Casting and Soldering Investments

Question 1

Casting Investment - Purpose

vUsed in Lost Wax Casting Technique

vCreates the __ ___ into which the __ __ will flow

vIn 1907 a Dentist,

Dr. William H. ___, came up with the techniques that made casting an everyday option.

Answer 1

vUsed in Lost Wax Casting Technique

vCreates the mold cavity into which the molten metal will flow

vIn 1907 a Dentist,

Dr. William H. Taggart, came up with the techniques that made casting an everyday option.

Question 2

vOver four thousand years ago man invented the lost wax technique .

vOnce you have waxed your pattern you need a way to change it from ___ into a ___ substrate.

Answer 2

vOver four thousand years ago man invented the lost wax technique .

vOnce you have waxed your pattern you need a way to change it from wax into a usable substrate.

Question 3

–

vIn this technique wax is placed into a medium:

v ___

v___

v___ or __ ___

vThe wax is__ __, and __ or ___ is ___, ___ or ___ into the space created by this melted wax.

Answer 3

–

vIn this technique wax is placed into a medium:

v sand

v mud

vceramic or casting investment.

vThe wax is melted out, and metal or glass is poured, pressed, or vacuumed into the space created by this melted wax.

Question 4

v___ your pattern

v___ your pattern

v___ t the pattern

v__ __(___)

v__

v__ and __ your casting

Answer 4

vMake your pattern

vSprue your pattern

vInvest the pattern

vWax elimination (Burnout)

vCast

vFinish and polish your casting

Question 5

vPattern is ____ -=and made ready to invest.

Answer 5

vPattern is created and made ready to invest.

Question 6

vAttach ___, place wax-up on a ___ ___

Answer 6

vAttach sprue, place wax-up on a crucible former

Question 7

___ and ___ of pattern in ring is important.

You can still get a casting but its difficult to get a good, complete casting

You want about a ___ mm spru about ___ mm from top of ring and have

You want___ ___ wax pattern

You don’t want any sharp angles

Metal will flow into there and the it will flow into your pattern

Hit a flat wall it will just splatter everywhere instead of flowing smoothinly

Ring liner is placed for____

You have to have expansion bc investment is made out of gypsum and gypsum expands upon setting

You have to have room for correct expansion so that your casting will end up the right size

Answer 7

vOrientation and height of pattern in ring is important.

You can still get a casting but its difficult to get a good, complete casting

You want about a 6 mm spru about 6 mm from top of ring and have

You want room around wax pattern

You don’t want any sharp angles

Metal will flow into there and the it will flow into your pattern

Hit a flat wall it will just splatter everywhere instead of flowing smoothinly

Ring liner is placed for expansion

You have to have expansion bc investment is made out of gypsum and gypsum expands upon setting

You have to have room for correct expansion so that your casting will end up the right size

Question 8

vCasting ring should have ring liner adapted to the inside of ring and ___ down with ___wax. After tacking, ___ liner lightly.

Wet the liner so that when you fill the ring up, it doesn’t suck water out of the investment.

If it sucks water out of the investment, that will change the Water to powder ratio of the investment. And that will change your expansion

Recall More is less and less is more

If you take water out your will get more expansion

If you have too much water you will get less expansion

Answer 8

vCasting ring should have ring liner adapted to the inside of ring and tacked down with sticky wax. After tacking, wet liner lightly.

Wet the liner so that when you fill the ring up, it doesn’t suck water out of the investment.

If it sucks water out of the investment, that will change the Water to powder ratio of the investment. And that will change your expansion

Recall More is less and less is more

If you take water out your will get more expansion

If you have too much water you will get less expansion

Question 9

vSpray your wax-up with ___ to break the __ ___ of the wax

vDo not allow the surfactant to ___

vIf you get a little too much, light __ ___excess

ST is not good when you are trying to invest.

You will end up with little ___

Little bubbles of air in an investment will end up as little bubbles in the gold

Don’t let it pool up because you will get weird surface bc of bad setting of investment

Answer 9

vSpray your wax-up with surfactant to break the surface tension of the wax

vDo not allow the surfactant to pool

vIf you get a little too much, lightly blow off excess

ST is not good when you are trying to invest.

