Failures Of Dental Amalgam - Presentation Transcript

1. FAILURES OF DENTAL AMALGAM Dr shabeel pn 2003 – 2004 BATCH ROYAL DENTAL COLLEGE

2. INTRODUCTION o FAILURE & SUCCESS ARE NOT ACCIDENTS; BUT JUSTICE OF NATURE o AMALGAMS ARE MOST COMMON RESTORATION FOR POSTERIOR TEETH o USUALLY AMALGAMS LASTS FOR ABOUT 10 YEARS o EXCELLENT IN BEGINNING, GRADUALLY SOME ALTERATONS OF TECHNICAL

FEATURES LEADING TO RESTORATION/TOOTH FRACTURE, RECURRENT CARIES, DISCOLORATION, CORROSION, LOSS OF RESTORATION

3.o “ CLINICAL FAILURE IS THE POINT AT WHICH THE RESTORATION IS NO LONGER

SERVICEABLE OR AT WHICH TIME RESTORATION POSSES OTHER SEVERE RISK IF IT IS NOT REPLACED”

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

o EVERYTHING DONE FROM TIME OF CAVITY PREPARATION UNTIL RESTORATION IS POLISHED HAS A DEFINITE AFFECT ON THE RESTORATION

4. FAILURES o AT VISUAL LEVEL o SECONDARY CARIES o MARGINAL FRACTURE o BULK FRACTURE o TOOTH FRACTURE o DIMENSIONAL CHANGE

o AT THE MICROSTRUTURAL LEVEL o CORROSION AND TARNISH o STRESSES ASSOCIATED WITH MASTICATORY o FORCES

o PAIN FOLLOWING AMALGAM RESTORATION o PULP AND/OR PERIODONTAL INVOLVEMENT

5. CAUSES o FAILURES DUE TO FAULTY CASE SELECTION o FAILURES DUE TO FAULTY CAVITY PREPARATION o FAILURE DUE TO POOR MATRIX ADAPTATION o FAILURES DUE TO FAULTY AMALGAM MANIPULATION

6. DUE TO FAULTY CASE SELECTION o EXTENSIVE OCCLUSAL CARIES o WIDE OPEN CONTACTS o DISSIMILAR METALS

7. DUE TO FAULTY CAVITY PREPARATION o GREATEST SINGLE FACTOR FOR FAILURE

o HEALEY & PHILIPS (1949) o * 56% - CAVITY o * 42% - MANIPULATION o RECURRANCE OF CARIES AND FRACTUREFAULTY CAVITY PREPARATION o # CAUSES FOR FAILURE OCCURING AT VARIOUS STEPS o 1.INADEQUATE OCCLUSAL EXTENSION: o INADEQUATE EXTENSION TO PITS AND FISSURE INCREASE CHANCE OF CARIES

RECURRENCE PARTICULARLY IN HIGH CARIES RISK INDIVIDUALS 8.o 2. INADEQUATE EXTENSION OF PROXIMAL BOX: o IF INADEQUATELY EXTENDED INTO EMBRASURES, THEY ARE NOT AMENABLE

TO BRUSHING SECONDARY CARIES.AND CLEANING BY MASTICATION o 3.OVEREXTENSION OF CAVITY PREPARATION WALLS: o IDEAL FACIOLINGUAL WIDTH OF CAVITY IS ¼ OF INTERCUSPAL DISTANCE o IF THE WIDTH IS MORE THAN ½ ,CAPPING SHOULD BE CONSIDERED o IF WIDTH MORE THAN 2/3, CAPPING IS A MUST o CHANCE OF FRACTURE BECAUSE RESTORATION ACT AS WEDGE AND TEND TO

SPLIT OPPOSING CUSPS APART o DURING CAPPING THERE SHOULD BE AN AMALGAM THICKNESS OF 2mm ON

FUNCTIONAL AND 1.5mm OVER NON-FUNCTIONAL CUSPS 9.o 4.AMALGAM CAVITY SHOULD HAVE MINIMUM DEPTH OF 1.5mm TO PROVIDE IT

BULK AND HENCE RESISTANCE TO FRACTURE o RESTORATION PRODUCES WEDGING EFFECT 5.IF PULPAL FLOOR IS NOT

FLAT FRACTURE OF TOOTH o BUTT JOINT6.CAVOSURFACE ANGLE o TOOTH FRACTUREIF ACUTE o COLLAPSE OF MARGINAL AMALGAMIF OBTUSE o 7.FAILURE TO ROUND OFF LINE ANGLES o # OF TOOTHCONCENTRATION OF STRESSES o /RESTORATION 10.o 8.INADEQUATE PROXIMAL RETENTION FORM/NARROW ISTHMUS o FRACTURE AT ISTHMUS PORTION o 9.EXTENSIVE MESIO-DISTAL EXTENSION o UNDERMINING OF MARGINAL RIDGE ENAMEL o FRACTURE o 10.INCOMPLETE REMOVAL OF CARIOUS TOOTH MATERIAL o FAILURE OF AMALGAM RESTORATION o 11.RETENTIVE DEVICES o SHOULD BE PREPARED ENTIRELY IN DENTIN o WITHOUT UNDERMINING ENAMEL o 12.POST OPERATIVE PAIN o REDUCED BY HIGH SPEED ROTARY INSTRUMENTS , INTERMITTENT CUTTING

AND COOLING 11. DUE TO POOR MATRIX ADAPTATION o PROPER CONTACTS AND CONTOUR IN RESTORATION OBTAINED BY MATRIX o DISTORTED RESTORATION,GROSS MARGINAL EXCESS ANDINSTABILITY OF

