Dental Amalgam

DENTAL AMALGAM

HISTORY

TERMINOLOGIES

MANUFACTURE OF ALLOY POWDER

ALLOY COMPOSITION

AMALGAMATION & RESULTING MICROSTRUCTURE

DIMENSIONAL STABILITY

STRENGTH

CREEP

CLINICAL PERFORMANCE OF AMALGAM RESTORATIONS

FACTORS AFFECTING SUCCESS OF AMALGAM RESTORATIONS

MERCURY/ALLOY RATIO

MECHANICAL TRITURATION

CARVING & FINISHING

CONDENSATION

CLINICAL SIGNIFICANCE OF DIMENSIONAL CHANGE

MARGINAL DETERIORATION

SIDE EFFECTS OF MERCURY

SUMMARY

CONCLUSION

REFERENCES

HISTORICAL BACKGROUND

Silver Amalgam in Clinical Practice- I.D. Gainsford

Used as a dental restorative material from the beginning of the 19th century.

Amalgams were made by mixing mercury with the fillings from Spanish or Mexican silver coins (high silver content).

Failure causes:1. Harsh mass which was difficult to mix2. Hardened very slowly3. Expanded enormously4. Stained the teeth black

YEAR EVENTS

1819 First dental silver amalgam is supposed to have been introduced into England by Bell – “Bell’s Putty”

1833 Introduced to the North American continent by Cawcour brothers termed as “Royal Mineral Succedaneum”.

1843 Resolution passed by the American Society of Dental Surgeons (the first organised Dental Society in the U.S.A declaring the use of amalgam a “Malpractice”.Thus the Amalgam War began

1845 “Amalgam Pledge” was adopted by the society.

YEAR EVENTS

1850 Pledge was rescinded officially ending the amalgam war.

1861 First research programme was conducted by John Tomes ( Trans.Odontol.Soc. G.B.,Vol III)Who measured shrinkage of a number of amalgams

1871 Charles Tomes measured shrinkage & expansions by specific gravity tests.

1874 Thomas B.Hitchcock (Trans.N.Y.Odontol.Soc) did some important work in measuring more accurately by means of a micrometer changes of amalgam form

YEAR EVENTS

1896 Classic work of G.V.Black that a more systematic study was made of the properties & manner of manipulation of silver amalgam and its relation to cavity preparation.Many of G.V.Black’s techniques for amalgam restorations are generally accepted today.New methods are often described as variations or modifications of those used by Black.

YEAR EVENTS

1930 A.D.A research organisation conducted a survey and showed that only a few of the proprietary amalgam alloys on the market & tested by the National Bureau of Standards were reliable.A.D.A specification No. 1 for Alloy.A.D.A specification No. 6 for Mercury.

1934 &1960

Revision of this specification

HISTORY OVERVIEW

1833 Crawcour brothers introduce

amalgam to U.S powdered silver coins mixed with mercury

expanded on setting

1895 G.V. Black developed

formula for modern amalgam alloy

67% silver, 27% tin, 5% copper, 1% zinc

overcame expansion problems

1960’s conventional low-copper

lathe-cut alloys smaller particles

first generation high-copper alloys

Dispersalloy (Caulk) Innes & Youdelis -1963 admixture of spherical Ag-

Cu eutectic particles with conventional lathe-cut

eliminated gamma-2 phase

Mahler J Dent Res 1997

1970’s first single composition

spherical Tytin (Kerr) ternary system

(silver/tin/copper)

1980’s alloys similar to Dispersalloy

and Tytin

1990’s mercury-free alloys Mahler J Dent Res 1997

TERMINOLOGIES & DEFINITIONS

AMALGAM DENTAL AMALGAM DENTAL AMALGAM ALLOY TRITURATION AMALGAMATION

Special type of alloy in that one of its constituents is mercury.Before these alloys combine with mercury they are known as dental amalgam alloys - ANUSAVICE (2003)

Amalgam

TERMINOLOGY DEFINITION

Amalgam Amalgam is an alloy which has mercury as one of its components – Marzouk (1997)

Dental Amalgam An alloy of mercury, silver, copper, tin, which may also contain palladium, zinc, and other elements to improve handling characteristics and clinical performance – Anusavice (2003)

Dental Amalgam Alloy /Alloy for Dental Amalgam

An alloy of silver, copper, tin, and other elements that is formulated and processed in the form of powder particles or as a compressed pellet– Anusavice (2003)

But to be more simple… AMALGAM = A + MASS OF GAM (GUM)

(HAND TRITURATION) AMALGAM = AMALGAMATED GAM (GUM)

(AMALGAMATOR)

FUTURE COULD BE…

AMALGAM = AMALGAMATED MASS DELIVERED FROM GUN

(COMPOSITE COMPULES)

TERMINOLOGY DEFINITION

Amalgamation The process of mixing liquid mercury with one or more metals or alloys to form an amalgam. – Anusavice (2003)

Trituration The process of grinding powder, especially within a liquid. In dentistry, the term is used to describe the process of mixing the amalgam alloy particles with mercury in an amalgamator. – Anusavice (2003)

Why Amalgam? Inexpensive Ease of use Proven track record

>150 years Familiarity Resin-free

less allergies than composite

Constituents in Amalgam

Basic Silver Tin Copper Mercury

Other Zinc Indium Palladium

Basic Silver Tin Copper Mercury

Other Zinc Indium Palladium

AmalgamConstituents

1895 G.V. Black develops

formula for modern amalgam alloy

67% silver, 27% tin, 5% copper, 1% zinc

Basic Constituents Silver (Ag)

increases strength increases expansion

Tin (Sn) decreases expansion decreased strength increases setting time

Phillip’s Science of Dental Materials 2003

Basic Constituents Copper (Cu)

ties up tin reducing gamma-2

formation increases strength reduces tarnish and

corrosion reduces creep

reduces marginal deterioration


Basic Constituents Mercury (Hg)

activates reaction only pure metal that is liquid

at room temperature spherical alloys

require less mercury smaller surface area easier to wet

40 to 45% Hg admixed alloys

require more mercury lathe-cut particles more difficult to wet

45 to 50% Hg


Other Constituents Zinc (Zn)

used in manufacturing decreases oxidation of other elements

sacrificial anode provides better clinical performance

less marginal breakdown Osborne JW Am J Dent 1992

causes delayed expansion with low Cu alloys if contaminated with moisture during condensation

Phillips RW JADA 1954


H2O + Zn ZnO + H2

Other Constituents Indium (In)

decreases surface tension reduces amount of mercury necessary reduces emitted mercury vapor

reduces creep and marginal breakdown increases strength must be used in admixed alloys example

Indisperse (Indisperse Distributing Company) 5% indium

Powell J Dent Res 1989

Other Constituents

Palladium (Pd) reduced corrosion greater luster example

Valiant PhD (Ivoclar Vivadent) 0.5% palladium

Mahler J Dent Res 1990

Classifications

Based on number of alloys Based on copper content Based on particle shape Based on method of adding

copper Based on manufacturing process Based on powder’s particle size Based on addition of Noble Metals

Copper Content

Low-copper alloys 4 to 6% Cu

High-copper alloys thought that 6% Cu was maximum amount

due to fear of excessive corrosion and expansion Now contain 9 to 30% Cu

at expense of Ag


Composition

LOW COPPER

HIGH COPPER

Admixed Unicomposition

Particle shape

Lathe- Cut /Spherical

Lathe-cut(2/3)

Spherical(1/3)

Spherical

Silver 63-70% 40-70 % 40-65 % 40-60 %

Tin 26-23 % 26-30 % 0-30 % 22-30 %

Copper 2-5 % 2-30 % 20-40 % 13-30 %

Zinc 0-2 % 0-2 % 0 % 0-4 %

COPPER CONTENT

Particle Shape Lathe cut

low Cu New True

Dental alloy high Cu

ANA 2000

Admixture high Cu

Dispersalloy, Valiant PhD

Spherical low Cu

Cavex SF high Cu

Tytin, Valiant

Method of Adding CopperSingle Composition Lathe-Cut (SCL)

Single Composition Spherical (SCS)

Admixture: Lathe-cut + Spherical Eutectic (ALE)

