Endo Flashcards
2 types of fibres which transmit dental pain & sensations they trigger
A delta fibres → sharp, shooting pain
C fibres → dull, aching pain
Special investigations for endodontic examination
- Percussion
- Palpation
- Mobility
- 6PPC of tooth
- Sensibility: EPT, cold
- Radiographs
- Frac finder/ tooth sleuth
- Test cavity
- Selective anaesthesia
Which nerves do EPT typically stimulate?
A-delta
C fibres may not respond
In what cases may EPT readings be unreliable?
Open apices
Recent trauma
2 diagnoses in AAE endodontic diagnosis
Pulpal diagnosis
Periapical diagnosis
AAE pulpal diagnoses (7)
- Normal pulp
- Reversible pulpitis
- Symptomatic irreversible pulpitis
- Asymptomatic irreversible pulpitis
- Pulpal necrosis
- Previously treated
- Previously initiated treatment
AAE apical diagnoses (6)
- Normal apical tissues
- Symptomatic apical periodontitis
- Asymptomatic apical periodontitis
- Acute apical abscess
- Chronic apical abscess
- Condensing osteitis
Contraindications to endodontic treatment
Myocardial infarction within last 6 months
Considerations for patients with CVD to undergo RCT (3)
- Stress reduction protocol:
- Short appointments
- Sedation
- Pain & anxiety control
Considerations for diabetic patients to undergo RCT
Schedule appt so that does not interfere with patients normal insulin & meal schedule
2 guides for assessing case difficulty and the need for referral for endodontic treatment
AAE endodontic case difficulty assessment form
NHS Restorative Dentistry Index of Treatment need - Complexity Assessment
Discussion points to cover when consenting patient to endodontic therapy
- Procedure
- Prognosis
Irreversible pulpitis: 90%
Pulpal necrosis: 80% - Alternatives to tx
No treatment
Wait for more definitive symptoms to develop
XLA - Risks of tx:
Perforation
Instrument separation
Damage to adjacent restorations
Missed canals
Increased risk of fracture
Failure of endodontic tx - Risks of no tx:
Pain
Infection
Swelling
Loss of teeth
Infection to other areas - Consent
When may sensibility tests yield false positives?
Pulp not totally necrotic
Multirooted teeth (pulp in some canals may still be vital)
3 advantages of CaOH as cavity base/ liners
- High pH & stimulates reparative dentine formation
- Stimulates recalcification of demineralised dentine
- Neutralises low pH of acidic restorative material
3 disadvantages of CaOH as cavity base/ liners
- Cytotoxic
- Weak cement
- Very soluble if not protected
3 design objectives of mechanical preparation
Continuous taper
Maintain original location of apical foramen
Keep apical opening as small as possible
Ideal properties of endodontic disinfection irrigants (14)
- Low cost
- Washing action
- Reduces friction
- Kills planktonic microbes
- Kills biofilm microbes
- Non toxic to periapical tissue
- Non-allergenic
- Enhances cutting of dentine by instruments
- Temperature control
- Dissolves organic & inorganic matter
- Penetrates root canal system
- Does not weaken dentin
- Does not react with negative consequences with other dental materials
4 advantages of NaOCl as endodontic disinfection irrigant
- Potent antimicrobial
- Dissolves pulp remnants & collagen
- Dissolves necrotic & vital tissue
- Disrupts smear layer by acting on organic component
Factors important for NaOCl function (5)
Concentration (0.5% - 6%)
Volume (30ml after instrumentation, final rinse)
Contact (adequate apical preparation + needle size & type)
Exchange
Mechanical agitation (endoactivator, manual dynamic irrigation)
Concentration of NaOCl used for endodontics
0.5% - 6%
3 limitations/ disadvantages of NaOCl
Affects dentine properties: elasticity, flexural strength
Unable to remove smear layer by itself
Effect on organic material
Advantage of EDTA (1)
Capable of removing smear layer when used with NaOCl
Complications of NaOCl use (4)
Discolours fabric
Eye injury (chemical burns)
Extrusion injuries
Allergic reactions
MOA of CHX (3)
Antiseptic
+ charged CHX attracted to - charged phospholipid molecules
Binds to cell wall and causes it to rupture
Cell cytoplasm leaks → lysis → cell death
antiplaque
adsorbs to pellicle, provides bacteriostatic effect lasting 12-14 hours
3 advantages of CHX as irrigant solution
- Antibacterial
- Antimicrobial substantivity - adsorption prevents microbial colonisation
- Biocompatible
Disadvantage of CHX
Sensitivity possible - anaphylaxis
Interaction between CHX & NaOCl
- What does it form
- Problems it causes
Para-chloroaniline
Forms precipitate which may be cytotoxic & carcinogenic
Proposed cleaning & shaping protocol
- 3% NaOCl irrigation throughout instrumentation
- 30ml NaOCl penultimate rinse after instrumentation complete with MDI for 10 mins prior to obturation
- 1 min EDTA rinse
- Final NaOCl rinse
- Dry with paper points between irrigants
Symptoms of NaOCl extrusion (6)
- Pain
- Swelling
- Ecchymosis
- Haemorrhage
- Bad smell/ taste if bleach extrudes into maxillary antrum
- Intraoral ulceration
