DENTAL CASTING DENTAL CASTING WAXESWAXES

CONTENTSCONTENTS• INTRODUCTIONINTRODUCTION

• Classification of waxesClassification of waxes

1) According to origin1) According to origin

2) According to use and application 2) According to use and application

• Inlay casting waxesInlay casting waxes

1) Composition1) Composition

2) Properties2) Properties

• Casting waxes Casting waxes

• Review of literature Review of literature

• ConclusionConclusion

• References References

INTRODUCTIONINTRODUCTION

• Over 4000, years ago in Mesopotamia………natural bees wax was Over 4000, years ago in Mesopotamia………natural bees wax was used for patterns.used for patterns.

• The investment casting has been used in the arts by The investment casting has been used in the arts by

many civilization.many civilization.

• The technique was largely ignored ,until the dawn of The technique was largely ignored ,until the dawn of

twentieth century, when it was rediscovered by dentaltwentieth century, when it was rediscovered by dental

profession for producing profession for producing crowns and inlayscrowns and inlays..

• Waxes were first used in dentistry in early Waxes were first used in dentistry in early eighteenth century………..edentulous eighteenth century………..edentulous impressions.impressions.

• Waxes are still employed in large quantities Waxes are still employed in large quantities in various clinical and lab procedure………in various clinical and lab procedure………patterns for cast restoration, bite registration.patterns for cast restoration, bite registration.

• Dr William.H.Taggart of Chicago formulated a Dr William.H.Taggart of Chicago formulated a wax pattern compound of excellent wax pattern compound of excellent properties.properties.

• He also described an investment He also described an investment technique ,developed an investment material technique ,developed an investment material and even invented an air pressure casting and even invented an air pressure casting machine.machine.

Waxes Waxes are organic polymers consisting of hydrocarbons and are organic polymers consisting of hydrocarbons and their derivative (eg ester and alcohol).their derivative (eg ester and alcohol).

ACCORDING TO GPT ACCORDING TO GPT Casting waxes can be defined as a Casting waxes can be defined as a composition containing various waxes with desired composition containing various waxes with desired properties for making wax patterns to be formulated into properties for making wax patterns to be formulated into metal casting.metal casting.

CLASSIFICATION OF WAXESCLASSIFICATION OF WAXES

1)According to origin1)According to origin

2)According to use and application2)According to use and application

ACCORDING TO ORIGINACCORDING TO ORIGIN

Natural Synthetic MineralParaffin, microcrystalline, ceresin Polyethylene waxesMontan, Polyoxyethylene glycol waxes PlantCarnauba, candelilla InsectBeeswax Animal Spermaceti wax

ACCORDING TO USE AND & APPLICATIONACCORDING TO USE AND & APPLICATION

PATTERN WAXES PROCESSING WAXES IMPRESSION PATTERN WAXES PROCESSING WAXES IMPRESSION WAXESWAXES

Inlay wax Boxing wax Bite registration Inlay wax Boxing wax Bite registration or or

Casting wax utility wax corrective wax Casting wax utility wax corrective wax

Base plate wax sticky wax Base plate wax sticky wax

carding waxcarding wax

Blockout waxBlockout wax

white wax white wax

INLAY CASTING WAXINLAY CASTING WAX• Inlay wax is a specialized dental wax that can be applied to Inlay wax is a specialized dental wax that can be applied to

dies to form direct or indirect patterns for the lost wax dies to form direct or indirect patterns for the lost wax technique used for casting metal or hot pressing of technique used for casting metal or hot pressing of ceramics.ceramics.

• Generally produced in deep blue, green or purple color.Generally produced in deep blue, green or purple color.

• Composition of inlay waxComposition of inlay wax ParaffinParaffin-60%-60% CarnaubaCarnauba-25%-25% BeeswaxBeeswax-5%-5% CeresinCeresin-10%-10% Natural resins(gum dammer)-Natural resins(gum dammer)-less than 1%less than 1% Organic fillers-Organic fillers- added to avoid excessive added to avoid excessive

shrinkage,expansion due to temp changeshrinkage,expansion due to temp change Microcrystalline wax-Microcrystalline wax- In minute amount.In minute amount. CandelillaCandelilla Coloring agentsColoring agents

Paraffin wax(mineral wax)Paraffin wax(mineral wax)

• Generally the main ingredient of inlay waxes.Generally the main ingredient of inlay waxes.

• Obtained from high boiling fractions of petrolem(methane Obtained from high boiling fractions of petrolem(methane series)series)

• Mixture of hydrocarbonsMixture of hydrocarbons

• Melting range 40-71Melting range 40-71o o C. increases with increasing molecular C. increases with increasing molecular wt.wt.

• Paraffin waxes have less than 0.5% oil.Paraffin waxes have less than 0.5% oil.

• Presence of oil lowers melting temp.Presence of oil lowers melting temp.

• During solidification and cooling a volumetric contraction in During solidification and cooling a volumetric contraction in the range 11%-15%.the range 11%-15%.

• This is not uniform ,since it is a mixture of hydrocarbons.This is not uniform ,since it is a mixture of hydrocarbons.

• Likely to flake when trimmed.Likely to flake when trimmed.

• Does not present smooth, glossy surfaceDoes not present smooth, glossy surface

• Consequently other waxes and natural resins are added.Consequently other waxes and natural resins are added.

Carnauba wax (plant wax)Carnauba wax (plant wax)

• Derived from tropical palmsDerived from tropical palms

• It is quite hard, melting range 84-91It is quite hard, melting range 84-9100CC

• Combined with paraffin to-Combined with paraffin to-

Decrease flow at mouth tempDecrease flow at mouth temp

increase the hardnessincrease the hardness

• It contributes to glossiness of the wax surface, even more It contributes to glossiness of the wax surface, even more than dammar resin.than dammar resin.