Admixture: Lathe-cut + Single Composition

Spherical (ALSCS)

Single Composition Lathe-Cut (SCL) More Hg needed than spherical alloys High condensation force needed due to

lathe cut 20% Cu Example

ANA 2000 (Nordiska Dental)

Single Composition Spherical (SCS)

Spherical particles wet easier with Hg less Hg needed (42%)

Less condensation force, larger condenser Gamma particles as 20 micron spheres

with epsilon layer on surface Examples

Tytin (Kerr) Valiant (Ivoclar Vivadent)

Admixture: Lathe-cut + Spherical Eutectic (ALE)

Composition 2/3 conventional lathe cut (3% Cu) 1/3 high Cu spherical eutectic (28% Cu) overall 12% Cu, 1% Zn

Initial reaction produces gamma 2 no gamma 2 within two years

Example Dispersalloy (Caulk)

Admixture: Lathe-cut + Single Composition Spherical (ALSCS)

High Cu in both lathe-cut and spherical components 19% Cu

Epsilon layer forms on both components 0.5% palladium added

reinforce grain boundaries on gamma 1 Example

Valiant PhD (Ivoclar Vivadent)

MANUFACTURE OF ALLOY POWDER Classification Lathecut powder Homogenizing Anneal Particle Treatments Atomized powder Lathecut powder Vs Atomized Spherical

powder

Manufacturing Process

Lathe-cut alloys Ag & Sn melted together alloy cooled

phases solidify heat treat

100 ºC for 8 hours grind, then mill to 25 - 50 microns heat treat to release stresses of grinding


Manufacturing Process

Spherical alloys melt alloy atomize

spheres form as particles cool sizes range from 5 - 40

microns variety improves condensability


ALLOY COMPOSITION Metallurgical phases in dental amalgams

The Silver-Tin system

The influence of Silver-Tin phase on amalgam properties

METTALURGICAL PHASESMETTALURGICAL PHASES

Sn8Hg

Ag2Hg3

Ag3Sn

STOICHIOMETRIC FORMULA

2

1

PHASESNUMBER OF ATOMS

NUMBER OF ATOMSSTOICHIOMETRIC

FORMULA

PHASES

Ag-CuSilver-Copper Eutectic

Cu6Sn5

Cu3Sn

(4) - 1 (5) - 1

Cu Ag

PHASE:Silver- Copper Eutectic

STOICHIOMETRIC FORMULA:

Ag-Cu

PHASE:Silver- Copper Eutectic

STOICHIOMETRIC FORMULA:

Ag-Cu

Basic Composition A silver-mercury matrix containing filler

particles of silver-tin Filler (bricks):

Ag3Sn called gamma can be in various shapes

irregular (lathe-cut), spherical,or a combination

Matrix: Ag2Hg3 called gamma 1

cement Sn8Hg called gamma 2

voids


Basic Setting Reactions

Conventional low-copper alloys Admixed high-copper alloys Single composition high-copper alloys

Dissolution and precipitation Hg dissolves Ag and Sn

from alloy Intermetallic compounds

formed

Conventional Low-Copper Alloys

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy

Mercury (Hg)

AgAgAg

Sn

Sn

Sn

Hg Hg

AgAg33Sn + HgSn + Hg AgAg33Sn + AgSn + Ag22HgHg33 + Sn + Sn88HgHg


1 2

Conventional Low-Copper Alloys Gamma () = Ag3Sn

unreacted alloy strongest phase and

corrodes the least forms 30% of volume

of set amalgam Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy

Mercury

Ag

AgAg

Sn

Sn

Sn

HgHg

Hg



1 2

Conventional Low-Copper Alloys Gamma 1 (1) = Ag2Hg3

matrix for unreacted alloyand 2nd strongest phase

10 micron grainsbinding gamma ()

60% of volume



1 2

1

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy


Gamma 2 (2) = Sn8Hg weakest and softest phase corrodes fast, voids form corrosion yields Hg which

reacts with more gamma () 10% of volume volume decreases with time

due to corrosion



1 2

2

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy

AgAg33Sn + HgSn + Hg AgAg33Sn + AgSn + Ag22HgHg33 + Sn + Sn88HgHg 1 2

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy

Mercury (Hg)

AgAgAg

Sn

SnSn

Hg Hg

1

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy 2

Ag-Sn Alloy

Ag-Sn Alloy

Ag-Sn Alloy


(30%) (60%) (10%)

Admixed High-Copper Alloys

Ag enters Hg from Ag-Cu spherical eutectic particles eutectic

an alloy in which the elements are completely soluble in liquid solution but separate into distinct areas upon solidification

Both Ag and Sn enter Hg from Ag3Sn particles


AgAg33Sn + Ag-Cu + HgSn + Ag-Cu + Hg AgAg33Sn + Ag-Cu + AgSn + Ag-Cu + Ag22HgHg33 + Cu + Cu66SnSn55 1

Ag-Sn Alloy

Ag-Sn Alloy

Mercury

Ag

AgAg

SnSn

Ag-Cu Alloy

AgHgHg


Sn diffuses to surface of Ag-Cu particles reacts with Cu to form

(eta) Cu6Sn5 () around unconsumed

Ag-Cu particlesAg-Sn Alloy

Ag-Cu Alloy

Ag-Sn Alloy




Gamma 1 (1) (Ag2Hg3)

surrounds () eta phase (Cu6Sn5) and gamma ()

alloy particles (Ag3Sn)Ag-Sn Alloy

1

Ag-Cu Alloy

Ag-Sn Alloy




Ag-Sn Alloy

Ag-Sn AlloyMercury

AgAgAg

SnSn

Ag-Cu Alloy

AgHgHg

Ag-Sn Alloy

Ag-Cu Alloy

Ag-Sn Alloy

Ag-Sn

Alloy 1

Ag-Cu Alloy

Ag-Sn

Alloy


Single Composition High-Copper Alloys

Gamma sphere () (Ag3Sn) with epsilon coating () (Cu3Sn)

Ag and Sn dissolve in Hg

Ag-Sn Alloy

Ag-Sn AlloyAg-Sn Alloy

Mercury (Hg)

Ag

SnAg

Sn

AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu + Cu66SnSn55


1

Single Composition High-Copper Alloys

Gamma 1 (1) (Ag2Hg3) crystalsgrow binding together partially-dissolved gamma () alloyparticles (Ag3Sn)

Epsilon () (Cu3Sn) develops crystals on surface of gamma particle (Ag3Sn) in the form of eta () (Cu6Sn5) reduces creep prevents gamma-2 formation

Ag-Sn Alloy

Ag-Sn AlloyAg-Sn Alloy

1

AgAg33Sn + CuSn + Cu33Sn + HgSn + Hg AgAg33Sn + CuSn + Cu33Sn + AgSn + Ag22HgHg33 + Cu + Cu66SnSn55


1

Material-Related Variables Dimensional change Strength Corrosion Creep

DIMENSIONAL STABILITY

DIMENSIONAL CHANGE

THEORY OF DIMENSIONAL CHANGE

EFFECT OF MOISTURE CONTAMINATION

Delayed Expansion

The gradual expansion of a zinc-containing amalgam over weeks to months, which is associated with hydrogen gas development caused by contamination of the plastic mass with moisture during its manipulation in a cavity preparation– Anusavice (2003)

DIMENSIONAL CHANGES DIMENSIONAL CHANGES

Dimensional changes on setting:Dimensional changes on setting:CONTRACTION during alloy dissolutionCONTRACTION during alloy dissolutionEXPANSION during impingement of reaction product crystalsEXPANSION during impingement of reaction product crystals(EXPANSION if side reactions due to H(EXPANSION if side reactions due to H22O contamination)O contamination)

EXP (+)EXP (+)

CONT (--)CONT (--)

TIMETIME

Dimensional changes depend on reaction variables:Dimensional changes depend on reaction variables:Particle size, Hg/alloy ratio, trituration time, condensation, ...Particle size, Hg/alloy ratio, trituration time, condensation, ...

