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Dental Waxes (1)

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DENTAL WAXES
• Waxes are thermoplastic materials
which are solids at room
temperature but melt without
decomposition to form mobile
liquids
WAXES
Definition(GPT-8)
One of the several esters of fatty acids with higher
alcohols.
Dental Waxes are combinations of various
types of waxes compounded to provide
desired physical properties.
DENTAL WAXES
• A low molecular weight ester of fatty acids
derived from natural or synthetic components.
Obrein,
268
CLASSIFICATION
(based on application)
DENTAL
WAXES
PATTERN
WAX
PROCESSING
WAX
IMPRESSION
WAX
• STICKY
• CARDING
• UTILITY
BLOCK
OUT
IMPRESSION
CASTING
INLAY
RESIN
BASEPLATE
PROCESSING
PATTERN
•
•
•
•
• BOXING
• UTILITY
• CORRECTIVE
• OCCLUSAL
REGISTRATIO
N
Mc Cabe
•
•
•
•
Bite registration
Disclosing wax
Utility wax
Low melting type
1 inlay wax
Lab waxes
Clinical use
CLASSIFICATION
• Boxing wax
• Sticky wax
• Beading wax
Based on source
•
•
•
•
Mineral
wax
Paraffin
Montan
Barnsdhal.
Ozokerite
Microcryst
alline
Plant wax
Insect wax
• Carnauba
• Ouricury
• Candellila
• Japan
wax
• Cocoa
butter
• Bees wax
Animal wax
• Spermaceti
wax
COMPOSITION OF DENTAL WAXES
•
•
•
•
•
•
•
•
Paraffin wax- 60%
Bees wax-5%
Carnauba wax-20%
Candelilla wax
Microcrystalline wax
Synthetic wax-2%
Gum damar-3%
Ceresin -5%
Paraffin wax
•
•
•
•
Most dental waxes contain 40-60% paraffin
A mineral wax obtained from refined crude oil
(high boiling fraction of petroleum)
White, transparent
• Presence of oils lowers the melting point.
• Paraffin wax used in dentistry have <0.5 %
oil.
• They crystallize in the form of plates,
needles and crystals, but are usually of the
plate type.
BEES WAX
• Derived from secretions that bees use to build
honey combs.(insect wax)
• Is a complex mixture of esters, consisting
mainly of myricyl palmitate plus saturated and
unsaturated hydrocarbons and organic acids.
•
• Brittle .
• Intermediate melting range-60-70 degree
• Added to dental wax because of its desirable flow
properties at oral temperature.
CARNAUBA WAX
• fine powder on the leaves of certain
tropical palms.
• It is known as "queen of waxes one of
the purest wax.
• usually comes in the form of hard
yellow-brown flakes.
• Hard ,tough with high melting range
• Added to toughen Paraffin and raise melting range
• So flow decreases .
• Imparts glossy surface.
Addition of 10 % carnauba wax to paraffin
wax with a melting range of 200C will
increase the melting range to 460C.
CANDELILA WAX
o leaves of the small Candelilla shrub native to northern
Mexico and the southwestern US.
o Melting range 68-75°C.
o Increases the hardness.
o
similar qualities as carnauba wax
Euphorbia antisyphilitica
CERESIN
• Ceresin is a term that describes waxes from distillates of
natural mineral, petroleum, or lignite refining.
• They contain straight and branched hydrocarbon chains of
higher molecular weights.
•
• Harder than other hydrocarbon waxes.
CERESIN
• Typically a white wax extracted from ozokerite- waxy
mineral mixture of hydrocarbons
• Replaces part of paraffin to modify toughness and
carving characteristics of wax.
MICROCRYSTALLINE WAX
• Litene and barnsdahl are micro crystalline waxes similar
to paraffin but obtained from heavier oil fractions.
• composed of branched hydrocarbons
• crystallize in small plates.
• tougher and more flexible than paraffin.
Ouricury Wax
• Ouricury wax is a brown-colored wax obtained
from the leaves of a Brazilian Feather Palm by
scraping the leaf surface.