(Addition of 10 % carnauba wax to paraffin wax with a melting (Addition of 10 % carnauba wax to paraffin wax with a melting range of 20range of 2000C will increase the melting range to 46C will increase the melting range to 4600C.)C.)

Ceresin wax (mineral wax)Ceresin wax (mineral wax)• May replace part of paraffin to modify toughness and May replace part of paraffin to modify toughness and

carving characteristic.carving characteristic.

• Like microcrystalline waxes they are branched chain and Like microcrystalline waxes they are branched chain and straight chain paraffin.straight chain paraffin.

• They have higher mol wt and greater hardness than They have higher mol wt and greater hardness than hydrocarbon waxeshydrocarbon waxes

• These waxes also may be used to increase the melting These waxes also may be used to increase the melting range of paraffin waxes.range of paraffin waxes.

Beeswax (insect wax)Beeswax (insect wax)

• Complex mixture of esters, consisting mainly of myricyl Complex mixture of esters, consisting mainly of myricyl palmitate, plus saturated and unsaturated hydrocarbons palmitate, plus saturated and unsaturated hydrocarbons and high molecular wt organic acids.and high molecular wt organic acids.

• Melting range 63-70Melting range 63-7000CC

• Brittle at room temp, becomes plastic at body tempBrittle at room temp, becomes plastic at body temp

• Used to modify the properties of paraffin waxUsed to modify the properties of paraffin wax

(also the main component of sticky wax)(also the main component of sticky wax)

Natural resin (gum dammer)Natural resin (gum dammer)

• Less than 1%Less than 1%

• Added to paraffin to improve its smoothness in moldingAdded to paraffin to improve its smoothness in molding

• It renders it more resistant to cracking and flakingIt renders it more resistant to cracking and flaking

• Increases the toughness of the wax and enhances the Increases the toughness of the wax and enhances the smoothness and lusture of the wax.smoothness and lusture of the wax.

Microcrystalline waxes(mineral)Microcrystalline waxes(mineral)• Similar to paraffin waxes, but obtained from heavier oil Similar to paraffin waxes, but obtained from heavier oil

fractions.fractions.

• It has a higher melting range 60-91It has a higher melting range 60-9100C C

• It is tougher and more flexible than paraffinIt is tougher and more flexible than paraffin

• It has less volumetric shrinkage during solidification than It has less volumetric shrinkage during solidification than paraffin.paraffin.

Candelilla wax (plant wax)Candelilla wax (plant wax)

• Same qualities as carnauba waxSame qualities as carnauba wax

• Added to paraffin to partially or entirely replace carnauba Added to paraffin to partially or entirely replace carnauba wax.wax.

• Its melting point is lower, and it is not as hard as carnauba Its melting point is lower, and it is not as hard as carnauba wax.wax.

Organic FillersOrganic Fillers

• Normally soft wax shrinks more than hard wax Normally soft wax shrinks more than hard wax

• High shrinking wax may cause significant pattern distortion High shrinking wax may cause significant pattern distortion when it solidifies.when it solidifies.

• For this reason organic filler is added , they should be For this reason organic filler is added , they should be completely miscible with components of inlay wax.completely miscible with components of inlay wax.

• They should not leave an undesirable residue after burnout.They should not leave an undesirable residue after burnout.

• In modern inlay waxes, carnauba wax is often replaced in In modern inlay waxes, carnauba wax is often replaced in part with certain synthetic waxes that are compatible with part with certain synthetic waxes that are compatible with paraffin waxparaffin wax

• One is a complex nitrogen derivative of higher fatty acids.One is a complex nitrogen derivative of higher fatty acids.

• The other is composed of esters of acids derived from The other is composed of esters of acids derived from montan wax, a petroleum derivativemontan wax, a petroleum derivative

• Control of properties of inlay wax is governed by Control of properties of inlay wax is governed by combination of factors-combination of factors-

-Amount of carnauba wax used. -Amount of carnauba wax used.

-The melting range of hydrocarbon wax.-The melting range of hydrocarbon wax.

-Presence of resin.-Presence of resin.

DENTARUM (Germany)DENTARUM (Germany)Crown and Bridge Inlay WaxCrown and Bridge Inlay Wax

In ropesIn ropes In bulkIn bulk

Melting point 72Melting point 7200CCAlso present in ivory color melting point 73Also present in ivory color melting point 7300CC

Also present in different coloursAlso present in different coloursVario wax setVario wax set

Dark blue-hardDark blue-hard, for crowns bridges and inlays. Add on and Dip use melting point 69, for crowns bridges and inlays. Add on and Dip use melting point 6900CC

Light blue-softLight blue-soft, for crowns bridges and inlays,add on and dip use melting point 72, for crowns bridges and inlays,add on and dip use melting point 7200CC

Lilac-stress freeLilac-stress free, for copings and cervical margins , melting point 79, for copings and cervical margins , melting point 7900C C

Red- adhesiveRed- adhesive, connecting and adhesive wax, melting point 70, connecting and adhesive wax, melting point 7000CC

Cervical wax-Cervical wax- for the cervical area, no shrinkage , a for the cervical area, no shrinkage , aVery accurate fit will be obtained, melting point 74Very accurate fit will be obtained, melting point 7400CC

Special wax for electrical wax heating unit(vario therm),dark blue-hard and light blue 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 stresssoft are for modelling,trimming and dipping application, lilac-medium hard , red stressFree for cervical margins, green-hard for trimming. Dip application yellow wax caps ofFree for cervical margins, green-hard for trimming. Dip application yellow wax caps ofUniform strength.Uniform strength.

