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  1. Faculty Of Oral & Dental Medicine, K.S.U Removable Prosthodontics Dept. Steps Of processing of complete Denture prepared by : Amr mohamed el.adle soheir mohamed abd almunem
  2. Introduction what is the processing ? It is the process by which the trail denture base is converted to the permanent base that fit the patient's mouth and compatible with the tissues. Denture processing use two techniques : 1) Compression Molding. 2) injection Molding. Compression Molding technique : ( the most commonly used technique for acrylic resins ) Preparation of the trail denture.
  3. steps:  Flasking.  Acrylic mixing.  Acrylic pressing.  Finishing.  Polishing.
  4. Flasking:  Flasking is the process of investing the cast with the waxed denture in a flask to make a sectional mold that is used to form the acrylic resin denture base.  What is flask?  The flask is a metallic mold that supports the models and the try in denture during the flasking procedure.  It is composed of 3 parts: 1. Base 2. Mid-part 3. cover
  5. Flasking steps:  Separating media added to flask.  Lower portion of flask is filled by dental plaster to fix the cast on it.  Plaster shouldn't make any undercut. After preparing upper and lower portion of flask,
  6.  Seat the upper portion of flask, dental stone is added on all surface.  Incisal and occlusal surfaces are minimally exposed to facilitate deflasking .  Apply spreading medium only on stone.  Add additional increment to fill the reminder of flask.  Then cover the flask and remove excess stone.  Put the flask in flask clamp.
  7.  Dewaxing, put the flask in boiling water 100 °C for 5 minutes to remove wax.  Open the flask and put it at boiling water again to remove residual wax.
  8. Acrylic mixing and pressing:  We use heat acrylic resin .  Polymer to monomer ratio 3:1 by volume until dough-like st.  Acrylic placed into mold cavity and covered with cellophane for trial packing to remove excess on hydraulic bench press.  compress the flask slowly in the hydraulic bench press so that the excess resin material flows out  remove the flask from the clamp, open the flask and remove the sheet  remove the excess flash with the blunt knife with out making a mark on the plaster surface  apply another coat of separating media on the surface before the final closure of flask
  9.  the flask kept in the bench press for 30 min before heat curing This is called bench set or bench cure *After the bench set, the flasks with the clamp are kept in the curing bath(water bath) The curing cycle can be short cycle or long cycle. I. Short cycle: The denture is placed on water at room temperature and the curing temperature is programmed to 74 C for one and half hour followed by 100 C for one hour under pressure. II. Long cycle :The curing temperature is programmed to 70 C for 7 hours then 100 C for 3 hours ( the total 10 hours) . *Polymerization can occur at any temperature but it very slow at temperature below 70 C *The best curing cycle is the long curing cycle because most of the conversion of monomer to polymer occur during the period at 70 C and the rapid cycle method may include greater dimensional changes in the dentures than slow cure.
  10. • *Mixture must pack in doughy stage with excess amount to make up for the shrinkage during polymerization and refrigeration; it will be unworkable.  Deflasking . deflaking should be done with care to avoid flexing and breaking of the acrylic denture.
  11. Finishing:  Each denture is hand finished using special burs to remove any excess acrylic around the edges and palatal area. The articulation is checked and adjusted if necessary.
  12. Polishing:  Finally, the denture is polished and smoothed with polishing mops and paste. To create a natural-looking luster.