Operative - Amalgam Finish

Front 1

3 Types of amalgam powder

Back 1

Spheralloy (spherical), Admix, and Dispersalloy; *They all have mercury (Hg)

Front 2

Admix

Back 2

made from metals melted together and ground into a fine powder.

Front 3

Spheralloy

Back 3

spherical powder is made from metals melted together and run through a screen while liquid.

Front 4

Admix vs Spheralloy

Back 4

Admix has more resistance (due to fine powder as grindings of cool metal) vs Spheralloy squishy

Front 5

Dispersaloy

Back 5

amalgam that has a pinkish tone due to the higher content of Cu.

Front 6

What kind do we use?

Back 6

Admix

Front 7

Amalgam

Back 7

Alloy of mercury with other metals in powder form; Mercury is 42 - 49%

Front 8

Characteristic of mercury

Back 8

only metal which is liquid at room temperature

Front 9

Contents of amalgam powder

Back 9

1) Ag 60 - 72%, 2) Cu 12 – 30%; 3) Sn 12 – 27%;`-6 *Ratios are determined by manufacturers to modify properties; Other metals may be added to adjust properties.

Front 10

Advantages of High Cu amalgam

Back 10

1) Low creep values due to Copper-tin eta phase (Creep is the expansion of amalgam within the tooth without a load placed on it causing it to appear as if it is bulging out of the preparation),

2) High corrosion resistance,

3) Decrease in residual mercury,

4) compression strength

Front 11

Do we have an obligation to inform patients that a mercury containing restoration is going to be placed in their tooth or teeth?

Back 11

In some cities, laws have been passed forcing dentists to inform their patients of this. An informed consent specific to this point has to be signed by the patient and place in the patient’s file.

Front 12

Chemical reaction of Admixed High-Copper Amalgam

Back 12

Ag3Sn + AgCu +Hg = Ag2Hg3 + Cu6Sn5 + Ag3Sn (unreacted) + AgCu (unreacted); *The lathe-cut Ag3Sn powder and the spherical Ag-Cu eutectic particles are mixed with mercury. Resulting unreacted particle parts actually STRENGTHEN the amalgam; However NO FREE MERCURY is present

Front 13

Gamma-1 phase

Back 13

Ag2Hg3

Front 14

Eta phase

Back 14

Cu6Sn5 phase (the eta phase of the Cu-Sn phase diagram); Reduces creep by acting as small pins that prevent gamma-1 phase from slipping

Front 15

What additional phase forms in low copper amalgam

Back 15

Gamma-2 phase (Sn7-8 Hg) which WEAKENS the amalgam; It corrodes faster creating porosities at the margins of the restoration contributing to the breakdown of the restoration; *Therefore high copper amalgam restorations are used now.

Front 16

What to check on patient before restoring

Back 16

1) Check occlusion with articulating paper at maximum intercsupation, MI (a superupted opposing tooth or posterior bite collapse will result in occlusal contacts and wear patterns that are not Class I relationship),

2) Check med history, radiographs, gingiva around tooth, and tooth itself for decay, fracture lines, and sensitivityObserve where the blue or red contact areas are on the tooth being restored and on the adjacent teeth,

3) Reflect gums to see if there is a parulus – If so, endo necessary

Front 17

11 Steps for Amalgam Restoration

Back 17

1) Place rubber dam,

2) Mix Amalgam (we use double spill of amalgam so 6 seconds),

3)Insert Amalgam,

4) Condense Amalgam,

5) Pre-carve Burnish Amalgam (while material still malleable),

6) Carve Amalgam,

7) Postcarve Burnish Amalgam,

8) Remove rubber dam,

9) Check Occlusion and function in lateral and anterior excursions,

10) Adjust restoration if in hyper occlusion (IMPORTANT STEP; Adjust if necessary so that all contact areas (colored dots have the same intensity of color – none stand out as dark heavy contact areas,

11) Finish and Polish at later time (after 24 hours or next visit)

Front 18

Functions of Rubber Dam (9)

Back 18

1) To keep working field free of saliva, tongue, cheeks,

2) To keep working field visible,

3) To prevent swallowing excess amalgam,

4) To collect excess amalgam with HV evacuation,

5) To keep old amalgam contained when removing previous restoration,

6) To keep patient comfortable,

7) To curtail pt. conversations and interruptions,

8) To keep germs in oral cavity,

9) To help prevent amalgam tattoos on gingiva

Front 19

How to prevent amalgam tattoos

Back 19

when the gingiva is knicked or a break occurs in the gingiva and amalgam is removed from the tooth and or is being used to restore the tooth be sure to check no amalgam is on the opening or break in the gingiva. Check very carefully. Wash with water. Wipe with cotton pellet; Scrape the broken surface to remove the clot to check no amalgam is on the exposed gingiva under the clot.

Front 20

Step before placing amalgam

Back 20

Place THIN layer of varnish on walls of prep before placing amalgam to seal the dentin tubules And prevent leaching of the metals into the tooth causing the dentin to stain grey (brand we use is Waterpik’s Barrier); Can thin the layer with air; *Used only with amalgam

Front 21

How long does amalgam take to set?

Back 21

We use regular set amalgam which sets in approximately 15 minutes. (Fast set sets in approximately 5 to 7 minutes)

Front 22

What went wrong if the material is powdery after amalgamating?

