Clinical Application of Amalgam Flashcards

Question

disadvantages proximo-occlusal amalgam cavity preparation

Answer 1

Destruction of tooth tissue for retention • Increased risk of weakening of the tooth

Answer 2

Include grooves or dimples within the cavity design Dentine Pin placement - titanium / stainless steel - Pin use is controversial - Used to increase retention in large non-retentive cavities.

Answer 3

Can work well in large restorations and for cores beneath crowns. Pins are self tapping screws Place pin into dentine in the greatest bulk of the tooth. - Place a hole with drill, smaller in diameter than pin, pin goes in half in half out, parallel to the long axis of the tooth - Hard to place Never in enamel or at the ADJ - Fracture the enamel Dentine can bend with screw Avoid the pulp and periodontal ligament Pack amalgam around the pin old fashioned

Answer 4

Stress in tooth around the pin. Cracking of dentine, Sensitivity of tooth due to temperature transference

Answer 5

filling can leak but will not fall out because of the pin → secondary caries which can progress further into the tooth because of the pin Caused by direct route from external silver amalgam into core of tooth - May have a lining elsewhere but pathway at pin never use pins with composite resins

Answer 6

Sealing (resin) + bonding restorations - ScotchbondTM - Prime&Bond®NT Must be dual curing bonding agent Bonding – Resin Cement e.g. PANAVIA®21 EX Resin Modified GIC e.g. Vitrebond Bond amalgam in - Amalgam Bonds to dentine bonding agents with MDP - Can pack in top of bonding agent low strength 4-5MPa compared to 20MPa to enamel Can use when wet Ultimately no evidence for bonded amalgam survival over non-bonded

Answer 7

Ensure all caries is removed Smooth and round internal line angles Check and finish cavo-surface angles Smooth cavity margins

Answer 8

Reduces Strength Increases creep Increases corrosion Increases porosity Critical but not as critical as in bonded composite restorations - Can be used under water - cannot for composite - Better to be dry - better strength, less creep, corrosion, less porosity

Answer 9

Because amalgam transmits temperature need to place a liner

Answer 10

- Cavity Varnishes - Normally with RMGIC - Can use DBA but this complicates the process (Need to keep cavity dry – would composite be more appropriate?)

Answer 11

Passage of fluid and bacteria in micro gaps (10 microns) between restoration and tooth

Answer 12

- Pulpal irritation and infection - Discolouration - Secondary Caries

Answer 13

mechanical loading and thermal stress Composite more dentine margins Amalgam both dentine and enamel margins

