4. Waxes Flashcards
Dental Waxes Compositions Three general components • \_\_\_\_ waxes: – \_\_\_\_ – Plant – \_\_\_\_ - Insect • \_\_\_\_ Waxes • \_\_\_\_
natural mineral animal synthetic additives
COMPOSITIONS Natural Waxes • Mineral Waxes (\_\_\_\_, Ceresin) From \_\_\_\_- mixture of \_\_\_\_ • Wide range of molecular \_\_\_\_ and \_\_\_\_ ranges • Partly \_\_\_\_ • Flaky, not \_\_\_\_ or glossy surface
paraffin ceresin petroleum hydrocarbons wt. melting crystalline smooth
COMPOSITION Natural Waxes Plant Waxes (\_\_\_\_)
- ____, Acids, Alcohols, resins
- Hard and ____, high ____ range
- Used to ____ the melting range and hardness of ____ waxes.
carnauba esters brittle melting increase paraffin
Plant waxes - Carnauba
From a Brazilian ____ - they pick the leaves, crush and ____ until the wax kind of flakes off the surface. Contributes to the glossy ness of the mineral waxes
Plant waxes - Candelillia
Found in ____ from Mexico, tend to be used in cosmetic industry. Extracted from ____ the plant to separate the wax (floats to the top) from the plant material.
palm tree
dry
shrubs
boiling
COMPOSITIONS Natural Waxes
Animal Waxes (____)
• ____, and unsaturated hydrocarbons
• Modifies ____
• Spermaceti wax is the coating for ____ from sperm whale
spermaceti
esters
properties
dental floss
COMPOSITIONS Natural Waxes • Insect (\_\_\_\_) Main component of \_\_\_\_ . Esters, Sat. and Unsat. \_\_\_\_, and organic acids . Brittle but becomes \_\_\_\_ at body temp.
This is the wax that you should stabilize your ____ with after you take a model, it becomes brittle so if the models ever shift from the articulation the wax will be brittle and dislodge
beeswax
sticky wax
hydrocarbons
plastic
impression
COMPOSITION Synthetic Waxes
- ____ from batch to batch
- Similar properties to ____ waxes
- Limited ____ with other waxes
Synthetic waxes include:
• ____ waxes, wax esters
• ____ glycol waxes
• ____ and hydrogenated waxes
Synthetic waxes are usually consistent and are usually used as ____ materials. They increase rigidity and modify the ____ of the wax
consistent
natural
compatibility
polyethylene
polyoxoethylene
halogenated
impression
crystallinity
COMPOSITIONS
Additives
• Gums : viscous, ____, harden on exposure to ____
• Fats : tasteless, ____, colorless, feel greasy. Increases ____ range and ____
• Resins : produce ____ products
Gums: since they are amorphous they have no definite ____ shape
Amalgam restorations used to be lined with something called a copalite and it was made from a resin called ____ (a naturally brittle resin dissolved in an organic solvent) and was thought to decrease ____ Only placed with ____ NOT resin bc it prevented them from curing
amorphous air odorless melting hardness harder
crystalline
copa
sensitivity
amalgam
Properties of Waxes • \_\_\_\_ Range • Thermal Expansion • \_\_\_\_ Properties • Flow • \_\_\_\_ Stress • Ductility
melting
mechanical
residual
PROPERTIES OF WAXES
Melting Range
• Waxes contain different types of molecules so they have melting ____ instead of melting ____.
• Most waxes contain ____ wax and ____ wax. When combined in a 75% to 25% mixture the ____ range dramatically increases
The graph is how it changes the melting of the waxes.
“At the beginning with just the mineral wax the melting range is very small, but as you increase the contribution of the plant to mineral wax the melting range increases”
ranges
points
paraffin
carnauba
PROPERTIES OF WAXES
Thermal Expansion
- Waxes ____ when subjected to a rise in temp and ____ as temp decreases.
- Dental waxes have the largest coefficient of ____ than any other dental material.
- Many waxes have at least ____ rates of expansion between ____ and ____o C . The changes occur at ____ points.