Wax Preforms are available (ceratom wax preforms, Dentaurum)Wax Preforms are available (ceratom wax preforms, Dentaurum)It simplifies wax up and shorten finishing procedure.It simplifies wax up and shorten finishing procedure.

DESIRABLE PROPERTIES OF INLAY CASTING WAXDESIRABLE PROPERTIES OF INLAY CASTING WAX

1)1) When softened the wax should be uniform.When softened the wax should be uniform.

It should be compounded with ingredients that blend with It should be compounded with ingredients that blend with each other so that there are no each other so that there are no grainy areasgrainy areas or or hard spotshard spots..

2) The color should be such that it contrasts with the die 2) The color should be such that it contrasts with the die material or prepared tooth.material or prepared tooth.

It is necessary to carve the wax margins close to the die It is necessary to carve the wax margins close to the die Therefore a definite contrast in color facilitates proper Therefore a definite contrast in color facilitates proper finishing of the margins.finishing of the margins.

3) There should be no flakiness or similar surface 3) There should be no flakiness or similar surface roughening when the wax is bent and molded after roughening when the wax is bent and molded after softeningsoftening

Such flakiness is likely to be present in paraffin wax , this is Such flakiness is likely to be present in paraffin wax , this is one of the reasons modifiers are added.one of the reasons modifiers are added.

4) During carving wax should not pull away with 4) During carving wax should not pull away with carving instrument or should not chip as it is carved.carving instrument or should not chip as it is carved.

Wax is carved at the margins so that the patterns conforms Wax is carved at the margins so that the patterns conforms exactly to the surface of the die, this procedure sometimes exactly to the surface of the die, this procedure sometimes require that the wax be carved to very thin layer.require that the wax be carved to very thin layer.

5) Wax should burn out , forming carbon which is later 5) Wax should burn out , forming carbon which is later eliminated by oxidation to volatile gases.eliminated by oxidation to volatile gases.

ANSI/ADA specification No 4 requires that the melted wax ANSI/ADA specification No 4 requires that the melted wax when vaporized at 500when vaporized at 50000C (932C (93200F) , leave no solid residue in F) , leave no solid residue in excess of 0.10% of the original wt of specimen.excess of 0.10% of the original wt of specimen.

6) The wax pattern should be completely rigid and 6) The wax pattern should be completely rigid and dimensionally stable at all times until it is eliminated dimensionally stable at all times until it is eliminated ..

wax pattern is subject to flow unless it is handled carefully , wax pattern is subject to flow unless it is handled carefully , it is also subject to relaxation , a factor that must be taken it is also subject to relaxation , a factor that must be taken into consideration in its manipulation.into consideration in its manipulation.

PROPERTIES OF INLAY CASTING WAXESPROPERTIES OF INLAY CASTING WAXES

FLOWFLOW• ANSI/ADA Specification No 4 covers two types of waxes ANSI/ADA Specification No 4 covers two types of waxes • Type IType I is medium wax, its hard, used for direct pattern in the is medium wax, its hard, used for direct pattern in the

mouth, where lower flow values at 37mouth, where lower flow values at 3700C tend to minimize any C tend to minimize any distortion of the pattern on its removal.distortion of the pattern on its removal.

• Type II Type II is a soft wax used in indirect technique is a soft wax used in indirect technique

• Flow at different temp when type I and II waxes are subjected Flow at different temp when type I and II waxes are subjected to 19.6 N load for 10 min requirement for ANSI/ADA sp no to 19.6 N load for 10 min requirement for ANSI/ADA sp no 44(JADA 1984)(JADA 1984)

Type of wax T=30Type of wax T=3000C T=37C T=3700C T=40C T=4000C T=40C T=4000C T=45C T=4500 T=45T=4500CC

(max) (max) (min) (max) (min) (max) (max) (max) (min) (max) (min) (max) I --- 1.0 --- 20 70 90I --- 1.0 --- 20 70 90 II 1.0 --- 50 --- 70 90 II 1.0 --- 50 --- 70 90

At body temp flow of type I is 1% and that of type II is 9%, to record cavity detail it At body temp flow of type I is 1% and that of type II is 9%, to record cavity detail it Must attain temp around 45Must attain temp around 4500C.C.

• Max flow permitted for type I waxes at 37Max flow permitted for type I waxes at 3700C is 1%, the low C is 1%, the low flow at this temp permits carving and removal of pattern flow at this temp permits carving and removal of pattern from prepared cavity at oral temp without distortion.from prepared cavity at oral temp without distortion.

• Type II wax is a softer wax shows greater flow, it allows Type II wax is a softer wax shows greater flow, it allows greater ease of carving and molding, since it is used in greater ease of carving and molding, since it is used in indirect pattern formation on die ,change of temp from oral indirect pattern formation on die ,change of temp from oral cavity to room temp is not a problem. cavity to room temp is not a problem.

• Each wax exhibits sharp transition point, above which it Each wax exhibits sharp transition point, above which it loses its plasticity, for soft waxes it is at lower temp, and loses its plasticity, for soft waxes it is at lower temp, and hard waxes at a higher temp.hard waxes at a higher temp.

• Waxes lack rigidity and may flow under stress even at room Waxes lack rigidity and may flow under stress even at room temp. temp.

careful handling is necessary during manipulation.careful handling is necessary during manipulation.