You will end up with little bubbles

Little bubbles of air in an investment will end up as little bubbles in the gold

Don’t let it pool up because you will get weird surface bc of bad setting of investment

Question 10

Lost Wax Technique - Investing

vUse your ___ mixing bowl to mix the investment.

v____ investment by Whip-Mix Co.

vRead the instructions on the package and follow the directions.

vThe ring will not be on the __ __ at this point

In casting it is really important that you get correct expansions of materials. Need to follow all instructions

When you first go to invest, the ring will not be on top of the crucible former

Mix the investment by hand

Vacuum mix for about 40 seconds

Then use a brush and vibrate the investment into and over the crown

Put ring on crucible former and fill it up

Answer 10

Lost Wax Technique - Investing

vUse your vacuum mixing bowl to mix the investment.

vNovocast investment by Whip-Mix Co.

vRead the instructions on the package and follow the directions.

vThe ring will not be on the crucible former at this point

In casting it is really important that you get correct expansions of materials. Need to follow all instructions

When you first go to invest, the ring will not be on top of the crucible former

Mix the investment by hand

Vacuum mix for about 40 seconds

Then use a brush and vibrate the investment into and over the crown

Put ring on crucible former and fill it up

Question 11

Lost Wax Technique - Investing

vMix the investment by ___ till completely ___ ( approx. __ seconds )

___ mix for ___ sec.

vUsing a ___, ___ investment into and onto wax pattern, place ring onto__ __r.

v___ the ring slowly, holding ring to ___ with ___ pressure

Answer 11

vMix the investment by hand till completely incorporated ( approx. 15 seconds )

vVacuum mix for 40 sec.

vUsing a brush, vibrate investment into and onto wax pattern, place ring onto crucible former.

vFill the ring slowly, holding ring to vibrator with indirect pressure

Question 12

Lost Wax Technique - Burnout

vInvestment should____ ___according to the manufacturers’ directions, ___ min. in this case

vRemove the ___ ___

v

Answer 12

vInvestment should bench set according to the manufacturers’ directions, 40 min. in this case

vRemove the crucible former

v

Question 13

Lost Wax Technique - Burnout

vPlace ___ in oven

vCheck __ __

vCheck___ end-point set

Answer 13

vPlace ring in oven

vCheck heat rate

vCheck temperature end-point set

Question 14

Lost Wax Technique - Burnout

vBurnout is to ___oF

vIt takes approximately ___ hour to reach temperature

vOnce it reaches temperature you hold for___minutes (__ ___).

Then you cast

Hold it at that temp for 15 min

When it reaches 1200, that’s only the outside is 1200

Answer 14

Lost Wax Technique - Burnout

vBurnout is to 1200oF

vIt takes approximately 1 hour to reach temperature

vOnce it reaches temperature you hold for 15 minutes (heat soak).

Then you cast

Hold it at that temp for 15 min

When it reaches 1200, that’s only the outside is 1200

Question 15

Lost Wax Technique - Casting

vCasting is the process by which the ___ from the pattern is converted to a replicate in ___ or ___

___ metal is accelerated into the ___ either by __ __ or __ ___ (___ or ___).

vGlass is “cast” using a ___ ___ to___ the molten glass into the mold.

Pressing of ceramics is casting of glass

But using pressurized ceramic rod to push the glass in rather than a casting machine to throw it in

Answer 15

Lost Wax Technique - Casting

vCasting is the process by which the mold from the pattern is converted to a replicate in alloy or glass.

vMolten metal is accelerated into the mold either by centrifugal force or air pressure (positive or negative).

vGlass is “cast” using a ceramic rod to press the molten glass into the mold.

Pressing of ceramics is casting of glass

But using pressurized ceramic rod to push the glass in rather than a casting machine to throw it in

Question 16

Lost Wax Technique - Casting

vOur casting will be done with a ___ __ ___machine

Two pieces move independently of each other

Wind the casting machine, pull up the bar and lock it into place

Answer 16

Lost Wax Technique - Casting

vOur casting will be done with a broken arm casting machine

Two pieces move independently of each other

Wind the casting machine, pull up the bar and lock it into place

Question 17

Lost Wax Technique - Casting

v___ the casting machine__ times _____

___ into place with __ ___

vPlace ___ and ___

vPull___ with crucible ___ from cradle

Its spring loaded

Place cradle and crucible

Put the gold in here

Pull platform with crucible away from cradle

And you start heating up the gold

Answer 17

Lost Wax Technique - Casting

vWind the casting machine 3 times clock-wise

vLock into place with locking bar

vPlace cradle and crucible

vPull platform with crucible away from cradle

Its spring loaded

Place cradle and crucible

Put the gold in here

Pull platform with crucible away from cradle

And you start heating up the gold

Question 18

Lost Wax Technique - Casting

vWork in ___. This is a must!

