The process of removable partial denture fabrication is divided into the following processes:
1. model making
2. model design
3. bracket fabrication
4. tooth arrangement and waxing
5. casing
6. debonding and heat treatment
7. grinding and polishing
The process of making the model:
The impression is first carefully examined, and any residual saliva or blood is washed out under running water and sterilized. The modeling material is mixed by placing a small amount of well-mixed plaster material from the roof of the palate and the higher part of the tongue, while shaking it continuously, or shaking it on a shaking machine. The impression is flipped over onto the plaster so that the impression's hinge surface is parallel to the glass plate, and the distance between the hinge surface and the base of the model is 3.5-4.0 cm for the mandible and 4.0-4.5 cm for the maxilla.A mixing knife is used to form the base of the model, and the model is trimmed at the same time.
According to different materials to take different methods for demolding. For the elastic impression material can be directly after the plaster solidified, the model will be removed. At this time, should first remove the tray around the plaster, so that the tray and the edge of the impression is not buried by plaster, and then hold the model base in one hand, a hand holding the tray, carefully along the direction of the long axis of the teeth will be loosened after the model is taken down. If the impression is made with impression adhesive, the tray should be removed and soaked in hot water at 55~60℃, and then demolded after the impression material is softened.
The working model taken out should be promptly abraded to remove the peripheral excess with a model trimmer (plaster sander), and then the tubercles on the occlusal surfaces and the excessively long edges at the mucosal transitions should be repaired with a carving knife. If it is a memorized model, it is then trimmed according to specific requirements.
Model design:
Using the analyzing rod of the observer to check the inversion of each abutment and mucosal tissue, the seating channel of the denture is determined, and the observation line on each abutment is plotted. The number and distribution of the abutments, the type and position of the clasps and large connectors, and the boundaries of the abutment extension were determined on the model. According to the different inclination direction of the abutment teeth, the observation line can be categorized into three types.
Next, it is necessary to determine the *** same seating channel, when there are two or more abutment teeth of removable partial denture, the seating direction of the retainer on the abutment teeth must be the same in order to make the denture get the same seating channel, so that the denture can be seated smoothly. There are two methods of determining this: the equal-concave method and the adjustable-concave method.
The final design of the model: according to the physician's design order, draw the position and type of the ring, support, indirect retainer, connector, and mesh bracket on the model with a blue pencil, and then draw the extension range of the denture base with a red pencil. After the design is completed, the areas that need to be cushioned, such as inverted recesses and bony prominences that are not conducive to denture seating, are processed to fill in the inverted recesses and cushion the model.