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120 Cards in this Set
- Front
- Back
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Use for taking impressions of the mouth. Negative copy of the tissues |
Impression plaster |
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Not used by dentist anymore |
Impression plaster |
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6 Impression materials |
Impression plaster Impression compound Reversibe hydrocolloid Irreversibly hydrocolloid Zinc Oxide Eugenol Impression Paste Elastomeric Rubber Impression |
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Classification acc of impressin materials to the manner in which they harden |
Physical Chemical Thermoplastic |
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Impression materials that did NOT CHANGE their chemical composition. |
Physical |
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Example of physical |
Agar (gelatin) Reversible hydrocolloid |
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Impression materials that hardens by chemical means |
Chemical |
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Example of chemical |
Alginate Gypsum Dental Plaster Impression Plaster Irreversible Hydrocolloid Zinc Oxide Eugenol Impression Paste Elastomeric Rubber Impression |
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Impression materials that soften underneath. |
Thermoplastic |
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Example of thermoplastic |
Modeling compounds Impression compound |
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According to their use in dentistry |
For edentulous mouth (no teeth)
For non-edentulous mouth (has teeth) |
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Example of material used for edentulous mouth |
Modeling compound ZOE impression paste Elastomeric rubber impression Alginate Agar |
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Example of material used for nom-edentulous mouth |
Alginate Agar Elastomeric rubber impression Modeling Plastic |
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There are procedures wherein we take impression of the single tooth |
Inlays |
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According to the state & condition |
Rigid (matigas) Flexible |
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Example impression materials for rigid |
Impression plaster Modeling compound ZOE impression paste |
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Examle impression materials for flexible |
Agar Alginate Elastomeric rubber impression |
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Composition of Impression Plaster |
Plastr of paris Chemical modifiers Potato starch Flavoring Coloring Scent |
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What is chemical modifiers |
It regulates setting time and controls setting expansion |
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regulates setting time and controls setting expansion |
Chemical modifiers |
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renders the impression plaster soluble in warm water |
Potato starch |
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facilitates easy removal of cast from the impression |
Potato starch |
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makes the impression plaster palatable |
Flavoring |
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for easy identification of the impression from the cast |
Coloring |
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Properties of impression plaster |
W/P Ratio: 0.6-0.7 Setting time: 3-5 mins Setting expansion: Lowest-0.06% |
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A thermoplastic material usually composed of gum dammar and prepared chalk |
Impression compound |
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Forms pf impression compound |
Cake form Stick form |
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Main composition of modeling compound; Makes compound flaky |
Beeswax |
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Composition of modeling compound |
Beeswax Burgundy Pitch,Shellac, Gutta percha Stearin & Kauri resin French Chalk Coloring ingredient |
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Improve the plasticity of the impression compound |
Burgundy pitch Shellac Gutta Percha |
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Type of modelling compound to make it hard |
Stearin & Kauri Resin |
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Is a filler (something that you put inside as paste) Makes the impression compound hard. |
French chalk |
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A kind of filler |
Diatomaceous earth |
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What is the flow of modeling compound |
It has a good flow if u soften uniformly well. Kneading purpose to improve the workability of compound |
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Properties of modeling compound |
Flow Thermal conductivity Distortion Viscosity |
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Use warm water in modeling compound |
Thermal conductivity |
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Relaxation occurs in modeling compound |
Distortion |
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most viscous of impression material in modeling compound |
Viscosity |
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Requisites of Impression Compound |
It should be free of poisonous or irritating ingredients. Harden completely. Should be plastic at temperature and not cause discomfort to the patient. Should harden uniformly. Will not deformed or fractured Has glosst appearance Not change dimension |
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Types of modeling compound |
Type 1 - true compound lowering fusing Type II - Tray compound higher fusing |
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Type pf modeling compound Available as sheets, sticks, cylinders, cones. |
Type I |
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Type of modeling compound should be capable of recording sharp grooves |
Type I |
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Type of modeling conpound that Soften with flame; tempered in a water bath before placing in the pt.’s mouth |
Type I stick |
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Type of modelimg compound Used to refine or modify peripheral extent of special tray for CD or edentulous region of RPD. |
Type I Stick |
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Type in modeling compound For securing rubber dam retainer and occlusal registration plate. |
Type I - Stick |
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Type of modeling compound For making impression tray |
Type II Tray Compound |
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Type of modeling compound Lacks dimensional stability and strength |
Type II Tray compound |
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Type in impression materials for replaced by acrylics and plastics. |
Tye II Tray Compound |
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Manipulation in Modeling compound |
Direct flame Use of Dry Heat Use of Warm Water Bath |
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If the modeling compound becomes grainy, what happened? |
It is overused |
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Failure of manipulating modeling compound |
Failure to flow Has fold Has hole |
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Elastic materials composed of colloidal gels or jelly-like substances made up of submicroscopic fibrils |
Hydrocolloids |
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in between these fibrils are spaces known as |
Micelles |
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Any solution in which the unit of the solute (has big particles) are sufficiently large so that it will not dialyze through a suitable membrane. |
Colloids |
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What are the 2 phases (in hydrocolloids) |
Dispersed Phase/Dispersed particles (solute) Dispersion phase/Dispersion medium (solvent) |
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If the dispersed phase and the dispersion medium are not of like phase. |
Suspension |
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If the dispersed phase is of the same phase as of dispersion medium |
Emulsion |
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Example of emulsion |
Toothpaste |
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Are solids suspended in liquids Lyophilic (water loving) |
Hydrocolloids |
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Ano significance sa atin ng water loving as clinicians? |
Storage |
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Definition of terms |
Aerosols Lyosols Lyophobic Gelation Gelation time Gelation temperature Liquefaction time Liquefaction temperature Hysteresis |
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Factors which affects gel strength |
1. Brush heap density or concentration 2. Temperature of reversible gel 3. Addition of certain modifiers |
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2 dimensional changes |
Imbibition Syneresis |
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Absorption of water into the surface of the gel causing swelling.
