Amalgam Quiz Flashcards
Amalgam capsule we use:
- Brand
- Company
- Type of alloy
- Permite C
- SDI
- Admixed (blend of lathe cut and spherical particles)
In clinic, the gray-capped amalgam capsules are ____ while the green-capped amalgam capsules are ____
Regular set
Extended carving time (ECT)
Define amalgam activation:
Push plunger down to rupture membrane and allow mercury in one compartment to come in contact with powdered alloy
Define trituration
Process by which mercury is allowed to react with alloy powder. Removes the oxide coating and wets each particle of alloy with mercury.
(Hand trituration or mechanical trituration/amalgamator)
List steps of amalgam placement:
- Turn on amalgamator and set to 7 seconds
- Activate capsule
- Triturate amalgam for recommended time according to manufacturer instructions
- Dump mix into dappen dish
- Use amalgam carrier to transfer increments into preparation (use biggest end that can fit into prep)
- Spread first increment on pulpal floor
- Condense starting with smallest condenser and using larger condensers with following increments
- Overfill the final increment and condense with largest condenser to seal the margins
- Carefully begin carving anatomy of tooth and removing flash
- Evaluate restoration (check for flash, underfilled, voids, anatomy)
- Remove and check rubber dam
- Check occlusion
Proper trituration yields what qualities of amalgam?
- Uniform consistent mass
- Shiny surface
- Smooth consistency
- Optimal mechanical properties, compressive strength, tensile strength
- Optimal physical properties
Over-trituration of amalgam yields what qualities?
- Very bright/shiny luster
- Brittle internally
- Decreases final strength
- Sets prematurely
- Excess matrix is formed
Under trituration of amalgam yields what qualities?
- Grainy
- Crumble and dull
- Reduced strength
- Hard to handle
Define condensation
The process of compressing the alloy into the tooth preparation and eliminating all voids (>5-10 lbs. pressure)
What is the purpose of condensation?
- Secure adaptation of amalgam to the walls, line angles, and margins
- Maintains homogeneity and compactness of amalgam by minimizing voids
- Expressing the residual mercury to the surface to form mercury rich matrix that will be carved out later
What are the sizes of our hand condensers?
- Oregon 2 (1.0 and 1.5 mm diameter)
2. Oregon 4 (2.0 and 3.0 mm diameter)
A small condenser has a ____ surface area, ____ condensation pressure, and ____ indications.
A large condenser has a ____ surface area, ____ condensation pressure, and ____ indications
Small
High
Lathe cut
Large
Low
Spherical alloy
What are the condensing/carving times of the follow amalgams:
- Fast Set
- Regular Set
- Slow Set
- Extended Carving Time (ECT)
- 2.5/5.5 min
- 3.5/5.5 min
- 4.5/5.5 min
- 5/7 min
Successful condensation requires the following 5 techniques:
- Dry field (proper isolation)
- Start promptly after trituration
- Use vertical overlapping strokes
- Proper size condenser (make sure amalgam is condensed into all angles of the prep)
- Adequate pressure (looks shiny, sounds crunchy)
Excessive condensation pressure will ___ and ___ the amalgam
Punch through
Perforate
The last increment (overfill) of amalgam should go ____ mm beyond the external outline of the preparation.
1.0
Condensation strokes should be:
Vertical- ___ to the long axis or ___ degrees
Lateral- ___ to the long axis or ___ degrees
Perpendicular
45
Parallel
45
Lateral/horizontal condensation strokes are only used in ____ cases
Class I with extension (buccal/lingual)
Condensation time should generally by completed in ___ mins, otherwise ___ will be created in the already formed matrix
3-4
Cracks
Purpose of carving:
- Reproduce the tooth anatomy and contours
2. Remove the mercury rich matrix
Identify the two types of carving strokes:
- Pull stroke (along cavosurface margin with tip of carver in groove area)
- Push stroke (from tooth to amalgam)
How do you check occlusion?
Use Acufilm marking paper or ribbon in Miller Forceps. Check gently in centric occlusion. Check all excursive movements
Define Ideal Margin.
