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22 Cards in this Set
- Front
- Back
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What are the three purposes for positive reproduction?
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study model
die cast |
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These are descriptions of what positive reproduction?
A substitute for patient Used for documentation (before/after) Diagnostic/Educational aid Treatment Planning Observe Treatment Progress |
study model
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These are descriptions of what positive reproduction?
Replica for a restoration/or appliance More than one tooth (quadrant or full arch) Partially or completely edentulous*** |
cast
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This is a description of what positive reproduction?
Working replica of a single tooth-typically removable |
die
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Casts and dies must be able to withstand ________, have hardness strength.
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manipulation
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Gypsum products are made from ______ that is mined and ground into a fine powder
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gypsum rock
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___________ process of heating gypsum to drive off the part of the water of crystallization changes
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Calcination
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Calcium Sulfate ____-hydrate (Rock)
to Sulfate _____ -hydrate= Plaster Stone Improved Stone |
Di
Hemi |
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__________ (white)
Type II _____-Hemihydrate Calcination Method-heat open container 110-120 C Particle size after calcination-_____, soft,irregular Uses-_________ Cost/Strength-least Water/Powder Ratio _____ml. Water 100 g. Powder Mixed Consistency-Thin Expansion Rate-most |
plaster
beta porous Study models 45-50 |
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___________ (unimproved, yellow)
Type III ______-Hemihydrate or ______ Calcination Method-heat under steam pressure-125 C closed container Particle arrangement-uniform Uses- _____ for diagnoses and complete and partial dentures Cost/Strength-intermediate Water/Powder Ratio _______ml. Water 100g. Powder Mixed Consistency-intermediate |
stone
alpha Hydrocal casts 28-30 |
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____________ (green)
Type IV Modified ______ Calcination method-_________ solution Particle Arrangement-dense, ______ Uses-____/______, crown and bridge,inlays Cost/strength-most Water/Powder Ratio-____ml. Water 100g. Powder Mixed consistency-putty-like |
improved stone
Alpha, calcium chloride cubodial dies/cast 19-24 |
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Mixing (Adding water) back to dihidrate
For best results: measure powder/water add powder to water in 30-60sec.- stirring rapidly with wide stiff- bladed spatula vibrate to remove air bubbles |
study
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Working time, or initial setting time-(mixing and pouring) ____ minutes
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5-7
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Loss of gloss marks the end of _______
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working time
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Setting time _____ min. (no more manipulation) may feel warm
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10-15
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Final Set-_____min. (failure to penetrate with fingernail)
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30 to 45
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How do I increase Setting Time?
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(Slower-setting)
Decrease mixing Higher water/powder ratio Cool water Add retarder (borax) done by manu. (Can be purchased this way) |
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borax = _____________
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retarder
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How do I decrease Setting Time?
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(Faster-Setting)
Increase Mixing Lower water/powder ratio Warm water Add accelerators (potassium sulfate) |
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potassium sulfate= _______
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accelerator
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length of time from the start of mix until the setting mass reaches a semihard stage
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working time or initial setting time
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length of time form the start of the mix until the setting mass becomes rigid and came be separated form the impression
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final setting time
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