title: Investigation of the effect of sealer use on the heat generated at the external root surface during root canal obturation using warm vertical compaction technique with System B heat source.
abstract: BACKGROUND
  During warm vertical compaction of gutta-percha, root canal sealers with different chemical compositions absorb the heat generated inside the root canal. The aim of this research was to assess physicochemical modifications of sealers subjected to the System B heat source (Analytic Technology, Redmond, WA) and to evaluate the effect that the use of different sealers has on the heat transfer to the external root surface.
  
  
  METHODS
  Three proprietary brand sealers (AH Plus [Dentsply International, Addlestone, UK], Pulp Canal Sealer [Kerr Corporation, Orange, CA], MTA Fillapex [Angelus Dental Solutions, Londrina, PR, Brazil]) and a prototype sealer based on Portland cement were assessed. The heat generated on the surfaces of System pluggers and the heat dissipation at different levels (apical, midroot, and cervical) over root surface while using different sealers was assessed using thermocouples. Data were collected in 3 different environmental conditions with the tooth suspended in air, immersed in Hank's balanced salt solution, or gelatinized Hank's balanced salt solution. Chemical changes in the sealers induced by the heat were monitored by Fourier transform infrared spectroscopy. The effect of heat changes on the setting time and compressive strength of the sealers was also assessed.
  
  
  RESULTS
  The continuous wave plugger sustained a rise in temperature at a maximum of 80°C at the instrument shank. The highest change in temperature on the external root surface was recorded after 1.5 minutes from the start of heating, and it was restored to body temperature by 6 minutes. Environmental conditions affected heat dissipation for all the sealers in the midroot and cervical regions and the highest increase in temperature (∼60°C) recorded in air. In the midroot and cervical regions, the type of sealer used did not affect the rise in temperature. In the apical region, AH Plus obturations resulted in a greater rise in temperature, and the chemical composition of this sealer was affected by high temperature; it also induced a reduction in sealer setting time and strength.
  
  
  CONCLUSIONS
  It could be concluded that surrounding conditions, such as temperature and humidity, exerted influence on heating dissipation during the continuous wave of the condensation obturation technique and that root canal sealers presented different conductive/isolating properties. Furthermore, the physical and chemical properties of AH Plus were negatively affected by the changes in temperature.
authors.affiliation: Department of Restorative Dentistry, Araraquara Dental School, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Raqueli
authors.initials: R
authors.lastname: Viapiana
authors.affiliation: Department of Restorative Dentistry, Araraquara Dental School, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Juliane Maria
authors.initials: JM
authors.lastname: Guerreiro-Tanomaru
authors.affiliation: Department of Restorative Dentistry, Araraquara Dental School, São Paulo State University (UNESP), Araraquara, São Paulo, Brazil.
authors.forename: Mario
authors.initials: M
authors.lastname: Tanomaru-Filho
authors.affiliation: Department of Restorative Dentistry, Faculty of Dental Surgery, University of Malta, Malta. Electronic address: josette.camilleri@um.edu.mt.
authors.forename: Josette
authors.initials: J
authors.lastname: Camilleri
mesh_terms: D000388:Air; D017607:Aluminum Compounds / Q000737:chemistry / Q000627:therapeutic use; D001831:Body Temperature / Q000502:physiology*; D017610:Calcium Compounds / Q000737:chemistry / Q000627:therapeutic use; D019245:Compressive Strength; D003786:Dental Pulp Cavity / Q000502:physiology; D004338:Drug Combinations; D004735:Energy Transfer; D004853:Epoxy Resins / Q000737:chemistry / Q000627:therapeutic use; D006171:Gutta-Percha / Q000737:chemistry / Q000627:therapeutic use; D006358:Hot Temperature; D006801:Humans; D007552:Isotonic Solutions; D008422:Materials Testing; D010087:Oxides / Q000737:chemistry / Q000627:therapeutic use; D012387:Root Canal Filling Materials / Q000737:chemistry / Q000627:therapeutic use*; D012389:Root Canal Obturation / Q000295:instrumentation / Q000379:methods*; D017640:Silicates / Q000737:chemistry / Q000627:therapeutic use; D017550:Spectroscopy, Fourier Transform Infrared; D013821:Thermometers; D013997:Time Factors; D019227:Tooth Apex / Q000502:physiology; D014092:Tooth Root / Q000502:physiology*; D014783:Viscosity; D015035:Zinc Oxide-Eugenol Cement / Q000737:chemistry / Q000627:therapeutic use
chemical_list: D017607:Aluminum Compounds; D017610:Calcium Compounds; D004338:Drug Combinations; D004853:Epoxy Resins; C072670:Hanks Balanced Salt Solution; D007552:Isotonic Solutions; D010087:Oxides; D012387:Root Canal Filling Materials; D017640:Silicates; D015035:Zinc Oxide-Eugenol Cement; C534916:epoxy resin-based root canal sealer; C086631:mineral trioxide aggregate; C076543:Kerr Pulp Canal Sealer; D006171:Gutta-Percha; C031293:calcium silicate
keywords: Characterization; System B; endodontics; physical properties; root canal obturation