ADA =ADA =± 20 ± 20 mm

Dimensional Change Most high-copper amalgams undergo a

net contraction Contraction leaves marginal gap

initial leakage post-operative sensitivity

reduced with corrosion over time


Dimensional Change Net contraction

type of alloy spherical alloys have more

contraction less mercury

condensation technique greater condensation = higher contraction

trituration time overtrituration causes higher contraction


STRENGTH Measurement of strength Effect of trituration Effect of mercury content Effect of condensation Effect of porosity Effect of amalgam hardening rate

Strength

Develops slowly 1 hr: 40 to 60% of maximum 24 hrs: 90% of maximum

Spherical alloys strengthen faster require less mercury

Higher compressive vs. tensile strength Weak in thin sections

unsupported edges fracture


Amalgam Properties Compressive

Strength (MPa)% Creep Tensile

Strength(24 hrs) (MPa)

Amalgam Type 1 hr 7 days

Low Copper1 145 343 2.0 60

Admixture2 137 431 0.4 48

Single Composition3

262 510 0.13 64


1Fine Cut, Caulk 2 Dispersalloy, Caulk 3Tytin, Kerr

CREEPCreep The time-dependent strain or deformation that is

produced by a stress. The creep process can cause an amalgam restoration to extend out of the cavity preparation, thereby increasing its susceptibility to marginal breakdown. – Anusavice (2003)

Marginal Breakdown

The gradual fracture of the perimeter of margin of a dental amalgam restoration that leads to the formation of gaps or ditching at the external interfacial region between the amalgam and the tooth. – Anusavice (2003)

Significance of creep on amalgam performance

Influence of microstructure on creep

Effect on manipulative variable on creep

Creep

Creep

Slow deformation of amalgam placed under a constant load load less than that necessary to produce fracture

Gamma 2 dramatically affects creep rate slow strain rates produces plastic deformation

allows gamma-1 grains to slide

Correlates with marginal breakdown


Creep High-copper amalgams have creep

resistance prevention of gamma-2 phase

requires >12% Cu total single composition spherical

eta (Cu6Sn5) embedded in gamma-1 grains interlock

admixture eta (Cu6Sn5) around Ag-Cu particles

improves bonding to gamma 1

Amalgam Type % Creep

Low Copper1 2.0

Admixture2 0.4

Single Composition3 0.13

Phillip’s Science of Dental Materials 20031Fine Cut, Caulk

2 Dispersalloy, Caulk

3Tytin, Kerr

AMALGAM PROPERTIESAMALGAM PROPERTIES

2.2. Clinical PerformanceClinical Performancea.a. Longevity = 20-25 yrs ideally, 8-12 yrs practicallyLongevity = 20-25 yrs ideally, 8-12 yrs practicallyb.b. Modes of failure = caries, marginal fracture, bulkModes of failure = caries, marginal fracture, bulk

UNITEDSTATES

WORLD

ADA FDI

ISOANSI

B.B. Properties:Properties:

1.1. PhysicalPhysical2.2. MechanicalMechanical3.3. ChemicalChemical4.4. BiologicalBiological

AA.. Introduction:Introduction:

1.1. Specifications for Amalgam PropertiesSpecifications for Amalgam Propertiesa.a. ADA / ANSI and ISOADA / ANSI and ISO

Physical Properties Physical Properties

1.1. Thermal conductivity =Thermal conductivity = 2.2. Electrical conductivity = Electrical conductivity = 3.3. Coefficient of thermal expansion = Coefficient of thermal expansion = 4.4. Radiopacity =Radiopacity =5.5. Color =Color =

[>2 mm Aluminum][>2 mm Aluminum][Lustrous, shiny, white][Lustrous, shiny, white]

25 ppm/ºC25 ppm/ºC[High][High]

[High][High]

Mechanical Properties Mechanical Properties TYTIN (Kerr Dental Mfg) = “tie up the tin”TYTIN (Kerr Dental Mfg) = “tie up the tin”High-Copper, Spherical, 1 Particle, Zn-freeHigh-Copper, Spherical, 1 Particle, Zn-free42% Hg mixed with alloy42% Hg mixed with alloyFast-settingFast-settingHigh early strengthHigh early strength

PolishedPolishedSurfaceSurface

FractureFractureSurfaceSurface

Mechanical properties compressive strength is more for

high cu amalgam Its much more for single composition,when

compared to admixed alloys.

Chemical Properties Chemical Properties

Clean Surface,High O2 Potential

(CATHODIC)

Plaque Buildup,Low O2 Potential

(ANODIC)

(a)

(b)

(a) (b)

PlaqueBuildup

Clean Surface,High O2 Potential

(CATHODIC)

Plaque Buildup,Low O2 Potential

(ANODIC)

(a)

(b)

(a) (b)

PlaqueBuildup

ELECTROCHEMICAL CORROSION:ELECTROCHEMICAL CORROSION:

• Galvanic corrosionGalvanic corrosion• Local galvanic corrosion (structure selective)Local galvanic corrosion (structure selective)• Crevice corrosion (concentration cell)Crevice corrosion (concentration cell)• Stress corrosionStress corrosion

Sn-O-ClSn-O

CHEMICALCHEMICALCORROSION:CORROSION: AgS

Biological Properties Biological Properties Mercury Toxicity:Mercury Toxicity:

OSHA maximumOSHA maximum TLV = 50 TLV = 50 g/mg/m33 (vapor) per 40 hr work week(vapor) per 40 hr work weekTransient intraoral release (<35 Transient intraoral release (<35 g/mg/m33))

Mercury Hypersensitivity:Mercury Hypersensitivity:Low level allergic reactionLow level allergic reactionEstimated to beEstimated to be < 1 / 100,000,000< 1 / 100,000,000

Amalgam Tatoo:Amalgam Tatoo:Can occur during amalgam removal if no rubber damCan occur during amalgam removal if no rubber damEmbedded amalgam particles corrode and locally discolor gumEmbedded amalgam particles corrode and locally discolor gumNo known adverse reactionsNo known adverse reactions

Clinical Performance Clinical Performance

Reasons for Failure:Reasons for Failure:Secondary Secondary cariescaries -- principally with low-copper amalgam -- principally with low-copper amalgamMarginal fractureMarginal fracture -- prevalent with low-copper amalgam -- prevalent with low-copper amalgamBulk fractureBulk fracture -- most common with high-copper amalgam -- most common with high-copper amalgam

Jorgensen theory of mercuroscopic expansionJorgensen theory of mercuroscopic expansion

Corrosion at marginsCorrosion at margins

Sn-O-Cl and Sn-OSn-O-Cl and Sn-O

Internal corrosionInternal corrosion

PENETRATING versus SUPERFICIAL CORROSIONPENETRATING versus SUPERFICIAL CORROSION

Clinical EvaluationClinical Evaluation

Mahler scale:Mahler scale:

??????

Hi-CuHi-Cu Low-CuLow-Cu

CLINICAL PERFORMANCE OF AMALGAM RESTORATIONS

Tarnish & Corrosion

Compositional effects on the survival of amalgam restorations

Corrosion

Reduces strength Seals margins TYPES Dry corrosion/chemical corrosion Wet corrosion/electrochemical corrosion Galvanic corrosion Hetrogenous Stress corrosion Concentration cell corrosion [crevice corrosion]

Sutow J Dent Res 1991

Manufacturer controlled variables The composition of the alloy The heat treatment of the alloy The size, shape, & method of production of

the alloy particles The surface treatment of the particles The form in which the alloy is supplied

Dentist-Controlled Variables Alloy Selection

Manipulation Mercury/Alloy ratio trituration Condensation technique Marginal integrity Anatomic characteristics burnishing polishing

Alloy Selection

Handling characteristics Mechanical and physical

properties Clinical performance

Handling Characteristics Spherical

advantages easier to condense

around pins hardens rapidly smoother polish

disadvantages difficult to achieve tight contacts higher tendency for overhangs


Handling Characteristics

Admixed advantages

easy to achieve tight contacts good polish

disadvantages hardens slowly

lower early strength

Overview of Manipulation Overview of Manipulation

Selection / Proportioning / Amalgamation / Manipulation / PolishingSelection / Proportioning / Amalgamation / Manipulation / Polishing