vLight the___ and adjust the ___

v__ __ your crucible.

vOnce the crucible is pre-heated place the___ and begin the __ ___

Answer 18

vWork in pairs. This is a must!

vLight the torch and adjust the flame.

v Pre-heat your crucible.

vOnce the crucible is pre-heated place the gold and begin the melting process

Question 19

Lost Wax Technique - Casting

vThe gold will __ and begin to __ __

vOnce melted it will look more like ____ than gold

vPlace the ring into the___

vPush the crucible platform ___ against the ring

Once the gold is heated and once it melts, it balls up

Answer 19

Lost Wax Technique - Casting

vThe gold will melt and begin to ball-up

vOnce melted it will look more like mercury than gold

vPlace the ring into the cradle

vPush the crucible platform up against the ring

Once the gold is heated and once it melts, it balls up

Question 20

Lost Wax Technique - Casting

vNow you are ready to actually cast.

vYou will reach in and grasp the___ on the end of the casting machine and move them approx.__ ___ clockwise. The pin will ___

___ the weight. Get your hand and the torch out of the way. Use a smooth quick motion.

If it hits your hand it will break it

Answer 20

Lost Wax Technique - Casting

vNow you are ready to actually cast.

vYou will reach in and grasp the weights on the end of the casting machine and move them approx.1 inch clockwise. The pin will drop.

vRelease the weight. Get your hand and the torch out of the way. Use a smooth quick motion.

If it hits your hand it will break it

Question 21

Lost Wax Technique - Casting

vTurn off torch.

vAllow the casting machine to ___ until adequate time has passed for the molten metal to ___ (20-30 sec.).

vThen, using the handle of the ___ stop the spinning.

Answer 21

Lost Wax Technique - Casting

vTurn off torch.

vAllow the casting machine to spin until adequate time has passed for the molten metal to solidify (20-30 sec.).

vThen, using the handle of the tongs stop the spinning.

Question 22

Lost Wax Technique - Casting

vRemove the ring, carry with the tongs to the sink. Place on the edge of the ___ then ___

vQuenching is the plunging of the hot ring into___

What happens when you drop that hot ring into water?

You have __ ___

Answer 22

Lost Wax Technique - Casting

vRemove the ring, carry with the tongs to the sink. Place on the edge of the sink, then quench

vQuenching is the plunging of the hot ring into water.

What happens when you drop that hot ring into water?

You have mini explosion

Question 23

Lost Wax Technique - Divesting

vThe casting is now ready to be ___ from the investment .

___ Crown

Clean it up. Cut off sprew and you fit it to your die

Answer 23

Lost Wax Technique - Divesting

vThe casting is now ready to be removed from the investment .

vCleaned Crown

Clean it up. Cut off sprew and you fit it to your die

Question 24

Casting Investments

vGypsum-bonded

vHigh-temperature

vPhosphate-bonded

vEthyl Silicate

vSoldering

Answer 24

Casting Investments

vGypsum-bonded

vHigh-temperature

vPhosphate-bonded

vEthyl Silicate

vSoldering

Question 25

Ideal Casting Investment - Properties ## Footnote v\_\_\_ to manipulate vSufficient \_\_\_\_ vResist \_\_\_\_ vSufficient\_\_\_n v\_\_\_ - gas escape vS\_\_\_surface v\_\_ \_\_\_temperature range vEasy to __ \_\_ v\_\_\_ v v v

Answer 25

vEasy to manipulate vSufficient strength vResist decomposition vSufficient expansion vPorous - gas escape vSmooth surface vNon-critical temperature range vEasy to break away vInexpensive v v v

Question 26

\_\_\_\_ casting investment on the market today fits the 9 ideal properties!