- That is very important bc all of the cast restorations are waxed up, so you want to make sure that you invest it and cast it and not let it sit for an extended period of time, bc the ____ change after its sat for a while. You will learn this when making a gold crown in GRD 2. If you make up and inlay or a PFM and dont invest and cast it in time then changes can occur and the final restoration may not fit
expand contract thermal expansion 2 22 52 transition
properties
PROPERTIES OF WAXES
Thermal Expansion
Clinical consequence of High ____
Changes in wax patterns after critical dimensions are set may be a major contributing factor to ____ of the finished restoration.
expansion
inaccuracy
PROPERTIES OF WAXES
Mechanical Properties
- Elastic Modulus, Proportional Limit and Compressive Strength are ____
- Dependent on ____
- The modulus of the inlay wax is important in the ____ of casting investment in which the wax pattern is subjected to stresses resulting from the expansion of investment during setting.
Elastic modulus - elasticity, when the impression is subject to ____ or compression
Proportional limit - greatest stresses the material can sustain before ____
Compressive strength - ____, especially within the forces of mastication in registration wax
low temperature hygroscopic expansion tension deviation resistance
PROPERTIES OF WAXES
Flow
• ____ of molecules over each other. Flow is dependent on the ____ of the wax
• Direct inlay wax technique
– ____ flow required a few degrees above ____ temp.
- instead of preparing a tooth for a class 1 amalgam you would prepare it for a class 1 inlay then melt the wax directly in you prep and set at mouth temp so you could remove it without ____ in any way. So this property of the flow of wax became very important
slippage temp high mouth deforming
PROPERTIES OF WAXES Flow
• Direct inlay wax technique
– At mouth temp. An inlay wax must have no ____ to prevent ____ of the pattern during removal from the tooth cavity
flow
distortion
PROPERTIES OF WAXES Residual Stress (____ Effect)
• Residual stress exists in a completed pattern due to ____ from adapting the wax
Why not just soften the wax in the preparation and have the pt bite down? This is memory effect (residual stress), if you force it into the cavity and take the impression but once you remove it and the external walls aren’t there to hold it in it tends to ____ again bc of all of the molc that were forced in there originally
memory
pressure
expand
PROPERTIES OF WAXES
Ductility
- Like flow, ductility increases as the ____. of the wax specimen is increased
- Waxes with ____ melting temps have a greater ductility at any given temp than those with higher melting temps
- Generally highly refined waxes are ____
- Ductility of mineral waxes increases if appreciable amounts of occluded ____ is present
All of the properties of wax are ____ dependent.
2. When you use beading wax you can mold it just from the heat of your ____, compared to something like inlay wax that you have to melt in order to flow and stretch
Ductility is defined as the ability of the material to be ____ deformed
temp lower lower brittle oils
temp
hands
plastically
Classification
Pattern: ____, inlay, ____
Processing: ____, boxing, ____
Impression: bite, ____
Classification based on ____ and ____
Pattern waxes have 2 important properties: 1. the thermal changes that occur in ____ (meaning its temp sensitive). 2. There is a tendency for the waxes to warp or distort on ____. You cant let it set for an extended period of time.
Processing waxes are used as auxiliary aids. What i said about beading wax and boxing wax so that you can pour up a model within an area as opposed to the double pour technique where you pour the model in the impression and make a patio on the desk of your red rubber cast formers. What you would do instead would bead of use the red utility wax to surround the impression then use the boxing wax to surround the utility wax and you can pour your model the ideal way. This was the air bubbles rise up as compared to a 2 pour technique where you flip the impression over onto a patio on the desk and air bubble rise to the occlusal surface as opposed to the base of the cast (listened to this 3x she is pretty wordy here idk rambles a ton)
Impression waxes used if you know that the pt has an ____ (especially for a denture) you can make the impression using a bite or corrective type wax to be able to remove it from the undercut easily
casting
baseplate
utility
sticky
use
application
dimesnion
standing
undercut
Dental Waxes • \_\_\_\_ Wax • Casting Wax • \_\_\_\_ Wax • Boxing Wax • \_\_\_\_ Wax • Sticky Wax • \_\_\_\_ Impression Wax • Bite Registration Wax
- Was used to create pattern for a ____ prosthesis
- Used for a ____ occlusal rim
inlay baseplate utility corrective RPD denture
DENTAL WAXES Inlay Pattern wax
Used to wax up many different abutments including a ____ unit crown/bridge
3
DENTAL WAXES
Inlay Pattern Wax
- Gold inlays, crowns, and bridge units are formed by a casting process that uses a ____ wax pattern technique.