• Gloss and hardness.
Synthetic Waxes
• Complex organic compounds produced by reaction with
natural waxes.
• More refined than natural waxes .
• Specific melting points.
• Use in dental formulations is limited as they have
limited compatibility with other waxes.
Types
• Polyethylene waxes
• Polyoxyethylene glycol waxes
• Halogenated hydrocarbon waxes
• Hydrogenated waxes
POLYETHYLENE WAX
• Polyoxyethylene waxes are polymers of ethylene
glycols.
• melting temperature - 37 °C - 63°C
function as plasticizers and toughen films of
wax
Montan Wax
• It is a hard wax obtained through solvent extraction of
certain different types of lignite or brown coals.
• As a result, montan wax is hard and brittle.
• Melting range 72-92°C
• Improve hardness and melting range of paraffin
waxes.
• Blends well with other waxes
Spermaceti Wax
• Obtained from sperm of whales.
• Mainly esters
• Used as a coating in the manufacturing of dental
floss
Gum Dammar
• Obtained from a certain family of trees in India and East
Asia
• Damar is produced by tapping trees
• some is collected in fossilized form from the ground.
• Clear to pale yellow
• fossilized form is grey brown
• Composition - less than 1%
• Added to paraffin to improve its smoothness in
molding.
• Increases the toughness of the wax- renders it more
resistant to cracking and flaking.
• enhances the lustre of the wax.
DESCRIPTION OF WAXES IN DENTISTRY
PATTERN WAXES
INLAY WAX
CASTING WAX
PATTERN
RESIN
BASEPLATE
WAX
Pattern Waxes
• Used to form general pre determined size & contour of
an artificial restoration
• Later it is replaced by more durable material such as
cast gold, cobalt- chrome nickel alloys etc
• They exhibit thermal change in dimension and warpage
on standing
•
INLAY WAXES
• used to make patterns for Inlays, crowns &
bridge units by lost wax casting technique .
• pattern of wax duplicates shape and contour of
casting .
• After investing & spruing the wax is eliminated
by heating
Composition of inlay wax
•
•
•
•
•
•
•
Paraffin- 60%
Carnauba- 2o%
Ceresin- 10%
Bees wax- 5%
Gum dammar-5%
Microcrystalline wax-minute
Coloring agents
Type I - Direct
• •Revised ANSI/ ADA Sp. No. – 4
• Hard wax used for forming patterns directly in
mouth.
• It must soften at a temp that is not hazardous to
pulp and must harden above mouth temp.
• Rarely used method because of its sensitivity to
changes in pressure, temperature and heating
and cooling rates during manipulation.
•
• A wax pattern made in the mouth will shrink
appreciably as it is cooled to room temperature
Type II - Indirect
• Softer wax used for indirect technique.
• Dark blue-hard, for crowns bridges and inlays. Add on
and Dip use –MP- 690C
• Light blue-soft, for crowns bridges and inlays,add on
and dip use –MP-720C
• Lilac-stress free, for copings and cervical margins
• MP- 790C
• Red- adhesive, connecting and adhesive wax, MP 700C
PATTERN RESIN
• Are characterised by higher strength and resistance
to flow than waxes.
• Good dimensional stability.
• Burn without residue.
• Full crown patterns made with resin and inlay
waxes have similar marginal discrepancies.
PATTERN RESIN
• A pattern is fabricated by applying resin in 3-5
mm layers and curing in a light chamber or with
hand held light curing unit.
• Resin is completely eliminated from mold before
casting by heating.
DENTAL CASTING WAX
• Used for thin sections of certain removable and
fixed partial denture patterns
• Convenient in preparation of copings or clasps
requiring uniformly thin regions
• ADA no 140
Types of casting wax.
CLASS 2
CLASS 3
• Blue sheets
• Burn outͦ
• No carbon
residue
CLASS 1
BASEPLATE WAX
• ADA no 24
• made from 75% paraffin or ceresin
• Used for constructing full denture patterns and
occlusal rims.
