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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Dental Bio-Materials Department Faculty of Dentistry Tanta & MUST Universities Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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How do you contact with me ?
Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Non Aqueous Elastomeric impression
Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Condensation Silicone Polysulfide Addition silicone Polyether Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Supplied as two pastes system
Point of comparison Polysulphide rubbers Silicon Polyether rubbers 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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Generally Greater dimensional stability than hydrocolloid Can be electroplated except 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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Polysulphide rubbers Polyether rubbers Silicon Quadrant impression 2) Application Whole edentulous jaw Single impression Quadrant impression Single impression Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Polysulfide Mercaptan Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Composition 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 Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Setting reaction Condensation polymerization reaction
Polysulfide + Lead dioxide Polysulfide rubber + water + lead oxide +H Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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Condensation Silicone
Base Polydimethl- siloxane with OH (hydroxyl group) Filler Accelerator (Paste or liquid) Tin octate Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Setting reaction Condensation polymerization reaction With formation of Alcohol as by product Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Addition Silicone Base Polymer with silane group Filler Accelerator Polymer with Vinyl group Chloroplatinic acid Filler Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Setting reaction Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Accuracy Addition Condensation 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 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 Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Polyether Base Polyether with ethylene imine ring group Filler Accelerator Aromatic sulfonic ester Filler Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Setting reaction :- addition polymerization reaction Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Comparison Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Stannous octoate or Tin octoate Aromatic sulfonic ester
Catalyst (accelerator) Reactive group Monomer Impress. materials Lead dioxide Mercaptan (-SH-) Polysulfide Stannous octoate or Tin octoate Hydroxyl (OH) Dimethyl silioxane Conden. silicone Chloroplatinic acid Vinyl group CH2 = CH Vinyl Siloxane Addition silicone Aromatic sulfonic ester Ethylene imine ring polyether Polyether Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Properties Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Condensation silicone Polysulfide
polyether Addition silicon Condensation silicone Polysulfide regular + diluent Light- regular –heavy - putty Light- regular- heavy Viscosity 2 pastes 2 pastes or one paste + liquid Form Better taste Pleasant Bad odor Odor ,taste Expensive Low cost Cost Easy Difficult Clean up Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Pitting of stone surface
Short Moderate Long time = 10 minutes Setting time Addition ( ring opening) (Ionic ) condensation Kind of reaction ----- Hydrogen Ethyl alcohol water + PbO By product Adequate Tear resistance Smooth Pitting of stone surface Model surface Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Bio-compatible 98.9% 99.5% 98% 0.25 % 0.05 % 0.6 %
hypersensitivity, contact dermatitis, and gingivitis. Bio-compatible Biological effect 0.25 % 0.05 % 0.6 % Dimensional change 98.9% 99.5% 98% Elastic recovery Less flexible than all rubber imp. and difficult in removal from undercut. Less flexibility than polysulifde less flexibility than polysulfide High flexibility, easy removed from under cut Flexibility, stiffness Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Limited due to deterioration of liquid accelerator
Hydrophilic, water sorption water absorption Not absorb water Water absorption Good Limited due to deterioration of liquid accelerator Shelf life Silver plated Electro-plating Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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Elastomeric impression materials Prof. Dr. Manal A. Elebiary
Thanks Elastomeric impression materials Prof. Dr. Manal A. Elebiary
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