Back 22

perhaps the membrane holding the Hg did not break or perhaps no Hg was present in the capsule.

Front 23

What went wrong if the material is hard and crumbling?

Back 23

mixing time was incorrect for this capsule. Amalgamation is exothermic which creates heat and causes the amalgam to set faster

Front 24

Using amalgam carrier

Back 24

Make sure amalgam not left in there and hardened; Put thumb under lever to keep amalgam in and press into amalgam 2-3 times to solidly fill; push lever to release amalgam

Front 25

Placing amalgam

Back 25

Place in INCREMENTS

Front 26

Where in the tooth should you put amalgam first?

Back 26

condense with significant pressure vertically into central fossa at the pulpal wall of the cavity prep. (or proximal box if class II) to avoid any voids

Front 27

Condensing amalgam

Back 27

Use small nib condenser for proximal box and large nib condenser for rest of tooth; Over step previous area when condensing; Condense amalgam along pulpal wall into line angles and point angles using lateral motion (buccal, lingual, mesial, and distal walls); Overfill the tooth

Front 28

Consistency of excess amalgam placed above cavosurface margin

Back 28

more squishy, with less resistance to condensation since this is the Hg rich layer of amalgam which is removed with the burnisher and carver; Use The torpedo burnisher to pinch off the excess at the cavosurface margin; Acorn burnisher can help created anatomy *This leaves the stronger/denser Hg-poor material inside the tooth

Front 29

Which nib exerts greater pressure?

Back 29

Smaller nibs exerts more force on the area it contacts than a wider diameter nib exerts on the area it contacts; You should use larger nib on soft excess layer

Front 30

Burnishing

Back 30

Burnish against cusps and also to form central fossa; Removes excess material; enhances the density of the amalgam and improves the adaptation of the amalgam to the cavosurace margins.

Front 31

Acorn burnisher

Back 31

Used to develop buccal and lingual grooves, mesial and distal fossae and central groove; For narrow preparations, the inclines of acorn are rested on cavosurface margins of occlusal preparations. For wider preparations, be careful not to ditch the soft amalgam inclines of the cusps by applying too much pressure which could also gauge out a deep occlusal groove.

Front 32

Grooves in ideal occlusion

Back 32

occlusal groove must be at the same level as the adjacent teeth in the ideal Cl I occlusion.

Front 33

Burnishing with large condenser

Back 33

Sometimes the large condenser is used to develop the cusps and central groove in the soft amalgam. After condensing it is in hand readily available to pinch off the surplus Hg rich amalgam layer at the cavosurfacce margin as it is pushed or pulled across the inclines of the cusps while simultaniously developing a crisp central groove with the right angle edge at the bottom of the condenser. The post carve burnish can round out the sharp grooves.

Front 34

Purpose of Carving Amalgam (3)

Back 34

1) Remove flash on cavosurface,

2) Define anatomy,

3) Restore occlusal function

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3 Instruments for Carving

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1) Cleiod Discoid Carver,

2) Hollenback Carver,

3) Use Interproximal Carver; *Bring instrument form natural tooth to amalgam and NOT vice versa to avoid ditching

Front 36

Scaler and explorer

Back 36

Interproximal carver is similar to a scaler. Sometimes a scaler can be used to clean up flash in the PROXIMAL AREAS and an explorer can be used to burnish the proximal area. Also Use Explorer to remove flash on occlusal at Tofflemier or segmental band and to check cavosurface margins for voids

Front 37

Hollenbach carver

Back 37

used to carve occlusal, facial, lingual and interproximal surfaces. One end perpendicular with shank and one end parallel

Front 38

What happens if flash is not removed?

Back 38

when patient begins chewing, these small excesses will fracture away leaving small step of amalgam rather than a smooth butt joint. small ditch, will collect debris and result in the beginning of the degradation of this restoration. (especially occurs at GROOVES and in marginal ridge of class ii); *Flash also occurs with composite and must be removed

Front 39

Removing debris

Back 39

A small cotton ball moistened with water will remove the light debris on the tooth.

Front 40

Tofflemier or segmental band

Back 40

Used in proximal box of Class II; A band is placed around the tooth and held in place where the missing M,D B or L wall is to be built up. Amalgam is condensed against this wall/band. Remove flash before you take band off so amalgam does not break

Front 41

Post carve Burnish of Amalgam

Back 41

Burnisher is rubbed against amalgam surface to smooth rough surface after carving and adapt amalgam to cavosurface margin

Front 42

Carving after material sets

Back 42

If too high for occlusion, can use finishing burs on slow speed and lightly touch the blue or red indicated spot of a heavy occlusion (cuts easily b/c only partially dry)

Front 43

Disposal of amalgam capsules

Back 43

In scrap jar , NOT biohazard bags which are incinerated because Hg becomes airborne and pollutes environment; *Although The mercury in amalgam restorations has not been proven to pollute the environment nor harm patients like free mercury would, we want to protect patients

Front 44

FDA classification of amalgam

Back 44

Was classified as a Class 2 material but Lawsuits occurred against the use of amalgam stating it was an unsafe material. Since no formal published studies are available to substantiate that amalgam is not harmful to infants, children and pregnant women, government gave amalgam the Class 3 rating. However, no one has proved amalgam is harmful to patients when used as a dental restoration and is properly handled by dental personnel and manufacturers.