Wax patterns in fpd / dentistry course in india

WAX PATTERNS IN FPD
www.indiandentalacademy.com

Contents
• Introduction
• History
• Waxes
• Armamentarium
• Wax pattern fabrication
 Coping fabrication
 Wax pattern removal and evaluation
 Proximal surfaces
 Axial surfaces
 Occlusal morphology
 Margin finishing
• Conclusion
• References www.indiandentalacademy.com

 INTRODUCTION
 HISTORY

WAXES
Dental waxes are organic polymers consisting
of hydrocarbons and their derivatives.
Molecular weight ranges from 400-4000

Classification
 According to origin
 According to use and application

ACCORDING TO ORIGIN
Natural Synthetic
- Mineral
- Plant
- Insect
- Animal

ACCORDING TO USE AND &
APPLICATION
Pattern waxes Processing Impression
waxes waxes

INLAY CASTING WAX
Composition
1. Paraffin-chief content
2. Gum dammar
3. Carnauba wax,Ceresin or Candelilla wax
4. Beeswax
5.Colouring agent

CLASSIFICATION
According to ANSI and ADA sp no 4
 Type 1 a medium wax. Used for direct
technique.
 Type 2 a softer wax.Used for indirect
technique.

Properties
1. Flow: flow % requirements for ADA sp no 4
Type of inlay
wax
30
Max
37
Max
40
Min Max
45
Min Max
Type 1 --- 1.0 --- 20 70 90
Type 2 1.0 --- 50 --- 70 90

2. Thermal properties
- Thermal conductivity
- Coefficient of thermal expansion
may expand 0.7% with an increase in
in temperature of 200
C
and contract as much as 0.35% when it is
cooled from 370
C to 250
C
- Average co-efficient of thermal expansion:
350 x 10-6 0
/C

3.Wax distortion
- Elastic memory
This can result from thermal changes,release of stresses
on cooling,time and temperature during storage etc.
Other desirable properties of inlay waxes include:
- Color
- Residue
ADA sp no 4 requires that the melted wax when
vaporized at 5000
C shall leave behind no solid residue
in excess of 0.10% of the original weight of the
specimen.

Armamentarium
• PKT waxing instruments (no 1 to no 5)
• No 7 wax spatula
• Laboratory knife with blade
• Sharp colored pencil (contrasting to wax)
• Sable brush
• Bunsen burner
• Inlay wax
• Occlusal indicator powder
• Die lubricant www.indiandentalacademy.com

WAX PATTERN FABRICATION
The following sequence is recommended:
1. Coping fabrication.
2. Wax pattern removal and evaluation.
3. Proximal surfaces.
4. Axial surfaces.
5. Occlusal surfaces.
6. Margin finishing.

COPING FABRICATION

WAX PATTERN REMOVAL &
EVALUATION

PROXIMAL SURFACES

AXIAL SURFACES
Emergence Profile

OCCLUSAL MORPHOLOGY
Cusp fossa Cusp marginal ridge
1. Location of occlusal
contact on opposing teeth.
Occlusal fossae only. Marginal ridges and
occlusal fossae.
2. Relation with opposing
tooth.
Tooth-to-tooth Tooth-to-two-teeth
3. Advantages. Occlusal forces are directed
parallel with long axis of the
tooth. These forces are near
the center of the tooth,
placing very little stress on
the tooth.
Found in 95% of all adults.
Can be used for single tooth
restorations.
4. Disadvantages. Rarely found in natural
teeth. Used when restoring
several contacting teeth and
teeth opposing them.
Food impaction and
displacement of teeth may
arise if functional cusps
wedge into a lingual
embrassure.
5. Application. Full mouth reconstruction. Most restorations in daily
practice
Classification of occlusal arrangements

WAXING TECHNIQUE
There are two wax added techniques for waxing
occlusal surface of restoration.
1st
technique given by E.V. Payne
H.L. Lundeen promoted the same technique using
wax of a different color for each of the features.
Usually associated with cusp-marginal ridge
occlusal scheme
2nd
technique given by P.K. Thomas
Most often associated with cusp-fossae occlusal
scheme www.indiandentalacademy.com

CUSP MARGINAL RIDGE FOR MAXILLARY TEETH

CUSP MARGINAL RIDGE FOR MANDIBULAR TEETH

CUSP-FOSSA ARRANGEMENT

MARGIN FINISHING

WAXING FOR ANTERIOR TEETH

Wax pattern for the functionally
generated path technique

SUMMARY & CONCLUSION

REFERENCES
• Contemporary Fixed Prosthodontics. 3rd
edition,
Rosensteil.
• Fundamentals of Fixed Prosthodontics. 3rd
edition,
Herbert T. Shillenburg.
• Philips Science of Dental Materials. 10th
edition,
Kenneth J. Anusavice.
• Restorative Dental Materials. 6th
edition, Robert J.
Craig.
• Theory and Practice of Ceramo-metal restorations.
Mashiro Kuwata.

• Periodontal considerations of crown contour. Perel
ML. JPD, 1971; 26: 627-630.
• Current controversies in axial contour design. Anthony
HL, Tjan. JPD, 1980; 44: 536-540.
• Crown contours and gingival response. Lee M.
Jameson, Willam Melone, JPD 1982; 47: 620-624.
• Emergence profile in natural tooth contour. Part 1,
Burney M. Croll, JPD 1989; 62: 4-10.
• Emergence profile in natural tooth contour. Part 2,
Burney M. Croll, JPD 1990; 63: 374-379.

Wax patterns in fpd / dentistry course in india

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