• Also for bite registration
• Hard and brittle at room
temp
TYPES OF BASEPLATE WAX
• Type 1- soft
• For veneers and contours
• Type 2-medium hardness designed for
temperate climate
• Type 3-hardest
• for pattern try in at tropical climates
• Hardness is based on amount of flow the wax
shows at 45 ͦ C
PROCESSING WAX
•
•
•
•
•
•
Boxing wax
sticky wax
carding wax
block out wax
white wax
utility wax
BOXING WAX
• Mouldable at room temp
• Can be easily pressed to desired contours around
the perimeter of an impression and
• To form containers for pouring casts.
Undercut/block out wax
• To fill voids and undercuts for RPD fabrication
Wax rim /bite rim
• Softening temp -above mouth temperature
• Tough and resist fracture during removal from
cast
• uses: arrange teeth
• Restoring occlusal relation
Sticky Wax
• A mixture of waxes, resins & other additives •
Sticky when melted, adheres closely to dry clean
surfaces
• Temporarily join gypsum components.
• Stabilize components of bridge befor soldering.
• Attach pieces of broken dentur prior to repair.
IMPRESSION WAXES
Iowa Wax-White
• H-L physiologic paste-yellow white
• Adaptol -.Green
• Korecta Wax No 4. - Orange
•
KORRECTA WAX
• Soft NO. 4 - (Orange)
Soft NO. 3 - (Red)
• Hard NO. 2 - (Yellow)
Extra Hard No. 1 - (Pink)
•
CORRECTIVE IMPRESSION WAX
• Paraffin wax:bees wax-3:1
• For flow at mouth temp
• Use; to correct small imperfections and air
blows in ZnOE impression.
• Disadvantages: easily distorted
• So pour cast immediately
BITE REGISTRATION WAX
• interocclusal records
• High resistance to closure
• High coeff of thermal expansion.
Bite Wafer-U-shaped-
• Used for checking occlusal relationships.
• Thin foil layer prevents teeth from biting through.
ALUWAX
• Alu Wax- used to verify jaw relation records.
• Contains Aluminum and Cuprex chloride
OCCLUSAL INDICATOR WAX
To detect areas of premature occlusal contact
Diagnostic wax
• diagnostic wax - formulated for planning and creating
esthetic life like presentations.( diagnostic wax up)
• It can be easily carved, excellent stability, low shrinkage
and burns out clean.
•
PONTIC WAX
Pontic wax is a general crown and bridge wax and can be
used for margins. It has zero shrinkage.
METHODS OF SOFTENING WAX
• Bunsen burner-hold wax in warm air above flame.
• Water bath-more regular softening.
▫
Dis adv-water incorporation.
▫
Components may leach out.
▫
Infrared lamp-250 W –standardisation test of waxes
Wax annealer-ideal method
▫ Thermostatically controlled oven.
Properties
•
•
•
•
•
•
• Melting range
• Thermal expansion
• Mechanical properties
• Flow
• Residual stress
• Ductility
Melting Range
• Have a range as they contain several types of
molecules, each having a range of molecular
weight
• Melting temperature:
• Beeswax is 62.8°C.
• Paraffin wax is 52°C.
• Melting range: Beeswax is 34-70° C.
• Paraffin wax is 44- 60°C
Thermal Expansion
• Waxes have the largest co- efficient of thermal
expansion among all dental materials.
Flow
• It indicates the degree of plastic deformation at a
given temp.
• Flow is greatly increased as melting point is
approached .
• Result of slippage of molecules over each other.
Application
• A direct inlay wax should have a high flow just a
few degrees above the mouth temperature so it is
not too hot in workable condition.
• Should have a no flow at mouth temperature so
that it does not distort during removal of
pattern.
• The flow of corrective wax at 37°C is 100%
• bite registration wax is 2.5%-22%
Mechanical Properties
•
•
•
•
• Elastic modulus
• Proportional limit
• Compressive strength
All are low when compared to other materials
Elastic Modulus
•
•
•
•
carnauba wax is highest
• Bees wax – lowest
• Decreases with increase in temperature.
