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DIRECT FILLING GOLD Dr. Madhu Billa I MDSDEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS SIBAR INSTITUTE OF DENTAL SCIENCES

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CONTENTSINTRODUCTIONHISTORYPROPERTIESINDICATIONSCONTRAINDICATIONSBIOLOGICAL CONSIDERATIONSDIFFERENT FORMS OF GOLD

Dr.MadhuBilla

METHOD OF DEGASSINGCONDENSATIONTYPES OF CONDENSATIONSTEPS FOR PLACEMENT OF DFGFINISHINGCAVITY PREPARATIONCONCLUSION

Dr.MadhuBilla

INTRODUCTIONAmong the available restorative materials, direct filling gold is the oldest filling material that is still used in restorative dentistry.

The vision to utilize the noble metals for the replacement of lost tooth structure stemmed from perfect harmony of its biological and mechanical properties.Dr.MadhuBilla

While most of metals can be welded and alloyed at a temperature above the room temperature, the pure gold can be cold welded and made to adhere to each other at room temperature.

For a pt gold foil means no second appointment, no second administration of L.A and no second application of rubber dam. Lastly as quoted by B.Smith it may serve the tooth for a lifetime.. SMITH B J OF SOTH CALIFORNIA STATE DENTAL ASSC. 1959 Dr.MadhuBilla

1483- Giovanni d arcoll first recommended gold leaf as restorative material1712-1786- Frederic used for pulp capping1795 - Robert woffendale introduced gold foil for restoration purpose in America1803 Edword Hudson used goldfoil to fill root canal 1838- Dr .E. Meritt of pittsburg introduced hand mallet for compaction.

HISTORYDr.MadhuBilla

In 1840 Jackson first introduced sponge (Crystal or crystalline) gold which was easier to condense.In mid 1850s Robert Arthur of Baltimore introduced the technique of heating pieces of sponge gold over a Spirit lamp to make them cohesive1892- Power And Bonwill developed the pneumatic hammer 1896- Bryan referred to mat gold

Dr.MadhuBilla

1964- Goldent powdered gold was introduced1969 R.V.Willams and C.Ingersoil introduced Electralloy 1980- E-Z gold were introduced by Baum1989-new granular type of gold stopgold was introduced by Dhiek and Regelstein

Dr.MadhuBilla

PROPERTIESGold (Au)Atomic number 79Atomic weight 196.966amuMelting point 1064.43cBoiling point 2807cBrinells hardness number 25Malleability - It exceeds all other metals in this respect. It may be reduced by beating to sheets of 1/250,000 of an inch in thickness.Ductility-It is most ductile of all metals

Dr.MadhuBilla

Tensile strength 19,000psi - 32,000 psiYield strength 30,000 psiCoefficient of thermal expansion 14.4x10-6/0cThermal conductivity 0.710/sec/cm2

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INDICATIONSIncipient carious lesionOcclusal, buccal, lingual pit Class II lesions on premolars and molarsClass III in mandibular anteriors Class V in bicuspids, cuspids (where esthetics permit)Erosion areas

Dr.MadhuBilla

Atypical lesionsProximal lesions on teeth adjacent to crown preparationsClass VI lesionsRetrograde root canal filling material

Dr.MadhuBilla

CONTRAINDICATIONSVery young and old patientTeeth with large pulp chamberPeriodontal weakened teethEconomy is limited factorHandicapped patientRoot canal treated teethDr.MadhuBilla

Under developed rootCaries prone mouthHypersensitive cavitiesExtensive cavities with weakened wallsLack of skill of operator

Dr.MadhuBilla

ADVANTAGESInsoluble in oral fluidsMore resistant to tarnish and corrosionPerfect adaptation to cavity wall because of ductility More edge strengthLow tendency to molecular change (free from shrinkage or expansion)Maintain high polish

Advantages of direct gold filling by L.ClarkeOperative dentistry 1985 10-22Dr.MadhuBilla

No intra cement substance neededThermal expansion similar to dentinOral tissue accepts readilyCauses no tooth discoloration

Advantages of direct gold filling by L.ClarkeOperative dentistry 1985 10-22Dr.MadhuBilla

DISADVANTAGES Inharmonious color Thermal conductivity can be a problem in a newly restored teeth. Can lead to sensitivity to hot and coldAdvantages of direct gold filling by L.ClarkeOperative dentistry 1985 10-22Dr.MadhuBilla

