This document provides information on the principles and techniques for fabricating wax patterns for crowns and fixed dental prostheses using the lost wax technique. It discusses the prerequisites for wax patterns including correcting defects on dies, providing cement space, and marking margins. Details are given on materials used for wax patterns and different waxing techniques. The sequence of wax pattern fabrication is outlined including coping formation, evaluation, shaping proximal, axial, and occlusal surfaces, and finishing margins. Occlusal schemes and developing cusp-fossa and cusp-marginal ridge relationships during waxing are also described. The goal is to produce highly accurate wax patterns to result in well-fitting cast restorations.

3. CONTENTS
 Introduction
 Prerequisites
 Material sciences
 Technique
 Armamentarium
 Waxing instruments
 Posterior teeth
 Anterior teeth
 Waxing for metal ceramic crowns.
 Conclusion

4. INTRODUCTION
 “Lost wax technique”  metal prosthesis.
Success in clinical practise depends upon on every
step in the treatment procedure.
 A large of percentage of time and effort spent in
fabricating fixed prosthesis is devoted to
producing a very accurate pattern.

6. • Most defects can be easily be corrected in wax
pattern but cannot be done in a metal casting.
• Follow:-
1. Precise technique,
2. Use the correct armamentarium
3. Handle the material(wax) carefully in order to
obtain

7. Prerequisites for wax patterns
1. Correction of defects.
 Small defects on the die like dimples due to caries or
loss of previous restorations
 Normally blocked out intraoral by GIC
 Can be blocked on the die as long as the defect does
not extend to within 1 mm of the cavity margin.
 Blocked out using zinc phosphate cement
 Autopolymerizing resin, monomer spray etc

8. 2. Provision of adequate cement space.
 Adequate cement space is of 20 to 40 um for each wall.
 So internal diameter of the wall of crown would be 40 to
80 um.
 1mm of band around the margin shouldn’t be given any
luting space.
 If no luting space is provided the crown wouldn’t seat
completely due to the hydraulic pressure from the viscous
cement.

10.  Die spacer is most commonly used to create space for the luting
cement.
 This material (similar to model airplane paint) is applied to the
die to increase the cement space between axial walls of the
prepared tooth and the restoration. It is formulated to maintain
constant thickness when painted on the die.
 Different types of die spacers are:-
 Red, 7 microns:
 Yellow, 7 microns
 Blue, 10 microns
 New dentin, 10 microns
 Gold 13 microns
 Silver, 13 microns

11. 3. Marking the margins
 The margins should be marked in order to locate it during wax
carving.
 It should be dileneated with a contrast coloured pencil like red
for green wax.
 Graphite pencil shouldn’t be used as it can abrade the die and
also act as antiflux.
 If required the marked area can be coated with a thin layer of
cyanoacrylate.

12. Material science
 GC inlay
waxes
 Cornings inlay waxes
 Bego inlay waxes
 Kemdent inlay waxes
 Kerr inlay waxes
 Charminar inlay waxes

13. Material science
Composition of inlay wax
 Paraffin-60% (Melting range 40-
71o C)
 Carnauba-25%(Melting range
84-91o C)
 Beeswax-5%
 Ceresin-10%
 Natural resins (gum dammer)-
less than 1%
 Organic fillers- added to avoid
excessive shrinkage, expansion
due to temp change
 Microcrystalline wax- In
minute amount.
 Candelilla
 Coloring agents

14.  According to ADA no 4 it is of two types:-
 Type I-a medium wax (generally used with the direct
technique for making patterns in the oral cavity)
 Type II-a softer wax (generally used for the indirect
fabrication of castings)
 Waxes used with direct techniques must not flow
appreciably at mouth temperature.
 Those used with indirect techniques must resist
flow at room temperature to maintain their newly
shaped forms.
Source:- Philips textbook of dental materials

15.  Points to be followed while using waxes:-
 Its has ELASTIC MEMORY should be thoroughly liquefied
before it is added to die, dipping method is best.
 STRESS RELEASE  as wax sets stresses are released.
 HIGH THERMAL EXPANSION AND CONTRACTION so it
should be heated only adequately.
 So because of above properties the wax patterns should be
remelted at the margins before it is invested for proper
adaptation.

