23544209-13-Wax

Dental Dentalwaxeswaxes

Dental waxes Dental waxes

• Waxes have several applications indentistry.

Components of dental waxes Components of dental waxes

Natural wa xes

Synthetic w axes

Additives

•Mineral•Plant•Insect•Animal

•Acrawax C• Aerosol O T•Castorwax• Aldo 33

• Stearic acid•Oils•Colorants•Resins

Natural waxes Natural waxes

Complex combination of organic compound s of high molecular weights.

It’s the primary components of dental wax. The dental manufacturers must blend the p

articular batches of waxes to obtain the pro perties desired for a particular application.

Natural waxes Natural waxes

• Mineral waxes • Parrain• Microcrystalline• Barnsdahl• Ozokerite• Ceresin• Montan

Synthetic waxes Synthetic waxes

• High degree of refinement,no contamination. Polyethylene waxes Polyoxyethylene glycol waxes Halogenated hydrocarbon waxes Hydrogenated waxes Waxes ester (fatty alcohol + acid)

FatsFats• Increase the melting range and the ha

rdness of compound waxes.• Hydrocarbon oils - soften mixture of w

axes.• Silicone oils - improve the ease of poli

shing with waxes.

ResinsResins

• Most natural resins are obtained from trees and plants.

• Insoluble in water• improve toughness, hardness, meltin

g range of waxes

Properties Properties of of waxes waxes

Melting range Melting range

• Waxes consist of similar type of molec ules of different of molecular weight.

• They may contain several types of mol ecules

• They have melting range rather than m elting point.

Thermal expansion Thermal expansion

• Expand when temp. is risen• Contract when temp. is decreased• Dental waxes have the largest coefficient

of thermal expansion.• Temp. change in wax patterns may be a

major contributing factor in inaccuracy o f the finished restoration.

Mechanical properties Mechanical properties

• The elastic modulus, proportional limit and compressive strength of waxes are low compare with those of other materi

als and these properties depend strong ly on the temperature.

FlowFlow• Flow is decidedly dependent on the te

mp. of the waxes.• Flow is greatly increase as the melting

point of the wax is approached.

Residual Residual

stress stress

DuctilityDuctility

• Ductility increase as the temp of a wax i s increase

• Waxes with lower melting temp. have a greater ductility.

• The ductility of a blended waxes wide melting range > narrow melting ra

nge• The highly refined waxes is quite brittle

- Dental wax Classification - Dental wax Classification

• Pattern waxes• Processing waxes• Impression waxes

Pattern wax Pattern wax

• Used to form the general predetermin ed size and contour of artificial dental

restoration , which is to be constructed of a more durable material.

Pattern wax Pattern waxeses

1. Inlay waxes

3. Baseplate waxes2. Casting waxes

Processing wax Processing wax• Used primarily as auxillary aids in th

e construction a variety of restoratio ns and appliances either clinically or in the laboratory

Processing waxes Processing waxes

1. Boxing waxes

2. Utility waxes

3. Sticky waxes

4. Carding waxes

Impression waxes Impression waxes

• Used for taking impression within the mouth.

– Bite registration waxes– Corrective waxes

Korecta wax

Alu wax

Inlay pattern wax Inlay pattern wax

• A pattern of the wax is first constructed tha t duplicates the shape and contour of the d

esired casting .


• The pattern then is embedded in a gyp- sum silica investment material to form

a mold with an ingate or sprue leading from the outer surface of the investme

nt mold to the pattern.


• The wax is subsequently eliminated by h eating & softening and the mold is furthe

r conditioned to receive the molten gold.


Inlay wax Inlay wax :: CCompositionomposition

Paraffin (major portion)

Microcrystalline waxCeresin

CarnaubaCandelillaBeeswax

Inlay waxes generally are produced in deep blue , green , or purple rods or sticks.

The flow can be reduced by adding more carnueba wax o r by selecting

higher melting paraffin waxes.

Inlay waxes : Properties Inlay waxes : Properties

ANSI/ADA Specification No. 4 for denta l inlay casting wax.

Type I wax = a hard wax that is prescribe d for forming direct patterns in the mouth.

Type II wax = a softer wax that is used as an indirect technique wax.

Thermal ex Thermal expansionpansion

FlowFlow The working temperature for making direc

t wax pattern must not to be so high as to cause damage to the vital tooth structure.

