FAILURES OF FAILURES OF DENTAL DENTAL

AMALGAMAMALGAMDr shabeel pnDr shabeel pn

ROYAL DENTAL COLLEGEROYAL DENTAL COLLEGE

INTRODUCTIONINTRODUCTION FAILURE & SUCCESS ARE NOT ACCIDENTS; BUT FAILURE & SUCCESS ARE NOT ACCIDENTS; BUT

JUSTICE OF NATUREJUSTICE OF NATURE

AMALGAMS ARE MOST COMMON RESTORATION AMALGAMS ARE MOST COMMON RESTORATION FOR POSTERIOR TEETHFOR POSTERIOR TEETH

USUALLY AMALGAMS LASTS FOR ABOUT 10 USUALLY AMALGAMS LASTS FOR ABOUT 10 YEARSYEARS

EXCELLENT IN BEGINNING, GRADUALLY SOME EXCELLENT IN BEGINNING, GRADUALLY SOME ALTERATONS OF TECHNICAL FEATURES ALTERATONS OF TECHNICAL FEATURES LEADING TO RESTORATION/TOOTH FRACTURE, LEADING TO RESTORATION/TOOTH FRACTURE, RECURRENT CARIES, DISCOLORATION, RECURRENT CARIES, DISCOLORATION, CORROSION, LOSS OF RESTORATIONCORROSION, LOSS OF RESTORATION

““CLINICAL FAILURE IS THE POINT AT CLINICAL FAILURE IS THE POINT AT

WHICH THE RESTORATION IS NO LONGER WHICH THE RESTORATION IS NO LONGER SERVICEABLE OR AT WHICH TIME SERVICEABLE OR AT WHICH TIME RESTORATION POSSES OTHER SEVERE RESTORATION POSSES OTHER SEVERE RISK IF IT IS NOT REPLACED”RISK IF IT IS NOT REPLACED”

FAILURES IN AMALGAM RESTORATION ARE FAILURES IN AMALGAM RESTORATION ARE NOT USUALLY BECAUSE OF POOR NOT USUALLY BECAUSE OF POOR MATERIAL MATERIAL

EVERYTHING DONE FROM TIME OF CAVITY EVERYTHING DONE FROM TIME OF CAVITY

PREPARATION UNTIL RESTORATION IS PREPARATION UNTIL RESTORATION IS POLISHED HAS A DEFINITE AFFECT ON POLISHED HAS A DEFINITE AFFECT ON THE RESTORATIONTHE RESTORATION

FAILURES FAILURES AT VISUAL LEVELAT VISUAL LEVEL SECONDARY CARIESSECONDARY CARIES MARGINAL FRACTURE MARGINAL FRACTURE BULK FRACTURE BULK FRACTURE TOOTH FRACTURETOOTH FRACTURE DIMENSIONAL CHANGEDIMENSIONAL CHANGE AT THE MICROSTRUTURAL LEVELAT THE MICROSTRUTURAL LEVEL CORROSION AND TARNISHCORROSION AND TARNISH STRESSES ASSOCIATED WITH MASTICATORY STRESSES ASSOCIATED WITH MASTICATORY

FORCES FORCES PAIN FOLLOWING AMALGAM RESTORATION PAIN FOLLOWING AMALGAM RESTORATION PULP AND/OR PERIODONTAL INVOLVEMENTPULP AND/OR PERIODONTAL INVOLVEMENT

CAUSESCAUSES FAILURES DUE TO FAULTY CASE FAILURES DUE TO FAULTY CASE

SELECTIONSELECTION

FAILURES DUE TO FAULTY CAVITY FAILURES DUE TO FAULTY CAVITY PREPARATION PREPARATION

FAILURE DUE TO POOR MATRIX FAILURE DUE TO POOR MATRIX ADAPTATION ADAPTATION

FAILURES DUE TO FAULTY FAILURES DUE TO FAULTY AMALGAM MANIPULATIONAMALGAM MANIPULATION

DUE TO FAULTY CASE DUE TO FAULTY CASE SELECTIONSELECTION

EXTENSIVE OCCLUSAL CARIESEXTENSIVE OCCLUSAL CARIES

WIDE OPEN CONTACTSWIDE OPEN CONTACTS

DISSIMILAR METALSDISSIMILAR METALS

DUE TO FAULTY CAVITY DUE TO FAULTY CAVITY PREPARATIONPREPARATION

GREATEST SINGLE FACTOR FOR FAILUREGREATEST SINGLE FACTOR FOR FAILURE HEALEY & PHILIPS (1949) HEALEY & PHILIPS (1949) * 56% - CAVITY* 56% - CAVITY * 42% - MANIPULATION* 42% - MANIPULATION FAULTY CAVITY PREPARATIONFAULTY CAVITY PREPARATIONRECURRANCE RECURRANCE

