Restorative Flashcards
What are the types of local anesthesia we use?
- lidocaine
- articaine
- mepivacaine
- prilocaine
what is the most common type of topical LA?
Benzocaine
What is the constituents in a cartridge of LA?
Vasoconstrictor - adrenaline (epinephrine) or felypressin
Solvent (sodium chloride, water)
Preservative
LA agent
What is the purpose of having a vasoconstrictor in a cartridge of LA?
- As it stops blood flowing out, it keeps the anaesthetic in the area
- Stops blood flowing in, therefore better haemostasis
- reduces haemorrhage
- extended duration of pulpal analgesia
What methods are used to obtain moisture control?
- 3 in 1
- cotton wool rolls
- gauze
- mirror - soft tissue retraction
- dental dam - GOLD STANDARD
- expasyl - paste for temporary gingival retraction. Astringent and haemostatic properties, by compression. Allows dry gingival sulcus to be achieved
- suction
What liners are used to protect the pulp?
- calcium hydroxide (hard setting)
- resin modified GI (vitrebond)
- zinc oxide eugenol
- zinc phosphate
- biodentine (bulk fill composite)
what are the objectives of pulp protection?
- therapeutic: stimulates odontoblasts to lay down reparative dentine and encourage remineralisation of dentine, act against any remaining bacteria
- protect from chemicals
- protect from temperature
- seals the dentinal tubules
What are the methods of pulp protection?
- moderately deep cavities: a layer of resin-modified GI to give thermal and chemical protection
- Deep cavities: a thin layer of hard setting CaOH as a therapeutic lining, followed by a layer of resin modified GI
What are the qualities of hard setting CaOH?
- irritates the pulp because of its high pH, pulp reacts and lays down tertiary/reactionary dentine
- bactericidal
- good restorative compatibility
- Biocompatible with other materials
- Doesn’t damage the pulp
- Thermal/electrical insulator
- Radiopaque
- Doesn’t withstand pressure of amalgam therefore vitrebond has to be placed on top
- not adhesive - no coronal seal
Explain the stages of a Stepwise procedure
- for grossly carious cavities stepwise can be used
- caries is removed in 2 steps. 6-12 mths apart
- at the first visit access is gained, caries is removed, from periphery only and soft caries is left on the cavity floor, making sure the ADJ is clear
- cavity is lined with CaOH ad restored and sealed well with GI
- at the subsequent visit, on re-entry into cavity the dentine is found to be harder and drier with fewer microorganisms present (arrested)
- a conventional restoration may then be placed
what type of acid is in etch?
phosphoric acid (around 37%)
what does etch do to the enamel?
Removes tiny part of enamel and changes structure of prisms.
Creates a lock and key effects as it creates a surface with undercuts that resin can flow into and allows to bond
why etch dentine?
- exposes dentine tubules to allow resin to flow into and bond
- removes the smear layer
- dentine conditioning
what is the smear layer?
they are created when hard tissue is cut with rotary instruments. It acts as a physical barrier for adhesion and penetration of material into dentinal tubules
what is the purpose of priming?
- acts as a go between
- because the bond has a solvent in it. the primer changes the dentine from hydrophobic to hydrophilic to allow bond
What is the purpose of using bond?
acts as the glue to hold composite in place
flows into dentinal tubules
what are the constituents of composite?
- filler (glass)
- resin matrix
- coupling agent
- activator (camphorquinone)
how do you categorise types of composite?
particle size; micro, macro. hybrid, nanofilled
how its cured; light cured, heat cured, chemical cured
flowable, conventional
what are the advantages of using composite?
- wear resistance and compressive strength matches tooth substance- durable
- command set
- good aesthetics - tooth coloured
- bonded to tooth - more conservative of tooth tissue
what are the disadvantages of using composite?
- polymerisation shrinkage
- moisture control essential during placement (hydrophobic)
- can be brittle in thin sections
- depth of cure only 2mm - increments needed
- more expensive - posterior not on NHS
- prone to staining
how do we overcome polymerisation shrinkage?
- as composite will shrink away from water (hydrophobic) keep operator field as dry as possible
- place in oblique increments, 2mm, oblique, C-Factor
What is the C - Factor?
The cavity configuration - is the ratio of the bonded to unbonded surface area. A high C- Factor is unfavorable. Placing composite in oblique increments minimises the number of bonded surfaces
what are the components of GI?
- malaic acid
- glass powder (silica)
- the mixing of the acid and powder together is an acid base reaction
- contains fluoro-alumino-silicate
What are the types of GI?
- resin modified
- light cured
- compomer
What are the advantages of GI?
- Tooth coloured
- Translucent
- Bonds directly to enamel and dentine
- Easy to mix and manipulate
- Not as moisture sensitive as composite
- Potential fluoride release and uptake
- Can be resin-modified to increase strength
- Good for temporary dressings or stabilisation
- Can be used as a fissure sealants where moisture control is poor
What are the disadvantages of GI?
- Compressive strength and wear resistance significantly lower than composite
- Poor aesthetics in anterior teeth
- Finite working time (not command set)
- Takes 24 hrs to fully set
What are the 3 setting reactions of GI?
Calcium reaction - initial set (a few minutes)
Alumnium reaction - 24 hrs to set
Vaseline is placed to keep water off it as it is moisture sensitive for first hour or so
What is amalgam?
a metal alloy
What are the contents of amalgam?
- mercury
- silver
- tin
- copper
- zinc
The > the mercury in the mixed material, the what…
The softer the material is and the easier it is to pack, but the set restoration will be weaker and more prone to corrosion
How do you reduce the amount of amalgam in the final restoration?
The amalgam is vigorously packed, as this causes excess mercury to rise to the surface and can be carved away and discarded in a safe manner. This is why we always overfill!
How long does it take for amalgam to fully set?
24 hours to reach its optimal strength
How do we classify amalgam?
High copper
Low copper
Shape of the grain - lathe cut or spherical
What are the advantages of amalgam?
- Durable material, long lasting
- Not as hydrophobic as composite
- Cheap
- Good compressive strength, good wear strength
What are the disadvanatges of amalgam?
- Not as aesthetic
- Needs good retention - removal of more sound tooth tissue
- Environemntal factors - crematation
- Can’t use it on pregnant women, under 15s or breastfeeding patients (MINIMATA)
- UK dont use it on any primary teeth
What is the aim of treatment?
To provide:
* functional dentition
* dentition that is free from dicomfort and disease
* dentition that is aesthetically pleasing
What are the 3 types of diagnosis and explain them?
Provisional - formed after initial assessment, still need to conduct special tests and investigate further e.g. radiographs, sensibility
Differential - a list of possible conditions or diseases that present with similiar signs and symptoms
Definitive - the final diagnosis. An accumulation of the history, clinical examination and special investigations
What is the order of tx plan?
- Emergency
- Prevention and disease control
- Stabilisation
- Restorative
- Maintenance and monitoring
- Referrals
Why might restorations fail?
- secondary caries
- NCTSL - proud restorations due to ersosion, bruxism pt prone to fractures
- pulp pathology
- trauma
- fractures
- bond failure
- ditching
- lack of retention
- defective contacts
- defective margins
- aesthetics
Why restore?
- to restore the integrity of the tooth surface
- to restore the function of the tooth
- to remove diseased tissue as neccessary
- to restore the eppearance of the tooth
how long to restorations typically last?
- amalgam - 10 yrs
- composite - 8 yrs
- GI - 3 yrs
however several factors will have a bearing on the survival rate of a restoration