Effect of light sources and curing mode techniques on sorption, solubility and biaxial flexural strength of a composite resin

adequate polymerization plays an important role on the longevity of the composite resin restorations. objectives: the aim of this study was to evaluate the effect of light-curing units, curing mode techniques and storage media on sorption, solubility and biaxial flexural strength (bfs) of a composite resin. material and methods: two hundred and forty specimens were made of one composite resin (esthet-x) in a stainless steel mold (2 mm x 8 mm ？), and divided into 24 groups (n=10) established according to the 4 study factors: light-curing units: quartz tungsten halogen (qth) lamp and light-emitting diodes (led); energy densities: 16 j/cm2 and 20 j/cm2; curing modes: conventional (cm) and pulse-delay (pd); and permeants: deionized water and 75% ethanol for 28 days. sorption and solubility tests were performed according to iso 4049:2000 specifications. all specimens were then tested for bfs according to astm f394-78 specification. data were analyzed by three-way anova followed by tukey, kruskal-wallis and mann-whitney tests (α=0.05). results: in general, no significant differences were found regarding sorption, solubility or bfs means for the light-curing units and curing modes (p>0.05). only led unit using 16 j/cm2 and pd using 10 s produced higher sorption and solubility values than qth. otherwise, using cm (16 j/cm2), led produced lower values of bfs than qth (p<0.05). 75% ethanol permeant produced higher values of sorption and solubility and lower values of bfs than water (p<0.05). conclusion: ethanol storage media produced more damage on composite resin than water. in general the led and qth curing units using 16 and 20 j/cm2 by cm and pd curing modes produced no influence on the sorption, solubility or bfs of the tested resin.