High molecular weight dimethacrylate systems within composite resins present a number of clinical deficiencies, including insufficient monomer conversion, polymerization shrinkage, and polymerization stresses. This study aimed to determine physical and chemical properties of a new high monomer conversion nanohybrid composite resin based on nano-dimer technology (N'Durance), compared to other principal products on the market. Specimens were polymerized using a visible light lamp following the manufacturers' instructions. Compressive and flexural strengths, flexural modulus, water sorption, and tensile strength were determined. Water absorption and solubility were measured. Monomer conversion, polymerization shrinkage, and polymerization stress were calculated. It was shown that products using conventional resin (Bis-GMA/TEGDMA) have an average conversion of 60% for the microhybrids and 50% for the nanofilled composites. The shrinkage stress and contraction with N'Durance are lower than most commercial products: shrinkage contraction was reduced from 2.3% (average of the regular composite) to 1.5%, and the shrinkage stress from 2.5% to 1.1%, with an increase of approximately 27% in the monomer conversion. For products that use conventional resin, volumetric shrinkage increases when the final double bond conversion is increased to reduce the unreacted monomers; however, N'Durance shows high conversion and low polymerization shrinkage.