Placement andPlacement andCondensationCondensation

CarvingCarving BurnishingBurnishing PolishingPolishing

Onset ofOnset ofMIXINGMIXING

Onset ofOnset ofWORKINGWORKING

Onset ofOnset ofSETTINGSETTING

End ofEnd ofSETTINGSETTING

24 hours24 hours

TIMETIME

ALLOY MANIPULATIONALLOY MANIPULATION

Manual Trituration Procedures:Manual Trituration Procedures:Alloy + Hg Alloy + Hg mortar + pestle mortar + pestle manual mixing manual mixing

Mechanical Trituration Procedures:Mechanical Trituration Procedures:Powdered alloy + Hg Powdered alloy + Hg capsule + pestle capsule + pestle amalgamator amalgamatorPelleted alloy + Hg Pelleted alloy + Hg capsule + pestle capsule + pestle amalgamator amalgamator

Powdered alloy + Hg Powdered alloy + Hg pre-capsulated pre-capsulated amalgamator amalgamator

Amalgamators Amalgamators

SPEEDSPEED TIMETIME

ENERGY ENERGY == SpeedSpeed x x TimeTime

Trituration

Mixing time refer to manufacturer

recommendations

Overtrituration “hot” mix

sticks to capsule decreases working / setting time slight increase in setting contraction

Undertrituration grainy, crumbly mix


kiran

Condensation Forces

lathe-cut alloys small condensers high force

spherical alloys large condensers less sensitive to amount of force vertical / lateral with vibratory motion

admixture alloys intermediate handling between lathe-cut and spherical

Burnishing

Pre-carve removes excess mercury improves margin adaptation

Post-carve improves smoothness

Combined less leakage

Ben-Amar Dent Mater 1987

Early Finishing

After initial set prophy cup with pumice provides initial smoothness to restorations recommended for spherical amalgams

Polishing

Increased smoothness Decreased plaque retention Decreased corrosion Clinically effective?

no improvement in marginal integrity Mayhew Oper Dent 1986 Collins J Dent 1992

ALTERNATIVES TO AMALGAM

1. Mercury-free direct –filling alloy: ADA-NIST (National Institute on Standards and

Technology) Patented this alloy Silver coated Silver-Tin particles that can be self-

welded by compaction (hand-consolidated) 2. Transitional Approaches:

Redesigning amalgam to have much less initial mercury

Alloy particles pack together well Reduce mercury for mixing to the 15%-25% range

PRIMM - Poly Rigid Inorganic Matrix Material - Porous Ceramic fibers. Condensable, curable, carvable, polishable. "White amalgam"

Restorations with >0.3% Zn and >12% Cu have minimal corrosion and the longest longevity. Zn and Cu act synergistically. (J. Dent Res, Nov 1997)

3. Gallium Alloys: Mercury controversy limits the use of Silver

Amalgam Toxic effects coupled with mercury hygiene led

the researchers think of mercury free alloys Suggested by PuttKammer -1928 PROPERTIES:

Wettability Sets in reasonable time and possesses strength Diametrical stability & corrosion resistance equal to

or greater than silver amalgam

COMPOSITION:

ALLOY LIQUID

Silver (Ag) – 60% Gallium (Ga) - 62%

Tin (Sn) -25% Iridium (Ir) - 25%

Copper (Cu) -13% Tin (Sn) -25%

Palladium ( Pd) - 20%

ALLOY CREEP % COMPRESSIVE STRENGTH (AFTER 6 HOURS)

SETTING(CONTRACTION/EXPANSION %)

Silver Alloy(High Copper)

1.04_0.06 370 MPa -0.05

Gallium Alloy

0.09_0.03 350 MPa +0.39

+

+

BONDED AMALGAM RESTORATIONS: Silver does not adhere properly to cavity walls Adhesive systems designed to bond amalgam to

enamel & dentin Improve adhesion, strengthen remaining tooth

structure, decreases the need for removal of health tooth structure

Pioneers were Sun Medical (Superbond), Kurrary (Panavia)

Superbond was based on 4-META/MMA resins Panavia was based on Bis GMAphosphonated

ester

Later dentin bonding agents have also been a subject of bonding amalgam to dentin

Various Agents are Amalgam Bond with HPA ( Parkell) All Bond 2 (Bisco) Optibond 2 (Kerr) Panavia 21(Kuraray) Clearfil Linear Bond 2 (Kuraray) Scothbond MP (3M)

a) etching the dental surface with acid,b) applying a treatment composition comprising an aromatic

sulfinate salt to the etched dental surface, c) applying a priming solution containing a film-former to the

treated dental surface, d) applying a chemically curable dental adhesive to the

primed dental surface, and e) applying amalgam to the adhesive-coated dental surface. The chemically curable adhesive comprises an oxidizing

agent and a reducing agent. The oxidizing agent is present in an amount sufficient to

interact with said aromatic sulfinate salt to achieve higher adhesion to the dental surface than a like method not comprising an aromatic sulfinate salt in the treatment composition.

- U.S Patent Issued on January 21, 1997

INDICATIONS: Auxillary retention Extensively carious posterior teeth Teeth with low Gingival-Occlusal height Temporary restorations Amalgam Sealants

ADVANTAGE: More conservative Reinforces tooth structure Eliminates the use of pins Decreases the incidence of marginal fracture Provides a bond at the tooth restoration interface Biologic sealing of the pulpo-dentinal complex Appointment time Cost effective

DISADVANTAGE: Technique sensitive Time to adapt to the new technique Clinical performance are not documented No sustained effects of amalgam bonding when

subjected to thermocycling Hydrolytic stability of the bond is questionable

"...amalgam bonding is an adjunct to and not a substitute for mechanical retentive form. The main advantage of conventional amalgam adhesives seems to be their ability to seal the tooth restorative interface, preventing microleakage into the dental tubules and pulp and reducing post-operative sensitivity.

- Cobb, et al, Am J Dent, Oct 1999 "Continuous microgaps were observed between

amalgam and dentin in the specimens using no lining material and Copal varnish compared to specimens using adhesive bonding system."

-Estafan, Gen Dent, March-April 2000

Criteria when considering amalgam substitutes: service life, radiopacity, wear properties, marginal adaptation, setting expansion/contraction, technique sensitivity, potential secondary caries risk. What materials are better than amalgam in

these areas? (Lutz and Krejc-2000)

CONCLUSION

SUMMARY “Dental alloys are manufactured for us.

Amalgams we make for ourselves and the strength and the stability of the hardened amalgam and the merit of the filling are only as good as the cause and the skill the dentist puts into it”.

- William E. Harper; J.Am.Dent.Assoc.13,119-125,1926.

“The tongue represents the best and the worst amongst things; amalgam restorations might be the most noble restorations but also the worst ignoble fillings”. - Aesop

REFERENCES Phillip’s Science of Dental Materials-

10th,11th Edition: Kenneth Anusavice Art & Science of Operative Dentistry-4th

Edition: Sturdevant. Restorative Dental Materials-11th Edition:

Robert G.Craig.

Jones DW: Putting dental mercury pollution into perspective. BDJ 2004;197:175-177.

Eichmiller FC: Research into Non-Mercury Containing Metallic Alternatives. Op Dent 2001;6:111-118.

Ronald K Harris: Dental Amalgam: Success Or Failure?. Op Dent 1992;17:243-252.

Dunne SM et al: Current materials and Techniques for direct restorations in posterior teeth. IDJ 1997;47:123-136.

