This document provides an overview of dental amalgam, including its:
- Classification based on composition and particle shape
- Generations and typical compositions
- Properties including strength, creep, corrosion resistance
- Toxicity and mercury levels
- Manipulation techniques for mixing, condensing, and finishing amalgam restorations
- Status and concerns about mercury levels from dental offices
Soldering and welding are the integral part of dentistry specially in prosthodontics and crown and bridge procedure. it is also used in implant supported prosthetic.
Soldering and welding are the integral part of dentistry specially in prosthodontics and crown and bridge procedure. it is also used in implant supported prosthetic.
THE GIVEN PRESENTATION IS PREPARED FROM PHILIPS SCIENCE OF DENTAL MATERIALS- ANUSAVICE BY DR.SWARNEET KAKPURE [MDS-CONSERVATIVE DENTISTRY AND ENDODONTICS]
DR. SWARNEET KAKPURE (DEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS)
THE TOPIC PRESENTED IN SEMINAR COVERS ALMOST ALL THE ASPECTS OF COMPLEX AMALGAM RESTORATIONS INCLUDING PIN RETAINED,SLOT RETAINED AMALGAM RESTORATIONS,CEMENTED,FRICTION LOCKED & SELF THREADING PINS, TMS SYSTEM,AMALGAM FOUNDATIONS ALONG WITH TECHNIQUES OF INSERTION AND MATRIX PLACEMENT.
An inlay may cap none, or may cap all but one cusp.
Sturdevant’s 4th ed. page579
Inlays may be used as single-tooth restorations for proximo-occlusal or gingival lesions with minimal to moderate extensions
Shillingburg page 1
An inlay may be defined as a restoration which has been constructed out of mouth from gold, porcelain, or other material & then cemented into the prepared cavity of a tooth.
William McGehee pg410
The cast metal restoration is versatile and is especially applicable to Class II onlay preparations. The process has many steps, involves many dental materials, and requires meticulous attention to prepration.
Tooth treatment planned to be restored with an intracoronal restoration, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would not be able to sustain or bear forces.
Additionally, when decay or fracture incorporate areas of cusp or remaining tooth structure that undermines perimeter walls of a tooth, an onlay might be indicated.
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
THE GIVEN PRESENTATION IS PREPARED FROM PHILIPS SCIENCE OF DENTAL MATERIALS- ANUSAVICE BY DR.SWARNEET KAKPURE [MDS-CONSERVATIVE DENTISTRY AND ENDODONTICS]
DR. SWARNEET KAKPURE (DEPT OF CONSERVATIVE DENTISTRY AND ENDODONTICS)
THE TOPIC PRESENTED IN SEMINAR COVERS ALMOST ALL THE ASPECTS OF COMPLEX AMALGAM RESTORATIONS INCLUDING PIN RETAINED,SLOT RETAINED AMALGAM RESTORATIONS,CEMENTED,FRICTION LOCKED & SELF THREADING PINS, TMS SYSTEM,AMALGAM FOUNDATIONS ALONG WITH TECHNIQUES OF INSERTION AND MATRIX PLACEMENT.
An inlay may cap none, or may cap all but one cusp.
Sturdevant’s 4th ed. page579
Inlays may be used as single-tooth restorations for proximo-occlusal or gingival lesions with minimal to moderate extensions
Shillingburg page 1
An inlay may be defined as a restoration which has been constructed out of mouth from gold, porcelain, or other material & then cemented into the prepared cavity of a tooth.
William McGehee pg410
The cast metal restoration is versatile and is especially applicable to Class II onlay preparations. The process has many steps, involves many dental materials, and requires meticulous attention to prepration.
Tooth treatment planned to be restored with an intracoronal restoration, but the decay or fracture is so extensive that a direct restoration, such as amalgam or composite, would not be able to sustain or bear forces.
Additionally, when decay or fracture incorporate areas of cusp or remaining tooth structure that undermines perimeter walls of a tooth, an onlay might be indicated.
Dental Ceramics and Porcelain fused to metal isabel
Dental porcelain (also known as dental ceramic) is a dental material used to create biocompatible lifelike dental restorations, such as crowns, bridges, and veneers.
