Dentistry >>>> Making of flexible removable dentures

Making of flexible removable dentures.

As mentioned here, the advantage of flexible removable dentures lies not only in the convenience of addiction and sparing effect on the oral mucosa. Flexible removable dentures are, first of all, allergen-free dentures, since the technology of their manufacture does not imply a two-component component (plastic powder and monomer liquid, which often becomes an allergy factor).

For the making of flexible removable dentures, the injection molding method is used. In order to cast such a prosthesis, an injection furnace is needed - a device that drives softened plastic material (briquettes, granules) into a mold for casting a prosthesis under high air pressure.

How is flexible removable dentures molded?

After determining the height of the bite, choosing and setting teeth, the stage of preparing the mold for casting a flexible denture begins. The wax composition of the prosthesis is poured with boiling wax to the plaster model, all plaster teeth and protrusions that can obstruct the further opening of the cuvette are cut off from the model.

The model with the wax prosthesis plunges into a metal cuvette filled with plaster so that the distance between the wax prosthesis and the opening for the plastic passage is as small as possible, but does not create preconditions for the plaster mold to break under the influence of high air pressure.

After the gypsum has solidified in the cuvette, a sprue system is supplied to the wax composition of the prosthesis, which must be thought out individually for each case of installed teeth and create opportunities for plastic to flow into all hard-to-reach places. To prevent underfilling and the formation of voids along the edges of the prosthesis, abductions can be made in the most difficult places (in the area of the location of the pilots - structural elements that hold the prosthesis on the teeth and alveolar processes; in the area of cut plaster teeth in the frontal area). The gating system should cover all areas of the prosthesis remote from the opening of the plastic passage and create sufficiently wide depots for the passage of plastic in a plaster form and prevent cavities and porosity of the future prosthesis.

The wax prosthesis, cast into a metal cuvette, is evaporated (wax components are removed from the plaster mold), the mold is lubricated with an insulating varnish so that the future plastic structure can be easily removed from the mold. The cuvette with the prepared mold is dried in a muffle furnace to remove the residual condensate and installed in the injection furnace, where a "cartridge" with the casting material is supplied to it. According to the established program, corresponding to the material, the prosthesis is cast.

The cuvette is cooled, disconnected and the cast soft removable denture is carefully removed, the gating system is cut off, the denture is processed with special cutters and polished (in the case of nylon dentures, only the fringe is cut off with scissors, but the denture is not polished). The prosthesis is ready to be seated in the oral cavity.