How do you detect it?
The junction between the external tooth structure and the amalgam is flushed. Crisp cavosurface margin with no excess or deficiencies.
Tactile sensation (run the tip of the explorer along the CSM from tooth to amalgam and vice versa)
Define open margin error, potential problems, detection, and treatment
Break/rift between tooth and amalgam restoration; Not continuous. Can trap food particles and allows passage for microorganisms. Tip of explorer catches when moved in both directions across margin. Replace.
Define submarginal/ditching error, cause, detection, and treatment.
Amalgam does not reach CSM. Caused by carving from amalgam to tooth (wrong direction). Detected by explorer catching from amalgam to tooth but not tooth to amalgam. Replace if ledge is > 0.2 mm, enameloplasty if ledge is < 0.2 mm
Define flash, potential problems, detection, treatment
Excess amalgam at margin. Patient can easily break when biting. Detected by tip of explorer catching from tooth to amalgam and not vice versa. Must remove during carving.
Define overcarving, potential problems
Deep anatomy. Potential submarginal defects (breaks off), no occlusion
Define undercarving, potential problems
Flash left at CSM; Poor occlusal anatomy
Describe the purposes of matrix bands
- Provide a wall against which one can condense amalgam
- Re-establish proximal contact of restoration with adjacent tooth
- Aids in isolation of preparation during fill
- Contains amalgam
- Prevents voids
- Shapes proximal contours
Identify the different types of tofflemire bands and retainers
Matrix Band No. 1 (no wings)
Matrix Band No. 2 (with wings)
Straight Retainer (for buccal side)
Contra-angle Retainer (for lingual side)
The open end of the retainer always faces the ____
Gingiva
Describe the functions of the wedge
- Adapts the gingival adage of matrix band against gingival cavosurface of prep (prevents flash Gingivally)
- Separates teeth slightly to compensate for band thickness
- Helps stabilize matrix band
Why should you overfill when condensing?
This brings excess mercury to the surface where it can be removed by carving and ensures well condensed amalgam at margins.
Define Quadrant vs Sextant
Quadrant- divide jaws into 4 parts from midline of arch to most distal tooth
Sextant: divide jaws into 6 parts (Max R, L, Ant; Mand R, L, Ant)
Define quadrant dentistry
Treating all the affected teeth in 1 quadrant/sextant during the same visit regardless of materials/techniques used
List the advantages of quadrant dentistry (for patient and dentist)
Patient
- Less appointments
- Less discomfort
Dentist
- More efficient/productive
- Single anesthetic procedure
- Single rubber dam placement
- Same rotary/hand instruments used
List the considerations of quadrant dentistry
- Chairside time
2. Sequence of treatment
List the indications for quadrant dentistry
- Multiple carious lesions/replacement of defective restorations
- Patient indicated for general anesthesia/sedation
List the contraindications of quadrant dentistry
- Lack of dentist experience
- Patient has TMJ dysfunction syndrome
- Patient cannot be reclined for long time
Low Copper Amalgam vs High Copper Amalgam:
Low- <12% Cu, has Y2 phase (weakest, corrosion prone phase), more vulnerable to marginal breakdown and creep
High- >12% Cu, sufficient Cu to prevent Y2 phase (stronger, more corrosion resistant), minimized marginal breakdown and creep
Compare amalgam particle shape classifications:
- Lathe Cut- low packing density (more spaces), higher condensation forces required, higher surface area (more Hg, more expansion)
- Spherical- pack efficiently, slide easily (less voids & higher strength); difficult to achieve proximal contact; large diameter condenser for proper condensation pressure
- Admixed (combination)
For multiple adjacent Class II preps, what is the best way to restore them (quadrant dentistry style)? Why?
Restore 2 non adjacent teeth, start with the most posterior tooth.
Restoring adjacent teeth simultaneously can result in excessive wedging and open contact.