Dental amalgam /certified fixed orthodontic courses by Indian dental academy Indian dental academy
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Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Lung Cancer: Artificial Intelligence, Synergetics, Complex System Analysis, S...Oleg Kshivets
RESULTS: Overall life span (LS) was 2252.1±1742.5 days and cumulative 5-year survival (5YS) reached 73.2%, 10 years – 64.8%, 20 years – 42.5%. 513 LCP lived more than 5 years (LS=3124.6±1525.6 days), 148 LCP – more than 10 years (LS=5054.4±1504.1 days).199 LCP died because of LC (LS=562.7±374.5 days). 5YS of LCP after bi/lobectomies was significantly superior in comparison with LCP after pneumonectomies (78.1% vs.63.7%, P=0.00001 by log-rank test). AT significantly improved 5YS (66.3% vs. 34.8%) (P=0.00000 by log-rank test) only for LCP with N1-2. Cox modeling displayed that 5YS of LCP significantly depended on: phase transition (PT) early-invasive LC in terms of synergetics, PT N0—N12, cell ratio factors (ratio between cancer cells- CC and blood cells subpopulations), G1-3, histology, glucose, AT, blood cell circuit, prothrombin index, heparin tolerance, recalcification time (P=0.000-0.038). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and PT early-invasive LC (rank=1), PT N0—N12 (rank=2), thrombocytes/CC (3), erythrocytes/CC (4), eosinophils/CC (5), healthy cells/CC (6), lymphocytes/CC (7), segmented neutrophils/CC (8), stick neutrophils/CC (9), monocytes/CC (10); leucocytes/CC (11). Correct prediction of 5YS was 100% by neural networks computing (area under ROC curve=1.0; error=0.0).
CONCLUSIONS: 5YS of LCP after radical procedures significantly depended on: 1) PT early-invasive cancer; 2) PT N0--N12; 3) cell ratio factors; 4) blood cell circuit; 5) biochemical factors; 6) hemostasis system; 7) AT; 8) LC characteristics; 9) LC cell dynamics; 10) surgery type: lobectomy/pneumonectomy; 11) anthropometric data. Optimal diagnosis and treatment strategies for LC are: 1) screening and early detection of LC; 2) availability of experienced thoracic surgeons because of complexity of radical procedures; 3) aggressive en block surgery and adequate lymph node dissection for completeness; 4) precise prediction; 5) adjuvant chemoimmunoradiotherapy for LCP with unfavorable prognosis.
4. Amalgam –
Dental amalgam is a metal like restorative
material composed of mixture of Ag/Sn/Cu alloy
and mercury
Almost 80% of dental restorations.
Reasons:
Ease of use
Self sealing ability
High compressive strength
Excellent wear resistance
Dentist friendly technique
Low cost than composite restoration
6. According to presence or
absence of Zinc
Zinc-containing alloys:
More than 0.01% Zn.
Zinc-free alloys:
Less than 0.01% Zn.
According to Copper
content
Low Copper alloys
(2-4% Cu)
High copper alloys
(13-30% Cu)
Admixed alloy
(LowCu + Ag-Cu eutectic)
Unicompositional alloy
According to number of
metals in the alloy
Binary : Ag; Sn
Ternary : Ag; Sn; Cu
Quarternary : Ag;
Sn;Cu;In
According to the shape
and size of alloy particles
Spherical (Smooth shaped
spheres)
Spheroidal (Irregular shaped
spheres)
Lathe-cut (Irregular shavings
or filings)
Micro-cut
Fine-cut
Coarse cut
8. 1st generation amalgam alloys
G.V.Black's formulation of 3parts Ag and 1 part sSn.
peritectic alloy
2nd generation amalgam alloys
Addition of 4% Cu (to ↓ plasticity and ↑strength) and
upto 1% Zn (scavenger and ↓ brittleness)
3rd generation amalgam alloys
1st gen + Ag-Cu eutectic spherical alloy.
9. 4th generation amalgam alloys
Ternary alloys - Alloying of Cu upto 29%toAg and Sn
to form Ag2CuSn.
5th generation amalgam alloys
Quarternary alloys - Ag, Sn, Cu, and Indium
6th generation amalgam alloys
Ag-Cu-Pd eutectic alloy (62%, 28%, and 10%
respectively) is added in a ratio of 1:2 to low Cu alloy.
