Endo Flashcards
What are the five biological objectives of endodontic treatment?
1) confine
2) prevent
3) remove
4) attempt
5) create
What does “confine” refer to in the endo biological objectives?
confine instrumentation to within the root canal
What does “prevent” refer to in the endo biological objectives?
prevent extrusion of necrotic debris in the periapical tissues
What does “remove” refer to in the endo biological objectives?
remove all vital and necrotic tissue from the root canal system
What does “attempt” refer to in the endo biological objectives?
attempt to complete all cleaning and shaping in one visit
What does “create” refer to in the endo biological objectives?
create sufficient space and taper for irrigation and placement of inter-appointment medicament
In Vertucci’s canal configurations, what types have only one canal at the apex?
type I, II and III
In Vertucci’s canal configurations, what types have two canals at the apex?
Type IV, V, VI and VII
In Vertucci’s canal configurations, what types have three canals at the apex?
Type VIII only
What three distinct patterns do accessory canals in mandibular first molars appear in?
1) in 13% a single furcation canal extends from pulp chamber to intraradicular region
2) in 23% a lateral canal extends from coronal third of major root canal to the furcation region (80% from distal canal)
3) about 10% have both lateral and furcation canals
Where is the apical limit for endo preparation?
Apical constriction
What is a general rule for locating the canals in endo?
you should not have to cross the oblique ridge in order to find all of the canals (usually mesially placed)
Generally, what is the distance from the pulpal floor to the furcation?
3mm
Generally, what is the height of the pulp chamber? (mandibular and maxillary molars)
mandibular molars - 1.5mm
maxillary molars - 2mm
Generally, what is the height from the buccal cusp to the pulp chamber roof?
maxillary and mandibular 6mm
In what percentage of mandibular and maxillary molars are the pulp chamber ceiling and CEJ coincident?
mandibular molars - 98%
maxillary molars - 97%
What root canals are present in a maxillary first molar?
3 - P, MB and DB
How many canals are there in a maxillary first molar?
3-4 canals
P, MB1, MB2, DB
MB2 located on line between MB and P orifices
How many canals are there in a maxillary second molar?
usually 3 (MB, DB, P), always look for 4
more variety in 2nd molar than 1st molar
How many roots are there in a mandibular first molar?
2 well formed roots
How many canals are there in the M root of the mandibular first molar?
2 canals - MB and ML
How many canals are there in the D root of the mandibular first molar?
1 or 2 - DB and/or DL
How many roots are there in a mandibular second molar?
two roots
How many root canals are in a mandibular second molar?
usually 3, always look for 4
What is considered one of the most important factors in enabling efficient and effective root canal preparation and obturation?
correctly sized and sited access cavity
What are the objectives of an access cavity?
- remove all caries
- conserve as much tooth tissue as possible
- remove roof of pulp chamber and pulp horns, create smooth axial walls
- remove all coronal pulp tissue
- locate all canal orifices
- avoid damage to pulpal floor or perforation
- achieve straight-line access to AF or initial curvature
- minimise marginal leakage of restored tooth
What is the access cavity design for maxillary molars?
- blunted triangle outline
- base of triangle toward buccal
- apex of triangle towards palatal
- orifice positioned at each angle of triangle
- access cavity entirely within M half of tooth
What is the access cavity design for mandibular molars?
- rhomboid shape to allow for exploration of second distal canal
- access cavity within mesial half of tooth but extended as far distally as necessary to allow ease of positioning of instruments
What complications can be caused by inadequate opening during access preparation?
- compromised cleaning and shaping of canals
- compromised instrumentation
- coronal discolouration
- prevents good obturation
- instrument breakage
- perforation
- ledging
What complications can arise by mutilation of coronal tooth due to removal of too much tooth structure in access preparation?
coronal fracture
What complications can arise due to inadequate caries removal in access preparation?
- carious destruction of tooth
- discolouration
What complications can arise due to labial/furcal perforation during access preparation?
- can cause periodontal destruction
- weakens tooth structure
What kind of debris can be created and cause the blockage of canals or orifices?
dentinal debris
amalgam fillings
What type of ProTaper files were designed in 2022?
ProTaper Ultimate
What is the special feature of ProTaper Gold instruments?
controlled memory
How is controlled memory instilled in ProTaper Gold instruments?
- files undergo multiple heating and cooling cycles
- reaches optimal phase transformation from martensite to austenite
What does the controlled memory characteristic of ProTaper gold instruments provide?
greater flexibility
improved resistance to cyclical metal fatigue
What lengths of ProTaper gold files are available?
21mm, 25mm and 31mm
What files are shaping files?
SX, S1 and S2
What files are finishing files?
F1, F2, F3, F4, F5
What is the cross down sequence?
flaring the coronal third using SX to achieve straight line access
How do you shape the coronal 2/3?
-flood access cavity with sodium hypochlorite
- use SX to flare coronal orifice and achieve straight line access
- irrigate
- glide path - scout coronal 2/3 with size 08 or 10 flexofile with paste lubricant, precurve tip in curved canals
- expand glide path with proglider
- irrigate
- shape coronal 2/3 with S1, brush, follow, irrigate, recapitulate, irrigate
- shape coronal 2/3 with S2, brush, follow, irrigate, recapitulate, irrigate
At what speed and torque is the SX used?
- 300 rpm
- 2Ncm
At what speed and torque is the ProGlider used?
- 300 rpm
- 2 Ncm
At what speed and torque is the S1 shaping file used?
300 rpm
4 Ncm
At what speed and toque is the S2 shaping file used?
