Metallic RestorationsMetallic Restorations

Student: Student: Alonso Martinez TapiaAlonso Martinez Tapia

Dr. Alfredo Nevarez RasconDr. Alfredo Nevarez Rascon

M E T A L SM E T A L S

DEFINITIONDEFINITION

““Chemical substance that Chemical substance that is a good electrical and is a good electrical and

thermal conductor, thermal conductor, when is polished is a when is polished is a

good reflector “good reflector “

FEATURESFEATURES

SHINESHINE RESISTANCE TO CORROSIONRESISTANCE TO CORROSION THERMAL AND ELECTRICALTHERMAL AND ELECTRICAL

CONDUCTORCONDUCTOR STRENGTH AND RIGIDITY STRENGTH AND RIGIDITY DRIVE RESISTANCEDRIVE RESISTANCE

ALLOYALLOY : This are unions of 2 or more : This are unions of 2 or more metallic elements.metallic elements.

In Dentistry, alloys are use except In Dentistry, alloys are use except for:for:

• pure gold laminatedpure gold laminated• commercial pure titanium commercial pure titanium • Silver points for endodonticSilver points for endodontic

CHANGES IN THE METAL STRUCTURE

lackluster : Loss of gloss or sheen in a alloy or metal surface.

Pigmentation : Partial impariment on metal surface, or color change.

CORROSION : Actual deterioration on metal surface.

• FACTORS CAUSING CORROSION– pH of the saliva.– Wrong adapted prosthesis.– Poor dental position.– Deposits of food.– Poor hygiene.– Food that release certain chemical

components.– Drugs.– Fluctuations in temperature.

ALLOYS USED IN DENTISTRYALLOYS USED IN DENTISTRY

Highly noble alloys (precious)Highly noble alloys (precious)

Alloys of noble metalsAlloys of noble metals

Predominantly base alloysPredominantly base alloys

PRECIOUS METALSPRECIOUS METALS

Corrosion resistance in the oral cavity: Corrosion resistance in the oral cavity: Gold, Platinum, Palladium, Rhodium, Gold, Platinum, Palladium, Rhodium, Ruthenium, Iridium, Osmium and Silver.Ruthenium, Iridium, Osmium and Silver.

There are four main metals: There are four main metals: Gold, Gold, Palladium, Platinum and Silver.Palladium, Platinum and Silver.

Cast Metal Or DrainCast Metal Or Drain

Process for the constuction of a Process for the constuction of a restoration or appliance out for the restoration or appliance out for the previously made a mouth waxed or previously made a mouth waxed or patternpattern..

CAST ALLOYS FOR HIGHLY NOBLECAST ALLOYS FOR HIGHLY NOBLE

Composition:Composition:1.1. Gold: malleability, resistance to Gold: malleability, resistance to

corrosion.corrosion.2.2. Silver: HardnessSilver: Hardness3.3. Zinc: decreases T fusionZinc: decreases T fusion4.4. Platinum or Palladium: HardnessPlatinum or Palladium: Hardness5.5. Copper: resistance andCopper: resistance and bactericidalbactericidal

Nota: the white gold casting whit less Nota: the white gold casting whit less gold and copper are not.gold and copper are not.

TIPOS DE OROS PARA COLADOSTIPOS DE OROS PARA COLADOS Type I (SOFT GOLD)Type I (SOFT GOLD) For the construction of scale in class III y VFor the construction of scale in class III y V

Type II (MEDIUM GOLD)Type II (MEDIUM GOLD)For all types of deposits, plus For all types of deposits, plus ¾ crowns and ¾ crowns and

completecomplete

Type III (HARD GOLD)Type III (HARD GOLD)For small fixed bridges and removableFor small fixed bridges and removable

Type IV ( GOLD EXTRA HARD)Type IV ( GOLD EXTRA HARD)For large fixed bridges and removable palatal bars For large fixed bridges and removable palatal bars

and lingualand lingual

NOBLE METAL ALLOYSNOBLE METAL ALLOYS(Semiprecious)(Semiprecious)

25% of noble metals, does not 25% of noble metals, does not require gold:require gold:

Silver - PalladiumSilver - Palladium Palladium - SilverPalladium - Silver Silver - TinSilver - Tin

SILVER-SILVER-PALLADIUM PALLADIUM

ALLOYSALLOYS(Ag-Pd)(Ag-Pd)

DDeveloped as an alternative to eveloped as an alternative to those based on gold. There are those based on gold. There are two varieties:two varieties:

Silver 60-70% Palladium 25-Silver 60-70% Palladium 25-30%30%

Note:Note: Some containe 10% Some containe 10% copper.copper.

Palladium 60% Silver 30%Palladium 60% Silver 30% Note:Note: El 10% of other metals to El 10% of other metals to failitate bonding with porcelain.failitate bonding with porcelain.

CHEMICAL CHEMICAL PROPERTIESPROPERTIES

Pigmentation and resistance to Pigmentation and resistance to corrosion properly handled. corrosion properly handled.

