Abstract: A mixing device for producing reduced porosity bone cement. The device having a movable member (6), preferably a movable piston, which is adapted to press out or discharge bone cement (2) from the mixing device (1). The piston is fixedly mounted in the mixing device. The piston maintains its position when bone cement (2) is mixed in a mixing space in the mixing device. The mixing device is under a vacuum during mixing. After mixing, the piston is released such that it can be drawn into the mixing device (1) toward a discharge opening (13) by a vacuum prevailing in the mixing device (1). The moving piston is used for collecting clumps of bone cement (2) in the mixing device (1) adjacent to the discharge opening (13). By collecting the clumps of bone cement by the moving piston (6) under a vacuum, the porosity of the bone cement (2) is reduced.

Abstract: A method for producing bone cement by mixing components forming part thereof, whereby mixing occurs in vacuum in a mixing device (1) and whereby ready-mixed bone cement (2) is collected in the mixing device (1) before it is ejected or discharged therefrom. For reducing the volume of porosity of the pores formed in the bone cement (2) during collection, the bone cement (2) is collected in vacuum to provide vacuum in those pores in the bone cement (2) which are formed during collection, whereby the volume of porosity in the bone cement (2) is reduced when the bone cement is subjected to atmospheric pressure after collection.

Abstract: A head guard, preferably annular brow-band, comprising a longitudinal, preferably annular unit (2) which completely or substantially is made of cellular plastic.

Abstract: The present invention relates to a method for producing bone cement for fixing protheses, whereby the bone cement is manufactured by mixing various substances with each other to provide a setting mass which in set condition is adapted to fix prostheses at surrounding bone tissue. In order to prevent large amounts of air from being stirring into the mixture, mixing of said various substances occurs under vacuum. The invention also relates to a device for carrying out the method for producing bone cement for fixing prostheses, whereby the bone cement is manufactured by mixing various substances with each other to provide a setting mass which in set condition is adapted to fix protheses at surrounding bone tissue, and whereby the mixture is applied to the bone tissue by means of a feed device (20) from which the mixture (19) may be pressed out.