MERCURY

TOXICITY

Mercury the Metal

Hg Facts & Uses

• Quicksilver• 13.6 times the weight of water• Evaporates at room temperature• Bacteria change to Methylmercury• Amalgam• Many Industrial uses

(thermometers, chemical reactions, gold mining)

Sources of Mercury Dental Schools Dental clinics Colleges & universities Hospitals, medical clinics & laboratories Home owners/communities Plumbers/electricians Junkyards/auto crushers & recyclers MSW incinerators Federal & other government facilities Farms

Mercury-Added Products Fever & lab thermometers Blood pressure devices Barometers, manometers, gauges Auto switches Elemental mercury from dental offices &

schools Appliances Fluorescent & other lamps

Mercury Collection Programs from Schools, Dental Offices & Households

Vapor Limits (TLV) = Vapor Limits (TLV) = 0.05 mg/m0.05 mg/m33 = 50 = 50 g/mg/m33 = 5 ppb = 5 ppb

Hg Liquid and VaporHg Liquid and VaporHg = odorless, colorless gasHg = odorless, colorless gasHg = penetrating liquidHg = penetrating liquid

Liquid

Gas

Vapor Toxicity CalculationsVapor Toxicity Calculations::

Sensitivity CalculationsSensitivity Calculations::

ADA ADA 1 / 100,000,000 1 / 100,000,000UNC UNC 1 / 180,000,0001 / 180,000,000

Current Controversy on Mercury (Types):1. Elemental - Least toxic. Very small contribution

to total body burden of Hg. Is the form found in dentistry. Lipid soluble, absorbed in lungs. Very short-lived due to rapid oxidation.

2. Inorganic - Moderate toxicity. Formed by oxidation of elemental. Limited lipid solubility. Becomes sequestered in kidney, excreted slowly in urine. Half life ~ 60 days.

3. Organic - Most toxic. High lipid solubility. Only from non-dental sources. 90% absorbed in gut. Accumulates in red blood cells, sequestered in CNS and liver. Not found in urine. Excreted in feces.

Elemental Mercury: Hg 0

InorganicMercury : Hg +1 or Hg +2

Organic Mercury;Compounds such as:Methyl mercury - HgCH3+Dimethyl mercury - Hg(CH3)2

PHYSIOLOGICAL Hg CYCLEPHYSIOLOGICAL Hg CYCLE

ElementalElementalHgHg

InorganicInorganicHgHg

OrganicOrganicHgHg

LUNGS

GITRACT

SKIN

BLOODBLOOD

Allothersites

Brain

Hair,Hair,NailsNails

URINE

FECES

EXFOLIATION ofSkin, Hair, Nails

BLOODBLOOD

Average Half-Life in Human Body = 55 DaysAverage Half-Life in Human Body = 55 Days

ABSORPTIONABSORPTIONROUTEROUTE

TRANSPORTION andTRANSPORTION andLOCALIZATIONLOCALIZATION

EXCRETIONEXCRETIONof Hgof Hg

HgHgFORMFORM

FF

MM

Chewing

MMFF

NoChewing

Hg Release from AmalgamsHg Release from Amalgams

TLV (40 hrs/wk)

1010

5050

4040

3030

2020

Me

rcu

ry R

ele

ase

(M

erc

ury

Rel

eas

e ( g

/mg

/m33 ))

FF

Time (minutes)Time (minutes)

3030 6060

Few

Many

No knownhealth effects.

Subtle changeson some tests.

Mild-to-moderatesymptoms.

Pronouncedsymptoms.

10001000

5050

100100

500500

1010

55

Hg Swallowed from AmalgamsHg Swallowed from Amalgams

10.010.0

1.01.0

Hg

Co

nce

ntr

aio

n in

Pla

sm

aH

g C

on

cen

tra

ion

in P

las

ma

(nm

ol /

L =

0.2

pp

b)

(nm

ol /

L =

0.2

pp

b)

TIME (days)TIME (days)

4040 80800.10.1

2020 6060

Af Geijersstam E, Sandborgh-Englund G, Jonsson F, Ekstrand J.Af Geijersstam E, Sandborgh-Englund G, Jonsson F, Ekstrand J.Mercury uptake and kinetics after ingestion of dental amalgam.Mercury uptake and kinetics after ingestion of dental amalgam. J Dent ResJ Dent Res 2001;80:1793-1796. 2001;80:1793-1796.

Controlled for baseline levels in volunteers.Controlled for baseline levels in volunteers. Pulverized fresh dental amalgam.Pulverized fresh dental amalgam. 1.0 gm amalgam powder placed in gelatin capsules.1.0 gm amalgam powder placed in gelatin capsules.Drew blood samples at 5, 24, 30 hrs and 2, 7, 14, 21, Drew blood samples at 5, 24, 30 hrs and 2, 7, 14, 21,

28, 56, 90 days.28, 56, 90 days.

Hg rapidly detected from GI track … but at very low levels.Hg rapidly detected from GI track … but at very low levels.No difference between 0 and 90 days. Hg half-life about 37 days.No difference between 0 and 90 days. Hg half-life about 37 days.

Body-Burden CalculationsBody-Burden CalculationsElementalElemental InorganicInorganic OrganicOrganic = TOTAL= TOTAL

AIR AIR 0.5 0.5 g/dayg/day …..….. …..….. = 0.5 = 0.5 g/dayg/dayWATERWATER …..….. 10 10 g/dayg/day …..….. = 10 = 10 g/dayg/dayFOODFOOD …..….. …..….. 100 100 g/dayg/day = 100 = 100 g/dayg/dayAmalgamsAmalgams 20 20 g/dayg/day …..….. …..….. = 20 = 20 g/dayg/day

TOTALTOTAL = 130.5 = 130.5 g/dayg/day

18 occlusal amalgams = all Hg release absorbed18 occlusal amalgams = all Hg release absorbed

Actual body burden due to amalgam estimated as <0.5% of totalActual body burden due to amalgam estimated as <0.5% of total

Environmental Impact of HgEnvironmental Impact of Hg

Humans are continually exposed to a variety of sources of Hg Humans are continually exposed to a variety of sources of Hg from the environment ----- Hg is omnipresent.from the environment ----- Hg is omnipresent.

AIRAIR supplysupply = natural sources, human pollution, …= natural sources, human pollution, …WATERWATER supplysupply = natural sources, human pollution, …= natural sources, human pollution, …FOODFOOD supplysupply = natural sources, human pollution, …= natural sources, human pollution, …DENTAL and MEDICALDENTAL and MEDICAL = amalgams, OTC ointments, ...= amalgams, OTC ointments, ...

AIRAIR Hg mine…………………....300 Hg mine…………………....300 g/mg/m33

Industrial emission…………3Industrial emission…………3Urban air……………………...0.05Urban air……………………...0.05Pure air………………………..0.002Pure air………………………..0.002

FOODFOOD Tunafish…………………..1000 Tunafish…………………..1000 g/kgg/kgCattle………………………..160Cattle………………………..160Humans………………………25Humans………………………25

MERCURY TOXICITYMERCURY TOXICITYHistorical Problems:Historical Problems:

TannersTannersThermometer techniciansThermometer techniciansHgS mine workersHgS mine workers

Recent Incidents:Recent Incidents:Almaden, Spain (Hg mine)Almaden, Spain (Hg mine)Minamata Bay, Kyushu, Japan (fish problem)Minamata Bay, Kyushu, Japan (fish problem)Iraq (grain problem)Iraq (grain problem)Alamogordo, NM (grain problem)Alamogordo, NM (grain problem)Sweden (environmental load problem)Sweden (environmental load problem)Michigan (redistillation problem)Michigan (redistillation problem)

Historical Awareness

SPAINSPAIN

ALMADEN, SPAINALMADEN, SPAINAlmaden Mercury MineAlmaden Mercury Mine2400 Years of Continuous Productions2400 Years of Continuous Productions

>300 >300 g/mg/m33

KYUSHU, JAPANKYUSHU, JAPAN1953, Minamata Bay, Chisso Corporation FactoryMethyl mercury waste dumped into bay.

CHISSO CORPORATIONCHISSO CORPORATIONProduced fertilizers, Produced fertilizers, chemcial, plasticschemcial, plastics

Minamata BayMinamata BayContaminationContamination

• Hg(CHHg(CH33))22 laden fish laden fish• Chronic Hg toxicityChronic Hg toxicity• 202 People Poisened202 People Poisened• 52 Deaths52 Deaths

SYMPTOMS ofSYMPTOMS ofchronic Hg poisoning:chronic Hg poisoning:

• Ataxic gait.Ataxic gait.• Convulsions.Convulsions.• Numbness in mouth and limbs.Numbness in mouth and limbs.• Constriction of visual field.Constriction of visual field.• Difficulty in speaking.Difficulty in speaking.

BANNED IN EUROPE ???BANNED IN EUROPE ???

