Dental waxes are the mainstay of the dental lab procedures and are technically sensitive in the procedures involved.

1. DENTAL WAXES
Dr. Hemlata Dwivedi

2. Dental Waxes
INTRODUCTION
 Thermoplastic
 Viscoelastic
 Uses
– To form pattern prior to casting
– Registration of patient occlusion
– To Stimulate Gingiva
– In teeth setting
– As impression material

3. CHEMISTRY OF WAXES
CH3 – (CH2) 15-42 - CH38
CH3 - (CH2 )13 -CH2 - C – O- CH2 (CH2)28 CH3
O
ll
Waxes are organic polymers made from high molecular
weight such as esters and alcohols.
The principal esters in Bees wax is Myricyl Palmitate.
CH15H31 – C – O – C30H61
Montan wax (an earth wax) contains large amounts of esters.
O
ll
CH28 H57 –C – O – C24 H49
O
ll

4. CLASSIFICATION
OF DENTAL WAXES
A) According to Source of Origin

5. B(i) According to Use in Dentistry
Pattern Processing Impression
Inlay Boxing Corrective
Casting Utility Bite
Sheet Sticky
Ready Shapes
Wax-up
Baseplate

6. B(ii) Methods of classification – ADA Specification

7. Characteristics of various waxes

8. SYNTHETIC WAXES
Synthetic waxes are complex organic compounds
and they possess certain physical properties such as
high melting temperature or hardness and have high
degree of refinement
Synthetic waxes include
(i) Poly ethylene waxes
(ii) Poly oxyethylene glycol waxes
(iii) Halogenated hydrocarbon waxes
(iv) Hydrogenated waxes
(v) Wax esters from the reaction of fatty alcohols
and acids.

9. RESINS
Natural resins are relatively insoluble in water but vary in
solubility in certain organic liquids. They have specific physical
behaviors rather than by any definite chemical composition
Shellac Wax
Shellac is a natural beetle
exudate which has a
considerably higher softening
temperature than ordinary
modelling wax.
Uses
as temporary denture base

10. CHARACTERISTIC
PROPERTIES OF WAXES
1. MELTING RANGE
Waxes have MELTING RANGES
rather than MELTING POINT.
When a mixture of 75 % paraffin and 25
% caranauba wax was prepared, the
paraffin component melted at essentially
the same temperature, but the melting
temperature of the caranauba wax was
decreased slightly.
The melting range for paraffin wax is from
44OC to 62OC and for caranauba wax from
50OC to 90OC.

11. THERMAL EXPANSION
Like other materials, waxes expand when subjected to a rise
in temperature and contract as the temperature is decreased.
The thermal dimensional change may be
affected by previous treatment of wax.
Curve A (in the slide) represents the
thermal expansion of an Inlay wax
(Paraffin wax) that has been previously
cooled under pressure and curve B
represents when same wax is allowed to
cool without pressure and again heated.
As shown the expansion rate increases
abruptly above approximately 35OC. The
temperature at which the change in rate
occurs is known as GLASS TRANSITION
TEMPERATURE.

12. Softening Temperature
The Mineral waxes generally have higher coefficient of
linear expansion than Plant waxes. The mineral waxes
expand more because they have weak secondary valence
forces , which are overcome easily by the energy absorbed
during a rise in temperature.
The changes in crystal structure of the
wax is converted from a relatively brittle
solid to a much softer, mouldable
material. For this reason the solid- solid
transition temperature is sometimes
referred as softening temperature.

13. MECHANICAL PROPERTIES
The elastic modulous, proportional limit
and compressive strength of waxes are
low compared with those of other material
and these properties depend strongly on
the temperature.
The elastic modulus of various waxes are
shown in this slide; with caranauba wax
having the highest values and bees wax
the lowest between 23º C and 40º C.

14. FLOW
Flow at 10 minutes
Slippage of molecules over each other.
A measure of flow in the liquid state of wax is the internal
friction of the molecules during movement.
Below the melting point flow actually would be a measure of
the degree of plastic deformation of the material at a given
temperature (CREEP).
This material must have a
relatively high flow a few
degree above mouth
temperature so that when it is
in a workable condition
Once the secondary valence
forces are overcome these
waxes flow rapidly, or they
will fracture.