OF CARIES AND FRACTUREOF CARIES AND FRACTURE# CAUSES FOR FAILURE OCCURING AT # CAUSES FOR FAILURE OCCURING AT

VARIOUS STEPSVARIOUS STEPS

1.INADEQUATE OCCLUSAL EXTENSION: INADEQUATE EXTENSION TO PITS AND INADEQUATE EXTENSION TO PITS AND

FISSURE INCREASE CHANCE OF CARIES FISSURE INCREASE CHANCE OF CARIES RECURRENCE PARTICULARLY IN HIGH CARIES RECURRENCE PARTICULARLY IN HIGH CARIES RISK INDIVIDUALSRISK INDIVIDUALS

2. INADEQUATE EXTENSION OF PROXIMAL BOX:2. INADEQUATE EXTENSION OF PROXIMAL BOX: IF INADEQUATELY EXTENDED INTO IF INADEQUATELY EXTENDED INTO

EMBRASURES, THEY ARE NOT AMENABLE TO EMBRASURES, THEY ARE NOT AMENABLE TO BRUSHING AND CLEANING BY MASTICATION BRUSHING AND CLEANING BY MASTICATION SECONDARY CARIES.SECONDARY CARIES.

3.OVEREXTENSION OF CAVITY PREPARATION 3.OVEREXTENSION OF CAVITY PREPARATION WALLS:WALLS:

IDEAL FACIOLINGUAL WIDTH OF CAVITY IS ¼ OF IDEAL FACIOLINGUAL WIDTH OF CAVITY IS ¼ OF INTERCUSPAL DISTANCEINTERCUSPAL DISTANCE

IF THE WIDTH IS MORE THAN ½ ,CAPPING IF THE WIDTH IS MORE THAN ½ ,CAPPING SHOULD BE CONSIDERED SHOULD BE CONSIDERED

IF WIDTH MORE THAN 2/3, CAPPING IS A MUSTIF WIDTH MORE THAN 2/3, CAPPING IS A MUST CHANCE OF FRACTURE BECAUSE RESTORATION CHANCE OF FRACTURE BECAUSE RESTORATION

ACT AS WEDGE AND TEND TO SPLIT OPPOSING ACT AS WEDGE AND TEND TO SPLIT OPPOSING CUSPS APARTCUSPS APART

DURING CAPPING THERE SHOULD BE AN DURING CAPPING THERE SHOULD BE AN AMALGAM THICKNESS OF 2mm ON FUNCTIONAL AMALGAM THICKNESS OF 2mm ON FUNCTIONAL AND 1.5mm OVER NON-FUNCTIONAL CUSPSAND 1.5mm OVER NON-FUNCTIONAL CUSPS

4.AMALGAM CAVITY SHOULD HAVE MINIMUM4.AMALGAM CAVITY SHOULD HAVE MINIMUM DEPTHDEPTH OF 1.5mm TO PROVIDE IT BULK AND OF 1.5mm TO PROVIDE IT BULK AND HENCE RESISTANCE TO FRACTUREHENCE RESISTANCE TO FRACTURE

5.IF PULPAL FLOOR IS NOT FLAT5.IF PULPAL FLOOR IS NOT FLATRESTORATION RESTORATION PRODUCES WEDGING EFFECT PRODUCES WEDGING EFFECT FRACTURE OF FRACTURE OF TOOTHTOOTH

6.CAVOSURFACE ANGLE 6.CAVOSURFACE ANGLE BUTT JOINTBUTT JOINT IF ACUTE IF ACUTE TOOTH FRACTURE TOOTH FRACTURE IF OBTUSE IF OBTUSE COLLAPSE OF COLLAPSE OF

MARGINAL AMALGAM MARGINAL AMALGAM

7.FAILURE TO ROUND OFF LINE ANGLES7.FAILURE TO ROUND OFF LINE ANGLES CONCENTRATION OF STRESSESCONCENTRATION OF STRESSES# OF # OF

