Increases in intrapulpal temperature during polymerization of composite resin.
BACKGROUND
The polymerization of dental composite resins can generate increases in intrapulpal temperature that may damage the pulp. The development of new polymerization devices such as the argon laser makes the assessment of these temperatures important.


OBJECTIVE
This study compared increases in temperature generated by argon laser and halogen light when polymerizing a bonding system and a composite resin, and also sought to determine whether both types of polymerization lights generate temperature increases below the safe limit of 5.5 degrees C.


METHODS
Thermocouples linked to a temperature reading system were positioned in the pulp chamber of 10 extracted bovine incisors. Class V cavities were prepared, etched, and filled with a 1-bottle bonding system (Single Bond) and composite resin (Z-100). The test groups were as follows (n = 5 for all groups): halogen light for bonding system (HB); halogen light for composite resin (HC); argon laser for bonding system (LB), and argon laser for composite resin (LC). The polymerization parameters were halogen light operated at 600 mW/cm2 for 40 seconds, which served as control, and argon laser operated at 200 mW for 10 seconds. Data were analyzed by a 2-way (light versus material) analysis of variance (ANOVA) (alpha = .05).


RESULTS
The average temperature increases were 2.35 degrees C (HB), 2.69 degrees C (HC), 1.25 degrees C (LB), and 1.5 degrees C (LC). Significant differences between halogen light and argon laser (P = .002), but not between composite and bonding system, were demonstrated.


CONCLUSIONS
The argon laser produced significantly lower increases in pulpal temperature than the halogen light, independent of the thickness of the polymerized material.
Martins
Giovana Ribeiro
GR
School of Dentistry, Ibirapuera University, Sao Paulo, SP, Brazil.
Cavalcanti
Bruno Neves
BN
Rode
Sigmar Mello
SM
D000704:Analysis of Variance; D000818:Animals; D001128:Argon; D017438:Bisphenol A-Glycidyl Methacrylate / Q000528:radiation effects; D001831:Body Temperature; D002417:Cattle; D003188:Composite Resins / Q000528:radiation effects*; D003748:Dental Equipment; D003782:Dental Pulp / Q000502:physiology*; D003793:Dental Restoration, Permanent; D006219:Halogens; D007834:Lasers; D008027:Light; D044367:Phase Transition; D019279:Resin Cements / Q000528:radiation effects; D012822:Silicon Dioxide / Q000528:radiation effects; D015040:Zirconium / Q000528:radiation effects
D003188:Composite Resins; D006219:Halogens; D019279:Resin Cements; C083568:Z100 composite resin; C115612:single bond; D017438:Bisphenol A-Glycidyl Methacrylate; D001128:Argon; D012822:Silicon Dioxide; D015040:Zirconium