Answer 26

No casting investment on the market today fits the 9 ideal properties!

Question 27

Investment Components ## Footnote vBinder - \_\_\_-temperature \_\_\_, \_\_\_ vRefractory - \_\_\_-temperature \_\_\_, \_\_\_ vModifiers - \_\_\_, ___ \_\_\_

Answer 27

vBinder - low-temperature strength, expansion vRefractory - high-temperature strength, expansion vModifiers - expansion, control tarnish

Question 28

Investment Binders ## Footnote \_\_ ___ - \_\_\_-temperature alloys \_\_\_e - \_\_-temperature alloys \_\_\_ - ___ -temperature alloys Calcium Sulfateà Gypsum Typical\_\_ ___ would be invested in a gypsum investment Phosphate: for nonprecious, high __ \_\_\_t, one that needs more heat to get the metal to melt. When you cast metals into these investments...if you don’t have correct temperature for investment, flow wont be correct and you wont get cast that you need Silica is not used very much anymore bc have to mix with __ \_\_ and it puts off ___ and its flammable

Answer 28

Investment Binders ## Footnote vCalcium sulfate - low-temperature alloys vPhosphate - high-temperature alloys vSilica - high-temperature alloys Calcium Sulfateà Gypsum Typical gold crown would be invested in a gypsum investment Phosphate: fornonprecious, high Pd, Pt, one that needs more heat to get the metal to melt. When you cast metals into these investments...if you don’t have correct temperature for investment, flow wont be correct and you wont get cast that you need Silica is not used very much anymore bc have to mix with fresh ingredients and it puts off ethanol and its flammable

Question 29

Investment Refractories ## Footnote u\_\_\_\_ - ___ expansion, at ___ temperatures u\_\_\_ u\_\_\_ -\_\_ expansion, at ____ temperatures C: Gives you a lot of expansion at higher temperatures Q: gives you less expansion at higher temperatures but if you look T: gives you the most expansion at\_\_\_\_ temperatures These 3 types of refractories, think about where the expansion is coming from T: Most of its expansion comes at lower T C and Q: most of its expansion comes at higher T Depending on the range of T for burnout determines how much of these materials you want to place in

Answer 29

Investment Refractories ## Footnote uCristobalite - most expansion, at higher temperatures uQuartz uTridymite - least expansion, at higher temperatures C: Gives you a lot of expansion at higher temperatures Q: gives you less expansion at higher temperatures but if you look T: gives you the most expansion at lower temperatures These 3 types of refractories, think about where the expansion is coming from T: Most of its expansion comes at lower T C and Q: most of its expansion comes at higher T Depending on the range of T for burnout determines how much of these materials you want to place in

Question 30

Investment Modifiers ## Footnote \_\_\_ - controls \_\_\_ \_\_\_- controls \_\_\_ \_\_\_ ___ -\_\_\_, \_\_\_ \_\_\_ ___ - \_\_\_, __ \_\_\_ Phosphate investments overall are a more course investment and they have to put Monomagnesium phosphate in there so you can have smooth surface to work with. Without that, surface comes out like sand paper

Answer 30

Investment Modifiers ## Footnote vNaCl - controls expansion vGraphite - controls tarnish vDisodium Phosphate - strength, expansion vMonomagnesium phosphate - expansion, surface finish Phosphate investments overall are a more course investment and they have to put Monomagnesium phosphate in there so you can have smooth surface to work with. Without that, surface comes out like sand paper

Question 31

Gypsum-bonded Investment - Composition ## Footnote v60-75% ___ and/or \_\_\_ v25-35% ___ \_\_\_ \_\_\_ v2-3% \_\_\_\_ vNote: Increasing the \_\_\_/\_\_\_ ratio ___ the hygroscopic expansion but \_\_\_\_the strength If you raise this gypsum ratio (put in more gyp) you’ll get more expansion but it will get weaker bc quartz is responsible for a lot of its strength at higher T

Answer 31

Gypsum-bonded Investment - Composition ## Footnote v60-75% quartz and/or cristobalite v25-35% calcium sulfate hemihydrate v2-3% modifiers vNote: Increasing the silica/stone ratio increases the hygroscopic expansion but decreases the strength If you raise this gypsum ratio (put in more gyp) you’ll get more expansion but it will get weaker bc quartz is responsible for a lot of its strength at higher T