List the initial stages of cavity design:
- Outline form and initial depth
- Resistance form
- Retention form
- Convenience form
List the final stages of cavity design:
- Removal of remaining enamel pits or fissures, infected dentin, old restorative material
- Pulp protection
- Secondary retention and resistance form
- Finishing enamel walls
- Cleaning, inspecting, conditioning
Define outline form and initial depth:
Outline- placing the cavity margins in the position that they will occupy in the final preparation
Initial Depth- 0.2-0.8 mm pupally from DEJ (usually 0.5)
Define resistance form
The shape and placement of cavity walls that best enable restoration/tooth to withstand long axis masticatory forces
Define retention form
The shape/form of the prepared cavity that resists displacement/removal of restoration from tipping/lifting forces
Define convenience form
The shape/form of the cavity that provides for adequate observation, accessibility, and ease of operation in preparing/restoring the cavity
List the functions of the Dentin/Pulp complex
- Formative (primary/secondary dentin)
- Defensive (reparative dentin)
- Nutritive (supplies vital cells)
- Sensory (protective)
Clinical methods to test pulp status
- Cold/Hot test (pain, duration)
- Electric Pulp Test (EPT)
- Percussion Test (Period ligament)
Why do we need liners and bases?
To protect the pulp and minimize post-op sensitivity (thermal, chemical, electrical, mechanical barrier; controls pulp inflammation and fluid movement). Many restorative materials do not have a positive pulpal response.
Define liner
Relatively thin layer of material that provides a barrier to protect dentin from residual reactants from restoration or oral fluids. Also provides initial electrical/thermal insulation
Which liner does Dr Sharples talk about the most in his lecture?
Copal Varnish
Define base
Provide thermal protection for pulp and supplement mechanical support for restoration by distributing local stresses across underlying dentinal surface.
Most commonly used bases?
GI (Glass Ionomer)
RMGI
Bases and Liners often only differ by ____
Powder/Liquid ratio (consistency)
Why have GI’s replaced ZnPO4’s?
GI Advantages:
- adheres to tooth structure
- Fluoride release
- Proven clinical record of retention
- Dimensionally stable
- Biocompatible
Summarize Pulpal Protection Procedures for varying excavations:
- Shallow Excavation (RDT [Remaining Dentin Thickness] > 2 mm)- varnish/sealer applied to walls
- Moderate Excavation (RDT .5-2 mm)- place liner, then varnish
- Deep Excavation (RDT < 0.5 mm)- light-cured calcium hydroxide placed in deepest region, then base of glass ionomer is inserted, then varnish.
When should a cusp be replaced/capped with a complex amalgam restoration?
If the extension from the primary groove toward the cusp tip exceeds 2/3 of the distance.
What is the purpose of pins?
They provide supplemental retention and resistance for large amalgam restorations
List the types of pins:
- Cemented
- Friction Locked
- Threaded
Identify the Threaded Pin that was promised to be on our exam:
Minim, Silver, .021/.53 (drill diameter in/mm), .024/.61 (pin diameter in/mm)
Which type of Kotex twist drill did we use?
Depth-limiting
How do you drill and place a pin?
Determine angulation for twist drill by lining up with external root surface. Drill hole 1.5 mm in from external surface (or two drill diameters inside DEJ).
Describe the 2-2-2-2 Rule for using pins:
2 mm pin hole depth 2 drill diameters inside DEJ 2 mm length of pin 2 mm amalgam over pin (Therefore, you need at least 4 mm depth for pin to work)
Use of a depth limiting drill to prepare a pinhole in a non-flat surface results in what?
A pinhole of inadequate depth
What can be used to substitute for a pin?
Retentive Well
How many pins should be placed in teeth that require pin placement?
One per missing cusp
Where should pins be placed in teeth that require pin placement?
At the line angles of missing cusps (2mm past DEJ)
What type of pins did we use in lab?
Minum Silver .021/.53 drill, .024/.61 pin
Why do you place CaOH in a prep that is <0.5 mm form the pulp?
To form reparative dentin
What (chemical name) is dentin conditioner?
Polyacrylic acid
What is the purpose of dentin conditioner
To remove the top smear layer, but keep the smear plugs for retention
What liner is not compatible with composite?
ZOE
Copalite