- A wax pattern is constructed, then embedded in a ____ investment material to form a mold with a ____ leading from the outer surface. The wax is eliminated by ____ and conditioned to receive the molten gold.
lost
gypsum
sprue
heating
Inlay Wax – Casting Process
You need a wax that flows just slightly above ____ temp but then once at that temp solidifies and forms. You retrieve you wax pattern, then sprew it and invest it, this is the lost wax technique.
Once you fill this ring with investment material (a mixture of cement and stone) you place it in a water bath to ____ and remove the crucible former.
Now your wax pattern is embedded in the investment and place it in the ____ (to burn out the wax pattern and the sprue) and place it on a ____ to place the melted metal (gold in this case) by the channel created by the sprue. There is different combinations of gold and other materials that can be used for your final restoration.
IMPORTANT for this technique to understand the ____ of the wax that you’re using bc the wax is subjected to quite a few ____ as the investment around it is setting.
mouth solidify oven centrifuge elastic modulus forces
DENTAL WAXES
Inlay Pattern Wax
Composition
- Parrafin ____
- Carnauba ____
- Ceresin ____
- Beeswax ____
ADA specification No. ____ (for inlay wax)
Classication
- Type ____- soft
- ____
- ease of ____
- Type ____- medium
- ____ (mouth)
- lower ____
60%
25%
10%
5%
4
II
indirect
carving
I
direct
lower
DENTAL WAXES
Inlay Pattern Wax - Features
- Wax patterns should have no ____ remain in the mold
- ADA specification 4 limits the non-volatile residue of these waxes to ____%.
- High coefficient of ____ and tends to warp or distort when allowed to stand ____.
This means when you burn out the wax in the oven that there shouldn’t be anything (like film) left in that investment pattern more than ____
residue
0.01
expansion
unrestrained
0.01%
Inlay Pattern Wax
• Distortion increases with ____ and time of ____.
• The higher the temp of the wax during adaptation the less tendency for ____ in the prepared pattern
• Distortion due to residual stress in the pattern is due to forces necessary to form the ____.
Distortion inc with temp and time of storage. This comes back to the fact that instead of warming the wax to soften and shoving it in the preparation you should melt the wax and slowly flow it into the prep aka the higher the temp that you melt it at the less distortion (remember this is due to the ____ effect)
temperature
storage
distortion
pattern
residual stress/memory
DENTAL WAXES Inlay Pattern Wax
• Minimize residual stress by
– Uniform ____ of wax
– Heat at ____ oC for at least 15 mins.
– Use ____ carving instruments and a warm die
– Add wax to the die in ____ amounts
– Investing the pattern ____
– Reduce distortion during spruing by using a ____ sprue or a hollow metal sprue filled with ____
softening 50 warm small immediately wax wax
DENTAL WAXES Inlay Pattern Wax
- If the pattern is stored, it should be ____
- Allow pattern to attain ____ temperature, then the margins should be ____ before investing.
refrigerated
room
readapted
DENTAL WAXES
Casting Wax
• Used for patterns for ____ framework of removable partial ____
• Available as ____ and ready made shapes
• Composition- ingredients similar to ____ waxes
• Slight degree of ____ to maintain their position on the cast and on each other
metallic dentures sheets inlay tackiness
DENTAL WAXES
Baseplate Wax
Used for record bases and ____ rims to establish ____, plane of ____ and initial ____ for complete dentures.