THERMAL PROPERTIESTHERMAL PROPERTIES

• Thermal conductivity of waxes is low and time is required to Thermal conductivity of waxes is low and time is required to both heat them uniformly and to cool them to body or room both heat them uniformly and to cool them to body or room temperature.temperature.

• Inlay wax thermally expand and contract more per degree Inlay wax thermally expand and contract more per degree of temp change than any other dental material.of temp change than any other dental material.

• This is one of the inherent disadvantages of waxes when This is one of the inherent disadvantages of waxes when they are used in the direct technique.they are used in the direct technique.

• This property is not significant when wax is used in indirect This property is not significant when wax is used in indirect techniquetechnique because the pattern is not subjected to a change because the pattern is not subjected to a change from mouth to room temp, provided no marked variations from mouth to room temp, provided no marked variations in temp occurs after the removal of pattern from die.in temp occurs after the removal of pattern from die.

• Waxes have high coefficient of thermal expansion .Waxes have high coefficient of thermal expansion .

The max linear thermal expansion allowed between 25 and The max linear thermal expansion allowed between 25 and 303000C is 0.20%, between 25 and 37C is 0.20%, between 25 and 3700C 0.60% is allowed.C 0.60% is allowed.

Thermal expansion of inlay waxThermal expansion of inlay wax(paraffin).(paraffin).A- cooled under PrA- cooled under PrB- cooled without PrB- cooled without Pr

• Knowledge of amount of wax expansion or contraction Knowledge of amount of wax expansion or contraction provides a basis on which to judge the compensation provides a basis on which to judge the compensation necessary to produce an accurate casting.necessary to produce an accurate casting.

• Data sufficient to show the thermal contraction of the wax Data sufficient to show the thermal contraction of the wax from its working temp to room temp are included in each from its working temp to room temp are included in each package of inlay wax that complies with ADA Sp No 4package of inlay wax that complies with ADA Sp No 4

• Specification also requires ,instructions regarding method Specification also requires ,instructions regarding method of softening and working temp for direct patterns. of softening and working temp for direct patterns.

WAX DISTORTION /WARPAGE OF WAX PATTERNWAX DISTORTION /WARPAGE OF WAX PATTERN

• Wax distortion is probably the most serious problem during Wax distortion is probably the most serious problem during forming and removal of the pattern from the mouth or the die.forming and removal of the pattern from the mouth or the die.

• Distortion results fromDistortion results from

-thermal changes-thermal changes

-relaxation of stresses (on cooling)-relaxation of stresses (on cooling)

-occluded air-occluded air

-molding-molding

-carving-carving

-removal and the time and temp of storage-removal and the time and temp of storage

• Waxes tend to return to their original shape after manipulation, Waxes tend to return to their original shape after manipulation, property is known as property is known as elastic memoryelastic memory..

• The casting fits best when the pattern is invested The casting fits best when the pattern is invested immediately after its removal from the die.immediately after its removal from the die.

Inlay wax softened over bunsen burner and left in room temp water for several hours Inlay wax softened over bunsen burner and left in room temp water for several hours It tends to return to its orignal shape, the inner mol were under compression whileIt tends to return to its orignal shape, the inner mol were under compression whileOuter ones under tension.Outer ones under tension.

Castings made from patterns with melted wax cooled under pressureCastings made from patterns with melted wax cooled under pressureA- Pattern invested immediatelyA- Pattern invested immediatelyB- Pattern stored for 2 hrB- Pattern stored for 2 hrC- Pattern stored for 12 hr C- Pattern stored for 12 hr

• One can minimize the incorporation of residual stress by One can minimize the incorporation of residual stress by softening a wax uniformly by heating at 50softening a wax uniformly by heating at 5000C for at least 15 C for at least 15 min before use , min before use ,

also by using warmed carving instruments and a warmed also by using warmed carving instruments and a warmed die, by adding wax to the die in small amounts.die, by adding wax to the die in small amounts.

• Greater warpage results at higher storage temp.Greater warpage results at higher storage temp.

• Inlay wax pattern if allowed to stand longer than 30 min, Inlay wax pattern if allowed to stand longer than 30 min, should be kept in a refrigerator , the distortion will be less should be kept in a refrigerator , the distortion will be less as compared to room temp.as compared to room temp.

• During spruing distortion can be reduced by use of solid During spruing distortion can be reduced by use of solid wax sprue or hollow metal sprue filled with sticky wax. If wax sprue or hollow metal sprue filled with sticky wax. If the pattern was stored margins should be re-adapted. the pattern was stored margins should be re-adapted.

• Sprue position- Ideal area for the sprue former is the point Sprue position- Ideal area for the sprue former is the point of greatest bulk in the pattern to avoid distorting thin areas of greatest bulk in the pattern to avoid distorting thin areas and permit complete flow of the alloy into the mold cavity.and permit complete flow of the alloy into the mold cavity.

• It should be attached with the pattern on the master die, It should be attached with the pattern on the master die, provided the pattern can be removed directly in line with its provided the pattern can be removed directly in line with its path of withdrawl from the die.path of withdrawl from the die.

• Sprue diameter- same size as the thickest area of the wax Sprue diameter- same size as the thickest area of the wax pattern ,if the pattern is small, the sprue former must also pattern ,if the pattern is small, the sprue former must also be small.be small.

• Length should be adjusted ,Length should be adjusted ,

Gypsum bonded investment – 6 mm of the open end Gypsum bonded investment – 6 mm of the open end of ringof ring

Phosphate bonded investment – 3 -4mm “ “ “ “Phosphate bonded investment – 3 -4mm “ “ “ “

MANIPULATION OF INLAY WAXMANIPULATION OF INLAY WAX

• Dry heat is preferred to the use of water bath (54-60Dry heat is preferred to the use of water bath (54-6000C)C)

• For type I (direct technique), it is softened over a flame For type I (direct technique), it is softened over a flame until it becomes shiny.until it becomes shiny.