15. RESIDUAL STRESS
If the specimen is held under compression during cooling,
the atoms and molecules are forced closer together than
when they are under no external stress.
When the specimen is heated , the
release of the residual stress is added to
the normal thermal expansion, and the
total expansion is greater than normal.

16. Ductility
Ductility is the ability of a material to be plastically deformed,
it is indicated by plastic strain. Ductility makes the material
workable in the mouth.
Whenever the wide range of melting temperature is present,
the softening point of the lowest component is approached
first. A further temperature rise begins to liquefy this
component and approach still closer to the softening point of
the higher softening components. This tends to plasticize the
entire wax mass, there by enhancing ductility.
Brittleness
Brittleness is another important property for example denture
waxes, toughness is required since the wax denture base
may have to be removed from a slightly undercut cast many
times without fracturing such as inlay waxes.

17. MANIPULATION OF DENTAL WAXES
Methods of softening wax prior to moulding include
A water bath
An infrared lamp 250 W
A bunsen burner
Annealer
Pattern waxes
A pattern wax is first constructed that duplicates the shape and
contour of the desired casting.
To form a mold with an ingate or sprue leading from the outer
surface of the investment mold to the pattern.
The wax is subsequently eliminated by heating.
COMPOSITION
an inlay wax may contain 40-60 % paraffin, 25% carnauba,
10% ceresin, 5% beeswax.

18. Supplied as
Deep blue , green , purple rods or sticks about 7.5 cm long &
0.6 cm in diameter. Some manufacturers supply the wax in the
form of small pellets or cones or in small, metal ointment jars.

19. PROPERTIES
Type of T=30º C T = 37º C T = 40º C T = 40º C T = 45º C T = 45º C
Wax (Maximum) (Maximum) (Maximum) (Maximum) (Maximum) (Maximum)
I – 1.0 – 20 70 90
II 1.0 – 50 – 70 90
Inlay Wax Flow (%) Requirements for ANSI/ADA Specification
Type I wax is a softer wax that is used as an Indirect Technique
Type II wax is a hard wax that is prescribed for forming Direct
Pattern in the mouth, where lower flow values act 37º C tend to
minimize distortion.
Type I Wax shows greater flow than Type II wax at
temperatures both below and above mouth temperatures . The
lower flow of Type II wax and a greater ease of carving the
softer Type I waxes are desirable characteristics for techniques
associated with each.

20. Desirable Properties
When softened, the wax should be uniform.
The color should be such that it contrasts with the die material .
There should be no flakiness or similar surface roughening
After the wax solidified, it is necessary to carve the original
tooth anatomy in the wax.
the melted wax, when vaporized at 500ºC leaves no residue in
excess of 0.10% of the original weight of specimen.
Thermal Coefficient of Expansion
A decrease of 12ºC - 13ºC in temperature from mouth
temperature to room temperature of approximately 24ºC, causes a
0.4% Linear contraction of wax, or about 0.04% change for each
degree change in temperature.
Gas and Solvent retention.

21. Warpage of pattern
Inlay wax shows not only a high coefficient of thermal expansion
but also a tendency to warp or distort when allowed to stand
unstrained.
Waxes tend to return partially to their original shape after
manipulation. The property responsible for this phenomenon
is known as ELASTIC MEMORY.
Distortion of Wax pattern can Occur
If is not at uniform temperature when inserted in the cavity.
If wax is not held under uniform
pressure under cooling.
If the wax is melted and added
in an area of deficiency
During cooling some
molecules of wax will be
disturbed and stress will result.

22. To Avoid Warpage of Wax Pattern
(a) Minimal carving and change in temperature.
(b) Minimal Storage of Pattern (Invest as early as possible)
(c) Use warm instrument for carving.
(d) Store in refrigerator if necessary.
Manipulation of Inlay wax
Dry heat is generally preferred to the use of water bath.
When stick wax is softened over a flame care should be taken
not to over heat it. The wax should be twirled around
Diping waxes are used, these waxes are kept molten for
constant usage.
Waxes oxidize on heating, and on prolonged heating some
evaporate. There will also be darkening and a precipitation of
gummy deposits. Therefore care should be exercised to use the
lowest temperature possible and to clean the pot and replace the
wax periodically.