Manipulation of gold is difficult to master. It requires skill and practiceNon-cohesive gold may be used on account of its rapidity of manipulation in simple cavities with four strong walls, located on surfaces not subject to wear. It is not indicated on surfaces subjected to stress of mastication or for contour workAdvantages of direct gold filling by L.ClarkeOperative dentistry 1985 10-22Dr.MadhuBilla

Energy of condensation which is not absorbed by the restorative material, may dissipate to the pulp dentin organThermal energy in the pellet, exceeding that needed for decontamination causes pulpal irritationFrictional heat of finishing and polishingGalvanic current between gold and other metallic restorations Ultrasonic energy from high condensation frequency can harm pulp

BIOLOGICAL CONSIDERATIONSDr.MadhuBilla

3mm or more of remaining dentin thickness no base2mm or more of remaining dentin thickness varnish on walls and floors, without cavo surface marginsBetween 1-2mm of remaining dentin thickness sub base of calcium hydroxide or unmodified zinc oxide eugenol and over this varnish is applied. and zinc phosphate cement or zinc poly carboxylate base is used .Less than 1mm of remaining dentin thickness direct filling gold contraindicatedNeed for baseDr.MadhuBilla

In a study done by Draheim et al., On the ability of cavity bases to withstand condensation of direct gold concluded that ZOE and calcium hydroxide containing bases have silmilar abilities to withstand condensations of direct filling goldAuthors concluded that ZoE and calcium hydroxide cavity bases tested had adequate strength to resist the forces of condensation of electraloyThe ability of cavity bases to withstand condensation of direct goldQuintessence International 11/1985Dr.MadhuBilla

GOLD - TYPESGOLD FOILELCTROLYTIC PRECIPITATED GOLD Mat gold Mat foil Gold calcium alloy

POWDERED GOLD/GRANULATED GOLD Gold dent

Dr.MadhuBilla

Dr.MadhuBilla

Gold foil:

Gold foil sheets are manufactured by a process called gold beating or rollingAll light weight sheets are formed by beating and heavy weight sheets are formed by rollingIn beating process, first heavier mallets are used followed by lighter ones as gold gets thinner.Dr.MadhuBilla

For rolling, it is passed through rolling mills until desired thickness is got.It comes in a book of 1/10 or 1/20 ounces. One book has 12 sheets with a common dimension of 4 x 4 No. 4 gold foil weighs 4 grains (0.259gm) and is 0.51m thickNo. 3 gold foil weighs 3 grains (0.194gm) and is about 0.38m thick

Dr.MadhuBilla

During manufacture, pure gold ingots are subjected to cold working, thereby creating sheets out of blocks. As the gold is subjected to strain hardening during this process, for further cold working towards the formation of these leaves or sheets, the material should be subjected to proper annealingThis alternate process of cold working and annealing - cold working continues until the desired thickness of the gold sheet is arrived at.Dr.MadhuBilla

Extra liable gold foil:

It was made to produce a more cohesive gold Extra labile gold has improved tendency to cohereFormed by wrapping a loosely formed, regular gold rope with an extra sheet of gold foil

Dr.MadhuBilla

Gold foil pellets:May vary from - 1/128th of a portion of No. 4 gold foilAfter removing the gold foil along with the tissue paper from the book. Foil is held on paper and is cut to the size needed. Paper supports the thin gold foil and prevents it from tearing and wrinkling during manipulation

Dr.MadhuBilla

Sizes used are from 1/10 onwards. Larger sizes of 1/2, 1/4, 1/8 are used for making cylinders. The desired piece is then grasped by index, thumb and middle finger of left hand. Ends are touched with tweezers towards the center and are rolled into loose ballsPellets are degassed and stored in separate compartment

Dr.MadhuBilla

Dr.MadhuBilla

Gold cylinderCan be hand rolled or commercially rolledMade by rolling the cut segment of No. 4 foil into 1/2, 1/4, 1/8 widths

Dr.MadhuBilla

Corrugated gold / carbonized gold foil

This was first observed by a dental dealer in the great Chicago fire of 1871.Corrugated gold foil is manufactured by placing a thinleaf of paper between two sheets of gold foil, after which the whole container accommodating paper leaves and gold foil is ignited. As the paper leaves are burned out, they shrivel, andthereby impart a corrugated shape to the gold foil It has been proven that corrugated gold foils are more cohesive than the plain ones.