Swedish National Board of Health and WelfareSwedish National Board of Health and Welfare(April 20th, 1992 --Report to the Government)(April 20th, 1992 --Report to the Government)

1.1. No amalgam restorations in deciduous teeth after No amalgam restorations in deciduous teeth after July 1, 1993.July 1, 1993.

2.2. No amalgam restorations in permanent teeth up to No amalgam restorations in permanent teeth up to age 10 after July 1, 1995.age 10 after July 1, 1995.

3.3. Evaluate in 1996 the possibility of discontinuing all Evaluate in 1996 the possibility of discontinuing all amalgam use after 1997.amalgam use after 1997.

Sweden

Minamata Bay, Japan 1953 startup of acetaldehyde production

at a coastal factory using mercuric oxide as a catalyst

Stray cats 1953- outbreak of polio-like disease among coastal fishing villages

went crazy after eating fish 1968-mercury diagnosed as cause of 2000

disease victims

Polluting with HG

Discharge in Minamata Bay

Minamata disease-infants Mental retardation in infants Abnormal reflexes, ataxia, involuntary

movements Cerebral palsy Developmental delays—some didn’t walk

until age 7

in Minamata disease adults Paresthesia-numbness “pins and needles” Cerebellar ataxia, tremors, convulsions Constriction of visual fields, loss of smell Loss of hearing, dizziness, insomnia Dysarthria -speech disorder. Speech was slow, weak, imprecise or

uncoordinated. Cognitive impairments, such as inattention,

excitement, hallucinosis, loss of intelligence

Life Long Effects of Methyl Hg

Ambient WaterSediments

Edible Fish

Inorganic Mercury

Methyl-Mercury

Methyl-MercuryIn Humans

Biomethylation

Bioaccumulation

Exposure

Discharge

Biotransformation of Mercury

Out Breaks of MeHg Poisoning

Place Year CasesMinamata 1953-60 1000

Negate 1964-65 646

Guatemala 1963-65 45

Ghana 1967 144

Pakistan 1969 100

Iraq 1956 100

Iraq 1960 1,002

Iraq 1971 40,000

On-going 2001 ???

Seed Grain Outbreaks

Mercury compounds applied as antifungal agent to seed grains

Iraq—made bread directly from treated seed grain

Planting Seed with Mercury

Iraq Mothers with Bread

Iraq Infant - Effects of Mercury

• Blindness - Deafness• Cerebral Palsy - Seizures• Abnormal reflexes & muscle tone• Retarded motor development• Visual and Auditory Deficits• Delayed motor development

Neurobehavioral Effects

• Decrease in Brain Size• Cell loss• Disorganization of cells• Cell migration failures

Effects On The Brain

Fetal Toxicity Birth defects may be due to a brief

exposure during critical periods of fetal development

Affected fetuses may spontaneously abort Relationship between exposure and

outcome is difficult to establish

• Natural Degassing of the earth• Combustion of fossil fuel• Industrial Discharges and Wastes• Incineration & Crematories• Dental amalgams

Hg0 Hg2+ CH3Hg+

Environmental Sources of Mercury

Mercury Release

50-75% mercury released in the environment related to human activities, but there is lots of mercury in the soil from millions of years ago

The Mercury Cycle

Mercury A Global Issue

Mercury distribution and exposure is a global problem

Hg and Heart Attacks 2002 case-control study showing higher

mercury in men who had heart attacks vs. controls

Hoping to start series of studies in Population Health Sciences on Hg and cardiovascular disease

Can Vaccines Containing Thimerosal (ethyl mercury)

Cause Autism? Parents say “yes” Science studies say “no” Hviid A, et al. Association between

thimerosal-containing vaccine and autism. (Denmark registry) JAMA October 1, 2003;290:1763-6 –totally negative

Inst. of Medicine: Immunization Safety Review: Vaccines and Autism Report: No Association, May 2004

Mercury in Dental Amalgams Dose is high in mouth, but low to the body Adult brain is developed Subtle changes in brain or kidney function

due to such a low dose? Alzheimer’s disease?

In one study, dentists with abnormally high concentrations of urinary mercury, attributable to their occupational exposure, showed no evidence of kidney impairment on several key measurements of renal function

Another study examined claims that dental amalgam interferes with immune function. The researchers found that subjects with dental fillings had the same number of disease fighting white blood cells as people who were amalgam-free.

A Swedish researcher found no differences between amalgam and non-amalgam groups in measures used to assess immune system health, liver and kidney function, and skeletal muscle status.

A Swedish study of 1024 women looked at the prevalence of 30 symptoms often claimed to reflect toxic effects of amalgam, including fatigue, dizziness, irritability, and back pain. Women with more than 20 amalgam fillings were no more likely to complain of these symptoms than women with few or no amalgams.

Another Swedish study examined mercury serum levels in a population of 1462 women in order to correlate the serum mercury level (from all sources including diet) to the vague symptoms often claimed to be due to mercury intoxication from amalgam.

The study correlated serum mercury levels with the incidence of Dizziness, Eye complaints.

Hearing defects, Headache, General fatigue, Sleep disturbances and 25 other symptoms over a period of 25 years.

This study found NO correlation between serum levels of mercury and the 31 symptoms studied.

(Note: In Sweden, serum mercury levels tend to be much higher than those found in North America or other non-Scandinavian parts of Europe because Scandinavians are more likely to eat large amounts of ocean caught fish which increases serum mercury levels much more than mercury from amalgam fillings.)

A study of 30,000 female dental assistants and the wives of 29,000 dentists, divided into high and low mercury exposure groups found no difference between the two groups in the incidence of miscarriage or of birth defects in their offspring.

Standards set by the Occupational Safety and Health Administration (OSHA) estimate the mercury-vapor concentration to which even the most sensitive workers can be chronically exposed without suffering adverse effects.

Under OSHA guidelines, the maximum safe occupational dose approximates roughly 300 to 500 micrograms of mercury vapor per day.

Current estimates predict that people with a moderate to large number of fillings are exposed to 1 to 4 micrograms of mercury per day, barely 1% of the dose considered safe.

INHALED MERCURY:

The results of one study in which patients with amalgam restorations were monitored with mercury vapor detectors over a 24-hour period showed that the amount of vapor inhaled was 1.7 µg/day.

Three other studies have confirmed that the magnitude of vapor exposure for a patient with 8 to 10 amalgam restorations is in the range of 1.1 to 4.4 µg/day.

The threshold value for workers in the mercury industry is 350 to 500 µg/day, depending on activity level, and is based on an exposure of 40 hours per week.

Blood Levels:

Mercury blood levels that were measured in one study indicated that the average level in patients with amalgam was 0.7 ng/mL compared with a value of 0.3 ng/mL for subjects with no amalgam.

This difference was found to be statistically significant (P 0.01).

However, one should be aware of a study in Sweden that demonstrated that one saltwater seafood meal per week raised average blood levels of mercury from 2.3 to 5.1 ng/mL, a sevenfold increase (2.8 ng/mL) compared with that (0.4 ng/mL) associated with amalgam restorations.

The normal daily intake of mercury is 15 µg from food, 1 µg from air, and 0.4 µg from water.

Total mercury vapor release was consistently found to be greater for admixed as compared to spherical amalgam.

Amalgam restorations prepared by an inexperienced operator demonstrated statistically less mercury vapor than a novice or experienced clinician for both spherical and admixed morphologies.

A statistically significant difference in mercury vapor using different condensation and carving techniques was found for the spherical amalgam but not for the admixed material.

Restoration design demonstrated significant differences in total mercury vapor dependent on volume and exposed surface area of the amalgam restoration.

Recommendations are changing – stay Recommendations are changing – stay current.current.

Understand recycling documentation. Understand recycling documentation. Look for similar recommendations for Look for similar recommendations for

other office materials.other office materials.

ADA Hg HYGIENEADA Hg HYGIENERecommendations

Dental mercury hygiene recommendationsDental mercury hygiene recommendations:: Sources of dental mercury in the office.Sources of dental mercury in the office. General mercury hygiene recommendations.General mercury hygiene recommendations.

Office emergencies.Office emergencies.

Hygiene recommendations during Hygiene recommendations during preparation and placement of dental preparation and placement of dental amalgam.amalgam.