Question 32

Gypsum-bonded Investment - Use at _____ °C ## Footnote v\_\_\_\_\_ decomposes above 700 °C vBreaks down to produce __ \_\_\_\_ or \_\_\_ vGasses\_\_\_\_ alloy vDon’t use with\_\_\_ and\_\_\_ metal alloys v(melting __ \_\_\_ high) vMust use an ___ \_\_\_ It starts releasing gases that will embrittle the alloy Gypsum investments are too weak to use without a ring. Ring is used for strength and to control expansion Without the ring, this stuff blows apart when you try to cast with it

Answer 32

Gypsum-bonded Investment - Use at \<700 °C ## Footnote vCaSO4 decomposes above 700 °C vBreaks down to produce sulphur dioxide or trioxide vGasses embrittle alloy vDon’t use with palladium and base metal alloys v(melting temp. too high) vMust use an investment ring It starts releasing gases that will embrittle the alloy Gypsum investments are too weak to use without a ring. Ring is used for strength and to control expansion Without the ring, this stuff blows apart when you try to cast with it

Question 33

Gypsum-bonded Investment - Silica Refractory ## Footnote u\_\_\_ change upon heating - \_\_\_ to \_\_\_transition uExpansion– thermal _____ of SiO2 cause ____ to open from typical ___ to \_\_\_ When you heat gypsum bonded investments, you get a displasive change upon heating Above\_\_\_ C you get __ \_\_\_ You don’t want to get to fused silica

Answer 33

Gypsum-bonded Investment - Silica Refractory ## Footnote uDisplacive change upon heating - alpha to beta transition uExpansion– thermal inversion of SiO2 cause bonds to open from typical 140o to 180o When you heat gypsum bonded investments, you get a displasive change upon heating Above 1700 C you get fused silica You don’t want to get to fused silica

Question 34

op0-9iGypsum-bonded Investment - Water ## Footnote uReacts with ___ \_\_\_ \_\_\_\_ uAllows\_\_\_ u\_\_\_\_s on heating u\_\_\_\_e + \_\_\_\_--\> \_\_\_\_

Answer 34

Gypsum-bonded Investment - Water ## Footnote uReacts with calcium sulfate hemihydrate uAllows mixing uEvaporates on heating uCaSO4dihydrate + Heating " CaSO4 anhydrate

Question 35

Gypsum-bonded Investment - Thermal Changes ## Footnote vRoom Temp. --\> 700 C - \_\_\_ v700 C --\> Room Temp - ___ \_\_\_ vReheat - __ \_\_, \_\_\_ What if you stick it I the oven and then realize I don’t have any gold Don’t turn the oven off So if you have it in the oven and don’t have any gold, don’t turn the oven off. Just try to find some gold

Answer 35

aQ45Gypsum-bonded Investment - Thermal Changes ## Footnote vRoom Temp. --\> 700 C - expansion v700 C --\> Room Temp - unpredictable contraction vReheat - unpredictable expansion, cracking What if you stick it I the oven and then realize I don’t have any gold Don’t turn the oven off So if you have it in the oven and don’t have any gold, don’t turn the oven off. Just try to find some gold

Question 36

Gypsum-bonded Investment - Dimensional Changes ## Footnote v\_\_\_ v\_\_\_ v\_\_\_ The reason why you want all of this expansion in your investment is that when you cast hot metal into the investment, Metal will ___ when it \_\_\_ You need a little expansion to accommodate for that or your casting wont fit

Answer 36

Gypsum-bonded Investment - Dimensional Changes ## Footnote vSetting vHygroscopic vThermal The reason why you want all of this expansion in your investment is that when you cast hot metal into the investment, Metal will shrink when it cools. You need a little expansion to accommodate for that or your casting wont fit

Question 37

Gypsum-bonded Investment - Role of Water ## Footnote v\_\_\_ ___ \_\_\_ affects setting expansion vExposure to water after mixing - allows ____ growth of crystals (hygroscopic expansion) ' More is less and less is more Too much waterà it will be smaller Hygroscopic investments Set in a water bath He could never get them to fit right

Answer 37

Gypsum-bonded Investment - Role of Water ## Footnote vWater-powder ratio affects setting expansion vExposure to water after mixing - allows greater growth of crystals (hygroscopic expansion) More is less and less is more Too much waterà it will be smaller Hygroscopic investments Set in a water bath He could never get them to fit right

Question 38

Manipulation of Gypsum Investments ## Footnote vIn gypsum investments always remember that ___ \_\_\_ ___ and ___ \_\_\_ \_\_e where W/P ratio is involved.