• It is kneaded, shaped and pressed in the prepared cavity.It is kneaded, shaped and pressed in the prepared cavity.

• Pressure is applied by finger or pt biting on it.Pressure is applied by finger or pt biting on it.

• It is cooled gradually, before taking out.It is cooled gradually, before taking out.

• For fabricating indirect pattern (type II) die should be For fabricating indirect pattern (type II) die should be lubricated, preferably with a lubricant, containing a wetting lubricated, preferably with a lubricant, containing a wetting agent.agent.

• Excess must be avoided .Excess must be avoided .

• Melted wax is added in layers with a spatula or waxing Melted wax is added in layers with a spatula or waxing instrument or may be painted on with a brush.instrument or may be painted on with a brush.

• Wax is then carved to proper contour.Wax is then carved to proper contour.

• A silk or fine cloth may be used, for final polishing.A silk or fine cloth may be used, for final polishing.

• Dipping waxes are kept molten for constant usage .Dipping waxes are kept molten for constant usage .

• Wax pots kept at different temp can be used.Wax pots kept at different temp can be used.

• Proportion of these waxes have not been characterized , Proportion of these waxes have not been characterized , nor do they fall in any present specification.nor do they fall in any present specification.

Wax heating unitWax heating unitTemp range 30-110Temp range 30-11000CC

Modeling instrument set, wax knifeModeling instrument set, wax knifeThomas modeling instrument No 1Thomas modeling instrument No 1Tweezer, wax pencil, rubber adapterTweezer, wax pencil, rubber adapterTooth brushTooth brush

An electric wax knife with temp An electric wax knife with temp Regulator and transformer, can be Regulator and transformer, can be Adjusted to a max of 250Adjusted to a max of 25000CC

Lubrofilm wax surface tension reducing agent, makesLubrofilm wax surface tension reducing agent, makesInvesting easierInvesting easier

CASTING WAXESCASTING WAXES• The pattern for metallic framework of RPD and other similar The pattern for metallic framework of RPD and other similar

structures is fabricated from casting waxes.structures is fabricated from casting waxes.

• They are available in the form of sheets (.3 to .6mm), ready They are available in the form of sheets (.3 to .6mm), ready made shapes and in bulk.made shapes and in bulk.

• Ready made shapes are supplied in round, half round and pear Ready made shapes are supplied in round, half round and pear shaped rods & wires of various gages in approx 10 cm length.shaped rods & wires of various gages in approx 10 cm length.

• Exact composition is not specified but they include ingredients Exact composition is not specified but they include ingredients similar to inlay waxes with various combination and proportions similar to inlay waxes with various combination and proportions ofof

-Paraffin-Paraffin

-Ceresin-Ceresin

-Beeswax-Beeswax

-Resins and other waxes being used-Resins and other waxes being used

• Casting wax sheets are used to establish min thickness in Casting wax sheets are used to establish min thickness in certain areas of partial denture framework such as palatal certain areas of partial denture framework such as palatal and lingual bar and to produce desired contour of lingual and lingual bar and to produce desired contour of lingual bar. bar.

DENTAURUM (Germany)DENTAURUM (Germany)

Model Casting, Wax PreformsModel Casting, Wax PreformsAvailable in green (clasps) and red (retentions) colors Available in green (clasps) and red (retentions) colors

Premolar clasps, molar clasps, bonyhardPremolar clasps, molar clasps, bonyhardClasp, ring claspClasp, ring clasp

Ring clasp, lingual bars, ridge retensionsRing clasp, lingual bars, ridge retensionsGrids ,coarse grids, fine grids.Grids ,coarse grids, fine grids.

Perforated retentions ,sprue former patterns ,loop Perforated retentions ,sprue former patterns ,loop Retensions.Retensions.

Wax profiles-Wax profiles- available as 0.6-5.0 mm dia, semi-circular profiles max and man available as 0.6-5.0 mm dia, semi-circular profiles max and man Profiles, arches, finishing strip, sprue former strip.Profiles, arches, finishing strip, sprue former strip.

Casting wax, Veined, Grained Casting wax, Veined, Grained For casting procedure available in For casting procedure available in differentdifferent

Thickness , 0.3, 0.35, 0.4, 0.45. 0.5, 0.6 mm.Thickness , 0.3, 0.35, 0.4, 0.45. 0.5, 0.6 mm.

Fine veined, medium veined, coarse veinedFine veined, medium veined, coarse veinedCoarse grainedCoarse grained

Connecting wax, dark green-Connecting wax, dark green- Special wax for rapid build up of connections Special wax for rapid build up of connections Between the base and the clasps and retainers, melting point 74Between the base and the clasps and retainers, melting point 7400CC

Thermo wax, pinkThermo wax, pink- high melting point blocking - high melting point blocking Out wax for undercuts, melting point 96Out wax for undercuts, melting point 9600CC

PHYSICAL CHARACTERSTICSPHYSICAL CHARACTERSTICS• These waxes possess certain degree of tackinessThese waxes possess certain degree of tackiness

• This helps to maintain their position on the cast and on each other This helps to maintain their position on the cast and on each other during assembly of pattern.during assembly of pattern.

• There is no ADA specification for these casting waxes.There is no ADA specification for these casting waxes.