Management of mercury spills.Management of mercury spills. Management of small mercury spills.Management of small mercury spills. Management of large mercury spills.Management of large mercury spills.

Residual Hg in CapsulesResidual Hg in Capsules

Stone ME, Pederson ED, Cohen ME, Ragain JC, Karaway RS, Auxer RA, Saluta AR. Stone ME, Pederson ED, Cohen ME, Ragain JC, Karaway RS, Auxer RA, Saluta AR. Residual mercury content and leaching of mercury and silver from used amalgam capsules. Residual mercury content and leaching of mercury and silver from used amalgam capsules. Dent MaterDent Mater 2002;18:289-294. 2002;18:289-294.

OBJECTIVE: Measure (1) residual Hg in capsules OBJECTIVE: Measure (1) residual Hg in capsules and (2) potential for leaching in landfill.and (2) potential for leaching in landfill.

METHODS: Residual Hg (USEPA Method 7471); METHODS: Residual Hg (USEPA Method 7471); Leaching Hg (USEPA Method 1311).Leaching Hg (USEPA Method 1311).

Capsule:Capsule: Residual HgResidual Hg Leached Hg – P/FLeached Hg – P/F(mg / capsule)(mg / capsule) (mg / L / capsule)(mg / L / capsule)

Dispersalloy Regular SetDispersalloy Regular Set 1.255 ± 0.7931.255 ± 0.793 0.0477 (P)0.0477 (P)Valliant PhDValliant PhD 0.770 ± 0.3300.770 ± 0.330 0.0261 (P)0.0261 (P)OptaloyOptaloy 0.650 ± 0.6440.650 ± 0.644 0.0340 (P)0.0340 (P)MegalloyMegalloy 0.590 ± 0.5040.590 ± 0.504 0.0399 (P)0.0399 (P)Valliant Snap SetValliant Snap Set 0.534 ± 0.3980.534 ± 0.398 0.0425 (P)0.0425 (P)Tytin Regular SetTytin Regular Set 0.266 ± 0.1840.266 ± 0.184 0.0104 (P)0.0104 (P)Tytin FCTytin FC 0.223 ± 0.1200.223 ± 0.120 0.1640 (P)0.1640 (P)Contour Self-ActivatingContour Self-Activating 0.181 ± 0.1210.181 ± 0.121 0.4120 (F)0.4120 (F)Sybraloy Regular SetSybraloy Regular Set 0.142 ± 0.1630.142 ± 0.163 0.2530 (F)0.2530 (F)Tytin Regular SetTytin Regular Set 0.125 ± 0.0630.125 ± 0.063 0.0110 (P)0.0110 (P)

Non-Contact AmalgamNon-Contact Amalgam

Spent fixer,Spent fixer,glycerine, glycerine, or wateror water

Unused amalgamUnused amalgamand mercury collectionand mercury collection

Pass-through Pass-through jar lidjar lid

Rubber damRubber damwith slitwith slit

Hg VaporHg Vapor

Hg Spill KitsHg Spill Kits

Spills = small; medium; largeSpills = small; medium; largeSpills = accidents; daily micro-spillsSpills = accidents; daily micro-spills

Hg-Spill KitHg-Spill Kit

AmalgamAmalgamStorageStorage

HG HYGIENEHG HYGIENE PLUMBINGPLUMBING

AmalgamAmalgamMixingMixing

• CapsulesCapsules• Non-Contact HgNon-Contact Hg

60%60% Large Particles Large Particles >100 >100 mm

30%30% Small ParticlesSmall Particles 10-100 10-100 mm

10%10% Very Small Particles,Very Small Particles, <10 <10 mmLiquid, and VaporLiquid, and Vapor

Sink TrapsSink Trapsand Plumbingand Plumbing SEWERSEWER

SeparatorSeparator

Vacuum PumpVacuum PumpFilter or TrapFilter or Trap

Vacuum PumpVacuum Pump

SEWERSEWER

SEWERSEWER

Suction / Mini-TrapSuction / Mini-Trap

Chairside FilterChairside Filter

Amalgam/Hg SeparatorsAmalgam/Hg Separators

Amalgam Separator:Amalgam Separator: EMPTY EMPTY FULLFULL Total Effluent HgTotal Effluent Hg(% Efficiency)(% Efficiency) (% Efficiency)(% Efficiency) (ppb, range)(ppb, range)

A1000A1000 96.09 ± 0.3996.09 ± 0.39 96.24 ± 0.4696.24 ± 0.46 30,200 - 34,89930,200 - 34,899Amalgam CollectorAmalgam Collector 99.89 ± 0.0699.89 ± 0.06 99.96 ± 0.0399.96 ± 0.03 1,180 - 3,350 1,180 - 3,350AsdexAsdex 99.10 ± 0.0999.10 ± 0.09 99.36 ± 0.1499.36 ± 0.14 9,930 - 15,750 9,930 - 15,750BullfroHgBullfroHg 98.88 ± 0.6498.88 ± 0.64 99.38 ± 0.4899.38 ± 0.48 5,850 - 16,270 5,850 - 16,270Durr 7800/7801Durr 7800/7801 98.06 ± 1.0898.06 ± 1.08 97.66 ± 0.3597.66 ± 0.35 970 4,070 970 4,070ECO IIECO II 98.17 ± 0.4398.17 ± 0.43 97.51 ± 0.7497.51 ± 0.74 16,310 - 26,34016,310 - 26,340HgSHgS 99.36 ± 0.1599.36 ± 0.15 99.28 ± 0.1099.28 ± 0.10 6,430 - 9,600 6,430 - 9,600Hg10Hg10 99.99 ± 0.0699.99 ± 0.06 (not tested)(not tested) 20 - 100 20 - 100MRUMRU 99.96 ± 0.0399.96 ± 0.03 99.95 ± 0.0499.95 ± 0.04 200 - 570 200 - 570MSS 2000MSS 2000 99.66 ± 0.3099.66 ± 0.30 98.94 ± 0.06 98.94 ± 0.06 730 - 4,040 730 - 4,040Rasch 890-4000Rasch 890-4000 99.93 ± 0.0399.93 ± 0.03 99.90 ± 0.0399.90 ± 0.03 600 - 1,250 600 - 1,250 RME 2000RME 2000 99.67 ± 0.1399.67 ± 0.13 99.66 ± 0.2499.66 ± 0.24 1,530 - 3,430 1,530 - 3,430

Fan PL, Batchu H, Chou HN, Gasparac W, Sandrik J, Meyer DM. Laboratory evaluation of amalgam Fan PL, Batchu H, Chou HN, Gasparac W, Sandrik J, Meyer DM. Laboratory evaluation of amalgam separators. separators. J Am Dent AssocJ Am Dent Assoc 2002; 133: 577-589. 2002; 133: 577-589.

OBJECTIVE: Remove amalgam and/or mercury OBJECTIVE: Remove amalgam and/or mercury from air/water stream in HVAC system.from air/water stream in HVAC system.

METHODS: ISO 11143 for Amalgam Separators.METHODS: ISO 11143 for Amalgam Separators.

