classification and reaction of dental amalgam diksha1.pptx

It is a restoretive material and it is very useful for bds dental academic

1. Good Afternoon Guided by: Dr. Unmesh Khanvilkar Dr. Siddhesh Bandekar Dr. Christeena Dr. Mrudula Sabale Dr. Janice Simpson Presented by: Diksha Kamble Bhumika Kharmate Lubna Khilji Sonali Kokare Megha Kolekar “Spread the knowledge & construct the world.”

2. CLASSIFICATION & REACTIONS OF DENTAL AMALGAM

3. CONTENTS : Introduction of Dental Amalgam Composition of Amalgam Classification of Amalgam Phases of Amalgam Basic setting reactions of amalgam Setting reactions of Amalgam

4. Introduction of Dental Amalgam Dental amalgam is a metallic restorative material composed of a mixture of mercury and silver - tin - copper alloy.

5. CONSTITUENT OF AMALGAM MERCURY Pre-amalgamation produce as a more rapid reaction SILVER Whitens the alloy Decreases creep Increases strength TIN Reduce tarnish and corrosion Reduce strength and hardness COPPER Increases hardness and strength Increases setting expansion ZINC Act as deoxidizer and scavenger Causes delayed expansion in amalgam

6. CLASSIFICATION OF AMALGAM Based on Copper content Low copper alloy High copper alloy Fine cut Spherical alloy Microfine cut Admixed alloy Based on amalgam alloy particle geometry and size Lathe –cut alloy New amalgam alloy High copper admixed alloy Based on zinc content Zinc free alloy High copper unicompositional alloy Regular cut Zinc containing alloy

7. Based on copper content Conventional or low copper amalgam : Low copper amalgam alloy contains 2-5% copper Typical modern low copper amalgam alloy may contains : a. silver - 70% b. tin – 25% c. copper – 4% d. zinc – 1%

8. 2) High copper amalgam : Contain 12-30% copper Typical high Cu amalgam alloy contain : a. silver – 60% b. tin – 27% c. copper – 13% d. zinc – 0% High copper admixed alloy – This type of alloy is known as admixed as the final alloy is a combination of lathe-cut low copper alloy along with spherical silver copper alloy. ii. High copper unicompositional alloy – Each particle in this type is made up of same composition.

9. Based on amalgam alloy particle geometry & size : TYPE OF ALLOY Lathe – cut alloy Irregular shape Spherical alloy Spherical shape Admixed alloy Combination of irregular and spherical shaped SHAPES OF PARTICLES

10. LATHE – CUT ALLOY Require more mercury (50%). They need more condensation force. Less ease in carving and burnishing. Manufactured by lathe cutting a cast ignot of an amalgam alloy. SPHERICAL ALLOY Require less mercury (42%). They need less condensation force. Undergo smooth surface during carving and burnishing. Manufactured by process called atomization.

11. ADMIXED ALLOY Blend of lathe – cut and spherical powders. The concept is to have combined advantages of both alloys. These alloys resist condensation better than spherical powders.

12. BASED ON ZINC CONTENT Zinc was added to conventional amalgam to suppress oxidation of the key elements by forming ZnO film that covers the surface of liquid alloy during manufacture. 2 types: 1. Zinc containing alloy 2. Zin free alloy

13. ZINC CONTAINING ALLOY 1% of zinc in final composition. Side effects : due to moisture before setting Zn is converted to Zn0 and H 2 gas . ZINC FREE ALLOY Non – zinc amalgam. Used as alternative. These alloys were often favored where isolation was difficult.

14. new amalgam alloy Due to mercury toxicity the new compositions of amalgam produced as mercury free or low mercury amalgam restorative materials. Alloys with gallium and indium or alloys using cold – welding techniques are presented as alternatives to mercury – containing amalgam .

15. Basic setting reactions of amalgam

16. Setting reactions of amalgam CONVENTIONAL LOW COPPER AMALGAM: This type of amalgam sets by the reaction of silver – tin from silver – tin particles with mercury to produce 2 reaction product phases: a) Gamma – 1 phase b) Gamma – 2 phase

17. Gamma phase (original alloy phase) Gamma – 1 Phase Ag – Hg crystals are generally small and forms most of the matrix Gamma – 2 Phase Sn – Hg crystals are long and blade like Constitute less than 1% of final composition

18. Setting reaction of conventional low copper amalgam alloy

19. 2) HIGH COPPER AMALGAM a) High copper Admixed alloy: Final powder is a mixture of 2 kind of particles. 2 step reaction . b) High copper Uni- compositional alloy: Single step reaction. Particles are in uniform amount.

20. High Copper Admixed Alloy : Composition of elements : Ag – 70% Sn – 17% Cu – 12% Zn – 1%

21. Setting reaction of high copper admixed alloy +Ag-Cu +Ag-Cu

22. b) High Copper Uni – Compositional Alloy : Ag , Sn & Cu are in uniform composition

23. Setting reaction of uni -compositional high copper amalgam alloy

24. References: Sturdevant’s (chapter 19 ; Pg.no. 339 - 344) Philips Internet

25. Thank you !!