TOOTH TOOTH

/RESTORATION/RESTORATION

8.INADEQUATE PROXIMAL RETENTION 8.INADEQUATE PROXIMAL RETENTION FORM/NARROW ISTHMUS FORM/NARROW ISTHMUS

FRACTURE AT ISTHMUS PORTIONFRACTURE AT ISTHMUS PORTION

9.EXTENSIVE MESIO-DISTAL EXTENSION9.EXTENSIVE MESIO-DISTAL EXTENSION

UNDERMINING OF MARGINAL RIDGE UNDERMINING OF MARGINAL RIDGE ENAMEL ENAMEL

FRACTUREFRACTURE

10.INCOMPLETE REMOVAL OF CARIOUS TOOTH 10.INCOMPLETE REMOVAL OF CARIOUS TOOTH MATERIALMATERIAL

FAILURE OF AMALGAM RESTORATION FAILURE OF AMALGAM RESTORATION

11.RETENTIVE DEVICES11.RETENTIVE DEVICES

SHOULD BE PREPARED ENTIRELY IN DENTIN SHOULD BE PREPARED ENTIRELY IN DENTIN

WITHOUT UNDERMINING ENAMELWITHOUT UNDERMINING ENAMEL

12.POST OPERATIVE PAIN12.POST OPERATIVE PAIN

REDUCED BY HIGH SPEED ROTARY REDUCED BY HIGH SPEED ROTARY INSTRUMENTS , INTERMITTENT CUTTING AND INSTRUMENTS , INTERMITTENT CUTTING AND COOLINGCOOLING

DUE TO POOR MATRIX DUE TO POOR MATRIX ADAPTATIONADAPTATION

PROPER CONTACTS AND CONTOUR IN PROPER CONTACTS AND CONTOUR IN RESTORATION OBTAINED BY MATRIX RESTORATION OBTAINED BY MATRIX

INSTABILITY OF MATRIX INSTABILITY OF MATRIX DISTORTED DISTORTED RESTORATION,GROSS MARGINAL EXCESS RESTORATION,GROSS MARGINAL EXCESS AND UNCONDENSED SOFT AMALGAM AND UNCONDENSED SOFT AMALGAM WITH VOIDSWITH VOIDS

CERVICAL EXCESS CAN RESULT IN CERVICAL EXCESS CAN RESULT IN

PERIODONTAL IRRITATION PERIODONTAL IRRITATION DESTRUCTION OF PERIODONTIUMDESTRUCTION OF PERIODONTIUM

DUE TO FAULTY AMALGAM DUE TO FAULTY AMALGAM MANIPULATIONMANIPULATION

A. MERCURY ALLOYA. MERCURY ALLOY RATIO:RATIO: IF RESIDUAL MERCURY IS IN EXCESS OF IF RESIDUAL MERCURY IS IN EXCESS OF

55%55%LOSS OF STRENGTHLOSS OF STRENGTH

INCREASD FLOW , DECREASED CRUSHING INCREASD FLOW , DECREASED CRUSHING STRENGTHSTRENGTH

INCREASED SUSCEPTIPBILITY TO TARNISH AND INCREASED SUSCEPTIPBILITY TO TARNISH AND

CORROSIONCORROSION

BETTER TO USE MINIMAL MERCURY TECHNIQUE BETTER TO USE MINIMAL MERCURY TECHNIQUE WITH DISPENSERS FOR CORRECT PROPOTIONING.WITH DISPENSERS FOR CORRECT PROPOTIONING.

MULLINGMULLINGCONTINUATION OF TRITURATION TO CONTINUATION OF TRITURATION TO ASSURE ALL ALLOY PARTICLES ARE COATED WITH ASSURE ALL ALLOY PARTICLES ARE COATED WITH MERCURY.MERCURY.

DONE MANUALLY OR MECHANICALLYDONE MANUALLY OR MECHANICALLY

IN MECHANICAL THE CAPSULE SHOULD IN MECHANICAL THE CAPSULE SHOULD BE CLEANED AFTER EACH MIX AS IT CAN BE CLEANED AFTER EACH MIX AS IT CAN CAUSE A HARD ISLANDS IN FUTURE CAUSE A HARD ISLANDS IN FUTURE MIXING PROCEDUREMIXING PROCEDURE

UNDER TRITURATIONUNDER TRITURATIONSOFT POWDERY SOFT POWDERY NON- COHERENT MIXNON- COHERENT MIX

OVER TRITURATIONOVER TRITURATIONBREAK ALREADY BREAK ALREADY FORMED MATRIXFORMED MATRIX

B. CONDENSATIONB. CONDENSATION

RATIONALE RATIONALE REDUCE RESIDUAL REDUCE RESIDUAL MERCURY,MERCURY,

TO ENSURE AMALGAM REACH ALL PARTS TO ENSURE AMALGAM REACH ALL PARTS OF THE PREPARATION AND OBTAIN OF THE PREPARATION AND OBTAIN HOMOGENOUS RESTORATION DEVOID OF HOMOGENOUS RESTORATION DEVOID OF VOIDSVOIDS