Answer 38

Manipulation of Gypsum Investments ## Footnote vIn gypsum investments always remember that more is less and less is more where W/P ratio is involved.

Question 39

High-Temperature Casting Investments ## Footnote vSpecial investments required for casting __ \_\_ __ and ___ \_\_ __ \_\_\_ alloys v\_\_\_ and \_\_\_metal alloys cast at higher temperatures, as do High ___ /High ___ alloys. This is bc The metals melt at a very high Temp PFM alloys have to melt at higher temp that gold bc you are bonding porcelain to it and you make porcelain at very high T

Answer 39

High-Temperature Casting Investments ## Footnote vSpecial investments required for casting removable partial denture and porcelain-fused-to-metal alloys vPalladium and base metal alloys cast at higher temperatures, as do High Gold /High Platinum alloys. This is bc The metals melt at a very high Temp PFM alloys have to melt at higher temp that gold bc you are bonding porcelain to it and you make porcelain at very high T

Question 40

Mold Temperature \_\_\_700 C - Requirements ## Footnote \_\_\_ investment \_\_\_ ___ investment vMore \_\_\_\_n (expansion) for ___ of alloys on cooling from higher temperatures Melting at a higher temperature so it shrinks \_\_\_ Need more expansion to commpensate for it

Answer 40

Mold Temperature \>700 C - Requirements ## Footnote vStronger investment vLess reactive investment vMore compensation (expansion) for shrinkage of alloys on cooling from higher temperatures Melting at a higher temperature so it shrinks more Need more expansion to commpensate for it

Question 41

High-Temperature Casting Investments ## Footnote \_\_ bonded - __ \_\_ \_\_\_-bonded

Answer 41

High-Temperature Casting Investments ## Footnote vPhosphate-bonded - most common vSilica-bonded

Question 42

Functional Components ## Footnote vRefractory vBinder (\<20%) vModifying chemicals Binders: \_\_\_, ______ \_\_\_ Fillers/Refractoy:\_\_\_/\_\_\_ Other ingredients are used as buffereing agents: C

Answer 42

Functional Components ## Footnote vRefractory vBinder (\<20%) vModifying chemicals Binders: MgO, Mono-ammonium phosphate Fillers/Refractoy: Quartz/Cristobolite Other ingredients are used as buffereing agents: C

Question 43

Types of Expansion ## Footnote \_\_\_ expansion \_\_\_ expansion

Answer 43

vThermal expansion vSetting expansion

Question 44

Phosphate-bonded Investment ## Footnote vAmmonium diacid phosphate -\_\_\_ temperature \_\_\_ vMagnesium oxide - __ temperature \_\_\_

Answer 44

vAmmonium diacid phosphate - room temperature strength vMagnesium oxide - room temperature strength

Question 45

Phosphate-bonded Investment ## Footnote vSilica - refractory vSilica reacts with \_\_\_P at high temperatures for ___ strength vDifferent particlep sizes affect \_\_\_ vCan be used ___ OR ___ a casting ring Ammonium Diphosphate Phosphate investments are usually a larger particle size, that’s why they add the modifers in to smooth the surface Normally recommend no casting ring Pour in plastic ring and pop it out before you put in oven Reason is so that it can expand more You want more expansion bc metal shrinks more

Answer 45

Phosphate-bonded Investment ## Footnote vSilica - refractory vSilica reacts with ADP at high temperatures for increased strength vDifferent particle sizes affect expansion vCan be used with or without a casting ring Ammonium Diphosphate Phosphate investments are usually a larger particle size, that’s why they add the modifers in to smooth the surface Normally recommend no casting ring Pour in plastic ring and pop it out before you put in oven Reason is so that it can expand more You want more expansion bc metal shrinks more

