Abstract: The modulus of elasticity and yield strength of a rigid core rod are set within predetermined limits as to limit the elastic deformation and prevent plastic deformation of a dental tray during multiple impression taking, bite registration and subsequent handling. The tray is formed with a frame which provides a positive recovery force when it is flexed. The cross section of the core rod may be optimized to further limit deflection in a predetermined plane. Various preferred materials including nonwoven spun-bonded filaments are selected for supporting impression material on the tray while minimizing the likelihood of obstructing a patient's teeth during full occlusion.

Abstract: An impression tray for making impressions of the upper and lower teeth, the impression tray includes a mouthpiece and a handle. Sectional and quadrant impressions may also be made using this impression tray. The mouthpiece including an outer wall, inner wall and a base connected between the outer and inner walls at a bottom thereof. The handle is connected to an outer side of the outer wall at a mid-section thereof. The outer and inner walls each have vertical slits spaced along their length. The vertical slits each have a shoulder within the slit providing an interlock for the impression material displaced through the slits. The base includes a number of ribs on its top, each rib extending between the outer and inner walls and in an alternating arrangement with the slits on the outer and inner walls. Between each adjacent pair of ribs are two holes extending through the base. The base is also attached, on its bottom, to a platform structure.