FRESHLY PREPARED AMALGAM HAS FRESHLY PREPARED AMALGAM HAS DESIRABLE WORKING PROPERTIESDESIRABLE WORKING PROPERTIES

EFFECTIVENESS OF REMOVING RESIDUAL EFFECTIVENESS OF REMOVING RESIDUAL MERCURY IS POSSIBLE ONLY IF USED MERCURY IS POSSIBLE ONLY IF USED WITHIN 4 MINUTES FROM TRITURATIONWITHIN 4 MINUTES FROM TRITURATION

DELAYED USE DELAYED USE DO NOT ALLOW PROPER DO NOT ALLOW PROPER

CONDENSATION AND ALSO DO NOT CONDENSATION AND ALSO DO NOT REMOVE MERCURY FROM THE REMOVE MERCURY FROM THE RESTORATION RESTORATION

LARGER CAVITIES LARGER CAVITIES MULTIPLE MIX MULTIPLE MIX SHOULD BE USED TO GET HOMOGENOUS SHOULD BE USED TO GET HOMOGENOUS RESTORATION RESTORATION

EXCESSIVE REMOVAL OF MERCURY EXCESSIVE REMOVAL OF MERCURY REDUCES STRENGTHREDUCES STRENGTH

CONDENSATION SHOULD BE DONE USING CONDENSATION SHOULD BE DONE USING STEPING PROCESS TO DRIVE AWAY VOIDSSTEPING PROCESS TO DRIVE AWAY VOIDS

CONDENSOR SIZE SHOULD NOT BE TOO CONDENSOR SIZE SHOULD NOT BE TOO SMALL OR TOO LARGESMALL OR TOO LARGE

SMALL INCREMENTS SHOULD BE USED TO SMALL INCREMENTS SHOULD BE USED TO ENSURE PROPER CONDENSATIONENSURE PROPER CONDENSATION

MECHANICAL CONDENSER SHOULD BE MECHANICAL CONDENSER SHOULD BE USED WITH CAUTION AS IT WOULD CAUSE USED WITH CAUTION AS IT WOULD CAUSE FRACTURE OF ENAMEL MARGINSFRACTURE OF ENAMEL MARGINS

C. CONTAMINATIONC. CONTAMINATION

MOISTURE CONTAMINATION CAN OCCUR MOISTURE CONTAMINATION CAN OCCUR DURING DURING

-TRITURATION-TRITURATION - MULLING - MULLING -CONDENSATION -CONDENSATION

WEAKEN THE RESTORATION ESPECIALLY WEAKEN THE RESTORATION ESPECIALLY IF ZINC CONTAINING IF ZINC CONTAINING

IT RESULT IN MARGINAL FLAWS, TARNISH, IT RESULT IN MARGINAL FLAWS, TARNISH, PITTING, CORROSION, AND BLISTERING. PITTING, CORROSION, AND BLISTERING. EXPANSION MAY ALSO LEAD TO PAINEXPANSION MAY ALSO LEAD TO PAIN

D.FINISHING AND POLISHINGD.FINISHING AND POLISHING

AMALGAM SHOULD BE FINISHED GENTLY AMALGAM SHOULD BE FINISHED GENTLY

EXCESS SPUR LIKE OVERHANGS OR THIN EXCESS SPUR LIKE OVERHANGS OR THIN FLAKES OF AMALGAM ON MARGINS CAN FLAKES OF AMALGAM ON MARGINS CAN FRACTURE EASILY WHICH CAN LEAVE FRACTURE EASILY WHICH CAN LEAVE CREVICES IN VULNERABLE AREASCREVICES IN VULNERABLE AREAS

OVERCARVING SHOULD BE AVOIDED AS IT OVERCARVING SHOULD BE AVOIDED AS IT WOULD REDUCE THE THICKNESS OF WOULD REDUCE THE THICKNESS OF AMALGAM RESULTING IN FRACTUREAMALGAM RESULTING IN FRACTURE

AMALGAM WITH TENDENCY FOR TARNISH AMALGAM WITH TENDENCY FOR TARNISH AND CORROSION DON’T RETAIN POLISH FOR AND CORROSION DON’T RETAIN POLISH FOR LONG,ROUGH AND CORRODED SURFACE LONG,ROUGH AND CORRODED SURFACE PREDISPOSE TO FAILUREPREDISPOSE TO FAILURE

