Denture base resins materials and its mechanism of action

polymerization ,pmma, mma, swagging technique, heat cure ,self cure, light cure

1. Denture base resins Dr. Shiva

2. Introduction ADA specification number :- 12

3. REQUIREMENTS OF DENTURE BASE MATERIALS

4. HEAT ACTIVATED DENTURE BASE ACRYLIC RESINS What is PMMA? What is Prepolymerized PMMA? Why the monomer bottle is dark?

5. Steps 1. Preliminaries 2. Flasking 3. Dewaxing 4. Separating medium 5. Proportioning and mixing 6. Trial closure 7. Final closure 8. Bench curing 9. Curing cycle 10. Bench cooling 11. Deflasking 12. Finishing and polishing.

6. Bench Cooling The denture flask should be cooled slowly to room temperature. Rapid cooling may result in warpage or distortion of the denture base because of differences in thermal contraction of acrylic resin and investing stone. 30 min and subsequently immersed in cold water for 10 min

7. Deflasking, Finishing and Polishing

8. CAD-CAM DENTURES

9. Why idly is one side smooth and other side porous ?

10. Swaging technique

11. Heat cure Composition

12. What did you understand from this?

13. The truth behind the story Physical reaction and chemical reaction

14. Why idly is one side smooth and other side porous ?

15. polymer/monomer ratio The polymer/monomer ratio is usually 3–3.5:1 by volume or 2.5:1 by wt. This amount of monomer in the mix results in about 7% of volumetric contraction.

16. Composition of self cure denture base resin • Powder Poly (Methyl methacrylate) or Copolymer beads. Benzoyl peroxide (maximum – 2.0%) – Initiator. Pigments Colored fibers (Nylon/acrylic) – added for esthetic effect Liquid Monomer – Methyl methacrylate. Ethyl glycol dimethacrylate – cross-linking agent. Hydroquinone – inhibitor. Dibutyl phthalate. Tertiary amine ( Di Methyl Para Toluidine ) – Activator (max. – 0.75%).

17. Setting Reaction When polymer powder and monomer liquid are mixed together at room temperature, free radicals are produced from benzoyl peroxide by a reaction with dimethyl para toluidine which initiates the polymerization reaction. Chain reaction propagates with the liberation of heat until it is terminated.

18. Difference between Heat cure and Self cure

19. Curing Cycle The curing cycle is the technical name for the heating process employed to control the initial propagation of polymerization in the denture mould.

20. Normal curing cycle Slow curing cycle Fast curing cycle

21. Crazing

22. MODIFIED ACRYLICS Rubber Reinforced Acrylics/High Impact Strength Materials Vinyl Acrylics Hydrophilic Poly (Acrylates) Rapid Heat Polymerized Acrylics/Hybrid Acrylics Fiber Reinforced Acrylic Light Activated Denture Base Resins Radiopaque Denture Base Resins

23. Radiopaque dentures

24. What is polymerization shrinkage? Name physical stages of denture base resins Name chemical stages of denture base resins Different types of curing cycles Crazing? Which curing cycle is better? Swagging technique? Different type of denture base resin Significance of prepolymerized PMMA

25. Thank you