Dureza knoop de resinas compostas em função do número relativo de radicais livres

The present study had the purpose of determining the relative number of free radicals of three composites with clear and dark colors. Intensities of irradiation were: 110, 180, 300, and 580 mW/cm2, for 10, 20, 30, 40, 50, 60, 80 and 90 seconds. Hardness was determined for the clear colors of the composites, using 110 and 300 mW/cm2 irradiation intensities, for 20, 40, 60, and 80 seconds, on front and deep surfaces, at the ages of 5 minutes, 1 hour, 1 day, 1 week, and 1 month. The conclusions were that: depending on the resin, clear colors present more free radicals; the number of free radicals increases with higher intensity and longer irradiation time; composite Z100 is much richer in free radicals than Silux Plus and Heliomolar RO; higher intensity of irradiation leads to increasing hardness; longer irradiation time increases hardness of Silux Plus and Heliomolar RO, but not that of Z100; hardness increases with age; in depth hardness is very low; Z100 is much harder than the other two resins; Z100 is less sensitive to irradiation intensity.