with group A.c when compared with groups B and B.c. Replication of intracanal anatomy with GP was always found in group A fillings at both levels but only 4 mm from the WL in group B fillings.
  
  
  CONCLUSIONS
  Positioning the plugger close to WL and a temperature rise of 6 degrees C were necessary to obtain replication of intracanal anatomy. A mean temperature rise of 4 degrees C at 2 mm from WL (group B) resulted in no replication of intracanal anatomy. Further studies simulating clinical conditions are necessary.
authors.affiliation: Division of Pulp Biology and Endodontics, Graduate School, Tokyo Medical and Dental University, Tokyo, Japan. camilo.endo@tmd.ac.jp
authors.forename: J C
authors.initials: JC
authors.lastname: Villegas
authors.forename: T
authors.initials: T
authors.lastname: Yoshioka
authors.forename: Ch
authors.initials: Ch
authors.lastname: Kobayashi
authors.forename: H
authors.initials: H
authors.lastname: Suda
mesh_terms: D000704:Analysis of Variance; D001831:Body Temperature; D003786:Dental Pulp Cavity; D006171:Gutta-Percha; D006358:Hot Temperature; D006801:Humans; D007180:Incisor; D012389:Root Canal Obturation / Q000379:methods*
chemical_list: D006171:Gutta-Percha