This has the highest nobility.
13. Other alloys
Hybrid alloys: Spherical particles of a ternary
Ag-Sn-Cu alloy with lathe-cut particles
containing Ag3Sn or Ag-Sn-Cu.
Fluoridated amalgam alloys: Fluoride is added
for anticariogenicity.
Pre amalgamated alloys: Mercury used is less
than 3%. Alloy particles are coated with
mercury so that they become self
condensable.
Noble metal amalgam alloys: Contain Au and/or
Pd for good corrosion resistance.
19. Dimensional change
Three stages of setting reaction:
initial contraction, then expansion and finally
limited delayed contraction.
Factors causing expansion: Expansion >> 4%
More gamma phase and tin
More Hg
Larger particle size
More energy of trituration
Lesser condensation forces
Moisture contamination for Zn alloys
20. Dimensional change
Most high-copper amalgams undergo a net
contraction.
contraction : Contraction < than 50µ/cm
type of alloy
spherical alloys have more
contraction due to lesser mercury
condensation technique
greater condensation = higher contraction
trituration time
overtrituration causes higher contraction
21. 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.
Minimum thickness required 1 to 1.5 mm.
22. Strength
Factors decreasing strength:
Temperature increase
Excess mercury and porosity
Factors Increasing strength:
More trituration and condensation energy.
Regular size, shape of particle and dispersion.
More ϒ and ϒ1 phase and lesser ϒ2.
23. Creep
Slow deformation of amalgam placed under a constant load leads
to marginal breakdown - load less than that necessary to produce
fracture.
Factors :
Gamma 2 dramatically affects creep rate.
allows gamma-1 grains to slide
Excess mercury and temperature rise increase it.
Over/under trituration increases it.
Dispersion can reduce it.
Increased condensation force reduces it.
24. 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) aroundAg-Cu particles
improves bonding to gamma 1
25. Electrochemical corrosion
occurs whenever
chemically different sites
act as anode & cathode
It requires the site to be
connected by an electrical
circuit in the presence of an
electrolyte eg saliva
The anode corrodes ,
producing soluble and
insoluble corrosion reaction
products
MECHANISM OF ELECTRO CHEMICAL CORROSION
27. Biological properties
The pulp needs to be protected from
amalgam due to its chemical, thermal,
electrical and physical nature.
Mercury can discolor dentinal tubules,
damage odontoblasts.
There should be an optimum barrier of ≥2mm
between pulp and amalgam.
28. Hypersensitivity
Type IV or cell-mediated immune response
Contact dermatitis
Lichenoid lesions adjacent to
amalgam
Most reactions subside
amalgam removal usually not necessary
True allergy is rare
< 1%
33. Amalgam Waste
Mercury is a naturally occurring metal
Half of environmental mercury comes from
human activity----< 1% dentistry.
52%
34%
13% <1%
Fuel Combustion
Waste Combustion
Manufacturers
Dentistry
34. Dental Hygeine mercury
Recommendation
Education to all persons involved in handling
the amalgam
Using a mercury spill kit
Reacting unused elemental Hg with Ag to
form scrap amalgam
Not throwing Hg to garbage or SINK
Use hi-volume evacuation when finishing or
removing amalgam
35. Floor coverings should be nonabsorbent , seamless & easy
to clean
Work in well ventilated spaces
Use an amalgammator with enclosed arm
Cleanup spilled mercury , dont use house hold vaccum
cleaner
Remove prof clothing b4 leaving the workplace
Regularly check the dental operatory atm. Dosimeter & Hg
vapor analyzer may be used
Current limit for Hg vapor is 50µg/m3 in an 8hr work shift
ovr a 40hr work week
37. Alloy selection
Alloy should be ADA/FDA certified.
Metallurgical modifications determine working
and setting time as well as strength.
Spherical particle are good for early strength but
requires a fast operator and are not good for
inaccesible contours.
Non zinc alloys should be used only in conditions
of impossible isolation.
Best mechanical properties are exhibited by
HCU alloys.
