Polymethyl methacrylate is susceptible to chemical shrinkage during polymerization. Considerable inaccuracy in the finished prosthesis is generally the result, especially in conventional methods of fabricating dentures. To resolve that problem, Ivoclar has developed the SR-Ivocap system, a special procedure which fully compensates for such shrinkage.

Through the use of controlled heat/pressure polymerization, acrylic resin shrinkage can be compensated by pressure feeding additional material.

The SR-Ivocap injection technique thus assures high quality products that have excellent physical and clinical characteristics.

The SR-Ivocap system uses specialized flasks and clamping presses to keep the molds under a constant pressure of 3000 lbs. Specially formulated and pre-dosed capsules of acrylic are vibration mixed for 5 minutes. After mixing is complete, the acrylic is continually injected into the molds under 6 bar of pressure for over 30 minutes under heat and an additional 20 minutes in cold water. Due to the design of the flasks and thermal insulators, the prosthesis is cured from the bottom up, with additional material constantly compensating for shrinkage.