Normally ____ color provides esthetics for the desired contour of the denture after the teeth are set
occlusal VDO occlusion arch pink
DENTAL WAXES
Baseplate Wax
Typical composition Ceresin - \_\_\_\_ Beeswax - \_\_\_\_ Carnauba - \_\_\_\_ Natural or synthetic resins \_\_\_\_ Microcrystalline or synthetic waxes \_\_\_\_ Normally supplied in pink or red sheets.
80% 12% 2.5% 3% 2.5%
Dental waxes
Baseplate wax
Classification
- Type ____- soft
- for building ____ and ____
- Type ____- hard
- for ____ in mouth
- ____ weather
- Type ____- extra-hard
- patterns in ____, ____ weather
1
contours
veneers
2
patterns
temperate
3
mouth
hot
DENTAL WAXES Baseplate Wax
Softened sheets shall cohere readily without becoming ____ or adhering to ____
No ____ of oral tissues. Trim ____with a sharp instrument at 23 °C
- ____ glossy surface after gentle flaming.
- No ____ on porcelain or plastic teeth
- ____ shall not separate or impregnate plaster during processing
- No ____ to other sheets of wax or separating paper on storage
flaky
fingers
irritation
easily
smooth
residue
coloring
adhesion
DENTAL WAXES
Baseplate wax
- Residual stress within the baseplate results from the ____ and ____ of wax with a hot spatula
- ____ and ____ affect the relief of these residual stresses.
- Invest waxed and articulated denture ____ to avoid distortion and movement of teeth.
Some trouble students have is softening the wax too much and then they set the tooth in the occlusal rim, but as it sets it will pull the tooth off the plane
You never want a situation where its pooling with baseplate wax. Also you should never let the impression wax set for a while.
cooling pooling time temp soon
DENTAL WAXES
Boxing wax
To form a ____ or ____ cast from an impression of an ____ arch, a wax box must first be formed around the impression.
Inside this final impression is a strip of beading/utility wax, which is very sticky and tends to adhere to the impression nicely. Outside is a rim of boxing wax. The air bubbles here will rise to the surface (the base not the occlusal)
plaster
stone
edentulous
DENTAL WAXES
Boxing wax: Features
• Pliable at ____ oC
• Retain its shape at ____ oC which defines its lower temp limit of ductility and flow.
• It should be slightly ____ and readily adapted to the impression at ____ temperature, with sufficient strength
21
35
tacky
room
DENTAL WAXES
Utility wax - Features
• Easily ____ adhesive wax.
• The ____ and ____are the ____ of dental waxes.
• Adhesiveness is required at ____ temp.
• For altering standard ____ tray to a more desirable ____ to prevent distortion of the material.
• Supplied in both ____ and ____ form in white, dark red or orange.
This is not the wax you use to stabilize your models, its very tacky and soft. Its ____ dependent and has one of the highest ductility and flow. If you want to make sure your models are articulated correctly this is not the wax to use (some upperclassman do bc its easier to use, dont listen to them)
workable ductility flow highest room impression contour stick sheet
temp
DENTAL WAXES
Utility wax - Features
Composition: ____, ____ and other soft waxes in various proportions
beeswax
petrolatum
DENTAL WAXES
Sticky wax
• A suitable sticky wax for prosthetic dentistry is formulated from a mixture of ____ and ____ or other additive ingredients.
• Should ____ rather than flow if deformed during soldering or repair procedures.
• ____ when melted and ____ closely to the surfaces on which it is applied.
The wax is firm, free from ____, and ____ at room temp
The sticky wax you have came in yellow or orange sticks. In prosth dentistry it is mostly for stabalizing models bc it fractures rather than flows. This way you know right away when working with it if the broken pieces have separated. When its melted it adheres closely to the surfaces from which its applied and very easy to remove it (since its brittle you can flake it off with an instrument)
waxes resins fracture sticky adheres tackiness brittle
DENTAL WAXES
Sticky wax
• This wax is used to assemble metallic, gypsum and resin pieces in a fixed, ____ position
• Sticky wax should have a ____ or vivid color so it is easily distinguished from the light colored gypsum materials.