• A federal specification has been formulated No U-W 140(march 1948)A federal specification has been formulated No U-W 140(march 1948)

Type of wax flow Breaking point working Type of wax flow Breaking point working

properties properties

Casting wax 35Casting wax 3500C-max,10% no fracture at Pliable and readilyC-max,10% no fracture at Pliable and readily

Class-A-28 gage 38Class-A-28 gage 3800C-min,60 % 23 C-min,60 % 23 00C +/- 1C +/- 100 adaptable at 40 to 45 adaptable at 40 to 4500CC

pink copy accurately surface pink copy accurately surface

Class-B-30 gage against which it is pressed Class-B-30 gage against which it is pressed

green shall not be brittle on coolinggreen shall not be brittle on cooling

Class-C-ready made shape ,blue vaporize at 500Class-C-ready made shape ,blue vaporize at 50000C,leaving no C,leaving no film film

other than carbonother than carbon

• The flow characteristic show a max of 10% flow at 35The flow characteristic show a max of 10% flow at 35ooC and C and min of 60% flow at 38min of 60% flow at 3800C.C.

• This is significantly different from inlay waxes.This is significantly different from inlay waxes.

• There is little need for casting waxes to exhibit low flow at There is little need for casting waxes to exhibit low flow at body temp.body temp.

• Requirement for ductility is high, federal specification Requirement for ductility is high, federal specification requires that it be bent double upon itself without # at a requires that it be bent double upon itself without # at a temp of 23temp of 2300C, and that they be pliable and readily C, and that they be pliable and readily adaptable at 40adaptable at 4000CC

• Like inlay wax they must vaporize at 500Like inlay wax they must vaporize at 50000C with no residue C with no residue other than carbon.other than carbon.

DIFFERENT COMMERCIALLY AVAILABLE DIFFERENT COMMERCIALLY AVAILABLE BRANDS FOR CASTING WAXESBRANDS FOR CASTING WAXES

• DENTAURUM (GERMANY)DENTAURUM (GERMANY) Supplied by kalabai in our college, 100 gms cost around Rs Supplied by kalabai in our college, 100 gms cost around Rs

540/-540/-• SHOFU (Kyoto, JAPAN)SHOFU (Kyoto, JAPAN)• GC Dental industrial Corp (Tokyo, JAPAN)GC Dental industrial Corp (Tokyo, JAPAN)• JELENKO (USA)JELENKO (USA)• SCHULER Dental (GERMANY), S-U Dental waxSCHULER Dental (GERMANY), S-U Dental wax• DEGUSSA AG (GERMANY), PlastodentDEGUSSA AG (GERMANY), Plastodent• Kerr Dental Casting WaxesKerr Dental Casting Waxes• Shiva ProductsShiva Products    MAARC INLAY/Pattern wax, MAARC Casting MAARC INLAY/Pattern wax, MAARC Casting

wax sheets wax sheets  http://www.indiamart.com/shivaproductshttp://www.indiamart.com/shivaproducts

REVIEW OF LITERATUREREVIEW OF LITERATUREJADA, Vol 90 feb 1975JADA, Vol 90 feb 1975

In year may 1975 the revision of ADA sp no 4 for dental inlay In year may 1975 the revision of ADA sp no 4 for dental inlay casting wax was approved by the council on dental casting wax was approved by the council on dental materials and devices of the American dental association.materials and devices of the American dental association.

Major differences from the previous specifications wereMajor differences from the previous specifications were

1)1) Inclusion of synthetic waxesInclusion of synthetic waxes

2)2) Change to three types and classes, of inlay waxesChange to three types and classes, of inlay waxes

3)3) Change in flow requirement.Change in flow requirement.

Revision became effective Jan 1 1976Revision became effective Jan 1 1976

Scope and classification Scope and classification

1.1 Scope- for inlay casting wax, consists essentially of natural 1.1 Scope- for inlay casting wax, consists essentially of natural and synthetic waxes , resins and hydrocarbons of paraffin and synthetic waxes , resins and hydrocarbons of paraffin series.series.

1.2 –Types and Classes1.2 –Types and Classes

Type-A HardType-A Hard

Class1-SticksClass1-Sticks

Class2-conesClass2-cones

Class3-other shapesClass3-other shapes

Type-B MediumType-B Medium

Class1-sticksClass1-sticks

Class2-conesClass2-cones

Class3-other shapesClass3-other shapes

Type-C softType-C soft

Class1-sticks Class1-sticks

Class2-conesClass2-cones

Class3-other shapesClass3-other shapes

Section 3.7 Outlines for flow requirementSection 3.7 Outlines for flow requirement

FLOW % WAX TEMP FLOW % WAX TEMP 00CC

Min max Type A Type B Type Min max Type A Type B Type CC

--- 1 43 37 34--- 1 43 37 34

1 15 46 40 371 15 46 40 37

50 85 49 43 4050 85 49 43 40

70 90 52 46 4370 90 52 46 43

Revision was done again in 1983 which was reaffirmed in 2003, it was decideRevision was done again in 1983 which was reaffirmed in 2003, it was decideTo follow the specifications in second revision, including flow requirements To follow the specifications in second revision, including flow requirements Which are presently being followed. Which are presently being followed.

DISTORTION OF WAX PATTERN CAUSED BY THE FORCES OF DISTORTION OF WAX PATTERN CAUSED BY THE FORCES OF SETTING EXPANSION OF GYPSUM BONDED INVESTMENTSETTING EXPANSION OF GYPSUM BONDED INVESTMENT

• Mahler and AndyMahler and Andy concluded that hygroscopic expansion concluded that hygroscopic expansion of gypsum products was an extension of normal crystal of gypsum products was an extension of normal crystal growth caused by the addition of water, rather than true growth caused by the addition of water, rather than true hygroscopic expansion resulting from water molecules hygroscopic expansion resulting from water molecules forcing particles apart. forcing particles apart.