FAILURE TO POLISH ACCELERATE FAILURE TO POLISH ACCELERATE CORROSION DUE TO SURFACE CORROSION DUE TO SURFACE IRREGULARITIES ,ROUGH SURFACE IRREGULARITIES ,ROUGH SURFACE PROMOTES ACCUMULATION OF PLAQUE PROMOTES ACCUMULATION OF PLAQUE RESULTING IN GINGIVAL IRRITATIONRESULTING IN GINGIVAL IRRITATION

POLISHING SHOULD BE DONE POLISHING SHOULD BE DONE JUDICIOUSLY, TEMPERATURE ABOVE 65 JUDICIOUSLY, TEMPERATURE ABOVE 65 00C C LEADS TO RELEASE OF MERCURY LEADS TO RELEASE OF MERCURY LEADING TO DEFFECTIVE RESTORATIONLEADING TO DEFFECTIVE RESTORATION

E. POST OPERATIVE PAINE. POST OPERATIVE PAIN

THIS OCCUR BECAUSE OF:THIS OCCUR BECAUSE OF:

1.1. HYPEROCCLUSIONHYPEROCCLUSION LEADING TO LEADING TO INFLAMMATION OF APICAL INFLAMMATION OF APICAL PERIODONTIUMPERIODONTIUM

2.2. CRACKS IN TOOTHCRACKS IN TOOTH SUCH CRACKS CAUSE SUCH CRACKS CAUSE PAIN DURING CHEWING BECAUSE OF PAIN DURING CHEWING BECAUSE OF EXPANSION OR CONTRACTION OF TOOTH EXPANSION OR CONTRACTION OF TOOTH STRUCTURE WITH EVERY BITESTRUCTURE WITH EVERY BITE

3.3. GALVANISMGALVANISM: MAY BE DUE TO DISSIMILAR : MAY BE DUE TO DISSIMILAR ADJACENT METAL RESTORATION OR ADJACENT METAL RESTORATION OR POORLY CONDENSED AMALGAM DUE TO POORLY CONDENSED AMALGAM DUE TO VARIATION IN SILVER CONCENTRATIONVARIATION IN SILVER CONCENTRATION

4.4. DELAYED EXPANSIONDELAYED EXPANSION

INADEQUATE PULP PROTECTION LEADING INADEQUATE PULP PROTECTION LEADING TO CONDUCTION OF HEATTO CONDUCTION OF HEAT

VARNISH SHOULD BE APPLIED UNDER VARNISH SHOULD BE APPLIED UNDER AMALGAM RESTORATION TO AVOID AMALGAM RESTORATION TO AVOID LEAKAGE AROUND RESTORATION WHICH LEAKAGE AROUND RESTORATION WHICH MAY LEAD TO POST OPERATIVE MAY LEAD TO POST OPERATIVE SENSITIVITY AND SENSITIVITY AND AMALGAM BLUESAMALGAM BLUES DUE DUE TO PENETRATION OF CORROSION TO PENETRATION OF CORROSION PRODUCTS INTO DENTINAL TUBULESPRODUCTS INTO DENTINAL TUBULES

RESTORATION FRACTURE MAY OCCUR IF RESTORATION FRACTURE MAY OCCUR IF PATIENT DOES NOT FOLLOW PATIENT DOES NOT FOLLOW INSTRUCTION PROPERLY AND BITES ON INSTRUCTION PROPERLY AND BITES ON RESTORATION BEFORE IT SETSRESTORATION BEFORE IT SETS

FROM THE MATERIAL FROM THE MATERIAL SIDESIDE

MICROLEAKAGE:MICROLEAKAGE:

PERCULATION OF ORAL FLUIDSPERCULATION OF ORAL FLUIDS CREEPCREEP

STATIC CREEPSTATIC CREEP

DYNAMIC CREEPDYNAMIC CREEP DIMENSIONAL CHANGEDIMENSIONAL CHANGE

DEPENDS ON RESIDUAL MERCURYDEPENDS ON RESIDUAL MERCURY

NEWER CONTRACT, OLDER EXPANDNEWER CONTRACT, OLDER EXPAND

MAY EVEN CAUSE PAINMAY EVEN CAUSE PAIN

REFERENCESREFERENCES TEXTBOOK OF OPERATIVE TEXTBOOK OF OPERATIVE

DENTISTRYDENTISTRY

- VIMAL K SIKRI- VIMAL K SIKRI ART & SCIENCE OF OPERATIVE ART & SCIENCE OF OPERATIVE

DENTISTRYDENTISTRY

- THEODORE M ROBERSON- THEODORE M ROBERSON JOURNALSJOURNALS

- TIMES OF NITRA- TIMES OF NITRA

THANK YOUTHANK YOU