38. Difference in manipulation:
LATHE CUT
Require more mercury
(50%)
Require more
condensation force
Overtrituration
increases strength
Undertrituration
decreases creep
Require smaller
condenser points
Less ease in carving
and burnishing
SPHERICAL
Require less mercury
(42%)
Require less
condensation force
Overtrituration
decreases strength
Undertrituration
increases creep
Require broader
condenser points
Smooth surface during
carving & burnishing
40. Proportioning
Proportioning should be done by wt. if possible.
Mercury Alloy ratio
Lathe cut alloys 1:1 or Eames ratio (50% Hg)
Spherical alloys 40.0% Hg
High copper alloys 43.0% Hg
Low copper alloys 53.7% Hg
Alternatives of dispensing:
Automatic mechanical dispensers
Preweighed pellets
Preproportioned capsules
41. Techniques
i. High Hg or increasing dryness technique
useful for large and complex restorations.
ii. Minimal mercury or Eame’s technique
beneficial to minimise Hg content.
42. Trituration
Trituration is the process by which mercury
is allowed to react with the alloy powder .
This procedure allows the rubbing of the
surface oxide on amalgam particles ,
exposing an active surface to react with
mercury .
Hand trituration
Mechanical trituration
43. Amalgamator (Triturator)
Speeds vary upward
from 3000 rpm
Times vary from 5–20
seconds
Mix powder and liquid
components to achieve
a pliable mass
Reaction begins after
components are mixed
44. 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
45. Effect of over-trituration and
under-trituration
Working time decreases with over- trituration.
Setting contraction increases with over- trituration.
Compressive and tensile strengths increase with over-
trituration of lath cut alloys;
however they decrease with over- and under-
trituration of spherical alloys.
Creep increases with over- trituration.
46.
47. Mulling
It’s a continuation of trituration to form a
coherent mass easy to manage.
The mix is rubbed between fingers in a dry
rubber dam for 2 to 5 sec.
For capsule it is done in the amalgamator for
2 to 3 sec after removing the pestle.
48. Condensation
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
49. Condensation
Usually only 3 to 3.5 minutes is available for
condensation.
After that the mix should be discarded.
At least force required for adequate
condensation. : 3 to 4 lbs. For this pressure,
force at the tip of the condenser point of 2
mm diameter is around 600 -800 psi.
Types- hand and mechanical or pneumatic.
50. Burnishing
Pre-carve
removes excess mercury
improves margin adaptation
Done with large burnisher
Post-carve
improves smoothness
Done with smaller burnisher
Inaccessible areas should be done by
beavertail
Done from amalgam to tooth surface.
51. Carving
Aims to reproduce physiologic contours.
Done with sharp instruments.
Strokes given from tooth to amalgam or
laterally along tooth surface.
52. Early Finishing
After initial set
prophy cup with pumice
provides initial smoothness to restorations
recommended for spherical amalgams
53. Finishing and polishing
Done usually after 24 hrs.
FINISHING: abrasive stones, rubber cups, or
rotary brushes.
POLISHING: with extrafine silex, slurry of chalk,
SnO, ZnO, or pumice-wet mix in a paste form
to avoid heat generation.
54. Factors for success
Osborne and Gale evaluated 196 amalgam
restorations 13–14 years after insertion.
They found that cavity width was the single
most significant factor for clinical survival.
Wider restorations showed greater marginal
fracture and a higher rate of replacement than
narrow restorations.
Reasons include reduced occlusal stress on the
margins and preservation of tooth strength.
55. SUBSTITUTES
1. CONSOLIDATED SILVER ALLOY SYSTEM.
It uses a fluoroboric acid solution to keep the
surface of the silver alloy particles clean.
The alloy strain hardens, so it is difficult to
compact it adequately to eliminate internal
voids and to achieve good adaptation to the
cavity without using excessive force.
56. 2. GALLIUM ALLOYS
1956, Smith and Caul and Smith and co-workers
claimed gallium as an alternate to mercury.
Mixing gallium with either nickel or copper and
tin produced a pliable, condensable mass.
Physical, mechanical properties suitable for a
restorative material.
Early moisture sensitivity, excessive expansion.
Toxic corrosion products accumulate on surface.