16.  Different types of waxes used:-
 Special wax for electrical wax heating unit
(vario therm),
 Dark blue-hard and light blue soft are for
modelling, trimming and dipping
application,
 Lilac-medium hard , red stress free for
cervical margins,
 Green wax-hard for trimming.
 Dip application yellow wax caps of uniform
strength
 Wax Preforms are available - It simplifies
wax up and shorten finishing procedure

17. Different techniques in wax pattern fabrication:
1. Dipping method.
2. Addition method.
3. Molten press method.
4. Injection method.
Source:- Google Web

18. Armamentarium required for wax pattern fabrication
1. PKT waxing instruments
2. No 7 wax spatula
3. Laboratory knife with no 25 blade
4. Sharp colored pencil (contrasting to wax)
5. Sable brush
6. Bunsen burner/electric wax knife
7. Inlay wax
8. Occlusal indicator powder(zinc-sterate or powdered
wax)
9. Die spacer
10. Die lubricant (separating liquid)
11. Soft tooth brush
12. Fine nylon hose

19. Waxing instruments:-
 Waxing instruments can be categorized by the intent of their
design:
1. Wax addition,
2. Carving, or
3. Burnishing.
 Of the popular PKTs (designed by Dr. Peter K. Thomas
specifically for the additive waxing technique),
 No. 1 and no. 2 are wax addition instruments,
 No. 3 is a burnisher for refining occlusal anatomy,
 Nos. 4 and 5 are wax carvers.

20. No1 & 2
No 3 No 4
No 5
No 7

21. Wax carvers. No. 2 Ward and nos./, and 3
Hollenback.
DPT no. 6 wax burnisher.
Electric waxing instrument

22. Sequence in wax pattern fabrication
1. Coping fabrication.
2. Wax pattern removal and evaluation.
3. Proximal surfaces.
4. Axial surfaces.
5. Occlusal surfaces.
6. Margin finishing.

23. 1. Coping fabrication
a) Before coping is fabricated die
lubricant is applied.
b) The wax is added  PKT no1 or no 2.
c) Initial layer should be completely
molten  Memory effect!!!!!
d) Whenever subsequent layers of wax
are added the previous layer which
was applied should be remelted or else
creases or folds would form on fitting
surface.
e) A large waxing instrument can be used
like PKT no 7 is adequate for this
purpose.

24. f) Adequate bulk should be provided
at proximal and axial surface in
order to prevent distortion while
removal.
g) Excess wax at the margins should
be scrapped of carefully.
h) Thin layers scrapping----
carefully-----damage to the die--
-use burnisher instead of sharp
carvers.
i) Dipping the die in molten wax pot
is easiest and better way to
fabricate a coping.

25. 2. Wax pattern removal and
evaluation
 The wax pattern  sufficiently cooled
 Removed using the thumb and forefinger
with light grip pressure.
 A small rubber dam piece.
 If the pattern is not coming out the
excess wax at the margin should be
trimmed of.
 After it remove the patterns is evaluated

26. 3. Proximal surfaces
 The proximal surfaces of natural teeth tend to be flat or
slightly concave from the contact area to the cementoenamel
junction, and any restoration must reproduce this feature.
 Over contouring maintaining periodontal health difficult
 Excessively concave or under contoured proximal surfaces
 flossing ineffective.
Proximal area gingival
to
The contact area are
Normally flat or concave

27.  Contact areas:-
 Abnormally large proximal contact make plaque
control more difficult can lead to periodontal disease
 Very small (point) contacts may be unstable and cause
drifting
 Deficient contacts can also lead to food impaction
On maxillary teeth more
Occlusal and buccal when
Progressing anteriorly
On mandibular
posterior teeth
Centrally located

28. Procedure:-
 The wax coping is seated back on to the die
 Wax is added  coping at the contact area  die
is seated back with wax is in molten state.
 After the wax is hardened the die is removed and
the wax gingival to the contact area is shaped
accordingly.
 The proximal surface is evaluated and the surface
should be either flat or slightly concave.
 They should adequate space for the lingual and
buccal embrasure.
 The wax should continue to the unprepared tooth
surface.