Dr.MadhuBilla

Platinised gold foil:Its a sandwich of gold and platinum with platinum content being 15% One sheet of platinum foil is sandwiched between two sheets of gold foil and is then hammered to the thickness of NO. 4 gold foilLayers of gold and platinum are rolled over together so that there occurs fusion of the two even before the beating procedure beginsPlatinum increases the hardness and wear resistance of the restoration. So this form can be used in stress concentration areas like incisal edges and cusp tips.

Dr.MadhuBilla

When a cube of gold ingot is cold worked in order to formulate a sheet, the cubical crystals of gold will he stretched and elongated in a specific direction. If the gold foil of that cube is viewed under a microscope. It appears fibrous, with the fibers parallel to each other in a specific pattern. Mechanically speaking, this type of gold foil material will have directional properties, i.e., It will be resistant to stresses in one direction better than the other. LAMINATED GOLD FOILDr.MadhuBilla

The idea of laminated gold foil is to combine two or three leaves of gold, each from different ingots which have been cold worked in different directions. Although each leaf will be directional in its properties, when combined together, they can be resistant in different directions. Therefore, laminated gold foil is definitely much stronger and much more resistant to stresses than the other forms of direct gold materials.

Dr.MadhuBilla

Cohesive gold:Is that form of gold which is essentially free of any surface contaminants and can be placed directly into the cavityGold can attract gases to its surface, and any adsorbed gas film can prevent intimate atomic contact required for cold welding. So manufacturer supply the foil free of surface contaminants and therefore inherently cohesive this type is reffered to as cohesive foil.

Dr.MadhuBilla

Semi cohesive gold:Some gold sheets have adsorbed protective gas film such as ammonia. This minimize the adsorption of other less volatile substances and prevent premature cohesion of sheets. The volatile film is readily removed by heating to restore the cohesive character of the foil.This type is reffered to as semi cohesive gold

Dr.MadhuBilla

Non cohesive gold:Non volatile contaminants like iron, sulphur, phosphorous are permanently deposited on the surface. This cannot be driven away by heat and so gold loses it cohesive property. Non cohesive forms are used as starting material, since they can be worked more easily than cohesive forms. But they dont have good strength and hardness.

Dr.MadhuBilla

Dr.MadhuBilla

MAT GOLDIt is an electrolytically precipitated crystalline form that is sandwiched between sheets of gold foil and formed into stripsThese strips are cut into desired sizesPreferred for its ease in building up the internal bulk of the restoration as it can be more easily compacted and adapted to the retentive portions of the prepared cavityDr.MadhuBilla

As it is loosely packed it is friable and contain numerous void spaces between the particlesSo it is recommended for the external surface of the restorationUsing this two material technique the mat is covered with veneer of foilLoosely packed crystalline form with large surface area of the mat powder it does not permit easy welding into a solid mass as does gold foilDr.MadhuBilla

Advantages:Rapid filling,Filling Internal bulk (cavity walls ,and retentive portions) It is used to form the core of the restoration Average size is 10 to 20mDr.MadhuBilla

Disadvantages:Difficult to handle, Voids ,surface pitting, and ditching, rough finishing,More condensation pressure required, crumbles during manipulationDoes not permit welding into homogenous mass

Dr.MadhuBilla

MAT FOILThis is a sandwich of Mat Gold placed in sheets of No 3 / 4 gold foil.The sandwich is sintered by heating to just below the melting point of gold and cut into strips of different widthsThe gold foil cover holds the crystalline gold together while it is being condensed.

Mat Gold Foil By Koser And Ingraham Operative Dentistry Vol 52 1956Dr.MadhuBilla

Mat gold foil differs from the so-called cohesive type foils. It is a fine, electrolytic, crystalline deposit made adhesive by the nature of its finely divided crystalline structure and by the extremely pure state of the metal itself. Its mechanical strength is the result of a special molding and heat treatment process. This property renders it easier to manipulate. Because mat gold foil is highly adhesive and cohesive, and because it is more readily adaptable than other types of foil, it is ideally suited for building up the internal bulk of Class V, Class I and the occlusal portion of Class II restorations.Dr.MadhuBilla

ALLOYED ELECTROLYTIC PRECIPITATEThis is an alloy of electrolytic gold and calciumThe calcium content is usually 0.1- 0.5 % by weight Its purpose is to produce stronger restorations by dispersion hardening.For convenience, the product is sandwiched between two layers of gold foil

Dr.MadhuBilla

ELECTROALLOY R.V.This is a mat gold manufactured by Williams Gold Refining Company, New York.R.V stands for R.V. Williams who developed thisDr.MadhuBilla