At mouth temp., direct inlay wax must hav e essentially no flow to minimize the possi

bility of distortion of the pattern during re moval from the tooth cavity.

Casting wax Casting wax

The pattern for the metallic framework of r emovable partial denture and other similar structures is fabricated from the casting wa

xes.

Casting wax : Casting wax : CCompositionomposition

The ingredients are similar to tho se found in inlay waxes.

Casting wax : Properties Casting wax : Properties

- - Federal specification No U W 1 4 0 f or cast i ng wax

Flow : 35o C - maximum, 10%

38

o C - minimum, 60 %

Breaking point : no fracture at 23o +1

o

Pl i abl e and r eadi l y adapt abl e at 40o to 45o C

Copy accurately surface against which it pressed

Shall not be brittle on cooling Vaporize at 500o C, leaving no fil

m other than carbon

Working properties Working properties

Baseplate wax Baseplate wax

Baseplatewax der i ves i t s name f r omi t s us e on the baseplate tray in the techn

ique for complete denture restorati on.

It’s normally pink color.

serves as the material to produce the des ired contour of the denture after the teet

h are set in position

Baseplate wax Baseplate wax

Baseplate wax : Baseplate wax : CCompositionomposition

- 70 80 % paraffin or ceresin small quantities of other waxes & additi

ves. typical composition

– - 80 12% ceresin % beeswax– 25. % carnuaba– 3% natural or synthetic resins– 25. % microcrystalline or synthetic wax

Baseplate wax : Baseplate wax : PPropertiesroperties

ANSI/ADA Specification No.24– Type I - Soft, building contours and

veneers– Type II - Medium, patterns in mouth, temperate– Type III - Hard, patterns in mouth,

hot weather

Linear thermal expansion from 25o-40oC < 08. %

Softened sheets shall cohere readily witho ut becoming flaky or adhering to fingers No irritation of oral tissue

trim easily with a sharp instrument at 23oC

Practical requirements Practical requirements

Smooth surface after gentle flaming No residue on porcelain or plastic teeth

Coloring shall not separate or impregnat e plaster during processing

No adhesion to other sheets of wax or se parating paper on storage

Practical requirements Practical requirements

Boxing wax Boxing wax Use to form a plaster or stone cast from an i

mpression of the edentulous arch

Boxing wax: Boxing wax: WW orking properties orking properties

- -Federal specification No U W 138 Smooth, glossy surface on flaming

Pliable at21o C , retain shape at35

o C

Seals easily to plaster with hot spatula

Utility wax Utility wax

Used in numerous instance most likely consists of beeswax, petrola

tum and other soft waxes

Utility wax: Utility wax: WW orking properties orking properties

- - Federal Specification No U W 156

Pliable at21o to24

oC

Tacky at21o to24

oC, sufficient adhesion t

o build up

Sticky wax Sticky wax

It is sticky when melt and adheres closely t o the surface on which it is applied. It is firm, free from tackiness and brittle at

room temp. Rosin & yellow beeswax are the usual majo

r constituents.

Sticky wax : Sticky wax : WW orking properties orking properties

- -Federal Specification No.U W 00149a Sticky when melt

Adhere closely Not more than02. % residue on burnout Not more than05. % shrinkage from

43o to 28Co

Corrective impression wax Corrective impression wax

Used as a wax veneer over an original imp ression to contact and register the detail o

f the soft tissue . Formulated from hydrocarbon waxes such

as paraffin,ceresin & beeswax and may co ntain metal particles

The flow at37o

C is 100%

Corrective impression wax Corrective impression wax

Bite registration wax Bite registration wax

Used to accurately articulate certai n models of opposing quadrant

Formulated from beeswax or hydro carbon waxes such as paraffin or ce

resin and contain alumina or coppe r particle


• Alu wax


• Occlusal indicator wax

Other polymers in dentistry Other polymers in dentistry

-Gutta percha Filling material :composite resin Dental cement

-Gutta percha-Gutta percha

A polyisoprene with the same empirical f -ormular as rubber (20 30%)

various natural resin -(soften the gutta percha) filler : ZnO,waxes

Composition


• Used to fill in the root canal

• Soften at -6070o C

• Viscoelastic material which is extremely s ensitive to the rate of straining.

• The best adaptation to the root canal is a chieve when maximum pressure is applie

d over an extended period of time.


The End of Polymerin

Dentistry

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23544209-13-Wax