Stress reduction in resin-based composites cured with a two-step light-curing unit
Ernst, C.P.; Kürschner, R.; Rippin, G.; Willershausen, B.
American Journal of Dentistry 13(2): 69-72
2000
ISSN/ISBN: 0894-8275 PMID: 11764829 Document Number: 525414
To examine the stress reduction of different resin-based composites, cured with a two-step polymerization unit (Elipar Highlight) by means of a photoelastic investigation. For each material (Pertac II, Tetric Ceram, Charisma F, Solitaire, Dyract, Dyract AP, Definite), a minimum of 10 resin samples, embedded in acrylic-glass plates, were polymerized using a standard polymerization process of 700 mW/cm for 40 s. Another 10 samples were polymerized with a light output of 150 mW/cm2 for 10 s and then with a light output of 700 mW/cm2 for 30 s. For Pertac II the reduction of polymerization stress in the two-step-mode was 15.5%, for Tetric Ceram 14.5%, for Solitaire 8.1%, for Dyract AP 6.5% and for Definite 4.7%. These differences in polymerization stress between the standard and two-step-polymerization mode were statistically significant (P < 0.01, Wilcoxon test). No statistically significant differences in polymerization stress could be found for Charisma F and Dyract.