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
What is type 1 etching pattern?
- prism core removed
- peripheral structure remains in tact
- most common etching pattern
what is type 2 etching pattern?
- prism core
- peripheral structure is removed
what is type 3 etching pattern?
- haphazourd effect
- not related to prism morphology
Why is dental dam the gold standard mositure control?
- protects the airway
- isolates the tooth alone
- protects tooth from salivary bacteria
what does pulp protection protect the pulp from?
- bacterial insult
- chemical attack
- thermal discomfort
what is bacterial insult?
caries - principal cause of pulpal inflammation
what is a chemical attack?
- constituents of certain restoative materials
- acids in certain dentine bonding agents (if close to pulp)
- residual acid from acidoegenic bacteria
what is thermal discomfort?
- polymerisation exotherm of some restorative materials (resin composite and RM glass polyalkenoate)
- light curing units themself
- hot/cold food/drinks
- cavity prep produces heat (must use coolant)
what would the ideal pulp protection consist of?
- non-toxic
- non irritant
- bacteriostatic
- gives good coronal seal
- thermal/electrical insulator
- strength to withstand restoration placement e.g. condensing amalgam
- radiopaque
- compatible with wide range of restorative materials
- obtundant (soothing) effect on pulp
- the ideal pulp protection is dentine
what are the most commonly used pulp protection?
calcium hydroxide (dycal)
reinforced/resin modified glass polyalkenoated (GI)
what are the qualities of glass polyalkenoates being used as a liner (vitrebond)?
- low pH but high acid - only mildly irritant to pulp
- Contains fluoride - bacteriostatic
- thermal/electrical insulator
- sufficient strength to withstand condensation
- directly adhesive so good coronal seal
- good compatibility with other materials
- may be chemical cured or reinforced with ‘resin modification’ and made light cured
what lining would you use in cavities of 2mm or less?
none
what lining would you use in significantly deep cavities (within 0.5mm from pulp)?
hard setting CaOH, only need to cover with RMGIC if restoring with amalgam
What may some clinicians place in cavities that are >2mm but less than 0.5mm from pulp?
RMGIC
where should a liner be used?
pulp-axial wall
what is a direct pulp cap?
- when exposed pulp (caries, trauma, tooth prep) is covered by a capping material
- micro exposure
- usually hard setting CaOH or more recently mineral trioxide aggregate (MTA)
- only successful outcome under certain conditions (50% success rate)
what is an indirect pulp cap?
- when the cavity extended to within 0.5mm of pulp
- capping material (CaOH) is applied to the deepest part of the cavity
- restored as normal
what is the criteria for direct pulp capping?
- tooth is vital
- no hirstory of pain in tooth
- no evidence of periradicular pathology
- pulp pink and healthy, no excessive bleeding
if any of above found to be untrue, RCT or XLA most likely required
what is the direct pulp capping technique?
- microexposure dried with cotton wool - NO AIR DRYING
- Pulp capping material applied to exposure and other areas if close to pulp
- tooth restored as normal, patient advised to return if problems with the tooth
- if in any doubt refer to dentist
what is NCTSL?
Non-Carious Tooth Surface Loss
The physiological or pathological loss of dental hard tissues (enamel and/or dentine/cementum) by any means other than the carious process or traumatic injury
what is attrition caused by?
tooth-tooth
What is abrasion caused by?
foreign object - tooth (mechanical habits)
what is erosion caused by?
acid-tooth
what is abfraction caused by?
occlusal overload
what are the tx options for NCTSL
- prevention, monitor
- fluoride therapy
- acrylic hard/soft splints
- restorations
why polish a restoration?
to remove the oxygen inhibited layer as well as smooth any rough or high surfaces to mimic the previous occlusion
what are the indications to use traditional GI to restore?
- abrasion and erosion cavities
- previously accepted as restoration of decidous teeth
- class V restorations
- tunnel preps (can be syringed into cavity and composite placed on top)
- temp restorations
- ART (caries is hand excavated and restored with GIC)
- Root caries
- luting cement for SSCR
When would resin modified GI be used? (vitrebond, riva)
- used to cover more fragile lining materials (CaOH)
- on its own for moderately deep cavities
- hand mix or capsules
- light cured
- self cure versions available
what is the open sandwhich technique?
- used when base of cavity is below ADJ
- GI used as a base material
- GI is in contact with oral cavity
What is the closed sandwhich technique?
- used when there is enamel remaining above the base of cavity
- the GI is sandwhiched between the tooth and the composite restoration
what are Black’s classification of cavities?
Class I - Occlusal surfaces of molars and premolars, buccal pits of molars
Class II - Approximal surfaces of molars and premolars
Class III - Approximal surfaces of incisors and canines
Class IV - Incisal edges of incisors and canines
Class V - Cervical margins
Black’s classification does not include root caries and secondary caries
Why do we Fissure seal?
- to remove stagnation area, you want shallow fissures
- to eradicate deep pits and fissures
- aid effective tooth brushing
- prevent development of caries
what surfaces are most commonly sealed?
- occlusal fissures of molars
- buccal pits of lower molars
- palatal pits of upper molars
- cingulum pits of upper molars
what is the clinical technique for F/S?
- mechanically cleanse
- isolate
- dry
- etch
- rinse
- isolate
- dry
- apply resin
- polymerise
- check occlusion
when evaulating your sealant what are you looking for?
- occlusal harmony
- are there any air bubbles present
- any under extension
- any over extension
- softness in material from under curing
- is it smooth
- is it bonded to the tooth
how do we catergorise F/S?
How are they polymerised
- UV, self polymerised/chemical cure/self cure-light polymerised
Their colour
Filled or unfilled
- filled contain lithium alumina-silicate and increases abrasion resistance. it can create tooth wear on opposing teeth
What are the clinical indications for doing F/S?
