Acrylic Resin Crowns
What is the combined, indirect/direct procedure for temporary crown fabrication? Previously fabricated ESF a temporary crown coming from the laboratory, is relined with additional quantity of self-curing resin material into the patient’s mouth (a chair-side relining procedure), for achieving perfect marginal fit of the restoration – to the finish line and to the gingival margin.
The quantity of relining material and the contact time are minimized and the probability for pulp damage or tooth sensitivity of the patient is greatly reduced.
Regardless of the technology – indirect or combined, for the fabrication of this type ESF, the impression needs to be taken before tooth preparation.
Another option, if the teeth have been prepared already, is the dental technician makes the modeling of the restoration in wax, fabricates a duplicate stone model, and then the ESF can be fabricated using the pressure or vacuum forming device.
Another method for indirect fabrication of acrylic resin restorations is the hydro-pneumatic heat curing process in a special device.
The polymerization cycle parameters depend on the instructions for use of the company that has produced the device, but most frequently these parameters are as follows: T=90 -120 degrees, Pressure 0,3 – 0,7 Mpa for 11 -15min; or 0,15.76 Mpa for 5 or 6 minutes.