57. 3. MODIFIED COMPOSITES
Packable composites
Nanocomposites
Fiber reinforced composites
Lab processed inlay, onlay or crown
4. All ceram restorations
5. Metal alloys
6. GIC modifications
59. Story begins ......
Amalgam -- First used by Chinese.There is a mention of
silver mercury paste by Sukung (659AD) in the Chinese
medic
1578-lshitichen used 100 parts if Hg, 45 parts ofAg and 100
parts of Sn
LiuWen-Thai (1508) and Li Shih-Chen (1578) discussed its
formulation; 100 parts of mercury to 45 parts of silver and
900 parts of tin, trituration of these ingredients produced a
paste said to be as solid as silver
60. Introduced in 1800’s in France alloy of
bismuth, lead, tin and mercury plasticized at
100ºC poured directly into cavity
1819, Bell advocated the use of a room
temperature mixed amalgam as a restorative
material, in England
1826, M.Traveau is credited with advocating
the first form of amalgam paste , in France.
61. 1833 Crawcour brothers introduced amalgam to
US > powdered silver coins mixed with mercury
expanded on setting
1895 To overcome expansion problems G.V.
Black developed a formula for modern amalgam
alloy > 67% silver, 27% tin, 5% copper, 1% zinc
Black’s formula was well accepted and not much
changed for nearly sixty years.(1890-1963)
1946 - Skinner, added copper to the amalgam
alloy composition in a small amount.This served
to increase strength and decrease flow.
62. Traditional or conventional amalgam alloys
predominated from 1900 to 1970.
1960’s - conventional low-copper lathe-cut alloy
was introduced
1962 - A spherical particle dental alloy was
introduced, by Demaree andTaylor
The work of Innes andYoudeis (1963) has led to
the development of high copper alloys.>Had
longer working time, less dimensional change,
easy to finish, set faster, low residual mercury,
low creep & higher early strength
63. Added spherical silver copper eutectic
alloy(71.9wt% Ag and 28.1wt%Cu)particles to
lathe cut low copper amalgam alloy particles.
These alloys are called admixed alloys
1971 – Johnson designed a spherical particle
alloy having the composition 64% Ag, 26% Sn
and 10% cu by weight, and exhibiting no
Sn8Hg after amalgamation.
1973 - first single composition spherical alloy
namedTytin (Kerr) a ternary system
(silver/tin/copper) was discovered by Kamal
Asgar of the University of Michigan
64. 1980’s alloys similar to Dispersalloy andTytin
was introduced
65. Social consideration
The first dental society, the American Society
of Dental Surgeons (ASDS), was founded in
1840 on the basis of the physician-surgeons
taking a stance against the use of amalgam
which it regarded as being unethical due to
the recognised toxic effects of mercury.
66. Amalgam WARS
1st amalgam war : American society of dental surgeons
condemmed the use of all filling materials other than gold as
toxic , therby igniting the 1st amalgam war
2nd amalgam war : In mid 1920 a german dentist named alfred
stock started the so called 2nd amalgam war . He claimed to
have evidence showing mercury from dental amalgam leads to
serious toxicity
3rd amalgam war (1970-1990) began primarily through seminars
, writing & videotapes if Dr HA huggins from colorado springs .
Pressure from mounting clinical evidence forced the ADA to
finally publicly concede that mercury vapour does escape from
the amalgam filling into the patient’s mouth
67. The derogatory term 'quack'
(from quecksilber, the German word
for mercury) was originally coined by
the physicians to refer to the
tradesmen who used amalgam fillings.
68. The Rise
The American Dental Association (ADA),
founded in 1859 actively promoted the use of
amalgam, for which it currently owns the
patents (U.S. Patents 4018600 and 4078921).
In 1877, J. Foster Flagg, managed to change the
attitude toward dental amalgams. He published
the results of his laboratory tests and 5-year
clinical observation of new alloys with 60% of
silver and 40% of tin as major constituents in
1881 and thus predated by some 15 years the
work of G.V. Black.
69. S.S.White manufactured the first
commercial alloy rich in silver,True Dentalloy
(1900), in which gold was replaced by copper.
70. Anti-Amalgamists
Dentists specialize in treating purported mercury
toxicity--becomes a marketing tool
Hal Huggins
publications, videotapes
and seminars
removal of amalgam cures
Leukemia
Hodgkins’disease
Multiple Sclerosis
71.
