Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)To evaluate physical-chemical properties of experimental diacetate chlorhexidine (CHX)-added resin blends. Methods: Blends were formulated: G1) TEGDMA; G2) TEGDMA/0.1% CHX; G3) TEGDMA/0.2% CHX; G4) TEGDMA/UDMA; G5) TEGDMA/UDMA/0.1% CHX; G6) TEGDMA/UDMA/0.2% CHX; G7) TEGDMA/BisEMA, G8) TEGDMA/BisEMA/0.1% CHX; G9) TEGDMA/BisEMA/0.2% CHX. Icon (R) was the control group. For sorption/solubility (SS), cylindrical specimens (n = 5) were prepared and their weight obtained. The specimens were immersed in deionized water for 7 days at 37 degrees C and their weight was verified again. SS were calculated using accepted formulas. For softening, cylindrical specimens (n = 10) were prepared and initial Knoop hardness number (KHN) obtained. The specimens were immersed in absolute ethanol for 24 h at 37 degrees C and final KHN accomplished. Softening values were calculated by KHN reduction percentage. For elastic modulus (EM) and flexural strength (FS) bar specimens were prepared (n = 10) and values obtained with a universal device (three point, 5 mm distance, 0.5 mm/min, load of 50 N). The data was analyzed using one-way ANOVA and Tukey test (alpha = 5%). Results: TEGDMA/BisEMA blends and Icon (R) showed the lowest sorption from blends (p > 0.05), and Icon (R) was the most soluble material (p < 0.01). TEGDMA/UDMA/0.1% CHX showed the highest softening, similar to Icon (R) (p > 0.05). For EM, all blends were different than Icon (R) (p < 0.01). For FS, TEGDMA blends were similar to Icon (R), showing the lowest averages (p > 0.05). Conclusions: Monomers chemical characteristics influenced the physical-chemical properties of experimental blends more than CHX. Between the blends tested, UDMA blends presented satisfactory results for assays evaluated. Clinical significance: Infiltrants CHX-added could arrest and reinforce initial caries lesions, and the antimicrobial effect could prevent new lesions in sound enamel adjacent to the infiltrated area. (C) 2016 Elsevier Ltd. All rights reserved.494045Sao Paulo State Research Foundation (FAPESP, Sao Paulo, SP, Brazil) [2011/22149-0]Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)