POWDERED GOLD It is a blend of atomized and precipitated powder embedded in a wax-like organic matrix.This form was introduced in 1962 by Baum and Lund.The atomised and chemically precipitated powders are first mixed with a soft wax to form pelletsThese wax gold pellets are wrapped with foilThe resulting pellets are cylindrical and are available in different diameters and length

Dr.MadhuBilla

Commercially available pellets of powdered gold wrapped in a gold foil are known as goldentIntroduced in 1960s The individual particles or granules are of 15m are gathered into mass of irregular shape ranging in size from 1-3mm precondensed lightly to facilitate handlingThese masses are encased in an envelope of foil to make it easier to convey them to the cavity

Dr.MadhuBilla

E- Z GoldIt is similar to Goldent but with improved working properties marketed by Williams Gold Refining Company, New York, introduced in the late 1980sIt is a mixture of pure gold powder and wax (less than 0.01% organic wax), wrapped in gold foilIts manipulative characteristics are similar to stiff amalgam yet more cohesive than gold foil hence the name e-z gold

EZ-Gold The New Goldent By Alperstein , YearwoodJod 1996,21, 36-41Dr.MadhuBilla

metallurgically similar to gold foil and powdered gold (Goldent) in that, when properly and thoroughly compacted, it has comparable properties: inertness (biocompatibility) and permanence. It is recommended for use in small class-I and class-V LESIONSIt is less time consuming and more predictableGreater expected longevity and more favourable tissue responseDr.MadhuBilla

Stopfgold: a new direct filling goldA new direct gold material that is considerably different from other direct golds has been available since 1989. The advantages are that the final restoration exhibits greater density than other forms of granular gold and has a 50% increase in shear strength when compared to gold foil. Clinical experience with the use of this new restorative material has been encouraging. Stopfgold: a new direct filling gold. Lambert RL; [Oper Dent] 1994 Jan-Feb; Vol. 19 (1), p. 16-9.Dr.MadhuBilla

REMOVAL OF SURFACE IMPURITIES /ANNEALING HEAT TREATMENT/DEGASSING

Degassing -Remove the surface impurities (ammonia gas, wax ,other gas)Annealing: Remove the surface impurities with internal stress relief, restores ductility and malleabilityAnnealing temperature ranges from 650to 700c,depended on selected method and heating timeProduce an atomically clean surface result in metallic bonding

Dr.MadhuBilla

OPEN ALCHOHOL FLAME METHODAlso called as piece methodHeating unit used is open flameAbsolute or 90% ethyl / methyl alcohol without any additives was used to produce a clean blue flameGold foil is held with a instrument and heated over a clean blue flame of absolute alchohol

METHOD OF DEGASSING

Dr.MadhuBilla

Gold is passed over the blue flame ( reducing zone/middle zone) for 3-5 secTemperature of the flame is 1300F and heating is done until gold becomes dull red

Advantages:Less contaminationLess wastage of the materialDesired size of piece can be selected

Disadvantages:Time consuming.Dr.MadhuBilla

2.BULK METHOD

MICA TRAY OVER A FLAME METHOD:A sheet of mica can be used over any type of flame and is used somewhat as a heating element.Divide the surface of the mica into several areas to indicate the time the pieces of gold were put on the mica Maximally five minutes are allowed for any piece of gold to be heated on micaDegassing of several gold pellets at the same time is possible

Dr.MadhuBilla

ELECTRIC ANNEALINGThis is the most controlled and standardized way of decontaminating gold materials. With this instrument, the heated compartment area is made of aluminum. An electric heater controls the time and the temperature. The surface of the heater is divided into small compartments. each accommodating a piece of direct gold. This eliminates the possibility of cohesion of the pieces before they are inserted into the cavity preparation. Maximally, five minutes are allowed for any piece to be kept in the electric decontaminator.

Dr.MadhuBilla

Electric annealing is maintained at temperature 343degree C (640 F)- 371degree C (700 F)Used for powdered gold to burn away waxDisadvantage: stick together if the tray is moved, size selection among the piece of degassed gold is limited ,more chance of contamination.