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Imbibition |
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Evaporation of water from the surface of the gel causing shrinkage. |
Syneresis |
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2 types of hydrocolloids |
Reversible Irrevesible |
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Is an organic hydrophilic colloid extracted from red seaweeds that is widely used in the food industry |
Agar-agar |
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What is reversible |
Hardens by physical change Subjected by heat |
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What is irreversible |
Hardens by chemical reaction Not subjected to heat |
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What is hydrocolloid that can reused? |
Reversible hydrocolloid |
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Has a high gel strength at low concentrations |
Agar |
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A higher temperature is needed to convert the gel into a sol. |
Agar |
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The first material to set is that which is in contact with the tray since it is cooler than the tissues. |
Agar |
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Exact gelation of agar depends on |
1. Molecular weight of agar 2. Purity of agar 3. Ratio of agar to other constituents |
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Composition of reversible hydrocolloid impression material supplied as a get with the following ingredients |
Agar (12-15%) gelling agent Borax (0.2%) improves strength K2SO4 (1-2%) provides good surfaces on gypsum models 85% water Alkylbenzoates (0-1%) preservative Trace amounts of coloring & flavoring agents |
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Properties of reversible hydrocolloid |
• Good surface detail ● Can be used on undercuts, but liable to tear on deep undercuts ● Evaporation or imbibition ● Non toxic and non irritant ● Slow setting time ● Poor tear resistance ● Adequate shelf life ● Can be sterilized by an aqueous solution of hypochlorite |
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Irreversible hydrocolloid |
Alginate |
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A casting material made from kelp used for making the negative impression of the teeth. |
Alginate |
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Composition of irreversible hydrocolloid impression material |
● Potassium Alginate ● Calcium Sulfate ● Zinc Oxide ● Potassium Titanium Fluoride ● Diatomaceous Earth ● Sodium Phosphate |
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Types od irreversible hydrocolloid |
Type I - fast setting Type II - normal setting |
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Methods pf controlling gelation in irreversible hydrocolloid |
1. By altering the W/P 2. By altering the mixing time 3. Addition of retarders 4. By altering temperature |
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Liquids or solids in air |
Aerosols |
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Liquids or solids in air |
Aerosols |
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Gas, solids, liquids in air |
Lyle old |
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Liquids or solids in air |
Aerosols |
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Gas, solids, liquids in air |
Lyosols |
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Water hating |
Lyophobic |
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Process of transforming sol to gel |
Gelation |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming gel to sol |
Liquefaction |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming gel to sol |
Liquefaction |
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Time needed to transform gel to sol |
Liquefaction time |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming gel to sol |
Liquefaction |
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Time needed to transform gel to sol |
Liquefaction time |
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● The temperature at which the gel is transformed to sol at a higher temperature. (60-70C) ● Applicable for agars |
Liquefaction temperature |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming gel to sol |
Liquefaction |
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Time needed to transform gel to sol |
Liquefaction time |
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● The temperature at which the gel is transformed to sol at a higher temperature. (60-70C) ● Applicable for agars |
Liquefaction temperature |
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The difference between gelation and liquefaction temperature. |
Hysteresis |
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Process of transforming sol to gel |
Gelation |
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The time needed to transform sol to gel. |
Gelation time |
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The temperature in which the sol is transformed into gel. (37 degrees celsius) |
Gelation temperature |
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Process of transforming gel to sol |
Liquefaction |
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Time needed to transform gel to sol |
Liquefaction time |
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● The temperature at which the gel is transformed to sol at a higher temperature. (60-70C) ● Applicable for agars |
Liquefaction temperature |
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The difference between gelation and liquefaction temperature. |
Hysteresis |
