title: Reaction exothermia of 2 relining resins for temporary crowns.
abstract: OBJECTIVE
  The aim of the study was to evaluate the reaction exothermia of 2 relining resins for temporary crowns. The resins used were Duralay, a methacrylate-based resin, and Protemp II, a bisacrylic resin.
  
  
  METHODS
  The coronal parts of an adult molar and of an impacted one were used. Abutments were obtained from the crowns, while the radicular part was sectioned in order to insert a thermocouple into the pulpal chamber. During the experiment the tooth with the polymerising resin was put into an oral cavity simulator to keep a constant temperature. The thermal increase during polymerisation of the 2 resins was recorded for 6 minutes at 5 seconds intervals and with 1 and 2.5 mm dentin thickness (n = 10). Data were statistically analysed by variance analysis with Scheffe test.
  
  
  RESULTS
  The intrapulpal thermal increase was significantly higher in relation to the type of resin (Duralay p < 0.0001), thickness (1 mm p < 0.0001) and type of dentin (young dentin p < 00001).
  
  
  CONCLUSIONS
  In order to protect the pulp, during the direct relining of a temporary crown, it is recommendable to choose the best combination among resin, type of dentin and its residual thickness, besides adequate cooling techniques.
authors.affiliation: Department of Surgical Sciences, University of Trieste, Trieste, Italy. l.bevilacqua@fmc.units.it
authors.forename: L
authors.initials: L
authors.lastname: Bevilacqua
authors.forename: M
authors.initials: M
authors.lastname: Biasotto
authors.forename: M
authors.initials: M
authors.lastname: Cadenaro
authors.forename: R
authors.initials: R
authors.lastname: Di Lenarda
authors.forename: E
authors.initials: E
authors.lastname: Dorigo
mesh_terms: D003188:Composite Resins; D003442:Crowns; D003794:Dental Restoration, Temporary; D006358:Hot Temperature; D006801:Humans
chemical_list: D003188:Composite Resins