• Shrinkage should be ____% or less between ____ and ____o C.
temporary dark 0.5 43 28
DENTAL WAXES Sticky Wax Composition: • \_\_\_\_ – Natural plant resin • Yellow \_\_\_\_ (main 2 ingredients) • \_\_\_\_ • Gum \_\_\_\_
rosin
beeswax
resins
dammar
DENTAL WAXES Corrective Impression Wax
- Used as a veneer over and register detail of the ____ tissues.
- Records the ____ membrane and underlying tissues in a functional state in which movable tissue is displaced.
* The flow of several corrective waxes measured by penetration at ____ oC is ____%
Let’s say you’re taking an impression of the maxillary arch and the palate was very steep or a deep mucobuccal fold, there are waxes that you can melt to fill those to get a good impression. Sometimes with edentulous pt there are big voids from where there were tori that weren’t removed and you are not able to get a rigid material over that surface you use and impression wax
Making an impression to get the ideal depth of the fold you place the wax and have the pt do a lot of different movements so that you understand how much room there is for the pt to function
soft
mucous
37
100
DENTAL WAXES Corrective Impression Wax
Composition:
• Formulated from hydrocarbon waxes such as ____,
____, and ____ and may contain ____ particles
paraffin
ceresin
beeswax
metal
DENTAL WAXES Bite Registration Wax
• Used to accurately articulate models of ____ quadrants.
- Composition:
- Formulated from ____ or hydrocarbon waxes such as ____ and ____. Certain bite waxes contain ____ or ____ particles
In order to accurately record how the pt occludes you soften the bite wax in warm ____ (doesnt need to be heated up) then place in the pt mouth
opposing beeswax paraffin ceresin aluminum copper
water
Pattern Materials
Resin Modeling material
- ____-cured acrylic plastics can be used for ____ patterns.
- Light-curing resins are also used for the fabrication of patterns for cast ____ or ceramic inlays, crowns and bridges and precision attachments
- They have lower heat of ____ .
- ____ strength and resistance to flow than waxes.
- Good ____
- Burnout without ____
Only concern we have with this is heat is released on polymerization and that can be damaging to the ____. The heat of polymerization is still less than that from provisional ____ compounds
self
inlay
metal
polymerization
higher
dimensional stability
residue
pulp
restoration
Resin Pattern Materials
This is probably what you will see on the clinic floor: ____ resin or ____
pattern
Duralay
Comparison of the dimensional stability of three inlay pattern materials
Analysis of data showed that none of the materials distorted and that all the patterns underwent a proportional contraction, with wax contracting ____ than Duralay and Modilux.
Significantly more contraction occurred at ____ hours than between onset (0 hour) and 1 hour. As contraction only occurred after 1 hour and ____ contracted the most, it is recommended that Duralay or Modilux be used as the ____ material, especially if a delay in investing is anticipated.
Remember you want to try and ____ your wax within a half an hour bc if it sits for longer the temp changes can cause ____ in the pattern
more 24 wax pattern invest distortion
This is one of the ways you would use the pattern resin. These are called speedy post and usually used in a powder/water ratio (salt and pepper technique). If you look carefully at the bottom, 3 crowns are being fabricated for final restoration. One has some tooth structure entact but the other 2 are missing tooth structure. If you try to place a crown on what’s left of those it wouldn’t be very retentive so we make a cast post and pour. You start with the speedy post and take the paintbrush to wet it with the monomer and add monomer/polymer powder and build it up on the post and insert in into the canal. In order to do this the tooth would have to have been endo treated then creating the post. Add the resin material while its still soft and wait until it starts to gel then insert into the canal. You pretend this is tooth structure and create your crown prep. (F)
So what you have is a crown prep attached to a prep and that gives increased retention of the final restoration. Usually this is cemented first then you take an impression of this (I)(it is invested and cast similar to the wax pattern with the lost wax technique and hygroscopic material). Then once it is retrieved it is now metal and you would take your final impression for restoration that would be cemented on top.
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