• Shell and Hollenback Shell and Hollenback found that vertical and horizontal found that vertical and horizontal expansion varied in proportion to the length of asbestos expansion varied in proportion to the length of asbestos liner, they found that castings made with full length liner liner, they found that castings made with full length liner were longer than the wax pattern by 0.4% and castings were longer than the wax pattern by 0.4% and castings made with liner 3mm short of both ends of the liners were made with liner 3mm short of both ends of the liners were shorter than the wax pattern by approx 0.6%.shorter than the wax pattern by approx 0.6%.

• Exploring the effects of different investments on marginal fit Exploring the effects of different investments on marginal fit of inlays and crowns ,of inlays and crowns ,Jenkins & PhillipsJenkins & Phillips found significant found significant differences in the marginal gaps of inlays depending on differences in the marginal gaps of inlays depending on which investment was used ,but noted no overall significant which investment was used ,but noted no overall significant differences.differences.

Complete crowns exhibited no Complete crowns exhibited no significant differences in marginal discrepancies regardless significant differences in marginal discrepancies regardless of the investment or technique.of the investment or technique.

• D.R.DavisD.R.Davis in 1997 conducted a study to determine whether in 1997 conducted a study to determine whether the magnitude and characteristics of distortion could be the magnitude and characteristics of distortion could be modified by limiting the vertical setting expansion.modified by limiting the vertical setting expansion.

Wax patterns were formed on standard dies of MOD inlays and Wax patterns were formed on standard dies of MOD inlays and complete crowns, Invested in conventional open ring and complete crowns, Invested in conventional open ring and modified closed ring using same investment and technique.modified closed ring using same investment and technique.

after casting thickness of the cement after casting thickness of the cement film was measured at specific sites.film was measured at specific sites.

The complete crown group exhibited less distortion than MOD The complete crown group exhibited less distortion than MOD inlay group. inlay group.

• Eleini Kotsiomiti and Athanasios.K Eleini Kotsiomiti and Athanasios.K

In the year 1994 conducted a study to see the behavior of crown In the year 1994 conducted a study to see the behavior of crown pattern waxes on heating and cooling, Flow and Linear pattern waxes on heating and cooling, Flow and Linear thermal expansion were determined and compared with thermal expansion were determined and compared with those reported by previous investigators.those reported by previous investigators.

They concluded,They concluded,

1)1) Increase in flow of the pattern waxes caused by in increase Increase in flow of the pattern waxes caused by in increase in temp occurs in the range of 37-47in temp occurs in the range of 37-4700C for the majority of C for the majority of the material tested.the material tested.

2)2) Most of the material flow by 61% to 82% at 47Most of the material flow by 61% to 82% at 4700C to C to 525200C .This % seems to be adequate for easy handling. The C .This % seems to be adequate for easy handling. The temp increase provokes a linear expansion of more than 1% temp increase provokes a linear expansion of more than 1% for most pattern waxes.for most pattern waxes.

3)3) Rate of expansion varies during an increase in temp, the Rate of expansion varies during an increase in temp, the changes that occur at transition points are related to changes that occur at transition points are related to structural changes in the material.structural changes in the material.

4)4) Similarity of arrest points in the material tested is indicative Similarity of arrest points in the material tested is indicative of similar compositions and proportions of the major of similar compositions and proportions of the major constituents.constituents.

• Michio Ito et al Michio Ito et al in 1996 conducted a study to evaluate in 1996 conducted a study to evaluate the relationship between flow characteristic, bonding the relationship between flow characteristic, bonding strength and softening temp of paraffin and dental inlay strength and softening temp of paraffin and dental inlay waxes to casting shrinkage when patterns were invested waxes to casting shrinkage when patterns were invested with a phosphate bonded investment.with a phosphate bonded investment.

They concluded They concluded

1)1) Casting shrinkage decreased when flow of wax pattern Casting shrinkage decreased when flow of wax pattern increased .increased .

2)2) The flow of wax pattern increased as the exothermic The flow of wax pattern increased as the exothermic reaction increased reaction increased

3)3) A larger casting ring is suggested for casting when a A larger casting ring is suggested for casting when a relatively thick wax pattern or an inlay wax that has a relatively thick wax pattern or an inlay wax that has a high strength, softening temp and low flow % is used.high strength, softening temp and low flow % is used.

4)4) Some industrial waxes demonstrated potential for dental Some industrial waxes demonstrated potential for dental casting but research is needed. casting but research is needed.

• Randa Diwan et al Randa Diwan et al in 1997 conducted a study to see in 1997 conducted a study to see inaccuracies of pattern waxes in fixed and removable inaccuracies of pattern waxes in fixed and removable partial denture castingspartial denture castings

they conclude that wax is not the only potential cause they conclude that wax is not the only potential cause of inaccuracies other factors are:-of inaccuracies other factors are:-

1)1) Clinical and technical errors caused by dentist and dental Clinical and technical errors caused by dentist and dental techniciantechnician

2)2) Lab errors – improper manipulation of other dental Lab errors – improper manipulation of other dental materials eg duplicating procedure of master cast, materials eg duplicating procedure of master cast, refractory investmentrefractory investment

3)3) Liquid-powder ratio for both stone and investment mixesLiquid-powder ratio for both stone and investment mixes

4)4) Spruing ,improper burnout, overheating or underheating Spruing ,improper burnout, overheating or underheating the metal, erratic finishing and polishing.the metal, erratic finishing and polishing.