29. Axial
surfaces:-  The buccal and lingual surfaces are shaped to follow
the contours of adjacent teeth.
 The height contour should be adequately placed
usually at the gingival third of all the teeth except in
mandibular molars it is present in the middle third.
 The natural teeth are rarely more than 1mm wider at
their height of contour than at CEJ

30.  The tooth surface gingival to its height of contour
immediately adjacent to the gingival soft tissues is
called emergence profile, it is usually flat or
concave.
 Straight profile  treatment objective
 Creation of convexity or a shelf or ledge
bacterial plaque removal difficult  to cause
inflammation of marginal gingiva.
 Special care should be taken when waxing teeth
with recession or exposure of furcation, providing
adequate space for hygiene procedures

31. Procedure:-
 Adjacent and contralateral teeth are used as guide
 A flat profile is created gingivally .
 No change of direction from unprepared tooth
structure to axial restoration contour
 Add wax to join axial and proximal surfaces and
smooth them, the line angles should correspond to
those on contralateral teeth if present

32. Evaluation:-
 Evaluate at greatest convexity
 Compare with contralateral tooth
 Each part of the outline is scrutinized
properly.
 Buccal and lingual contours and the
embrasures should all be assessed.
 Each contact area has four
embrasures: gingival, buccal, lingual
and occlusal, except occlusal all will
be complete by now
 All the embrasure should be
symmetrical.

33. Occlusal surfaces:-
 The cusps and ridges of the occlusal surfaces
should be shaped to allow even contact with the
opposing teeth while stabilizing the teeth and
directing forces along their long axes.
 Non-functional cusps should provide adequate
horizontal and vertical overlap.

34.  Why put all those grooves on the occlusal
surface????
 Why not simple inclined planes on a flat
table????

35. Numerous occlusal contacts Small centric contacts allow for
disclusion in excursion
Occlusal morphology with inclined plane
produce
Large contacts in centric occlusion A and in
Excursions B

36. Importance of Occlusal
Morphology
 Point contacts between opposing teeth are preferred
to broad, flat occlusal contacts because
1. Wear of the restorations will be minimized and
2. Mastication of tough or fibrous foods improved.

37. Effect of anterior guidance
 The contact of anterior teeth in excursions affects the movements of
the mandible
 Change in morphologic features of anterior restoration can change
the anterior guidance
Increase in vertical overlap- longer cusp and vice versa
Increase in horizontal overlap - shorter cusp and vice versa

38. Types of Centric Contacts
 There are three basic ways by which centric
contacts are usually established:-
1. Surface to surface contact
 Not recommended because it is stressful and it
produces lateral interferences.
2. Tripod contact
 In tripod contact the tip of the cusp never touches the
opposing tooth. Instead, contact is made on the sides of
the cusps which are convexly shaped. It is a stable
contact. 3 point contact is seen.
3. Cusp tip to fossa contact
 In this the cusp tip is properly located in the most
advantageous fossa. It offers good function and stability.
This type of occlusion is easy to equilibrate.

39. Occlusal schemes
 Occlusal schemes are basically classified on
the basis of contact made by the functional
cusp on the opposing tooth in the centric
relation:-
1. Cusp to fossa occlusal scheme.
2. Cusp to marginal ridge occlusal scheme.

40. Cusp to fossa occlusal scheme
 Functional cusp contacts  opposing fossa in the centric
relation.
 Tooth to tooth type of arrangement.
 Hence forces are directed parallel to the long axis of the tooth
and also near the centre of the tooth, thus minimizing lateral
stresses.
 Rarely seen in the natural dentition it can only be given in
cases of full mouth reconstruction.

41. Cusp to marginal ridge occlusal
scheme
 Functional cusp contacts  fossa and marginal ridge of opposing
pair of teeth.
 One tooth to two teeth type of an arrangement.
 It is the most commonly found scheme, almost in 95% of adult
patients.
 Hence commonly practiced for constructing single unit restorations
or small span fixed partial dentures.
 It has a disadvantages of causing food impaction.

