Unit 307 Flashcards
Cavities are caused by..
Dental caries
In line with the GDC scope of practice document who is able to complete fillings?
Dentist or therapists
Who do we usually complete temporary restorations on…
Less co-operative patients
If a fixed is being considered - high caries risk, deep fill
Are temporary restorations also used as base liners?
Yes
Examples of temporary restorations…
- Zinc oxide and eugenol cement
- Zinc phosphate cement
- zinc polycarboxylate cement
Amalgam restorations are used in…
Posterior teeth
Composite restorations are used in….
Anterior teeth AESTHETIC purposes
Glass ionomer restorations are used in…
Deciduous teeth - fluoride release
Cavity sites where retention is difficult
Blacks Classification Class I
1 surface
Pits and fissures
Blacks Classification Class II
2 surfaces
Posterior teeth
Blacks Classification Class III
mesial or distal surface of anterior tooth
Blacks Classification Class IV
same as class III but also involves the incisal edge
Blacks Classification Class V
Cervical margin of any tooth
Examples of what cavity preparation will ensure:
- Plaque biofilm and soft carious dentine is removed
-As much enamel as possible is conserved
-Base lines placed on deep fills - making sure of no overhangs
Caries is a….
Bacterial disease
What bacteria is involved with caries progression?
Streptoccus Mutans
Examples of plastic fillings:
Temporary cements
amalgam
glass ionomer cements
Composites
Examples of pre-constructed fillings:
INLAYS
Gold
Porcelain
other ceramic materials
Retention for plastic fillings is obtained by…
Cutting tiny grooves in the cavity walls
Dovetail effect means?
Grooving cavity walls to prevent the filling coming out mesially and distally.
self-tapping dentine pins for amalgam and other restorations.
what do linings do? - shallow cavity
protect the pulp against chemical irritation from the permanent fill material - calcium hydroxide
what do bases do? - deep cavity
protect the pulp against chemical irritation and thermal changes/pressures. - anything containing zinc.
What does microleakage mean?
fluid/debris/bacteria leak through microscopic gaps between the filling n cavity wall, enter the dentinal tubules and then contaminate the pulp tissue = irritation
Hydrodynamic theory is…
the swishing effect of fluids n bacteria washing the microscopic gaps.
Examples of modern lining:
Resin modified - fuji and vitrebond
Dentine bonding agents - scotchbond and clearfil
Examples of why moisture control is important:
- inhalation/indigestion
-patient is comfortable - good visability
-retract oral tissues
Examples of methods to control moisture:
- cotton wool rolls
-absorbent oral inserts, dryguard, drydent (salivary duct)
-rubber dam
High speed suction is used for…
fast removal of moisture
Wide bore aspirator
Low speed suction is used for…
continual moisture control
saliva ejector
Moisture control prevents cross infection by..
minimising the aerosol of infected debris
High speed handpiece uses which burs?
Friction grip diamond or tungsten carbide burs
Cut through enamel n dentine
Slow/low speed handpiece uses which burs and what are they made of?
Steel
Latch grip stainless steel or tungsten carbide burs
Friction grip stainless steel acyrlic trimming burs
What does a high speed do?
Quick removal of enamel, dentine and old fillings.
what does a slow speed do?
Removing caries, cutting dentine NOT enamel, trimming dentures
round shaped burs are used to:
gain access to cavities and at low speed for removing caries.
Pear shaped burs are used to:
shape and smooth cavities
fissure burs are used to:
shape and outline the cavity.
Examples of polishising instruments:
Comprise fine abrasive stones, wheels, discs, and strips
finishing burs, brushes and polishing pastes.
What are finishing burs and stones used for?
smoothing cavity margins and trimming fillings.
What are abrasive discs and strips used for?
fine trimming and polishing.
Conventional wheels and metal discs are fitted using what type of mandrel?
Huey
Sand paper discs and soflex discs are fitted using what type of mandrel?
Moore
Plain sandpaper discs are fitted using what type of mandrel?
Pinhead
What should hand instruments chisels and excavators be sharpened using?
Small flat oilstone - arkansas stone
On high risk patients are burs single use?
YES
Slow speed burs are single use
What does air abrasion do?
removes hard tissue, soft carious tissue or surface stains and abrade metal or composite restorations before repairs.
Reasons why temporary restorations are used?
Emergency, endo treatment, inlay prep, to allow symptomatic teeth to settle.
Zinc oxide and eugonel advantages?
CHEAP
sedative dressing
Zinc oxide and eugonel disadvantages?
reacts with composite restorations + can burn soft tissues
Zinc phosphate advantages?
adhesive to dentine - luting cement
sets quickly and hard
Zinc phosphate disadvantages?
irritant to the pulp + moisture sensitive
Zinc polycarboxylate advantages?
Most adhesive cement
Zinc polycarboxylate disadvantages?
sticks easily to instruments so difficult to place.
For zinc phosphate what does a warm glass slab do?
accelerates the setting time
For zinc phosphate what does a cold glass slab do?
slows down the setting time
Calcium hydroxide lining is used during what procedures?