• Inlay wax (simulates a mixture of 75% paraffin
& 25% carnauba wax) – 760 to 48.2 MPa ( 23°C& 40°C
Residual Stress
• Residual stresses always exist in a prepared wax
pattern .
To minimize distortion
• .Use higher temperature at time of formation –
less force to shape – less residual stresses
Soften the wax uniformly at 50°C for 15 min
Warmed carving instruments & die.
DIMENSIONAL CHANGE AND WAX PATTERN DISTORTION
DURING AND AFTER MOLDING
• Wax molded into a cavity will show two types of
shrinkage:
• one is the shrinkage during solidification,
• and the other is the cooling shrinkage after
solidification.
• contraction during solidification is much larger
than the thermal shrinkage that occurs after
solidification.
Rheology of dental waxes.
• “pressmolding”-technique in which softened wax was
molded in the mold by a heavy finger pressure.
• “pour and press-molding” technique in which fluid
wax was poured in the mold and held by a heavy finger
pressure before hardenin.
• “pour-molding” technique in which fluid wax was
poured in the mold and no pressure was applied.
• the press-molding technique produced the most
accurate patterns
• the other two techniques using fluid wax
resulted in greater shrinkage.
Penetration of Commercialand
DentalWaxes J. M. POWERS, R. G.
CRAIG,JDR,1974
• Annealing paraffin increases the crystallinity of
the lattice
• increased crystallinity offers more resistance to
penetration
• Annealing paraffin at 40 C for 24 hours was
shown to increase the resistance to penetration.
CONCLUSION
• These different dental waxes work quite well and
are inexpensive and surprisingly not replaced by
newer high tech materials..
REFERENCES
• Dental Materials And their Selection William J
.O Brien 3 rd ED
• Kenneth j. Anusavice ; Phillips Science of dental
material .Eleventh edition, Elsevier,2004.
• Robert C. Craig John M. Powers, John
C.Wataha ;Dental materials properties and
manipulation,. Eight edition,2004.
• Kenneth j. Anusavice ; Phillips Science of dental
material .Eleventh edition, Elsevier,2004.
• Robert C. Craig John M. Powers, John
C.Wataha ;Dental materials properties and
manipulation,. Eight edition,2004.
• Craig’sRestorative Dental Materials. John M.
Powers.Ronald .Sakaguchi
• Dental Materials And their Selection William J
.O Brien 3 rd ED
Yellow bite wax
Carnauba did not flow until it reached a
very high temperature close to its setting
range, and the sharpCarnauba
sloping curve
did not flow until it reached a
illustrates that this wax
flowed
over a smallclose to its setting
very high temperature
temperature range. range, and the sharp sloping curve
illustrates that this wax floweCarnauba did
not flow until it reached a very high
temperature close to its setting range, and
the sharp sloping curve illustrates that this
wax flowed over a small temperature
range.
d over a small temperature range.
Red Indicator Wax
• The user scans a model
• A virtual wax-up is designed using 3-D software
• Data is sent to the ProJet™ Production System
to "print" wax-ups in layers
• Accepts standard STL file
• The system can generate hundreds of units each
cycle. The wax-ups have a smooth surface finish
and can be cast or pressed with conventional
techniques.