MATRIX UNCONDENSED SOFT AMALGAM WITH VOIDS

o CERVICAL EXCESS CAN RESULT IN PERIODONTAL IRRITATION DESTRUCTION OF PERIODONTIUM

12. DUE TO FAULTY AMALGAM MANIPULATION o A. MERCURY ALLOY RATIO: o LOSS OF STRENGTHIF RESIDUAL MERCURY IS IN EXCESS OF 55% o INCREASD FLOW , DECREASED CRUSHING STRENGTH o INCREASED SUSCEPTIPBILITY TO TARNISH AND CORROSION o BETTER TO USE MINIMAL MERCURY TECHNIQUE WITH DISPENSERS FOR

CORRECT PROPOTIONING. o CONTINUATION OF TRITURATION TO ASSURE ALL ALLOY PARTICLES

AREMULLING COATED WITH MERCURY. 13.o DONE MANUALLY OR MECHANICALLY o IN MECHANICAL THE CAPSULE SHOULD BE CLEANED AFTER EACH MIX AS IT

CAN CAUSE A HARD ISLANDS IN FUTURE MIXING PROCEDURE o SOFT POWDERY NON- COHERENT MIXUNDER TRITURATION o BREAK ALREADY FORMED MATRIXOVER TRITURATION

14. B. CONDENSATION o REDUCE RESIDUAL MERCURY,RATIONALE o TO ENSURE AMALGAM REACH ALL PARTS OF THE PREPARATION AND OBTAIN

HOMOGENOUS RESTORATION DEVOID OF VOIDS o FRESHLY PREPARED AMALGAM HAS DESIRABLE WORKING PROPERTIES o EFFECTIVENESS OF REMOVING RESIDUAL MERCURY IS POSSIBLE ONLY IF

USED WITHIN 4 MINUTES FROM TRITURATION 15.o DO NOT ALLOW PROPER CONDENSATION AND ALSO DO NOT

REMOVEDELAYED USE MERCURY FROM THE RESTORATION o MULTIPLE MIX SHOULD BE ULARGER CAVITIES SED TO GET HOMOGENOUS

RESTORATION o REDUCES STRENGTHEXCESSIVE REMOVAL OF MERCURY 16.o CONDENSATION SHOULD BE DONE USING STEPING PROCESS TO DRIVE AWAY

VOIDS o CONDENSOR SIZE SHOULD NOT BE TOO SMALL OR TOO LARGE o SMALL INCREMENTS SHOULD BE USED TO ENSURE PROPER CONDENSATION o MECHANICAL CONDENSER SHOULD BE USED WITH CAUTION AS IT WOULD

CAUSE FRACTURE OF ENAMEL MARGINS 17. C. CONTAMINATION o MOISTURE CONTAMINATION CAN OCCUR DURING o -TRITURATION o - MULLING o -CONDENSATION o WEAKEN THE RESTORATION ESPECIALLY IF ZINC CONTAINING o IT RESULT IN MARGINAL FLAWS, TARNISH, PITTING, CORROSION, AND

BLISTERING. EXPANSION MAY ALSO LEAD TO PAIN 18. D.FINISHING AND POLISHING o AMALGAM SHOULD BE FINISHED GENTLY o EXCESS SPUR LIKE OVERHANGS OR THIN FLAKES OF AMALGAM ON MARGINS

CAN FRACTURE EASILY WHICH CAN LEAVE CREVICES IN VULNERABLE AREAS

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

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

19.o FAILURE TO POLISH ACCELERATE CORROSION DUE TO SURFACE

IRREGULARITIES ,ROUGH SURFACE PROMOTES ACCUMULATION OF PLAQUE RESULTING IN GINGIVAL IRRITATION

o POLISHING SHOULD BE DONE JUDICIOUSLY, TEMPERATURE ABOVE 65 0 C LEADS TO RELEASE OF MERCURY LEADING TO DEFFECTIVE RESTORATION

20. E. POST OPERATIVE PAIN o THIS OCCUR BECAUSE OF: o HYPEROCCLUSION LEADING TO INFLAMMATION OF APICAL PERIODONTIUM o CRACKS IN TOOTH SUCH CRACKS CAUSE PAIN DURING CHEWING BECAUSE OF

EXPANSION OR CONTRACTION OF TOOTH STRUCTURE WITH EVERY BITE o GALVANISM : MAY BE DUE TO DISSIMILAR ADJACENT METAL RESTORATION OR

POORLY CONDENSED AMALGAM DUE TO VARIATION IN SILVER CONCENTRATION

o DELAYED EXPANSION 21.o INADEQUATE PULP PROTECTION LEADING TO CONDUCTION OF HEAT o VARNISH SHOULD BE APPLIED UNDER AMALGAM RESTORATION TO AVOID

LEAKAGE AROUND RESTORATION WHICH MAY LEAD TO POST OPERATIVE SENSITIVITY AND AMALGAM BLUES DUE TO PENETRATION OF CORROSION PRODUCTS INTO DENTINAL TUBULES

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

22. FROM THE MATERIAL SIDE o MICROLEAKAGE: o PERCULATION OF ORAL FLUIDS o CREEP o STATIC CREEP o DYNAMIC CREEP o DIMENSIONAL CHANGE o DEPENDS ON RESIDUAL MERCURY o NEWER CONTRACT, OLDER EXPAND o MAY EVEN CAUSE PAIN

23. REFERENCES o TEXTBOOK OF OPERATIVE DENTISTRY o - VIMAL K SIKRI o ART & SCIENCE OF OPERATIVE DENTISTRY o - THEODORE M ROBERSON o JOURNALS o - TIMES OF NITRA 24.o THANK YOU