Pulp capping, pulpotomy, cavity lining, promotes formation of secondary dentine.
Shallow cavities
Examples of permanent restoration materials:
amalgam, composite, glass ionomer.
What is toxic in an amalgam restoration?
mercury
The powdered alloy and liquid mercury mixed together in an amalgam filling creates what?
Plastic mass
What is included in amalgam alloy powder?
Silver, copper, tin and zinc.
Modern amalgams tend to have what?
High copper content
Siqveland or tofflemire matrix are used for what type of cavities?
Class II
Sectional matrix are used for what type of cavities?
All
Wedges are to be used..
Interproximally
Are all matrix bands single use?
YES
What are amalgam finishing burs made of?
steel - low speed handpieces
Why are matrix bands used?
To prevent overspill and to keep the interproximal margins open + to keep the shape of a tooth.
Main advantages of amalgam:
- easy to use
- cheap
- good strength, lasts a long time.
Main disadvantages of amalgam:
- mercury is toxic
- corrosion in the environment
-aesthetics are poor
in relation to mercury vapour the higher the temperature..
the more vapour is released.
Amalgam waste containers should be kept in a..
cool well ventilated place.
Early symptoms of mercury poisoning include:
- headache
- fatigue
- irritability
- nausea
- diarrhoea
Final stage of mercury poisoning is:
kidney failure - death
what tests can be carried out on staff to see if they have been exposed to high levels of mercury vapour?
urine tests
Small amount of waste amalgam can be gathered by what?
damp paper towel
in regards to large mercury spillages who will need to be informed?
- environmental health team
- HSE under RIDDOR
What do composite materials consist of?
Inorganic filler in a resin binder
What does inorganic filler act as?
A strengthener
Does composite require a catalyst to set?
Yes
Microfine composites
Very small particle size
Polishing and gloss finish
ANTERIOR
Hybrid and nano composites
Various size particles
Strength n wear resistance
POSTERIOR
Universal composite
Posterior and anterior
Combination
What makes a catalyst in composite fillings?
Exposure to light
Can blue light curing penetrate metal?
NO
What is the name of the composite material that has been developed to chemically cure metallic restorations?
Dual cure composite
Advanatge of light cure composite?
The dentist has more control over the setting time.
What is a composite gun called?
Injector gun
What is another option of giving the dentist composite rather than the injector gun to avoid cross contamination?
inject material onto a waxed pad or glass block
what is the correct name of single dose capsules (composite)?
compoules
Composite curing light cannot penetrate layers thicker than…
2mm
Bulk-fill composites can go to a depth of..
4-5mm
How can you check a curing lights effectiveness?
cure a small portion of composite on a glass block or mixing pad
Which linings tend to be used for composite restorations?
Calcium hydroxide
glass ionomer
What is the correct name for a clear strip?
transparent matrix strip
acid etchant is…
phosphoric acid 33%
how long is etch left on a tooth?
15 seconds
what does acid etchant do?
roughens the enamel surface
What can phosphic acid do?
acid burns and permanent scaring of a patients soft tissues, including facial skin.
What is the best recommended permanent treatment for fractured incisors?
all ceramic crowns and porcelain jacket crowns
A child comes in with a fractured incisor and a composite is necessasary to correct this, why cant the child have a crown?
Because the pulp chambers of deciduous teeth are too large and the pulp is likely to become damaged during a crown prep.
What is the reasoning behind fissure sealant?
caries prevention measure.
Where are the stagnation areas that fissure sealants would be needed?
occlusal fissures
buccal pits
retention of fissure sealants is obtained by?
acid etching the pits or fissures
if a child is to young to co-operate with fissure sealants what is another preventative for the time being?
fluoride varnish - duraphat
what makes a filled resin?
resin + inorganic filler
what makes a unfilled resin?
the resin on its own
what material is used for fissure sealants?
unfilled resin
what makes flowable composite?
resin + small amount of filler material
what are flowable composites usually used for?
lining cavities
examples of advantages of composite?
aesthetically pleasing
adhesive to tooth without having to remove more tooth tissue
fast set
disadvantages of composite?
sensitive
longer procedure compared to amalgam
more expensive
what does bond do?
bonds the dentine to composite
can dentine bond be irritant to the pulp?
YES
when are glass ionomer cement restorations used?
class V cavities
little natural retention of the restoration is available
what is glass ionomer cement made of?
aluminosilicate particles and polyacrylic acid + water
light curing glass ionomer cement is called?
resin modified glass ionomer cement
why does resin modified glass ionomer use light cure to set?
because of the resin
why is a “conditioner”, placed onto the cavity before the glass ionomer is?
increases the adhesion of the material to the tooth and improves the marginal seal.
examples of “conditioner” in a glass ionomer restoration?
polyacrylic acid or tannic acid
what type of matrix is used for restoring class V abrasion cavities?
cervical foil matrix
advantages of glass ionomer?
adhesive to enamel, dentine n cementum
good marginal seal
releases fluoride
disadvantages of glass ionomer?
low strength
moisture control - failure
exact proportation of materials to make the ideal mix
examples of which materials are used for fissure sealants?
glass ionomer
composite