23. Casting Wax
The pattern for the metallic frame work of removable partial
dentures
Casting wax be bent double on itself without fracture at a
temperature of 23ºC and that the waxes be pliable and
readily adaptable at 40ºC-45ºC.
Vaporize at about 500ºC with no residue other than carbon.
These waxes are available in the form
of sheets, usually of 28 and 30 gage
(0.40 and 0.32mm) thickness,
readymade shapes, and in bulk.

24. Base Plate Wax
Composition
A typical composition might include 80% ceresin, 12%
beeswax, 2.5% carnauba, 3% natural or synthetic resins,
and 2.5% micro crystalline or synthetic waxes
Type Temperature Flow (%)
( º C ) Minimum Maximum
Type 1 – Soft, building 23 – 1.0
contours and veneers 37 5.0 90.0
45 – –
Type-2 - Hard, patterns 23 – 0.6
in mouth, temperate 37 – 10.0
weather 45 50.0 90.0
Type-3 - Extra Hard 23 – 0.2
patterns in mouth, 37 – 1.2
hot weather 45 5.0 50.0

25. Use of Wax Spacer for putty wash impression
of implant snap on impression coping
Impression coping captured in
impression with base plate wax
The Putty wash impression is
recommended for making an
impression of dental implants including
the impression coping and positioning
cylinder a stock tray with putty
impression material must be used to
register an unmodified solid abutment.
Conclusion
Relief of putty impression material
is accomplished to provide stability
to the coping and there is sufficient
space for the light body material.

26. Boxing Wax
Cardin wax was the original material on which the porcelain
teeth were fixed when received from the manufacturer. The
terms cardin and boxing wax have been used interchanging.
boxing wax stipulated that this wax should be pliable at 21ºC
and should retain its shape at 35ºC.
Boxing wax supplied as long 4 cm strips that are 4-5 cm wide
0.1cm thick.
Utility Wax
An easily workable, adhesive wax is desirable in numerous
instances.
Pliable at a temperature of 21ºC-24ºC which makes it
workable and easily adaptable at normal room temperature.
The flow of this wax should not be less than 65% or more
than 80% at 37.5ºC.
Supplied in both stick and sheet form in dark red or orange
colour, as long beads 40 cm or more, about 0.5 cm in dia.

27. Sticky Wax
Sticky Wax when melted it adheres closely to the surface
on which it is applied. However, at room temperature the
wax is firm, free from tackiness, and brittle.
In addition to rosin and yellow bees wax colouring matter
and other natural resins such as gum dammar may be
present.
Shrinkage of sticky wax should be 0.5% at temperatures
between 43ºC - 48ºC.
Sticky wax should fracture rather than flow if it is
deformed during soldering or repair procedures.

28. Corrective Impression Wax
Corrective waxes are formulated from hydrocarbon waxes such
as paraffin, ceresin, and beeswax and may contain metal
particles.
The flow of several corrective waxes measured by penetration
at 37ºC is 100%. These waxes are subjected to distortion during
removal from mouth.
It is used as a wax veneer over an original impression.
To make functional impression of free end saddles.
To record posterior palatal seal in dentures.
Functional impressions for obturators.
Bite Registration Wax
The flow of several bite waxes as measured by penetration at
37ºC ranges from 2.5% to 22%.
It is used to accurately articulate certain models of opposing
quadrants.

29. Plastic Patterns
In addition to casting wax, patterns for RPD frameworks are
often combined with pliable plastic patterns.
The physical properties of the waxes could be variables that
create structural inhomogeneity with an increase in internal
stresses. On cooling to room temperature, the released
stresses would eventually cause some distortion.
Disclosing Wax
To check the extensions of denture borders.
Borders devoid of wax indicate overextension of borders.
Regions of thick wax indicate underextension of borders

30. Thank you!!!