Curing Efficiency and Temperature Increasement Produced by Photo-activation Devices

Objectives: Asses the curing efficiency and the temperature increasement produced by curing units during the photo-activation of the composite, Filtek™Z250 (3M ESPE) and Filtek™Z350 (3M ESPE). The emission spectrum and power of the curing units were tested. The curing units used were a halogen lamp Optilux 401 (Demetron) and three light emitting diode devices (LED), LEDemetron I (Kerr), Bluephase (Ivoclar Vivadent) and Elipar Freelight (3M ESPE).

Methods: The curing efficiency was evaluated by Vickers hardness, the specimens prepared in steal mold, which it was filled with the composite, and stored during 24 hours. Using a thermocouple type-K, placed under a dentin disk with 0,5 mm thickness, it was observed the temperature increasement produced by the four devices was measured during the photo-activation of the adhesive system and of an increment of 2 mm of thickness of composite, which were activated for 20 and 40 seconds, respectively. The results of Vickers hardness and of temperature increasement were submitted to the statistical analysis ANOVA 2 way and post test Bonferroni with 5% significance.

Results: the four units curing devices did not present statistical differences in the superficial hardness oh the Filtek™Z250 (3M ESPE). For the composite Filtek™Z350 (3M ESPE), the unit curing Elipar Freelight (3M ESPE) with less light intensity produced statistical lower hardness (p < 0,05). The composite Filtek™Z250 (3M ESPE) presented higher hardness than resin Filtek™Z350 (3M ESPE) (p < 0,05). The unit curing Bluephase (Ivoclar Vivadent) with higher light intensity (1229 mW/cm2) and Optilux 401 (Demetron) (661 mW/cm2) emitted the same temperature increasement statistically, reaching (17,6°C), during the photo-activation of the adhesive system. The lower value of temperature increase was registered for the unit curing Elipar Freelight (3M ESPE) in the composite (3,1°C) (p < 0,05).

Conclusion: device light emitting diode with high light intensity produced high temperature increseament.