A hardenable multi part acrylic composition comprises a solid first part and a storage stable liquid second part and optionally further solid and/or liquid parts the parts being operable to form a cement which hardens to a solid mass upon mixing. The composition further comprises an acrylic monomer component in the second part an initiator component a first sub population of acrylic polymer particles in the first and/or further parts a second sub population of acrylic polymer particles in the first and/or further parts and optionally one or more further sub population(s) of acrylic polymer particles and a radiopacifying filler. The initiator component amount is effective to polymerize the acrylic monomer component upon mixing. At least some of the radiopacifying filler is encapsulated within and/or adsorbed on the first sub population of acrylic polymer particles and the second sub population of acrylic polymer particles has a lower average particle size than the first.