ALTERNATIVE TO PATTERN WAXESALTERNATIVE TO PATTERN WAXES

• Pattern waxes are being replaced to some extend by Pattern waxes are being replaced to some extend by preformed plastic pattern.they are completely combustible.preformed plastic pattern.they are completely combustible.

• Plstic retentions Plstic retentions

Plastic retensionsPlastic retensions

Preformed plastic pattern in different Preformed plastic pattern in different Shapes and sizesShapes and sizes

Pattern resinsPattern resins• Available in both Available in both Autopolymerizing acrylic resin (Duralay)Autopolymerizing acrylic resin (Duralay) Light curing resins (Modilux)Light curing resins (Modilux)

• Pattern resins are characterized by higher strength Pattern resins are characterized by higher strength and resistance to flow than waxes, good dimensional and resistance to flow than waxes, good dimensional stability and burn out without residue.stability and burn out without residue.

• Full crown patterns fabricated from pattern resins and Full crown patterns fabricated from pattern resins and inlay waxes have shown similar marginal discrepancies.inlay waxes have shown similar marginal discrepancies.

• A pattern is fabricated by applying the resin in in 3-5 A pattern is fabricated by applying the resin in in 3-5 mm layers and curing in a light chamber or with a mm layers and curing in a light chamber or with a hand held light curing unithand held light curing unit

• Resin is completely eliminated from the mold before Resin is completely eliminated from the mold before casting by heating at 690casting by heating at 69000C for 45 min.C for 45 min.

• Cahi E, Rosen M, Becker PJ in 1996 did a comparison of the Cahi E, Rosen M, Becker PJ in 1996 did a comparison of the dimensional stability of three inlay patternsdimensional stability of three inlay patterns

- Kerr’s Type II blue inlay casting wax- Kerr’s Type II blue inlay casting wax

- Modilux (light curing resin)- Modilux (light curing resin)

- Duralay (autopolymerizing acrylic resin)- Duralay (autopolymerizing acrylic resin)

They concluded that They concluded that

- Wax underwent more contraction than Duralay - Wax underwent more contraction than Duralay and Modiluxand Modilux

- More contraction occurred at 24 hr than between - More contraction occurred at 24 hr than between onset and one hr.onset and one hr.

- As contraction occurred after one hr and the wax - As contraction occurred after one hr and the wax contracted the most , it was recommended that Duralay contracted the most , it was recommended that Duralay and Modilux be used as pattern material, especially if delay and Modilux be used as pattern material, especially if delay in investing is anticipated.in investing is anticipated.

• M.Krane et al in 1998 conducted a study on the surface of M.Krane et al in 1998 conducted a study on the surface of resins that burn without residues in the lost wax procedure.resins that burn without residues in the lost wax procedure.

A total 480 specimen from 16 different manufactures were A total 480 specimen from 16 different manufactures were examinedexamined

They concluded that surface structure of the residue from They concluded that surface structure of the residue from resins examined were in a range acceptable for the dental resins examined were in a range acceptable for the dental casting technique.casting technique.

An increased application of residue free resins in An increased application of residue free resins in dental casting technique is therefore recommendable. dental casting technique is therefore recommendable. These resins could not only complement waxes or wax/resin These resins could not only complement waxes or wax/resin composition, but could even ,in whole or in part replace composition, but could even ,in whole or in part replace them.them.

CONCLUSIONCONCLUSION

• Waxes have been popular and useful dental material.Waxes have been popular and useful dental material.

• Easily manipulatedEasily manipulated

• Low in cost and serve variety of purposesLow in cost and serve variety of purposes

• Nevertheless use of dental waxes is associated with control Nevertheless use of dental waxes is associated with control of certain characteristics that affect their applicability, such of certain characteristics that affect their applicability, such asas

-Effect of heating on flow-Effect of heating on flow

-Thermal expansion-Thermal expansion

-Distortion-Distortion

• Way back in 1939 Hollenback et al published the results of Way back in 1939 Hollenback et al published the results of their extensive work on properties of waxes.their extensive work on properties of waxes.

They concluded that waxes are They concluded that waxes are sufficiently stable material if handled properly.sufficiently stable material if handled properly.

• REFERENCESREFERENCES

Kenneth j. Anusavice ; Phillips Science of dental material .Eleventh edition, Elsevier,2004.

Jack L. Ferracane ; Materials in Dentistry principles and application. Second edition ,Lippincot williams, 1995.

William J. O’Brien; Dental materials and their selection. Third edition, quintessence Publishing co. 2002.

Robert C. Craig John M. Powers, John C.Wataha ;Dental materials properties and manipulation,. Eight edition,2004.

Marcia gladwin; clinical aspects of dental materials Lippincott Williams 2000 E.C.Combe; Notes on dental materials, sixth edition Churchill livingstone 1992 Revised ADA specification No 4 for dental casting wax,JADA Vol 90 Feb 1975 Davis.D.R, 1987, “Limiting wax pattern distortion caused by setting expansion”.JPD

Aug 58(1):229-32 Kotsiomiti E. Kaloyannides A,1994, “Crown pattern waxes: A study of their behavior

on heating and cooling “JPD May 71: 511-6 Ito M et al,1996, “Effect of selected physical properties of waxes on investments and

casting shrinkage”JPD Feb 75: 211-6 Diwan R et al,1997, “pattern waxes and inaccuracies in fixed and removable partial

denture castings” JPD May 77:553-5 Krane M et al 1998, “study on the surface of resins that burn out without residues

lost-wax procedure”,JPD, 79:389-92 Waxes crown and bridge casting procedures, DENTAURUM

Thank you