Question 46

Phosphate-Bonded Investment - Special Liquid ## Footnote v\_\_\_ ___ in water \_\_\_ strength vIncreased __ \_\_\_n due to ___ expansion Don’t just use plain water to mix the phosphate investments Special liqu: Silica sol in water Ratio of special liquid to water affects the expansion If casting with gold, use less % of special water Not easy to work with for gold

Answer 46

Phosphate-Bonded Investment - Special Liquid ## Footnote vSilica sol in water vIncreased strength vIncreased setting expansion due to hygroscopic expansion Don’t just use plain water to mix the phosphate investments Special liqu: Silica sol in water Ratio of special liquid to water affects the expansion If casting with gold, use less % of special water Not easy to work with for gold

Question 47

Investment for All-Ceramics ## Footnote vTwo types developed v __ \_\_/\_\_\_ ___ Investment v\_\_\_ ___ Investment Refractory Die material, the ___ is built ___ Onto the die and fired Pressable: Wax up, invest, burn down, glass pressed into the mold

Answer 47

Investment for All-Ceramics ## Footnote vTwo types developed v Cast Glass/Pressable Ceramic Investment v Refractory Die Investment Refractory Die material, the porcelain is built directly onto the die and fired Pressable: Wax up, invest, burn down, glass pressed into the mold

Question 48

Investment for All-Ceramics ## Footnote vCast Glass/ Pressable Ceramic Investment \_\_\_-bonded investment vMust be ___ to withstand the pressures directed on it from the __ \_\_\_in the pressable ceramic \_\_\_ Set up to where they have a ___ \_\_\_ Put ring in oven, burn it out When it reaches a certain T, take it out, flip it up and it has a specific shape where it was on the screw former and you put a ceramic rod in there, set it oven. When glass gets molten, hydraulics kick in and it presses that glass into the mold

Answer 48

Investment for All-Ceramics ## Footnote vCast Glass/ Pressable Ceramic Investment vPhosphate-bonded investment vMust be strong to withstand the pressures directed on it from the ceramic rod in the pressable ceramic furnaces. Set up to where they have a hydraulic press Put ring in oven, burn it out When it reaches a certain T, take it out, flip it up and it has a specific shape where it was on the screw former and you put a ceramic rod in there, set it oven. When glass gets molten, hydraulics kick in and it presses that glass into the mold

Question 49

Investment for All-Ceramics ## Footnote vRefractory Die Investment v\_\_\_\_-Bonded Investment with __ \_\_ \_\_\_for ___ reproduction vMaterial is poured into an impression of preparations similar to\_\_ __ materials. vThe all-ceramic restoration is constructed ____ on the refractory die. vNote: Coefficient of Thermal Expansion of ___ AND ___ must be matched. Use this just like you would take an impression Lets say we wanted to make some veneers Take impression of veneers and then pour it up with this refractory investment and then restoration is constructed directly on that refractory die Negative: They are pretty specific for the porcelains that you use on them

Answer 49

Investment for All-Ceramics ## Footnote vRefractory Die Investment vPhosphate-Bonded Investment with fine grain filler for detail reproduction vMaterial is poured into an impression of preparations similar to gypsum die materials. vThe all-ceramic restoration is constructed directly on the refractory die. vNote: Coefficient of Thermal Expansion of investment and porcelains must be matched. Use this just like you would take an impression Lets say we wanted to make some veneers Take impression of veneers and then pour it up with this refractory investment and then restoration is constructed directly on that refractory die Negative: They are pretty specific for the porcelains that you use on them

Question 50

vRefractory Die Investment Trim it up Take a spacer and paint on the stone Put it in oven Let it set Has high ammonium content Let it cool Mark margins with special ceramic pencil Build porcelain on it, fire it

Answer 50

Trim it up Take a spacer and paint on the stone Put it in oven Let it set Has high ammonium content Let it cool Mark margins with special ceramic pencil Build porcelain on it, fire it

Question 51

Titanium Investments ## Footnote v\_\_\_-based, \_\_\_-based\_\_\_ bonded investments vSiO2, ZrSiO4, NH4H2PO4 vTicoat vShera \_\_\_\_, ____ based investments vMgO, Allumina, CaO vTitavest CB vGiulini vRematitan Ultra vSelevest D Use these for Titanium Titanium doesn’t act like any other metal If use the wrong investment, Titanium can pull the investment into the surface of the metal

