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Prof. Dr. Manal A. El Ebiary Dental Bio-Materials Department Faculty of Dentistry

Prof. Dr. Manal A. El Ebiary Dental Bio-Materials Department Faculty of Dentistry Tanta & MUST Universities. How do you contact with me ?. manalahmed727@yahoo.com. Non Aqueous Elastomeric impression. Elastomers. Consists of long chain molecules that are coiled

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Prof. Dr. Manal A. El Ebiary Dental Bio-Materials Department Faculty of Dentistry

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  1. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  2. Prof. Dr. Manal A. El Ebiary Dental Bio-Materials Department Faculty of Dentistry Tanta & MUST Universities Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  3. How do you contact with me ? manalahmed727@yahoo.com Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  4. Non Aqueous Elastomeric impression Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  5. Elastomers • Consists of long chain molecules that are coiled • The materials are easy to deform and the deformation is largely reversible Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  6. Condensation Silicone Polysulfide Addition silicone Polyether Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  7. Point of comparison Polysulphide rubbers Polyether rubbers Silicon Supplied as two pastes system 1) Form of supply Light Regular Heavy Putty Light Regular heavy Light Regular heavy Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  8. Generally • Greater dimensional stability than hydrocolloid • Can be electroplatedexcept polyether • It is preferable to cast within the first hour after removal from the mouth • Available in different viscosities according to the molecular weight and amount of fillers • Used in as impression in case of inlays crowns, bridges Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  9. Polyetherrubbers Polysulphide rubbers Silicon Quadrant impression 2) Application Whole edentulous jaw Single impression Quadrant impression Single impression Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  10. Polysulfide Mercaptan Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  11. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  12. Base Polysulfied with terminal and pendant (SH ) Filler as titanium dioxide ( 12 : 50%) = provide strength = control consistency Catalyst Lead dioxide for polymerization and crosslinking oxidation of SH group Plasticizer Composition Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  13. Setting reaction Condensation polymerization reaction Polysulfide + Lead dioxide Polysulfide rubber + water + lead oxide +H Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  14. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  15. Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  16. Accuracy • High flow • Polymerization shrinkage = 0.25 % at the first 24 H • There is water as by-product • It should cast within one hour • Elasticity:- viscoelastic material , elastic recovery = 98% • The most flexible of all rubber materials • Compatible with die materials and surfactant improve surface wettability Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  17. Base Polydimethl- siloxane with OH (hydroxyl group) Filler Accelerator (Paste or liquid) Tin octate Condensation Silicone Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  18. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  19. Setting reaction • Condensation polymerization reaction • With formation of Alcohol as by product Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  20. Base Polymer with silane group Filler Accelerator Polymer with Vinyl group Chloroplatinic acid Filler Addition Silicone Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  21. Setting reaction Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  22. Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  23. Accuracy Condensation Addition High flow Shrinkage = .05% No by- product More ideally elastic than polysulfide Rapid elastic recovery = 99.5% Less flexible than polysulfide but less than polyether • High flow • Shrinkage = 0.6% • Presence of alcohol as by- product • More ideally elastic than polysulfide • Rapid elastic recovery • = 99.5% • Less flexible than polysulfide but less than polyether Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  24. Compatibility with die materials • Most materials compatible with die material • While addition silicone may produce hydrogen gas during setting it can be eliminated by addition of absorber in its composition to improve wettability Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  25. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  26. Addition of surfactant to facilitate casting because it is hydrophobic materials • Tear strength :- less than polysulfide and polyether • Can be disinfected • Can be electroplated Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  27. Disadvantage of addition (vinyl silicone) • It is hydrophobic materials this decrease the ability of the material to wet the soft tissue and at the same time decease the wetting of soft die materials then addition of surfactant is necessary • Sulfur contamination from latex gloves inhibit polymerization reaction of addition silicone Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  28. Base Polyether with ethylene imine ring group Filler Accelerator Aromatic sulfonic ester Filler Polyether Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  29. Setting reaction :- addition polymerization reaction Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  30. Accuracy • High flow • Polymerization shrinkage = 0.25 % at the first 24 H • Elasticity:- viscoelastic material , elastic recovery = 98.9% • The Least flexible of all rubber materials • Compatible with die materials and producing excellent surface Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  31. Tear resistance :- better than silicone but less than polysulfide • Disinfection :- dimensional change if immersion time longer than 10 minutes because hydrophilic nature • Cannot electroplated because hydrophilic nature comparison Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  32. General factor affecting accuracy • Record fine details • Small contraction due to polymerization shrinkage and cooling from mouth temp. to room temp. • Sufficient elastic to be withdrawn from undercuts Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  33. Less likely to tear than alginate • An adhesive should be used to assure adherence of the imp. Materials with the acrylic tray. • Silver electroplated except polyether because it is a hydrophilic materials Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  34. Thickness • Hydrocolloid = 4:6 mm • Rubber base = 2:3 mm • Polyether = not less than 4mm to facilitate removal because its low flexibility Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  35. Comparison Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  36. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  37. Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  38. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  39. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  40. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  41. Elastomeric impression materials Prof. Dr. Manal A. Elebiary

  42. Thanks Elastomeric impression materials Prof. Dr. Manal A. Elebiary

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