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Amalgam & Placement, Carving, Finishing & Polishing
Chapters 6 & 26
Terms in this set (70)
_______________ is a safe, affordable, and durable material used predominantly (mainly) to restore premolars and molars.
Amalgam is considered a direct restorative material. It is held in place by ______________________.
_____________ are metals that are a combination of several metals.
_________________ is made by mixing approximately equal parts (by weight) of powdered metal alloy with liquid mercury.
The powdered metal of a dental amalgam is called a ____________________ and is predominately silver & tin. It may also be called an _______________.
amalgam alloy; amalgam
What are the advantages to using dental amalgam?
- Toughness & wear resistance
- Ability to seal its margins
- Less technique sensitive (if a little bit of saliva touched it, it's okay, it's still going to work)
- Only material that might work when placed in a wet environment
The mixing process of the alloy with the liquid mercury is called _________________ or _______________.
A ______________ or ____________ shakes the capsule containing the alloy powder & mercury at high speed, mixing the two components into a plastic mass.
Increasing the ____________ content reduces the percentage of the weakest phase of the resulting dental amalgam.
__________________ amalgams are the state of the art & dominate the market.
Amalgam Alloy Powder consist of:
_______________ causes setting expansion and increases strength and corrosion resistance.
_____________ causes setting contraction and decreases strength and corrosion resistance
_____________ functions similarly to silver; increases strength and corrosion resistance.
_____________ reduces oxidation of the other metals during manufacturing which appears to extend clinical life expectancy
The mercury/alloy ratio is the.....
correct amount of mercury that is mixed with the correct amount of amalgam alloy.
Minimizing ____________ results in an improved restoration. Therefor the strength of the amalgam is increased, & marginal breakdown is reduced.
An inadequate mercury/alloy ratio results in voids & poor restorations.
Both the manufacturer & the dentist control factors that affect the handling & performance of dental amalgam. The manufacturer controls:
- Alloy composition & shape
- Particle size & distribution
Excess mercury decreases the.....
strength of the amalgam.
Under-triturated amalgam has a __________&_________ feel because not all of the particles were broken up & is difficult to condense.
mushy & grainy
A properly triturated amalgam is a cohesive mass that might be slightly ___________ to the touch. The surface is ____________, & the mass has a plastic feel. Easy to work with.
Over-triturated amalgam tends to ___________ & is difficult to condense. Which shorten working time & may have voids in restorations.
Proper handling of amalgam is required for optimum results. Why is minimal change important in the dimension after condensation?
Excessive contraction/expansion leads to leakage & postoperative sensitivity.
The strength of an amalgam must resist _______________ and needs to be supported by ______________ for clinical success long term, which is approximately _____ to ____ years.
____________ is the slowchange in shape caused by compression
Amalgam is used to restore what?
- Carious lesions such as filling small cingulum pits.
- Tooth fractures
- as a foundation for future crowns to restore a severely decayed tooth (amalgam build up)
Moisture will _________________ of a dental amalgam.
reduce the quality
Delayed expansion of an amalgam results when.....
amalgam is condensed in a contaminated (wet) cavity preparation (moisture excessive amalgam expansion)
What is the goal of finishing an amalgam?
- To produce margins that are continuous with the adjoining tooth
- To produce proper contours
Mercury is toxic to ____________ & ____________________. (i.e. mad hatter)
kidneys & central nervous system
Mercury in dental amalgams is intermetallic and thus has.......
low or no toxicity
If mercury were to spill, what would you use to clean it & when?
use a spill kit & immediately
Reasons for using amalgam:
- In individuals of all ages
- In stress-bearing areas of the mouth
- When there is severe destruction of tooth structure
- As a foundation for a crown
- When personal oral hygiene is poor
- When moisture control is problematic
- When cost is an overriding patient concern
Reasons NOT to use amalgam:
- Esthetics is important.
- Patient has a history of allergy to mercury or other amalgam components.
- The cost of other restorative materials or treatment options is not a factor.
What are the Amalgam Hygiene Guidelines?
- Don't allow mercury to come into contact with your skin - PPE's
- Protect against spillage during Amalgamation/Trituration
- Keep the lid closed during amalgamation/trituration
- Don't discard scrap amalgam in waste containers or down the sink.