- Intraoral necrosis
- Airway obstruction
- Neurovascular deficit
- Altered sensation in areas of supply by mental nerve & infraorbital nerve
Risk factors of NaOCl extrusion
- Excessive pressure during irrigation
- Needle locked in canal
- Loss of control of working length
- Large apical diameters
– Root resorption
– Immature teeth
– Developmental abnormalities - Roots of maxillary molars close to sinus
Management of NaOCl extrusion (10)
- Stop tx
- Reassure pt and explain what’s happened + management
- Provide LA
- Irrigate with saline
- Allow haemostasis if profuse bleeding
- Dress with odontopaste
- Temporise and seal access cavity
- Post op advice
– Analgesia (Paracetamol +/- ibuprofen)
– Cold compress initially to reduce swelling
– Warm compress after to reduce ecchymosis - Refer if severe
- RV in 24 hours
How to prevent NaOCl accidents (12)
- Pre-op assessment for apices, perforations
- Good isolation: pre-endo build up if needed, caulking agent (opaldam), check seal of dam, dam approved by clinician
- Use index finger to depress plunger
- Luer lock syringe
- Fill syringe less for better control
- Side vented needle
- Needle should not bind
- Use rubber stopper on needle 2mm short of WL
- Bib and glasses for patients
- Pass syringe behind patient
- Report irrigation/ endodontic incident to staff
- Report any concern about clinical handling of NaOCl
Contents of odontopaste (4)
- ZOE
- Triamcinolone acetonide (corticosteroid)
- Clindamycin hydrochloride (antibiotic)
- CaOH
Use of odontopaste (1)
To reduce inflammation in inflamed +/ hyperaemic pulps to be root treated
Contents of ledermix (2)
- Demeclocycline (tetracycline antibiotic)
- Triamcinolone acetonide (corticosteroid)
Uses of ledermix
To reduce inflammation in inflamed +/ hyperaemic pulps to be root treated
3 advantages of non setting CaOH
- High pH, antibacterial (hydrolysis of LPS reducing its inflammatory potential)
- Removes tissue debris
- Improves cleaning ability with NaOCl
3 types of inter-appointment temporary dressings in endodontics
- GI
- Coltosol
- Cavit
Difference between K-reamers, K-files and H-files
- Cross section
K files (square), K reamers (triangle), H files (comma shaped) - Method of use
- Purpose
What motion are Hedstrom files used with?
Filing motion
Uses of Hedstrom files
GP removal
Fractured instrument removal in retreatment cases
What motion are K-reamers used with?
Winding (¼ to ½ turn CW)
Advantages of NiTi material as endodontic file (2)
- Superelasticity
– Less transportation, zipping & ledging
– Maintains original canal shape
Advantages of NiTi over SS files
More flexible
More efficient cutting
Safe
User friendly
Disadvantages of NiTi files
- Expensive
- Access difficult posteriorly
- Unsuitable for complex canal anatomy
- Instrument fracture
How to select which Reciproc files to use (R25, R40 or R50)
R25 if canal partially/ completely invisible on pre-op radiograph // if visible on radiograph but size 20 file cannot go to WL passively
R40 If visible on radiograph but size 20 file can go passively to WL
R50 if size 30 file can go passively to WL
2 causes of instrument separation
Torsional fatigue (incorrect file size, locked tip)
Cyclic fatigue (repeated use of file)
Constituents of GP (4)
Gutta percha 20%
Zinc oxide 65%
Radio opacifiers 10%
Plasticizers 5%
GP obturation techniques
Cold lateral compaction
Size matched cones
Warm vertical compaction
Continuous wave obturation
Carrier based obturation
Functions of sealer (3)
Seals space between core material and dentinal wall
Fills voids and irregularities in canals, lateral canals and between GP in lateral condensation
Lubricates during obturation
Properties of an ideal sealer
- Tacky to provide good adhesion
- Establishes hermetic seal
- Easily mixed
- Slow set
- No shrinkage on setting
- Non staining
- Bacteriostatic
- Insoluble in tissue fluids
- Tissue tolerant
- Soluble on retreatment
4 types of sealers
ZOE based sealants
GI sealants
Resin based sealants
Calcium silicate sealants
Advantages (1) and disadvantages (2) of ZOE based sealer
Advantage: antimicrobial
Disadvantages
Free eugenol - irritant
Loses volume with time
Advantages (1) and disadvantages of GI sealers (2)
Advantage: good dentine bonding
Disadvantage:
Minimal microbial activity
Difficult to retrieve
Advantages of resin sealers (3)
Good seal
Good flow
Slow setting
Advantages of calcium silicate sealers (6) and 1 disadvantage
Advantage
- Hydrophilic
- Biocompatible
- Does not shrink on setting
- Non resorbable
- Good seal
- Quick set
- Easy to use
Disadvantage
- Difficult to retrieve
Criteria for successful outcome post endo (according to ESE guidelines)
At 1 year assessment:
- Absence of pain, swelling, sinus tracts and other symptoms of inflammation
- No loss of function
- No radiographic signs of PA pathology
Criteria for uncertain outcome post endo (according to ESE guidelines)
Initial radiographic lesion remains same size, or slightly reduced in size