Answer 14

Composite more dentine margins | Amalgam both dentine and enamel margins

Answer 15

``` Recreate wall(s) of the cavity - Need to get smooth walls of restorations joining to tooth ``` Allows creation of proximal form and adequate condensation - Pressure need to compact can cause filling of gap - impossible to clean Confines amalgam to the cavity

Answer 16

Should be < 0.05mm thick (better contact area) Smooth and strong Allow close adaptation especially at the cervical margin Allow good contact with adjacent tooth

Answer 17

Essential to produce adaptation of the matrix at the cervical margin, Buccal or lingual approach Temporary tooth separation Prevents excess amalgam gingivally Aids proximal wall contour Prevents movement of matrix band (Wizard wedges, Anatomical wedges)

Answer 18

Handling characteristics Working time Amalgam microstructure Restoration longevity

Answer 19

Vertical and lateral pressure needed (packing the amalgam) very important

Answer 20

Expels excess mercury bringing it to the surface where it will be carved off - Weakest form Adapts material to cavity walls ``` Reduces layering (homogenous) - Sufficient force to avoid distinct layers between gunfulls – prevents voids ``` Eliminates voids

Answer 21

Require correct size of instruments - Easier to control initial increment with a large plugger (keep material in cavity) Smear into the cavity; - Smaller plugger (if use initially will end up stuck to and removing from cavity); Overlapping axial strokes Lateral as well as axial condensation Spherical alloys require less force for condensation

Answer 22

Lack of adaptation to cavity - Spaces round the edge - food and plaque lead to secondary caries Poor bonding between layers - Weak due to voids Inadequate mercury expression and consequently removal during carving Inferior mechanical properties

Answer 23

at the top, where it is expressed

Answer 24

overfill the cavity

Answer 25

carving burnishing/finishing use high volume aspiraion

Answer 26

Recreate anatomical contour - Marginal Ridge - Inter-proximal contact areas - Fissure Pattern - Cusps and cuspal inclines - Re-establishes occlusal contacts

Answer 27

Only if required to adjust anatomical contour after amalgam has set - Amalgam finishing burs with water spray Aspiration Adverse effects of heat Mercury risk? Polishing considered unnecessary - Free up mercury in material - greater risk. - Head shakes - unpleasant procedure

Answer 28

“detrimental change in the character of amalgam due to reactions in the mouth” Associated with Gamma 2 phase (hardly any Gamma 2 phase amalgams on market most are Cu enriched) – but can be already placed in patient

Answer 29

marginal breakdown with creep and ditching

Answer 30

Expansion of amalgam during corrosive process may assist in the development of a marginal seal Most amalgam is now non-gamma 2, high copper, so less of a problem.

Answer 31

“slow internal stressing and deformation of amalgam under stress” Apply smaller force over a long period of time - material moves away

Answer 32

Copper incorporated to decrease creep - Ag-Sn-Cu phase stronger (therefore less of an issue) The greater the amount of creep the weaker the amalgam Reduced creep should maintain marginal integrity Correct cavo-surface angle is essential

Answer 33

- Secondary caries - Bulk fracture - Removal of an amalgam core within an extracoronal restoration

Answer 34

need: Dental dam, High volume aspiration Minimal and selective cutting - Don’t want to grind out like power - Cut mesial to distal and then cross ways - bits will pop out as not bonded to tooth Hand instruments Operator and assistant protection Easy to see that you have removed due to colour difference

Answer 35

During Insertion - Amount is proportional to the restorations` free surface area During removal - Vapour + particles

Answer 36

Vapour into lungs Contact with skin Gastro-intestinal tract Gingiva and mucosa Dentine and Pulp as metal ions (?)

Answer 37

Inorganic mercury vapour is released - very slowly from an amalgam - about 0.5 microgrammes/surface/day 490 amalgam surfaces would be required in a mouth to reach the exposure dose limit set by the WHO. - Not possible to overcome safe dose in reality from dental care Only about 15% of the mercury released is absorbed (0.08 microgrammes) from the lungs and GI tract. Organic Mercury in food (tuna) is absorbed much more easily (About 90% of that ingested)

Answer 38

Usual protection for dental personel Dental dam High Volume aspiration Amalgam traps – separators Spillage Kit (prevent Hg going into water system) Correct disposal of waste amalgam Correct disposal of unused amalgam

Answer 39

natural sources - ocean evaporation - geothermal activity - rock erosion in the USA 80% of mercury pollution is from burning fossil fuels for energy <1% is from dentistry (small part)

Answer 40

Dental Amalgam can produce delayed hypersensitivity contact reactions on the skin and mucous membrane Higher levels than found in dentistry can cause: - Neuro-toxicity (mad hatter effect (used in top hats)) - Kidney dysfunction - Reduced immunocompetence - Effects on the oral and intestinal bacterial flora - Effects on general health - Foetal and birth effects Can kill

Answer 41

can produce delayed hypersensitivity contact reactions on the skin and mucous membrane

Answer 42

global treaty to protect human health and the environment from the adverse effects of mercury - Governs use of all mercury containing products. - Global treaty 128 countries signed up. agreed in Geneva, Switzerland on Saturday, 19 January 2013 and adopted later that year on 10 October 2013 at a Diplomatic Conference held in Kumamoto (Minamata), Japan. Ratified in June 2017 ‘Regulation on Mercury’ is the EU plan for reducing mercury in the environment

Answer 43

to protect human health and the environment from anthropogenic emissions and releases of mercury and mercury compounds. Trying to get rid of amalgam use - Limit and phase out mercury use throughout world

Answer 44

15 Years Post Ratification (2032) There will be no mining for new Mercury There will be no import or export of Mercury or Mercury containing compounds

Answer 45

Governs use of all mercury containing products. - Known as Mercury-added products After 2020 it will be illegal to manufacture or export any of these products: • Batteries • Switches • Fluorescent lights • Some cosmetics • Antiseptics • Barometers, thermometers, manometers etc. (can be replaced with LED) Dental Amalgam is different it is subject to a phase down Nowhere in the regulations does it suggest phase out

Answer 46

May 2018 EU guidelines on Mercury use

Answer 47

Dental Amalgam is different it is subject to a phase down | Nowhere in the regulations does it suggest phase out

Answer 48

Encapsulated Amalgam - From January 2019 Already in use in the majority of practices in uk Amalgam Separation - Amalgam separation mandatory from 2021 - All amalgam separators installed from June 2017 must retain at least 95% of amalgam particles - Part of practice inspection All amalgam waste must be authorised waste management establishment From July 2018 Silver amalgam should not be used in: - Children under 15 - Pregnant Women - Breastfeeding Women Unless there is an appropriate reason for it’s use. Essentially the decision to use the material will still be based on the dentist’s clinical judgement and the informed consent of the patient.

Answer 49

Acknowledges that there is no justification on health grounds for not placing amalgam restorations. o No reason for not placing There is no justification for removal of sound amalgam restorations except in patients with a proven allergic reaction to constituents of the material. o If sound no need to remove limited itself to article 10(2) From July 2018 Silver amalgam should not be used in: - Children under 15 - Pregnant Women - Breastfeeding Women Unless there is an appropriate reason for it’s use. Unless there is an appropriate reason for it’s use. - Read “Unless there is a specific Dental Reason for it’s use.”

Answer 50

- Lack of cooperation - Inadequate moisture control Dental reasons e.g. 14 year old MOD in upper 6 and cannot get dry as subgingival or cannot keep dam on long enough - use amalgam It doesn’t matter how good you are at doing composite restorations. If it’s not dry, they don’t work

Answer 51

As we stand there are no restrictions to the use of dental amalgam in the bulk of the adult population. There is no prospect of a phase out of amalgam. There is a natural phase down happening. In Scotland the main Phase down action is continuation of a preventative programme - similar scheme in Ireland, England has nothing in place currently

Answer 52

Class I: Pit and fissure caries (occlusal) Class II: Approximal caries (posterior teeth) (MO/DO) Class III: Approximal caries (anterior teeth) Class IV: Approximal caries involving incisal angle Class V: Caries affecting cervical surfaces Class VI: Caries affecting cusp tips (rare) Arranged in how often they occur

Answer 53

Pit and fissure caries (occlusal)

Answer 54

Approximal caries (posterior teeth) (MO/DO)

Answer 55

Approximal caries (anterior teeth)

Answer 56

Approximal caries involving incisal angle

Answer 57

Caries affecting cervical surfaces

Answer 58

Caries affecting cusp tips (rare)