• DTA measurements2 indicate that the beeswax used in this study is
a mixture of hydrocarbon and ester waxes, each of which has a
distinct endothermic melting transition. At the lower stress, the
higher melting component provides sufficient integrity to the wax
for it to resist penetration, although the lower melting component
has undergone a major phase transition. The resistance of beeswax
to penetration is influenced at high stress levels by the temperature
at which the lower melting component transforms. Carnauba wax is
a relatively pure, highmelting ester wax.2 Penetration at both stress
levels corresponds to the melting transformation: penetration at the
higher stress level occurs at the onset of the melting transition and
penetration at the lower stress level occurs near the completion of
the melting transition. At the two levels of stress studied, the solidsolid transition of carnauba, which occurred at 61.0 C, had no
influence on penetration
• mineral waxes generally expanded SETTING
RANGE Time Interval, Minutes 0 0 I- 401 , , , a I I I
0 10 20 30 40 50 60 70 80 Length of Run, Minutes
FIG. 2.-Setting-range test of Kerr hard wax and
Japan wax. J. dent. Res. November-December 1965
the greatest amount. Paraffin had the highest
coefficient of thermal expansion of any wax tested,
which was 1,631 ± 237 X 10-6/0 C. between 27.80
and 34.0 C. Litene, a mineral wax, had higher
coefficients of thermal expansion between 220 and
520 C. than did ouricury, a plant wax, even though
both waxes solidified over the same temperature
range.
• Yellow beeswax, which is also primarily an ester wax,
flowed extensively 240 C. below its setting range and
displayed an 80 C. temperature difference between 1 and
70 per cent flow. This may be explained by the fact that
yellow beeswax contains a large number of impurities
which interfere with the secondary valence forces. As
beeswax goes through the bleaching process and some of
these impurities are removed, the secondary valence
forces increase. The flow data illustrate this point, since
bleached beeswax required a temperature closer to its
setting range to produce a large amount of flow, and the
temperature difference between 1 and 70 per cent flow
was only 40 C
• MIontan wax was the only mineral wax which required a
temperature as high as 710 C., or 80 C. below its setting
point, in order to flow 50 per cent. This wax, however, is
similar to the plant waxes in that it is composed mainly
of esters formed in nature by the union of higher
alcohols with the higher fatty acids. The plant waxes also
required temperatures close to their setting ranges to
produce 50 per cent flow. Due to the presence of esters
groups in these waxes, the secondary valence forces are
rather strong, and a high temperature is necessary to
overcome these forces. Once the secondary valence
forces are overcome, these waxes flow rapidly; below this
point, however, they often appear to fracture in a
manner similar to a brittle material.
• Bennett'5 as the transformation from needleshaped
crystals to rhomboid plates or leafy masses. These
findings also are in agreement with those of
Lasater,5 who has reported arrest points in dental
waxes which he related to the distortion of wax
patterns. This second-order transition point
presents difficulties in that internal stresses result in
wax patterns and it would be better if this point
were well below room temperature. The use of
microcrystalline waxes which have minute crystals
and less orientation is preferred, and these should
produce a more stable wax.
• jor waxes. The setting-range measurements illustrate that waxes are
partially amorphous and partially crystalline, with the rate of FLOW
vs. TIME KERR HARD WAX (blue) Bennett'5 as the transformation
from needleshaped crystals to rhomboid plates or leafy masses.
These findings also are in agreement with those of Lasater,5 who
has reported arrest points in dental waxes which he related to the
distortion of wax patterns. This second-order transition point
presents difficulties in that internal stresses result in wax patterns
and it would be better if this point were well below room
temperature. The use of microcrystalline waxes which have minute
crystals and less orientation is preferred, and these should produce
a more stable wax. The importance of flow of wax at different
temperatures has been emphasized by Taylor et al.1 2 and Stanford
et al.3 Yellow beeswax did not flow extensively until it THERMAL
EXRPNSION 40.0 eC 5 6 7 8 9 10 Time, Minutes FIG. 4. Flow
curves at various times for Kerr hard wax. temperature change
during solidification indicating the degree of crystallinity
• Kerr's hard inlay wax expanded less than Kerr's
regular inlay wax. It is interesting to note that Kerr's
hard inlay wax showed an increase in the rate of
expansion at 37.50 C., or mouth temperature, and a
decreased rate of expansion at 45.0° C. Kerr's
regular inlay wax, however, had an increase in the
rate of thermal expansion at 32.70 C., a decrease in
rate of expansion at 40.9° C., and an increase again
at 46.90 C. The linear coefficient of thermal
expansion for the mineral, plant, and insect waxes
increased as the temperature ranges approached the
solidification ranges of the waxes.
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