72. The debate goes on
The debate over the safety and efficacy of
amalgam has raged since time immemorial BUT
Amalgam has served the dental profession for
more than 165 years.
Incidents of true allergy to mercury have been
rare and attempts to link its usage with diseases
like multiple sclerosis and Alzheimer’s disease
have not been significantly proven, although
there may be some association between
amalgam restorations and oral lichenoid lesions.
73. Recently however, its popularity has diminished
somewhat due to aesthetics, environmental
pollution, health, and the availability of
improved, reliable, composite materials .
In particular, concerns about the toxicity of
mercury have made its use increasingly
controversial.
74. Countries banning amalgam
As of 2008, the use of dental amalgam has been banned
in Norway, Sweden and Finland, Denmark and some other
developed countries and a committee of the US Food and
Drug Administration (FDA) has refused to ratify assertions
of safety.
75. In May 2011, the 47 nations of the
Parliamentary Assembly of the Council of
Europe passed a resolution calling for all
member nations to start "restricting or
prohibiting the use of amalgams as dental
fillings".
76. United States
In US, three Californian cities have banned
amalgam.
And many others are phasing down
77. RESEARCHES….
In 2004, the Life Sciences Research Office
analyzed studies related to dental amalgam
published after 1996. Concluding that mean
urinary mercury concentration was the most
reliable estimate of mercury exposure
78. However,WHO states mercury levels in
biomarkers such as urine, blood, or hair do not
represent levels in critical organs and tissues.
Additionally, Gattineni et al. found that mercury
levels do not correlate with the number or
severity of symptoms. It concluded that there
was not enough evidence to support or refute
many of the other claims such as increased risk
of autoimmune disorders, but stated that the
broad and nonspecific illness attributed to dental
amalgam is not supported by the data.
79. Scientists agree that dental amalgam fillings
leach mercury into the mouth, but studies
vary widely in the amount and whether such
amount presents significant health risks.
Estimations run from 1-3 micrograms (µg)
per day (FDA) up to 27 µg/day (Patterson).
The effects of that amount of exposure is also
disputed.
80. ANIMAL STUDIES
Research on monkeys has shown that mercury
released from dental amalgam restorations is
absorbed and accumulates in various organs such as
the kidney, brain, lung, liver, gastro-intestinal tract,
the exocrine glands.
It was also found to have crossed the placental barrier
in pregnant ratsand shown to cross the
gastrointestinal mucosa when amalgam particles are
swallowed after amalgam insertion or after removal
of old amalgam fillings.
81. HEALTH RISKS
Review published in 2005 by the Freiburg
University Institute for Environmental Medicine
found that
"mercury from dental amalgam may lead
to nephrotoxicity, neurobehavioural
changes, autoimmunity, oxidative stress, autism,
skin and mucosa alterations or non-specific
symptoms and complaints", that "Alzheimer's
disease or multiple sclerosis has also been linked to
low-dose mercury exposure", and that "removal of
dental amalgam leads to permanent improvement
of various chronic complaints in a relevant number
of patients in various trials."
82. Maths Berlin 2002 study concludes:
mercury is a multipotent toxin with effects on several levels of the
biochemical dynamics of the cell, amalgam must be considered to
be an unsuitable material for dental restoration.
This is especially true since fully adequate and less toxic
alternatives are available.
With reference to the risk of inhibiting influence on the growing
brain, it is not compatible with science and well-tried experience
to use amalgam fillings in children and fertile women.
Every doctor and dentist should, where patients are suffering
from unclear pathological states and autoimmune diseases,
consider whether side-effects from mercury released from amalgam
may be one contributory cause of the symptoms.
83. Occupational Exposure
UK published in the Occupational and
Environmental Medicine Journalconcluded that
dentists had on average 4 times the urinary
mercury excretion levels of 180 people in a
control group. Dentists were significantly more
likely than control subjects to have had disorders
of the kidney or memory disturbance.
Urine testing is unreliable for showing lifetime
mercury accumulation rather than recent
exposure.
84. Environmental hazard
TheWHO reports that mercury from
amalgam and laboratory devices accounts for
53% of total mercury emissions, and that one-
third of the mercury in the sewage system
comes from dental amalgam flushed down the
drain.
