title: Pulp chamber temperature rise during curing of resin-based composites with different light-curing units.
abstract: OBJECTIVE
  The purpose of the present study was to measure the intrapulpal temperature rise occurring during polymerisation of different shades of resin-based composites (RBCs), and two light-emitting diode (LED) units.
  
  
  METHODS
  Seventy non-carious permanent molars, that had been extracted for orthodontic purposes and stored in 2% thymol for not more than four months, were selected. Patient age range was 11-18 years. Standard cavity preparation with standardised remaining dentine thickness and placement of thermocouples (TCs) was prepared using a novel split-tooth technique. Cavities were filled with one of two shades of RBC (A2 and C4, Filtek Z250, 3M ESPE, Seefeld, Germany), and cured with two LED high-intensity units (Elipar Freelight2, 3M ESPE, Seefeld, Germany; Bluephase, Ivoclar Vivadent, Schaan, Liechtenstein) and a conventional halogen light-curing unit (LCU) (Prismetics Lite 2, Dentsply, Weybridge, Surrey, UK) as a control.
  
  
  RESULTS
  Pulp temperature rises during bonding [A2 results: H;2.67/0.48:E;5.24/1.32;B;5.99/1.61] were always greater than during RBC curing [A2 results: 2.44/0.63;E3.34/0.70;B3.38/0.60], and these were significant for both LED lights but not for the halogen control, irrespective of shade (Mann-Whitney test: 95% confidence limits). Temperature rises were at times in excess of the values normally quoted as causing irreversible pulp damage. Pulp temperature rises during bonding were higher with the LED lights than with the halogen control. There was no significant difference in temperature rise between the two LED lights when bonding but there was a significant difference between the two LED lights and the halogen control LCUs (Kruskal-Wallis Test: 95% confidence limits).
  
  
  CONCLUSIONS
  The results support the view that there is a potential risk for heat-induced pulpal injury when light-curing RBCs. The risk is greater during bonding and with high energy, as compared to low-energy output systems. As the extent of tolerable thermal trauma by the pulp tissues is unknown, care and consideration should be given to the choice of LCU and the exposure time when curing RBCs, and especially during bonding.
authors.forename: Kathryn
authors.initials: K
authors.lastname: Durey
authors.forename: Ario
authors.initials: A
authors.lastname: Santini
authors.forename: Vesna
authors.initials: V
authors.lastname: Miletic
mesh_terms: D000180:Acrylic Resins / Q000528:radiation effects / Q000627:therapeutic use*; D000293:Adolescent; D001831:Body Temperature / Q000528:radiation effects*; D002648:Child; D003188:Composite Resins / Q000528:radiation effects / Q000627:therapeutic use*; D016001:Confidence Intervals; D003786:Dental Pulp Cavity / Q000737:chemistry / Q000528:radiation effects*; D003793:Dental Restoration, Permanent / Q000379:methods*; D006219:Halogens; D006358:Hot Temperature; D006801:Humans; D008027:Light; D011140:Polyurethanes / Q000528:radiation effects / Q000627:therapeutic use*; D018709:Statistics, Nonparametric
chemical_list: D000180:Acrylic Resins; C029012:Composite Dental Resin; D003188:Composite Resins; D006219:Halogens; D011140:Polyurethanes