Dr.MadhuBilla

Heating time depend on size and configuration of gold segment (powdered gold-15-20 sec, gold foil pellet, electrolytic gold -1-2 sec)Avoid over heating and under heating

Over heating: recrystallization, grain growth Incorporation of impurities ,more stiffness, less ductile, difficult to condense, non cohesive, particles adhere to each other, excessive sinteringUnder heating: partial cohesiveness, peeling away of adjacent segment or layer, pitting, porosity in final restorationDr.MadhuBilla

Precautions to be taken using flame:

Lamp should not run out of fuel during procedureThere should be no surface contaminants on lamp and wickwick should be properly trimmed and rounded to produce a tear drop flamesulphur in matches could adhere to the wick and contaminate the gold. So ignite with other end of the match

Dr.MadhuBilla

STORAGE OF GOLD FOILGold is packed into the preparation under pressure so that under welding minimal porosity occursProtecting Gold Foil from contamination by gases with a thin film of alkaline salts. This protective film, usually of ammonia, prevents deleterious gases from condensing directly on the Foil. Instead, these gases combine with ammonia, to form other salts, and they are neutralized by it when it is present in excess. They are then driven off by annealing.

Dr.MadhuBilla

Condensation /compactionObjectives: Two main processes which control the quality of final direct gold restorations are welding and wedging.Welding: process of forming atomic bonds between pellets, layers of gold as a result of compactionWedging: process of pressurized adaptation of gold form within the space between tooth structure walls or corners minimizing voids between margin of tooth and surface of gold.

Dr.MadhuBilla

PRINCIPLES OF CONDENSATION1. Force of condensation must be 45 to the cavity walls and floors,

Bisect the line angle and trisect the point angle (result in maximum adaptation ,minimum irritation to vital pulp and dentin

Dr.MadhuBilla

2.forces of condensation must be directed at 90degrees to previously condensed gold3. always start at point angle on one side and proceed to other side. (tie formation)

Ensure condenser has covered entire piece of goldCondenser has to over lap at least of the previously condensed area

Dr.MadhuBilla

4. use minimum thickness of pellet as possible 5 Energy of condensation :Less energy is used inside cavity preparationGradually increase the energy of condensation as build up proceeds to surfaceMaximum energy is used at surface of restoration

Dr.MadhuBilla

6. Condensation can be either from one periphery of the increment to other or preferable from center of the increment to periphery (reduces voids , air entrapment)

Dr.MadhuBilla

CONDENSERSCondensors are used to deliver forces of compaction to DFG

These condensors have three Parts:

Handle shank, nib (working end)Dr.MadhuBilla

CONDENSER NIB:Common feature of all Condenser are faces are serrated with pyramidal shape configurationConensors based on Shapes of nib:Round condenser/bayonet condenser-used starting, nib face is 0.4 to 0.55mmParallelogram and hatchet condenser - preliminary condensation, create bulk in restoration, nib face is approximately 0.5x1mm Varney Foot condenser - has rectangular face, it measures approximately 1x1.3mm - used for bulk built upDr.MadhuBilla

CONDENSER SHANKSAvailable as :straight ,monoangle, offset, binangleCondenser used for hand malleting have longer shank, than condensors used in other mechanical means.

Dr.MadhuBilla

Force required for compaction is proportional to size of nib of the condenser.Force delivered by compaction is inversely proportional to size of the nib of the condenser.Smaller the nib face more square inch force is delivered f = 1/d2 (d is reduced by , force /square inch delivered by condensation increase by 4 times more)

Dr.MadhuBilla

There are several methods for the application of these forces:Hand pressureHand malletingAutomatic hand malletingElectric malletingPneumatic malleting

Dr.MadhuBilla

METHODS OF CONDENSATION1.Hand pressure condensationUsed as first step in 2 step condensation as Initial confinement of material within the cavity,Compaction method is similar to amalgam condensation except force and duration of force is more The condensation energy produced by this method is not always sufficient to fulfill the objectives of the condensation however it can be used simply to effect the initial confinement of the material within the cavity preparation.

Dr.MadhuBilla

AUTOMATIC HAND CONDENSERThis is a spring loaded instrument Blows are delivered by releasing a spiral spring Its main advantage is it gives a series of well regulated blowsDisadvantage: blow descends before full pressure is applied Dr.MadhuBilla

CONDENSATION BY HAND MALLEATING

One of the oldest, preferred by most cliniciansRequires trained assistantCorrect form of hand malleting : requires light force, bouncing application of mallet to condenser rather then delivering heavy blows (blow must be carefully adjusted it must not be too strong or too heavy,), mallet must travel parallel to central axis of Handle of condenserAdvantage: greater control of malleting force, varying force are used, rapid change of condenser tip.

Dr.MadhuBilla

CONDENSATION BY MECHANICANAL MEANSconsist of condenser with working tip and short shank (