42. Aims and Objectives of Selecting Correct
Occlusal
Scheme and Giving Correct Occlusal Morphology
While Restoring Patients’ Teeth are
1. To direct the occlusal forces properly by
minimizing lateral forces during excursive
movements of the mandible.
2. To make the occlusion stable.
3. To increase the masticatory efficiency.
4. To reduce the frictional wear.

43. Waxing Technique to Develop Cusp to
Marginal Ridge Relationship
 Proposed by E V Payne.
 First proposed waxing technique.
 Called as the wax additive technique
 Steps in this technique are:-

44. Step:- 1

45. Step:- 2

46. Step:- 3

47. Completed wax pattern

48. Waxing technique to achieve Cusp to Fossa
Occlusal Scheme
 Developed by P K THOMAS.
 Mostly used in full mouth rehabilitation cases.
 In this occlusal scheme, mandibular functional cusps arise
opposite the middle of maxillary teeth; similarly maxillary
functional cusps are positioned half way between the
mandibular buccal and lingual cusp tips.
 Hence occlusal forces are transmitted parallel to long axes of
teeth.

49. Steps:-
1. Cones  mandibular functional cusps first.
2. Located approximately one third the distance from the buccal to
lingual surface. Also they should fall into appropriate fossae
mesiodistally.
3. Then the cones for maxillary palatal cusps are placed.
4. Next non functional cusps are placed, i.e. Maxillary buccal and
mandibular lingual.

50. Certain morphological differences which need to
be carved while doing wax ups to achieve Cusp To
Fossa Occlusion
 In Mandibular Teeth.
 During working excursion, buccal cusp of each maxillary
premolar will pass distal to the buccal cusp of each mandibular
premolar.
 To facilitate easy and rapid disocclusion, it is necessary to place a
small depression in the form of notch on the distal incline of
buccal cusp of each mandibular premolar. This notch is referred
as Thomas notch.

51.  During non working excursive movement of the mandible, mesiopalatal
cusp of maxillary molar passes through the area distal to the distobuccal
cusp of mandibular molar.
 A notch is developed to form three buccal cusps in both the mandibular
molars to prevent this non working interference
 Lingual cusps of mandibular molars and premolars
should be short enough to allow easy and rapid
disocclusion

52.  In Maxillary Teeth:-
 During non working excursive movement of the
mandible, distobuccal cusp of mandibular molar moves in
a mesiolingual direction across the buccal incline of
mesiopalatal cusp of maxillary first molar.
 To provide the escape way for opposing cusp, it is
necessary to place a groove on the mesiopalatal cusp of
maxillary 1st molar. It is referred as Stuart’s groove

54. Margin finishing:-
 To optimize adaptation it is done.
 Done before investing by reflowing the
margins.
 It minimizes dissolution of cement and
helps in plaque control in the final
casting.
 1mm of area at the margin is reflowed.

55. Note:-
 Over waxing:-
 Shouldn’t be done.
 Any little excess flash over the margins should be
trimmed off.
 Open margins:-
 A gap between the wax and the die, resulting in an
open margin, can be difficult to detect.
 If the wax is not well adapted, a black shadow line
will be visible.
 Ripples:-
 Rough margins on wax patterns if not polished can
be carried to metal causing accumulation of plaque.
 Thick margins:-
 Thick rounded margins, improper seating and poor
contour,
 Causing periodontal problem.

56. Finishing
 Occlusal surface is polished by dipping a
cotton in die lubricant and slowly passing
it over the occlusal surface without any
pressure.
 It is done same over the axial surface, then
with dry cotton pellet the surface is
smoothened off carefully.
 Die lubricant should not be left on the
pattern.
 Any depressions are filled with wax.

57. Waxing of anterior teeth:-
 It is completely different from posterior teeth.
 In case of multiple replacement of anterior teeth a guide is
used for labial and lingual contours.
 The labial and lingual contours influences articulation of
anterior teeth.
 It is recreated by custom anterior guidance table made by
diagnostic mounting of diagnostic cast.
 Usually the contralateral teeth is taken as guide while carving
the teeth.