Note:Note: It is possible to achieve It is possible to achieve adequate accuracy casting and a adequate accuracy casting and a good polishing and acceptable good polishing and acceptable

welds.welds.

CLINICAL CLINICAL APPLICATIONAPPLICATION

Scale Scale CrownsCrownsFixed partial Fixed partial

DentureDenture

EndopostesEndopostes

PALLADIUM- PALLADIUM- SILVER ALLOYSILVER ALLOY

(Pd-Ag)(Pd-Ag)

They are an They are an alternative to gold alternative to gold alloy for ceramics.alloy for ceramics.

This are alloys of high This are alloys of high melting point and which melting point and which

support the firing of support the firing of ceramics of porcelain.ceramics of porcelain.

(1400(1400°°C)C)

ADVANTAGESADVANTAGESGood physical properties and Good physical properties and

bonding with ceramics.bonding with ceramics.

BiocompatibBiocompatiblele

DISADVANTAGEDISADVANTAGESS

The likely change in color The likely change in color of porcelain baked.of porcelain baked.

ExpensiveExpensive

SILVER-TIN SILVER-TIN ALLOYALLOY(Ag-Sn)(Ag-Sn)

These alloys have been used for These alloys have been used for decades in dentistry to make decades in dentistry to make

deposits, not being suitable for deposits, not being suitable for prosthetic purposesprosthetic purposes..

INDICATIONS:INDICATIONS:

Temporary inlays.Temporary inlays.

ADVANTAGESADVANTAGESCheapCheapEasy handlingEasy handlingPoor precision Poor precision

castingcasting

DISADVANTAGEDISADVANTAGESSFragile marginal edgesFragile marginal edges

PigmentationPigmentationCan not be weldedCan not be weldedSlight corrosion resistanceSlight corrosion resistance After a short clinical use and After a short clinical use and

even before cemented in the even before cemented in the mouth have lost shine and mouth have lost shine and later changed to darklater changed to dark

BASE METALSBASE METALS These are noble elements.These are noble elements.

Is the so called because it Is the so called because it reacts with the environment reacts with the environment and are use to protect an alloy and are use to protect an alloy against corrosion by passivity.against corrosion by passivity.

COBALT-COBALT-CHROMIUM CHROMIUM

ALLOYSALLOYS(Co-Cr)(Co-Cr)

FEATURESFEATURES High hardenessHigh hardeness Good glossGood gloss Mechanical strengthMechanical strength Resistance to corrosionResistance to corrosion

y corrosióny corrosión Cheap Cheap

CLINICAL CLINICAL APPLICATIONAPPLICATION

Development Development of bases in of bases in removable removable dentures.dentures.

Basis of Basis of denturesdentures

PRESENTATIONPRESENTATIONForm of granulesForm of granules

IngotsIngots

TRADE NAMESTRADE NAMES Vitalium (Co-Cr)Vitalium (Co-Cr) Ticonium (Ni-Cr)Ticonium (Ni-Cr) Dentillium (Dentillium (FFe-Cr)e-Cr)

ADVANTAGESADVANTAGES

Cheap Cheap

Very lightVery light

More durable adjusting hooks.More durable adjusting hooks.

DISADVANTAGES

Excessive hardness

Minor casting accuracy

Complicated heat treatment

Welds

WeldsWelds

WELDINGWELDING : Intermediate : Intermediate element that is used to element that is used to join metallic surfaces join metallic surfaces each other.each other.

It’s a technique for join 2It’s a technique for join 2Or more metal elements,Or more metal elements,Rebuild or repair a metal Rebuild or repair a metal

surfacesurface..

REQUIREMENTSREQUIREMENTS

Free toxic substanceFree toxic substanceResistantResistantFlowFlowSimilar colorSimilar colorLower temperature of Lower temperature of

• fusionfusionCorrosion resitantCorrosion resitant

TECNICAS PARA SOLDARTECNICAS PARA SOLDAR

1.1. TECHNICAL COMMTECHNICAL COMM : Requires the use : Requires the use of an intermediate (welding).of an intermediate (welding).

2.2. WELD TECHNICALWELD TECHNICAL : Application of heat : Application of heat to melt the two metal surfaces.to melt the two metal surfaces.

3.3. ELECTRICAL TECHNICALELECTRICAL TECHNICAL : Application : Application of electric current-tap to join metallic of electric current-tap to join metallic surfacessurfaces..

FLUXFLUX Facilitate the flow of welding,Facilitate the flow of welding,

Eliminating impurities.Eliminating impurities.

They come in powder and pasteThey come in powder and paste

Composition of flux for alloys with Composition of flux for alloys with chromium :chromium :

pottasium fluoride, boric acid, borax glass, pottasium fluoride, boric acid, borax glass, and sodium carbonate or silica. And for and sodium carbonate or silica. And for gold alloys: Borax powder, boric acid and gold alloys: Borax powder, boric acid and silica.silica.