Answer 51

vSilica-based, Zircon-based phosphate bonded investments vSiO2, ZrSiO4, NH4H2PO4 vTicoat vShera v MgO, MgAl based investments vMgO, Allumina, CaO vTitavest CB vGiulini vRematitan Ultra vSelevest D Use these for Titanium Titanium doesn’t act like any other metal If use the wrong investment, Titanium can pull the investment into the surface of the metal

Question 52

Silica-bonded Investment ## Footnote vSilica-bonded, ingredients - ethyl silicate/HCl, colloidal silica in water, sodium silicate vSilica – \_\_\_\_ vUsed for\_\_\_ melting base metal alloys in the construction of ___ \_\_\_ frameworks

Answer 52

vSilica-bonded, ingredients - ethyl silicate/HCl, colloidal silica in water, sodium silicate vSilica – refractory vUsed for high melting base metal alloys in the construction of partial denture frameworks

Question 53

Silica-bonded Investment ## Footnote vTechnique - ___ ingredients must be mixed before use vDisadvantages of ethyl silicate - ____ components released during processing,\_\_\_ Ethanol is released Instead of silica, they have many good phosphate investments Pretty much all labs have gone away from silica for partials

Answer 53

Silica-bonded Investment ## Footnote vTechnique - fresh ingredients must be mixed before use vDisadvantages of ethyl silicate - flammable components released during processing, expensive Ethanol is released Instead of silica, they have many good phosphate investments Pretty much all labs have gone away from silica for partials

Question 54

Soldering Investment - Purpose ## Footnote v\_\_ \_\_s,\_\_\_ \_\_\_ vSolder \_\_\_, \_\_\_. ___ \_\_ \_\_ Lets say you have a partial denture And you have a clasp Patient comes in bc clasp is broken off of the partial How are you going to put another clasp on there? You can solder one on In the old days you had to solder together your gold bridges

Answer 54

Soldering Investment - Purpose ## Footnote vHold parts, protect metal vSolder crowns, bridges, partial denture clasps Lets say you have a partial denture And you have a clasp Patient comes in bc clasp is broken off of the partial How are you going to put another clasp on there? You can solder one on In the old days you had to solder together your gold bridges

Question 55

Soldering Investment - Composition ## Footnote uType I \_\_\_-bonded dental brazing (soldering) investments uType II : ))))-bonded dental brazing (soldering) investments What we actually do in dentistry is \_\_\_\_...not really soldering Type I: use with lower T melting metals Type II: use for higher T melting metals

Answer 55

Soldering Investment - Composition ## Footnote uType I : Gypsum-bonded dental brazing (soldering) investments uType II : Phosphate-bonded dental brazing (soldering) investments What we actually do in dentistry is brazing...not really soldering Type I: use with lower T melting metals Type II: use for higher T melting metals

Question 56

Soldering Investment - Properties ## Footnote uANSI/ADA Specification No. 93 Quality – uniform and free from foreign matter and lumps Fluidity Setting Time – shall not vary by more than \_\_\_% of time claimed by manufacturer vCompressive Strength – _____ MPa vLinear setting expansion – shall not vary by more than \_\_% of manufacturers claim vLinear thermal expansion – shall not vary by more than\_\_\_ % of manufacturers claim

Answer 56

Soldering Investment - Properties ## Footnote uANSI/ADA Specification No. 93 Quality – uniform and free from foreign matter and lumps Fluidity Setting Time – shall not vary by more than 30% of time claimed by manufacturer vCompressive Strength – 2.0 – 10.0 MPa vLinear setting expansion – shall not vary by more than 15% of manufacturers claim vLinear thermal expansion – shall not vary by more than 15% of manufacturers claim

Question 57

Soldering Investment - Properties ## Footnote vDesigned to have ___ setting and thermal expansion vType I for \_\_\_r melting point alloys vType II for\_\_\_\_ melting point alloys vParticle size normally ___ since smoothness of the mass is\_\_\_\_

Answer 57

Soldering Investment - Properties ## Footnote vDesigned to have low setting and thermal expansion vType I for lower melting point alloys vType II for high melting point alloys vParticle size normally larger since smoothness of the mass is immaterial

Question 58

Investments contain

Answer 58

free silica