Waxes in dentistry

1. Yaman Yousof DDS MDS PhD
Waxes in Dentistry

2. Natural waxes
Synthetic waxes
Minerals Plants Animals
Paraffin Carnauba Beeswax Acrawax
Microcrystalline Ouricury Spermaceti Aerosol
Barnsdahl Candelilla Lanolin Castorwax
Ozokerite Japan wax Flexowax
Ceresin Cocoa butter Epolene
Montan Durawax
(Fraunhofer, 2013; Manappallil, 2016)

3. Dental Waxes
by Origin
by Use
• Pattern waxes
• Processing waxes
• Natural waxes
• Synthetic waxes

4. Lost-wax Technique
Photographs showing fabrication of full gold crown. A. Wax pattern with sprue attached. B. Wax
pattern attached to sprue base and casting. Note reproduction of shape and size. C. Wax pattern and
casting ring. Casting ring slips over wax pattern and fits into sprue base (Gladwin & Bagby, 2013).
A B C

5. Lost-wax Technique
D. Sprued and invested wax pattern inside sectioned casting ring. E. Cross-section through casting
ring after burnout and completed casting. F. Completed casting on die (Gladwin & Bagby, 2013).
D E F

6. Lost-wax Technique
Wax pattern of restoration is made on die with
pattern wax (usually inlay wax). Sprue, sprue
base, and casting ring are added, and then sprue
and pattern are invested (filled) with gypsum-
based material. After investment sets, base of
sprue is removed, and invested pattern and
sprue are placed into oven to burn out wax
(hence the name “lost-wax”). Once wax is
burned out, space remains where sprue and wax
pattern were. Molten metal is cast into this space
(Powers & Wataha, 2017).

7. Melting Range
Because waxes are mixtures of different components, they do not melt at a single
temperature and do not have a melting point. Rather, they have a melting range. At
the low end of the range, some but not all of the components melt, which causes the
wax, still solid, to flow much more. As the temperature increases through the melting
range, more of the components melt and the wax flows severely, and eventually all
components become a liquid (Powers & Wataha, 2017).

8. Flow
Flow is the change in shape under an applied
force. Flow is highly dependent on temperature,
time, and force. For pattern waxes, flow is
generally not desirable at room or mouth
temperature, because it results in a permanent
distortion of the wax pattern. For processing
waxes, flow is a highly desirable property
because these waxes need to be pliable at room
temperature (Powers & Wataha, 2017).

9. Thermal Expansion
Waxes have the highest coefficients of
thermal expansion of any dental material. As
wax is heated, a significant expansion occurs
but may not be linear with the increase in
temperature. As the wax cools, contraction
occurs but not reversibly. Thus, a wax pattern
that goes through a heating-and-cooling cycle
may have dimensions different from what it
had originally (Powers & Wataha, 2017).

10. Residual Stress
Residual stress is stress remaining in wax as a result of manipulation during heating,
cooling, bending, or carving. These hidden stresses are generally released as the
temperature of the wax increases, causing irreversible deformation of the wax
pattern. To prevent residual stresses from forming, waxes should not be carved or
manipulated at temperatures well below their melting range (Powers & Wataha,
2017).

11. A. Two forms of inlay waxes. B. Wax bath used for dipping technique. C. Wax patterns of crowns
made from inlay wax. D. Inlay pattern (Manappallil, 2016).
Inlay Wax
A
B C D

12. RPD Casting Wax
A B
Removable Partial Denture (RPD) casting waxes A. Preformed casting waxes. These waxes are tacky
and highly adaptable. B. Pattern made from preformed waxes for constructing RPD (Manappallil, 2016).

13. Milling Wax
A B C
A. CAD/CAM milling. B. Milling (machinable) wax. C. Milling with handpiece (Manappallil, 2016).

14. Baseplate Wax
A B
A. Baseplate (modeling) wax is used to build removable acrylic dentures. B. Occlusion rims
(Manappallil, 2016).

15. Boxing Wax
Boxed impression ready for pouring (Manappallil, 2016).

16. Utility Wax
Utility, beading, or periphery wax are often used for tray extension. These waxes are soft, pliable,
and tacky at room temperature and can easily stick to the tray (Manappallil, 2016).

17. Sticky Wax
Sicky wax is hard and brittle at room temperature. When heated, it is sticky and will adhere closely
to the surfaces to which it is applied.

18. Bite Registration Wax
A B
Bite registration wax is used to record the relationship between the upper and lower teeth
(Manappallil, 2016).

19. Dental Waxes
Processing Waxes
Pattern Waxes
Boxing Wax
Utility Wax
Sticky Wax
Bite Registration Wax
Inlay Wax
RPD Casting Waxes
Milling Wax
Baseplate (Modeling) Wax

20. References
Fraunhofer, J. A. (2013). Dental Materials at a Glance (Second Edition). Wiley
Blackwell.
Gladwin, M., & Bagby, M. (2013). Clinical Aspects of Dental Materials: Theory,
Practice, and Cases (Fourth Edition). Lippincott Williams & Wilkins, A Walters
Kluwer Business.
Manappallil, J. (2016). Basic Dental Materials (Fourth Edition). New Delhi: Jaypee.
Powers, J. M., Wataha, J. C. (2017). Dental Materials: Foundations and Applications
(Eleventh Edition). Elsevier.