Water sorption of CH3- and CF3-Bis-GMA based resins with additives

Objectives: to evaluate the effect of additives on the water sorption characteristics of bis-gma based copolymers and composites containing tegdma,ch3bis-gma or cf3bis-gma. material and methods: fifteen experimental copolymers and corresponding composites were prepared combining bis-gma and tegdma,ch3bis-gma or cf3bis-gma,with aldehyde or diketone (24 and 32 mol%) totaling 30 groups. for composites,barium aluminosilicate glass and pyrogenic silica was added to comonomer mixtures. photopolymerization was effected by 0.2 wt% each of camphorquinone and n,n-dimethyl-p-toluidine. specimen densities in dry and water saturated conditions were obtained by archimedes' method. water sorption and desorption were evaluated in a desorption-sorption-desorption cycle. water uptake (%wu),water desorption (%wd),equilibrium solubility (es; μg/mm3),swelling (f) and volume increase (%v) were calculated using appropriate equations. results: all resins with additives had increased %wu and es. tegdma-containing systems presented higher %wu,%wd,es,f and %v values,followed by resins based on ch3bis-gma and cf3bis-gma. conclusions: aldehyde and diketone led to increases in the water sorption characteristics of experimental resins.