- high caries risk
- deep pits and fissures
- limited manual dexterity
- medically compromsied
- tooth must be able to be isolated - biggest problem is if a sealant fails and part is retained
What LA is the gold standard?
Lidocaine
What LA can we not use on a pregnant lady?
Those that contain felypressin as this is related to oxytocin
when should you restrict from using LA with adrenaline?
patients with cardiac problems e.g. unstable angina or severe dysrhythmias
explain the technique of doing an infiltration
Identify site
dry with 3 in 1
apply topical on cotton wool roll
leave for 2 minutes
remove cotton wool
use mirror to retract soft tissues, hold taught
ensure bevel is facing bone
syringe at 45 degree angle to bone
gently insert needle until bone is contacted
withdraw needle slightly and aspirate
if clear aspiration, slowly inject solution
withdraw needle
massage site
should have anaesthesia of the tooth and labial tissues
explain the technique of an IDB
get patient to open as wide as they can
identify pterygomandibular raphe
place supporting thumb in coronoid notch of ramus
inject needle half way between thumb and raphe
insert until bone is contacted (bevel facing operator)
withdraw needle by 1-2mm and aspirate
if no blood, start to slowly inject
leave a small amount to administer when withdrawing to catch the lingual nerve
key sign if its worked is a numb lower lip
explain the technique of a long buccal nerve block
anterior and lateral to the anterior edge of the ramus
inject at the level of the occlusal surface of the most posterior molar
explain the technique of a mental/incisive nerve block
palpate the mental foramen
apply topical to site
inject approximately 1cm towards the mental foramen
why does anaesthesia of the upper jaw usually only require an infiltration?
the outer bone is covering the maxillary teeth and is usually quite thin and porous
how do we overcome anaesthesia failure of the upper first molars?
as the zygomatic arch arises from the maxilla it can be obstructed
do 2 infiltrations mesially and distally of the first molar
explain the technique to give a palatal injection?
apply pressure with the mirror to the area for several seconds prior to injection - “counter irritant” procedure
aim for equidistant point between median raphe and gingival margin of target tooth
inject a small amount slowly, blanching indicates anaesthesia has been achieved
caution must be taken to avoid injecting directly around the greater palatine foramen
avoid rugae
why doe infiltrations not work so well in the lower molar region?
they are covered by a thick compact lamina bone which prevents diffusion of analgesic solution
what are the 2 ways to anesthetise the lingual nerve?
by an infiltration just under the attached gingivae on the lingual aspect
interpapillary injection
explain the technique of an interpapillary injection
injection of LA solution into soft tissue of the ID papillae
insert needle to the centre of the papilla near the crest of the bone
small amounts injected slowly
blanching confirms analgesia
What POIG should you give regarding LA?
warn patient that they will feel numb for a few hours after tx with a gradual return to normal
this return may be accompanied with a tingling/itching feeling
lidocaine with adrenaline should give pulpal anaesthesia for 1 hr but soft tissues will be longer
try reduce trauma by avoiding drinking hot liquids and chewing of lips whilst numb
slight discomfort may be felt at injection site hours after
why might analgesia fail?
- individual patient variations - delayed anaesthesia/ anaesthesia active period is very short
- intravascular injection - little or no anaesthetic affect as all is carried away in blood stream
- intramuscular injection - inadequate anaesthesia
- too little solution is used
- injection into infection site - analgesics works best in alkaline conditions, it may spread infection
If you penetrate too far with your needle during an IDB what can happen?
can risk injecting LA into parotid gland
block facial nerve
muscles of facial expression paralysed
loss of muscle tone - unilateral
unable to blink - risk of eye damage
how would you manage facial nerve palsy?
- reassurance
- explain
- provide eye patch
- arrange review
- document - what happened, what have you done?
- unlikely to last longer than duration of LA - sometimes can but this is unusual
What 4 nerves does an IDB catch?
Inferior alveolar nerve - pulpal anaesthesia to teeth 8-5
lingual nerve - branch of IAN - soft tissues to lingual gingivae and side of tongue
mental nerve - branch of IAN - soft tissues anaesthesia to buccal soft tissue 4-1
incisive nerve - branch of IAN - pulpal anaesthesia 4-1
what are black’s principles relating to cavity form?
outline form
resistance form
retention form
treatment of residual caries
correction of enamel margins
cavity debridement
what is outline form?
- Dependent upon location of caries: either by direct access or by gaining access through another part of tooth (more destructive)
- Traditionally- by cutting through overlying enamel (high speed handpiece and diamond bur)
what is resistance form?
- To enable the restoration and remaining tooth structure to withstand masticatory forces.
- Cavity floor at right angle to the direction of the occlusal forces
- Sufficient depth of material compatible with its physical properties
what is retention form?
to retain the material in the cavity
forms:
- grooves in wall
- undercuts and occlusal keys
- use of acid etch and bonding agents
- dentine pins
- Retention need only be modified fornon-adhesive materials (e.g. amalgam)
what is treatment of residual caries?
- Always remove caries from enamel-dentine junction first, then move on to the base ofthe cavity
- General rule of thumb –soft dentine is infected ,and should therefore be removed
- Firm, but stained dentine in the base of the cavity can be left
- Differing views onwhether stained but firm dentine should be removed from ADJ –general view – should be removed in anterior teeth if it will show through enamel
- using a slow speed rose head bur
- often finished with hand excavator
what is correction of enamel margins?
- Unsupported enamel is weak and prone to fracture
- Can be splinted by adhesive materials
- Remove weakened tooth substance
- Facilitate placement of matrix retainers
- Bevel to increase surface area for bonding
what is cavity debridement?
- Cavity should be thoroughly washed anddried to remove debris and bacteria.