58. Waxing of lingual and incisal
surfaces:-
 Determined by overall arch form ,
functional occlusal requirements
 Opposing incisors should contact evenly
during protrusion but not during lateral
excursion
 It is achieved by the concavity in the
lingual surface of the maxillary incisors
 In centric closure they should be just out
of contact

59. Waxing of labial surface:-
 The mesiolabial and distolabial line angles determines the
appearance of anterior teeth and its shape.
 If the labial surface is too bulbous, plaque control may be
difficult, and there may be lingual tilting of the tooth caused by
the force exerted by the upper lip.
 When waxing individual anterior teeth, careful study of the
embrasure form of adjacent teeth can be particularly helpful.

61. WAXING CONNECTORS
 The connector should be as large
as possible for optimum strength
 Should not impinge on gingival
tissue and should be at least 1mm
above the crest of interproximal
soft tissue
 Should permit optimum plaque
control
 Cervical aspect should be arch like
 In esthetic area connector should
be hidden behind the esthetic
ceramic veneer, therefore slightly
placed lingually

62. WAX-UP FOR METAL-CERAMIC
RESTORATION
 Prerequisites are:-
1. Waxing to anatomic contours
 Normal anatomic configuration wax
up is done.
 At the porcelain metal interface the
ceramic material should be at least
0.5mm thick
 Distinct margin so that the porcelain is
not overextended.
 There should be no abrupt contour
change between the metal and the
adjacent porcelain.
 All this can be achieved by waxing to
anatomic contour first then cutting it
back.

63. 2. Occlusal stops:-
 The centric stops  located on
either porcelain or metal.
 At least 1.5 mm away from the
junction to prevent porcelain
fracture.
 Opposing restorations must be
carefully planned so that
contacting surfaces will be of
the same material (i.e., metal
opposing metal, porcelain
opposing porcelain)

64. Techniques for waxing up copings
for metal ceramic restorations.
1. Single coping wax pattern.
2. Plastic shell technique.

65. 1. Single coping wax pattern.(cut back)
 Full contoured wax pattern is
completely fabricated.
 Then sketch the outline of the wax
pattern to be removed with a sharp
scalpel.
 The ceramic veneer should extend far
enough interproximally, particularly in
cervical half to avoid metal display.
 Remove 1.5 mm from the incisal
portion of an anterior pattern with the
knife.
 Depth cuts of 1mm are places and
horizontal vertical grooves are given
connecting the depth cuts.
 Then the islands in between the
grooves are removed with a scalpel
blade.

66.  The porcelain metal interface should be given a 90
degrees butt joint.
 The margins are reflowed again.
 The troughing or depth grooves can be placed using a
specialized chisel.
 Any sharp margins should be finished off.

67. 2. Plastic shell technique

71. Sprueing of wax pattern.
 Wax, plastic and metal is used as sprue.
 2.5 mm(10 gauge) to 2 mm(12 gauge) diameter sprue is
used in fpd.
 Location:- sprue should be attached to bulkiest portion of
the pattern.
 Attached at an angle 135 degrees to the nearest axial wall.
 The attachment should be smooth and blended to prevent
turbulence.

72. CONCLUSION
• If the waxing procedure is followed in a sequential order,
inexperienced but conscientious operators should have
no problem achieving excellent results.
• With more experience, they can combine and modify
some of these steps; however, waxing up teeth "from
memory" is not advised. Even the most
experienced technician should copy the shape of
natural teeth rather than redesign them.

73. References:-
 Waxing Techniques to Develop Proper Occlusal
Morphology in Different Occlusal Schemes J Indian
Prosthodont Soc (Oct-Dec 2011) 11(4):205–209.
 Contemporary Fixed Prosthodontics STEPHEN F. ROSENSTIEL,
4th edition.
 Shillingburg, Herbert T., et al., eds. "Fundamentals of Fixed
Prosthodontics, ed, 1997." Learning 10 (1997): 40.
 Anusavice, Kenneth J., et al. Phillips' science of dental
materials. Elsevier Health Sciences, 2012.