Abstract: Two-chamber cartridges for dispensing viscous pastes in which at least one of the chambers has a target break point that does not lie on the surface, of a common wall between the chambers.

Abstract: An apparatus for making a mold for forming positive models identical to a positive master has upper and lower mold shells having confronting and contiguous rims lying in respective planes. The shells are dimensioned when juxtaposed to spacedly contain the master. A clamp is engageable with the shells generally at the rims to hold the shells together with the plane of their rims spaced apart.

Abstract: The device for measuring the thickness of the mucous membrane in the region of the jawbone ridge consists of an evaluation instrument and a hand probe interconnected by a cable. The hand probe has a probe housing and an ultrasonic oscillator fitted therein on which are arranged a damping member on the back and a lead member on the front, in which the lead member forms a coupling surface for coupling to the mucous membrane and consists of a material with an acoustical impedance corresponding to 0.3 to 3 times the value and preferably 0.5 to 2.4 times the value of the acoustical impedance of water. A control electronic system and an evaluation electronic system, an electric power supply and a display unit are fitted in the evaluation instrument.

Abstract: A method of inspecting a positive dental model having an impression plane comprises the step of first projecting a small beam of light of predetermined cross section on individual teeth of the model generally perpendicular to the impression plane, that is the plane perpendicular to which the impression fork was fitted to and removed from the patient's jaw. Thus the beam forms on each tooth a spot having a shape dependent on the contours of the respective tooth and the inclination of the respective tooth surface to the beam. The spot is moved from tooth to tooth on the model and the shapes of the spots of the beam on adjacent teeth are compared. If the shape changes, the teeth are not parallel and if there is a shadow or interruption of the teeth there is an undercut, and both conditions have to be corrected by regrinding the patient's tooth stumps. Similarly as the spot is moved, it can be used to measure the height and width of the teeth, the space between them, and even the overall arch length.