Effect of curing mode on polymerization kinetics, mechanical properties, and dentin adhesion of self-adhesive and conventional resin cements

Objectives The objective was to evaluate the effect of curing mode on polymerization kinetics, biaxial flexural strength (FS) and modulus (MO), and dentin bond strength (BS) of self-adhesive and conventional resin-based cements.Materials and methods Two materials were evaluated: one self-adhesive G-Cem LinkAce (GC) and one conventional resin cement RelyX Ultimate (RU). Polymerization kinetics was followed by infrared spectroscopy (n = 5). Disc specimens of light-activated or self-cured materials were tested for FS and MO (n = 10). Extracted human molars were divided into 4 groups (n = 10) according to resin cement, curing mode, and evaluation time (24 hs and 1 year). Composite discs were used to simulate indirect restoration which bonded to occlusal dentin with the resin cements, and light-activated or allowed to self-cure, and restored teeth were tested for microtensile BS. Data were submitted to statistical analysis at 5% significance level.Results A rapid rise in conversion was observed when materials were light-activated. When self-cured, RU demonstrated a slower polymerization rate and lower conversion than GC. Dual curing yielded higher FS, MO, and BS than self-curing mode to RU cement, while no significant differences were observed for GC.Conclusions Light-activation influences polymerization kinetics of resin-based cement, but it did not influence the mechanical properties and adhesion of the self-adhesive cement tested (GC).