Mercury is an environmental toxin and
theWorld Health Organization, OSHA,
and NIOSH have established specific
occupational exposure limits.
85. Environmental hazard
The Association of Metropolitan Sewerage
Agencies (AMSA) studied seven major waste-
water treatment plants and found that dental
uses were "by far" the greatest contributors of
mercury load, on average contributing 40%,
over 3 times the next greatest contributor
86. ADA
The ADA has asserted that dental amalgam is safe
since its foundation in 1859.
In its advisory opinion to Rule 5.A. of the ADA Code of
Ethics, it has also held that, "the removal of amalgam
restorations from the non-allergic patient for the
alleged purpose of removing toxic substances from
the body, when such treatment is performed solely at
the recommendation or suggestion of the dentist, is
improper and unethical".
87. "A dentist who is found guilty of violating the ADA
Code of Ethics can be sentenced, censured,
suspended, or expelled from the ADA" and the "ADA
forbids its dentists from suggesting mercury
removal under threat of license suspension“
Perhaps louder than its words are the actions of the
ADA which has deleted reassuring statements
about the safety of amalgam from its website.
The Center for Disease Control (CDC) has also
deleted an entire webpage refuting amalgam as a
cause of illness.
88. Conclusion of ADA report
no health consequences from exposure to such
low levels of mercury released from amalgam
restorations have been demonstrated.
there currently appears to be no justification for
discontinuing the use of dental amalgam.
89. FDI World Dental Federation
Use of Dental Amalgam
Intergovernmental Negotiating Committee 2
January 24, 2011
China, Japan
Dr. Peter Cooney
Chair, Public Health Section, FDI
Chief Dental Officer, Canada
90. FDI :Use of Dental Amalgam –
Country Example: Canada
Extensive Review led to 1996 Health Canada
Recommendations*. Now on product labels.
• Avoid in baby teeth of children if possible.
• If possible, avoid in pregnant women and people
with impaired kidney function.
• Use safe handling practices and provide
information to patients.
91. FDI Resolution – Brazil,
September 2010
FDI voice of the dental profession resolved that,
Amalgam is a safe and highly effective restorative
material.
To maintain and protect global public health, a phase
down of amalgam will be only appropriate when an
alternative and suitable restorative material is
available.
92. FDI Conclusions
Mercury from dental amalgam is a very small
component of the environmental problem
Amalgam use has continued in Canada and in 10
years we have seen a large reduction in use.
Results of blood/urine testing on Canadians
shows very low mercury exposure levels.
Increased emphasis on prevention and clear
guidelines for mercury use can safeguard the
health of the public.
93. WHO
GENEVA , Oct. 11, 2011
TheWorld Health Organization released its
long-awaited 2009 meeting report on the
"Future Use of Materials for Dental
Restorations"
PR Newswire (http://s.tt/1bMlK)
94. WHO Report
According to the report:
"Mercury is one of the ten chemicals of major
public health concern thatWHO prioritizes.
Dental amalgam is a significant source of
exposure… National, regional and global
actions, both immediate and long-term, are
needed to reduce or eliminate releases of
mercury and its compounds to the environment.
95. WHO is committed to work with the health sector and national,
regional and global health partners to:
reduce mercury exposure;
eliminate the use of mercury wherever possible;
promote the development of alternatives to the use of mercury;
lead the profession in the negotiations of the development of
the legally binding instrument on mercury.
PR Newswire (http://s.tt/1bMlK)
96. For primary (baby) teeth, theWHO report states
that, "The report makes clear that alternatives
are here today worldwide for children, who are
the ones most vulnerable to amalgam's
neurotoxic effects," "For example, (ART) is
especially suitable for children."
97. CONCLUSION
Removal of existing amalgam fillings should not be
undertaken unless there are medical reasons for
doing so.The reason is that the risk of complications
from the removal may exceed the risk of side-effects
from the amalgam. (ADA)
"For medical reasons, amalgam should be eliminated
in dental care as soon as possible.This will confer
gains in three respects:The prevalence of side-effects
from patients’ mercury exposure will decline;
occupational exposure to mercury can cease in dental
care; and one of our largest sources of mercury in the
environment can be eliminated."