title: Comparison of two vertical condensation obturation techniques: Touch 'n Heat modified and System B.
abstract: OBJECTIVE
  The aims of this study were firstly to compare the area of canal occupied by gutta-percha, sealer or voids using the System B heating device with that obtained by a modified vertical condensation technique using the Touch 'n Heat: and secondly to compare the temperature changes at the root canal wall and external root surface during obturation with the above techniques.
  
  
  METHODS
  Forty-five resin blocks, each with a standardized, simulated, prepared main root canal and five lateral canals, were assigned to three equal experimental groups. The canals were obturated using either the System B technique at two different temperature settings, or vertical condensation with a Touch 'n Heat instrument as the heat source. A heat transfer model was used to simultaneously record internal and external root surface temperature elevations during obturation by the three techniques. Data were analysed using unpaired Student's t-test and Mann-Whitney U-test.
  
  
  RESULTS
  Both obturation techniques produced root fillings consisting of over 90% gutta-percha at most levels, although the percentages of sealer and voids 2-3 mm from the working length following System B obturation were higher than those found following modified vertical condensation. Modified vertical condensation resulted in more gutta-percha in lateral canals. Obturation was accomplished more quickly using the System B, and temperature elevations produced during obturation with the System B were significantly less (P < 0.001) than with vertical condensation. An elevation of external root surface temperature by more than 10 degrees C occurred during vertical condensation.
  
  
  CONCLUSIONS
  The results suggest that the System B may produce an acceptable obturation and that the use of a Touch 'n Heat source during vertical condensation may result in damage to the periodontium.
authors.affiliation: Department of Oral Rehabilitation, University of Otago School of Dentistry, Dunedin, New Zealand.
authors.forename: G K
authors.initials: GK
authors.lastname: Silver
authors.forename: R M
authors.initials: RM
authors.lastname: Love
authors.forename: D G
authors.initials: DG
authors.lastname: Purton
mesh_terms: D006171:Gutta-Percha; D006801:Humans; D003765:Models, Dental; D008961:Models, Structural; D016062:Porosity; D012387:Root Canal Filling Materials; D012389:Root Canal Obturation / Q000379:methods*; D018709:Statistics, Nonparametric; D013696:Temperature; D015035:Zinc Oxide-Eugenol Cement
chemical_list: D012387:Root Canal Filling Materials; D015035:Zinc Oxide-Eugenol Cement; C076543:Kerr Pulp Canal Sealer; D006171:Gutta-Percha