For Udell, using the traditional manual approach to make removable partial denture frames (RPD) took many steps and was not efficient enough to meet increasing demand. The traditional process required 96 minutes of work by a dental technician and was highly dependent on their skill and attentiveness to ensure an accurate fit. Using an impression taken by a dentist of the patient’s mouth, a skilled technician pours the stone model and then duplicates it into a refractory model that becomes part of the mold used to cast the metal RPD framework. The technician designs a wax pattern to the refractory model that defines the geometry of the RPD and fills in undercuts in the gums to provide a smooth path for RPD placement. Sprues are attached to the wax pattern and refractory model, and the assembly is placed in an investment ring.
Silica casting investment is poured into the ring to create a mold for investment casting. Molten metal is cast into the mold through the sprues, replacing the wax pattern. When the metal cools, the refractory and silica investment are removed to reveal the finished frame.