- Collect all scrap amalgam & store it under water or a photographic fixer solution in a closed container.
How many mg of alloy would you use for small or single-surface restorations?
600mg of alloy
How many mg of alloy would you use for larger restorations?
800 mg of alloy
A proper amalgam condensation requires a three-dimensional "form" or box with only one surface or side open. Therefore why would the Tofflemire matrix band be used for a Class II restoration?
A class II restoration has at least two open surfaces & therefore lacks the box-like shape for proper condensation SO the band is placed around the tooth to establish the missing sides of the box
The __________ holds the Tofflemire matrix band in a loop & tightens the band around the tooth.
An amalgam ______________ is used to break the separating membrane in the capsule.
Direct Application of Amalgam:
Mixed amalgam is placed in an _____________________.
Direct Application of Amalgam:
After the amalgam is placed in the well, it's carried to the prepared tooth using the _______________.
Direct Application of Amalgam:
The amalgam is then placed in __________________ in the prepared tooth.
Direct Application of Amalgam:
Each increment is condensed immediately. The restoration will be overfilled & the excess will be _____________ away.
carved (picture is of a condenser)
A ___________ is used to smooth the amalgam.
_________________ are used to carve the anatomy into the amalgam.
When finishing a restoration, you need to make sure that you maintain the original _____________ of the restoration.
What are the results of poor carving?
- Overextension or flash (thin ledge of amalgam extends beyond the cavosurface margin)
- Submarginal area or Deficient Margin (margin is overcarved - creating a deficiency of amalgam)
- Open Margin (result of poor condensation or when an opposing cusp fractures an overextended portion of the amalgam)
After the placement & carving of an amalgam is done, the restoration's occlusion is checked with ______________.
Typical problems with amalgam restorations include:
An excess amount of amalgam that extends beyond the cavosurface margin is known as a ______________.
A lack of functional anatomy increases the risk for ________ & _____________ retention.
plaque & food debris
______________ of an amalgam is removable surface film or discoloration. It does NOT affect the internal integrity (function) of the restoration.
_______________ of an amalgam is the surface or subsurface chemical deterioration that occurs on or within an amalgam restoration.
A _______________ is a common result of recurrent caries and lack of support to part of the restoration. If remained in place, it can be a source of sensitivity, leakage, & recurrent caries.
Amalgam restorations should be finished & polished after ______ hours.
Amalgam finishing & polishing improves:
- Marginal deficiencies
- Surface tarnish
- Marginal flash
Goal for amalgam polishing is to produce a smooth & lustrous surface to _____________________ and the ability for plaque to collect.
Advantages of amalgam polishing:
- Decrease biofilm retention
- Higher resistance to tarnish & corrosion
- Increase longevity of restoration
- Improved esthetics
Disadvantages of polishing amalgam:
Localized melting of the amalgam with mercury smearing
What are the two methods of amalgam polishing?
- Pumice and tin oxide slurries
- Rubber cups & points impregnated with abrasive particles
Rubber cups & points impregnated with abrasive particles come in three colors. Each color denotes a degree of _________________ and they achieve___________________.
abrasiveness; high surface luster
What is the best method of amalgam packaging & mixing to minimize the escape of mercury vapor?
- proper trituration technique (speed & time) to obtain the proper consistency of the mix
- proper condensation techniques reduce or eliminate voids (worst component of the amalgam)
Rubber cups & points impregnated w/ abrasive particles: state the colors & order to use them in....
Super greenies (yellow-banded)
Cups are used on ______________ surfaces
Points are used on ____________ surfaces.
What are the advantages & disadvantages of rubber cups & points impregnated w/ abrasive particles?
- polish quickly
- less messy
- wear quickly
- heat production
Complications that may occur if an operator overheats an amalgam during an amalgam polishing procedure:
- plural injury
- release of mercury
- a dull appearance to restoration
Procedure for use of rubber cups & points impregnated w/ abrasive particles:
Start with coarser abrasives & finish with finer abrasive (allows the larger scratches in the amalgam to be reduced to less defined scratches)
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