Criteria for unfavourable outcome post endo (according to ESE guidelines)
Signs & symptoms of infection
- New lesion appeared post tx/ pre existing lesion increased in size
- Pre-existing lesion remained same size/ reduced in size 5 years post endo
- Continuing root resorption
4 pre-op factors affecting endodontic success
- Presence (absence) of pre-op lesion
- Filling to within 2 mm of radiographic apex but not extruded
- Well condensed fillings with no voids
- Quality coronal restoration
3 laws of access & canal location (3 + 3)
- Law of symmetry I & II:
- Orifice of canals are equidistant from (I) & perpendicular to (II) a line drawn in a MD direction through pulp chamber floor - Law of colour change
Pulp chamber floor is darker than pulpal walls - Law of orifice location I, II & III
Orifice of canals located at junction of the floor & walls (I), and at its angles(II), and at the terminus of the developmental fusion lines (III)
Reasons for endodontic failure (8)
- Missed canals
- Perforation
- Instrument separation
- Root fracture
- Ledges
- Radicular cysts
- Faults in obturation: not to length (2mm of radiographic apex), extruded sealant, poorly condensed filling with voids
- Coronal leakage
Rotary file systems suitable for retreatment
Protaper D1 - D3
Reciproc
What file can be used to bypass ledges?
Pre-curved C+ file
5 complications of endodontic instrumentation
- Perforation
- Ledging
- Zipping
- Apical transportation
- Fractured instrument
How to avoid perforation
- Good pre-op assessment & planning: radiographs
- Good knowledge of anatomy
- Measure pre-op radiograph to pulp chamber roof/ floor
- Use DG16 and rubber stopper as depth gauge
How to avoid zipping/ transportation (3)
- Pre curving initial small hand instruments for curved canals
- Do not skip instruments in sequence
- Do not rotate instruments in curved canals
How to avoid short obturation
- Good pre-op assessment: EWL
- Apical gauging
- Reference point selection
- Cone fit radiograph
How to avoid blockages
- Don’t skip files
- Ensure file is passive before moving onto a bigger file
- Don’t force files
- Copious irrigation and recapitulation
- Reservoir of irrigant in pulp chamber while instrumenting
How to avoid fractured files
- Aware of limitations of instrument
- Use recognised technique
- Pay attention to degrees of rotation
- Stay focused
- Lubricate canal
- Know settings of rotary
How to avoid loss of control during obturation
- Obturate one at a time
- Super endo alpha to remove excess
- Buchanan plugger to condense
- Magnification
Anterior restoration option for anterior teeth with intact marginal ridges
Composite
Anterior restoration option for anterior discoloured teeth with intact marginal ridges
Bleaching + composite
Veneer
Anterior restoration option for anterior teeth with marginal ridges destroyed
Core build up with crown
Post core + crown
Type of teeth unsuitable for post placement (think anatomy of teeth)
- Mandibular incisors
- Curved canals
- Incisors & canines if sufficient coronal dentine
- Premolars (if needed consider placing in widest root canals)
Post design:
- Minimum post length : crown length ratio
- Length of post into root
- Maximum width
- Remaining root filling length
1 : 1
Half of post length into root
No more than ⅓ of root diameter at narrowest point & 1mm of remaining circumferential coronal dentine
4-5mm of apical GP
What is a ferrule and why is it important? Minimum height and width of ferrule
Collar of sound dentine within the walls of a crown
To prevent tooth fracture
1-2 mm vertical axial tooth structure
3 ideal post designs and why (3 + 4)
Parallel (no wedging effect + retentive)
Non threaded (passive - incorporates less stress to remaining tooth)
Cement retained (buffer between masticatory forces and post/ tooth)
3 post materials
Metal
Ceramic
Fibre
Advantages (1) & disadvantages (5) of metal posts
Advantages:
High strength
Disadvantages:
- Poor aesthetics
- Root fractures
- Corrosion
- Nickel sensitivity
- Radiopaque on radiographs
Advantages (3) and disadvantages (2) of ceramic posts
Advantages:
Aesthetic
High flexural strength
High fracture toughness
Disadvantages:
Difficult to retrieve
Root fracture common
Advantages (5) of fibre posts
Aesthetic
Retrievable
Flexible
Bonds to dentine with DBA
Radiolucent on radiographs
Recommended use for tapered & parallel prefabricated posts
Circular, small canals
Recommended use for custom cast post & core
Elliptical or flared canals
4 important bits of information to include in a cast post & core prescription to the lab
Size of preparation (para post colour)
Core 6 degree taper
Amount occlusal clearance needed for crown
Shade
4 complications of post placement
Perforation
Core fracture
Root fracture
Post fracture
3 indications for non surgical root canal treatment
- New complex restoration with technically poor endo
- Failed endodontic treatment: inflammation, symptomatic, PA pathology
- Loss of coronal seal
