Dental Amalgam presentation by Syeda Hafsa

Dental Amalgam presentation by Syeda Hafsa

1. Dental Amalgam: A Comprehensive Overview by Syeda Hafsa

2. The Introduction of Dental Amalgam: • A malgam: an amalgam is an alloy that contains mercury as one of its constituents . • Dental Amalgam: An alloy of mercury, silver, copper and tin which may also contain palladium, zinc and other elements to improve handling characteristics and clinical performance • Mercury is liquid at room temperature , it reacts with other metals that are in solid state, to form a plastic mass, which can be conveniently packed into a prepared tooth preparation .

3. Classification 1 Based on Copper content 2 Based on Zinc content 3 Based on shape of alloy particles 4 Based on number of alloy metals 5 Based on size of alloys

4. Based on Copper content: Low copper alloy (less than 6%) High copper alloy (more than 6%) Based on Zinc content: Zinc containing (more than 0.01%) Zinc free (less than 0.01%)

5. Based on shape of alloy particles: a) Lathe cut alloy (irregular ) b) Spherical alloy c) Spheroidal alloy Based on number of alloy metals: a)Binary alloy b)Ternary alloy c)Quaternary alloy Based on size of alloy: a) Microcut b)Macrocut

6. FUNCTION OF EACH CONSTITUENT •SILVER a) 2/3rd of conventional amalgam alloy b) Whitens the alloy c) Decrease the creep d) Increase the strength e ) Increase the expansion on setting f) Increase tarnish resistance •PALLADIUM a) Whitens the alloy b) Increase hardness

7. •TIN Control the reaction b/w silver and mercury Reduce hardness & strength Reduce resistance to tarnish and corrosion •COPPER a) Increase hardness & strength b) Increases setting expansion •ZINC a) Act as scavenger or deoxidizer b)Causes delayed expansion •PLATINUM a)Increase hardness & strength b) Increase tarnish resistance

8. HIGH COPPER ALLOYS LOW COPPER ALLOYS 1. COPPER CONTENT 2.MERCURY REQUIRED FOR AMALGAMATION . 3.SETTING REACTION 4.AMALGAMATION SPEED AND ENERGY 6-30 % LESS FAST SETTING REQUIRE HIGH SPEED AND ENERGY FOR AMALGAMATION <6% MORE SLOW SETTING REQUIRES LOW SPEED AND ENERGY FOR AMALGAMATION

9. HIGH COPPER ALLOYS LOW COPPER ALLOYS 5. DORMANT PHASE 6.TARNISH AND CORROSION 7. CREEP 8.COMPREHENSIVE STRENGTH 9.DIMENSIONAL CHANGE IT IS CU₆SN₅ i.e. η PHASE IT IS DUE TO COPPER RICH PHASE i.e. CU₆SN₅ LESS CREEP HIGH LESS IT IS Ag₂Hg₃ ,i.e. γ₁ PHASE. IT IS DUE TO γ₂ PHASE i.e. Sn7-8Hg₃ MORE CREEP LOW MORE

10. ADVANTAGES • Ease of use • High compressive strength • Excellent wear resistance • Favorable long-term clinical results • Economic • Can be bonded to tooth structure • Self-sealing ability

11. DISADVANTAGES • Lack of aesthetics • Less conservative • Mercury toxicity • Corrosion and galvanism • Lack of reinforcement of weakened tooth structure • Difficulty in restoring proper tooth anatomy • Do not bond to tooth structure

12. MERCURY POISONING: Mercury poisoning (also Known as hydrargyria or mercurialism) is a disease caused by exposure to mercury or its Compound. Mercury (Hg) is a heavy metal occurring in several forms, all of which can produce toxic effects in high enough doses .

13. MERCURY EXPOSURE : When Amalgam raw material being stored in use . During trituration, insertion During finishing & polishing. Removal of old restoration .

14. TOXIC EFFECTS OF MERCURY DEPENDS ON : a)Amount of exposure b)Length of exposure c)Length of mercury exposure in body d)Amount of accumulated mercury

15. HOW MERCURY ENTER THE BODY FROM AMALGAM RESTORATION: Hg released from amalgam & inhaled with 80% uptake in the lungs ↓ Hg distributes and throughout body and nervous System ↓ Hg breaks down to nonorganic mercury (Hg) ↓ Hg accumulates in the nervous system, liver and kidney .

16. TREATMENT OF MERCURY TOXICITY: Chelation therapy is the administration of chelating agents to remove heavy metals from the body . ➤ Chelation agents are chemical substances that contain molecules capable of bonding securely to minute particles of metal called ions. In addition to directly supporting vital body functions, this bonding process---called Chelation--provides a means of trapping harmful metals in your bloodstream and making them susceptible to safe excretion in urine. The process of Chelation, called Chelation therapy, is commonly used in the treatment of heavy metal poisoning