Hg Release from AmalgamHg Release from AmalgamChemical and Electrochemical Corrosion Chemical and Electrochemical Corrosion NO Hg RELEASED NO Hg RELEASED

a.a. Low-copper dental amalgam:Low-copper dental amalgam:[Sn-Hg] [Sn-Hg] [Sn] + saliva [Sn] + saliva [Sn-O-Cl] [Sn-O-Cl] (soluble)(soluble)

[Sn] + saliva[Sn] + saliva [Sn-O] [Sn-O] (insoluble)(insoluble) [Hg] + [Sg-Sn][Hg] + [Sg-Sn] [Sg-Hg] + [Sn+Hg] [Sg-Hg] + [Sn+Hg] (more rx)(more rx)

b.b. High-copper dental amalgam:High-copper dental amalgam:[Cu-Sn][Cu-Sn] [Sn] + saliva [Sn] + saliva [Sn-O-Cl] [Sn-O-Cl] (soluble)(soluble)

[Sn] + saliva[Sn] + saliva [Sn-O] [Sn-O] (insoluble) (insoluble) [Cu] + saliva[Cu] + saliva [Cu-Cl] [Cu-Cl] (soluble)(soluble)

Company:Company: Location:Location: Telephone NumberTelephone Number

SOLMETEXSOLMETEX (Northburough, MA)(Northburough, MA) 978-262-9690978-262-9690DRNA DRNA (Hackensack,NJ)(Hackensack,NJ) 800-360-1001800-360-1001Max. Separ. Systems Max. Separ. Systems (Sanichton, BC)(Sanichton, BC) 800-799-7147800-799-7147AB Dental Trends AB Dental Trends (Lynden, WA) (Lynden, WA) 360-354-4722 360-354-4722 Rebec Rebec (Edmonds, WA) (Edmonds, WA) 800-569-1088 800-569-1088 Air Techniques Inc. Air Techniques Inc. (Hicksville, NY) (Hicksville, NY) 800-Air-Tech800-Air-Tech

Current Separator TechnologiesCurrent Separator Technologies

http://http://www.ncddental.orgwww.ncddental.org

P.O. Box 1069P.O. Box 1069Hackensack, NJ 07601Hackensack, NJ 076011-800-360-1001 (TEL)1-800-360-1001 (TEL)1-201-489-4740 (FAX)1-201-489-4740 (FAX)

SEWER 99+ %99+ %

SolmeteXSolmeteX29 Cook Street29 Cook StreetBillerica, MA 01821Billerica, MA 01821TEL = 978-262-9690TEL = 978-262-9690FAX = 978-262-9889FAX = 978-262-9889

$695 for installation$695 for installation$150 per cartridge exchange$150 per cartridge exchange

99.5% recovery is typical99.5% recovery is typical

SOLMETEXSOLMETEX

Air-Water SeparatorAir-Water Separator

Filter and Hg AbsorberFilter and Hg Absorber

DETECTION OF HgDETECTION OF Hg

DENTALDENTALOFFICEOFFICE

Work Place Monitoring:Work Place Monitoring:Air sampling -- 3M badgesAir sampling -- 3M badgesAir sampling -- Jerome Hg analyzerAir sampling -- Jerome Hg analyzer

Patient Monitoring:Patient Monitoring:Intraoral air measurementsIntraoral air measurementsPatch testing (by dermatologist or allergist)Patch testing (by dermatologist or allergist)Immune system testsImmune system tests

Dental Personnel Monitoring:Dental Personnel Monitoring:Air sampling -- 3M badgesAir sampling -- 3M badgesBlood testsBlood testsUrine testsUrine testsHair testsHair tests

HOMEHOMEENVIRONMENTENVIRONMENT

Hg ROAD MAPHg ROAD MAP

FDAFDA

Safety,Safety,EfficacyEfficacy• Patients• Personnel

TRASHTRASH

SanitarySanitaryLandfillLandfill(audits)(audits)

IncineratorIncinerator(audits)(audits)

RECYCLINGRECYCLINGPLANTPLANT(audits)(audits)

EPA / NCDENREPA / NCDENR

BMP’sBMP’s

• PurchasePurchase• StorageStorage• UsageUsage• Non-ContactNon-Contact• FiltersFilters• Training, SpillsTraining, Spills

OSHA / ADAOSHA / ADA

• Leach Field• Stream Dumping

• Burning• Land Spreading

WASTE-WATER

TREATMENTPLANT

CITY / EPACITY / EPA

HgHg

OFFICEOFFICEPLUMBINGPLUMBING

• [Chairside Filter]• [Vacuum SystemSystem and Trap]• Separators• Flushing Plumbing Lines

PR

OC

ED

UR

ES

/ 1

00

pts

200

1960 1970 1980 1990 2000 2010

0

50

100

150

DATE (year)

Total Amalgams

New Amalgams

PRESENT

The US Food and drug administration has this to say about international acceptance of dental amalgam:

"The safety of dental amalgams has been reviewed extensively over the past ten years, both nationally and internationally. In 1994, an international conference of health officials concluded there is no scientific evidence that dental amalgam presents a significant health hazard to the general population, although a small number of patients had mild, temporary allergic reactions. The World Health Organization (WHO), in its Consensus Statement on Dental Amalgam reached a similar conclusion. They wrote: "Amalgam restorations are safe and cost-effective. Components in dental restorative materials, including amalgam, may, in rare instances, result in local side-effects or allergic reactions. The risk of adverse side-effects is very low for all types of restorative materials, including amalgam and all resin-based materials.” Similar conclusions were reached by the United States Public Health Service, the European Commission, the National Board of Health and Welfare in Sweden, the New Zealand Ministry of Health, Health Canada and the province of Quebec."

Dental amalgam is NOT banned in any state in the US or in any Western country. However, legislation to ban it exists all over the map. The legislation is not the work of scientists. It is the work of anti-amalgamists pushing a political, not a scientific agenda, and the fact that it is not passed into law is because there is no scientific evidence that it is harmful to the general public and lots of evidence that

Making a amalgam restoration might be considered to be a chain process.

The strength of a chain depends upon its weakest link.

Misjudgment of its properties or the smallest neglect as to its manipulation might have unfavorable effects with regard to the restoration & even result in its total failure.

A.D.A & F.D.A state that use of amalgam is safe scientifically

Mercury and the American Dental Association

The American Dental Association (ADA) continues to remain in denial about the toxicity of mercury.

A news release by the American Dental Association (ADA) on June 13, 2001 contains a significantly erroneous statement. The American Dental Association (ADA) President Dr. Robert M. Anderton is reported as saying,

"There is no sound scientific evidence supporting a link between amalgam fillings and systemic diseases or chronic illness''. However, it is a well known fact in the published, peer-

reviewed dental journals that mercury leaks directly from amalgam into adjacent oral tissues causing periodontal disease (gum disease).

Dr. Murray Vimey is one of the top mercury researchers in the world and he has provided a detailed chronology documenting how mercury has been clearly established as a contributing factor for periodontal disease. Dr. Vimy is one of the leading mercury researchers and his rebuttal to the ADA press release is most informative:

Fact #1: In 1957, Zander (JADA, 55:11-15) reported "materials used in restorative dentistry may be a contributing factor in gingival disease. "Fact #2: In 1961, App (J Prosth Dent 11:522-532) suggested that there was greater chronic inflammation around amalgam sites than non-amalgam areas .Fact #3: In 1964, Trott and Sherkat (J CDA, 30:766-770) showed that the presence of mercury amalgam correlates with gingival disease. Such disease was not present at contralateral amalgam-free sites. Fact #4: In 1969, Sanches Sotres et al (J. Periodo. l40: 543-546) confirmed Trott and Sherkat findings .Fact #5: In 1972, Turgeon et al. (J CDA 37:255-256) reported the presence of very significant erythema around amalgam restorations which was not present at control non-amalgam sites.

Fact #6: In 1973, Trivedi and Talim (J. Prosth. Dentistry, 29:73-81) demonstrated that 62% of amalgam sites have inflammatory periodontal tissue reaction.

Thus, as early as 1973, a case can be made that the presence of dental mercury-amalgam results in chronic inflammation and bleeding in the gingival tissue adjacent to it; in other words, 'in situ' amalgamproduced chronic Gingivitis.

Fact #7: In 1974, Freden et al. (Odontol. Revy, 25: 207-210) showed that gingival biopsy material from sites not adjacent to amalgam had 1-10 µg mercury/gram of tissue (mean=3); whereas, gingival biopsy sites near amalgams contained 19-380 µg mercury/gram of tissue (mean=147).

Fact #8: In 1976, Goldschmidt et al (J. Perio. Res., 11:108-115) demonstrated that amalgam corrosion products were cytotoxic to gingival cells at concentrations of 10-6; that is, micrograms/gram of tissue.

Fact #9: In 1984, the year of the NIDR/ADA Workshop, Fisher et al (J Oral Rehab, 11:399-405) reported that at amalgam sites alveolar bone loss was very pronounced and statistically significant as compared to control non-amalgam sites. In other

Therefore, for the American Dental Association (ADA) to conclude "There is no sound scientific evidence supporting a link between amalgam fillings and systemic diseases or chronic illness'' is not correct.

THANK YOU

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Dental Amalgam