300 rpm
4 Ncm
What are the 6 steps of endo instrumentation?
1) coronal 2/3 shaping
2) working length
3) shape apical 1/3
4) finish apical 1/3
5) final irrigation
6) obturation
How do you establish the working length?
- place a size 10 flexofile in each canal in turn
- ideally use electronic apex locator
- if not take WL radiograph using reproducible reference point (cusp tip)
- record length and ref point in pt notes
- achieve apical patency
Where should endodontic preparation end?
at the junction of pulpal and periodontal tissue
apical constriction
What is apical patency?
the ability to pass a small flexofile passively through the apical constriction without widening it
How do you establish working length with the EAL?
- Use EAL and size 10 flexofile
- irrigant in canal but not pulp chamber
- ask patient to wet lip clip with tongue
- ensure no contact with metal restorations when file in canal
- use a little Glyde to improve conductivity
What steps are involved in the shaping of the apical 1/3 of the tooth?
- take glide path to WL
- ensure size 10 flexofile is loose at WL, expand glide path using ProGlider
- irrigate with sodium hypochlorite
- use S1, brush, follow to WL, irrigate, recapitulate, irrigate
- use S2, brush, follow to WL, irrigate, recapitulate, irrigate
What is involved with finishing the apical third?
- Use F1 to WL, follow
- gauge with size 20 flexofile and inspect F1 file for debris on apical flutes
- irrigate, recapitulate, irrigate
- when required, use F2 to WL and repeat apical gauging procedure
- continue until correct apical size achieved
What is involved in the final irrigation?
- 3ml sodium hypochlorite (+ultrasonic activation)
- 3ml citric acid (+ultrasonic activation)
- 3ml sodium hypochlorite
- dry canals with corresponding size paper points and dress with non-setting calcium hydroxide, cotton wool/sponge, coltosol, glass ionomer
What is involved in the obturation step?
- pt returns, check dressing intact, symptoms improved and no presence of sinus
- give LA, place rubber dam and remove dressing
- irrigate canals with citric acid to remove CaOH paste, leave canals wet
- select correct size gutta percha master points, measure to correct WL and place in the canals to take radiograph (trial point or master apical cone radiograph)
- have checked and carry out repeat final irrigation
- dry canals to WL
- use minimum sealer and lateral compaction using size B finger spreader and size B accessory cones
How do you obturate converging canals?
- during insertion of GP points for MAC radiograph, you will be unable to seat both cones to full WL
- one GP should be placed to full WL
- 2nd GP is inserted as fat as possible (short of WL)
- remove this GP point and measure how short it is
- cut this length off from apical end
- it should now reach the point of merger
- trial cone radiograph
- following final irrigation and drying of canals, obturate the first canal to WL then obturate 2nd using the slightly shorter cone
Different species of microbes dominate at different stages of the endodontic process, what factors influence which microbes are present?
- availability of nutrition
- oxygen level (redox potential)
- local pH
What is the development of a biofilm?
-deposition of a conditioning film
- adhesion and colonisation of planktonic microorganisms in an extracellular amorphous matrix
What is the function of a biofilm?
biofilms protect microorganisms from adverse environmental changes and effects of biocides
Is rotary of mechanical instrumentation better at removing the biofilm?
rotary instrumentation is not any better at removing bacteria.
What is a limitation of instrumentation?
In oval shaped canals only 40% of the walls can be contacted by the instruments
What is the chemical objective of a root canal irrigant?
- inactivate biofilm and endotoxins, dissolve tissue remnants/smear layer
What is the physical objective of a root canal irrigant?
allow flow of irrigant throughout RCS so as to detach biofilm, flush out debris
What are the properties of an ideal irrigant?
- broad antimicrobial spectrum against anaerobic and facultative microbes organised in biofilms
- dissolve necrotic pulp tissue remnants
- dissolve smear layer
- be systemically non-toxic
- non caustic to periodontal tissues
- little potential of anaphylactic reaction
What will laminar flow of irrigants in root canals do?
will remove planktonic bacteria
only effective slightly beyond tip of needle - area of stagnation known as vapour lock effect
What is a disadvantage of laminar flow of irrigants?
only effective slightly beyond tip of needle - area of stagnation known as vapour lock effect
What is turbulent flow of irrigants in root canals?
acoustic streaming, cavitation
- caused by agitation of irrigation solutions, more likely to penetrate RCS and disrupt/remove biofilm
What type of flow of irrigant is most likely to penetrate the RCS and disrupt/remove the biofilm?
turbulent flow
What frequency does ultrasonic disinfection of the RCS operate at?
25000 cycles/second
What does ultrasonic disinfection of the RCS involve?
acoustic streaming, cavitation and increase in temperature of irrigant
Why is the pulpal floor sealed following obturation?
entrance to root canals and floor of pulp sealed to prevent coronal leakage
What is used to seal the pulpal floor?
resin modified GI (vitrebond)
smart dentine replacement (SDR) -
What is smart dentine replacement?
a flowable bulk filler that can be placed up to 4mm, self levels and minimises shrinkage stress
How do you provide the coronal seal following obturation?
- clean access cavity with alcohol on microbrush
- etch and bond access cavity
- place SDR in pulp chamber and access cavity
- leave 2mm to be filled with conventional composite if an indirect restoration is not prescribed
When should an endodontic treatment be reviewed?
clinical and radiographic follow-up at least 1 year after treatment
What is an endodontic emergency?
defined as pain or swelling caused by various stages of inflammation or infection of the pulpal or periapical tissues
What are the causes of an endodontic emergency?
usually caries or defective restorations
85% of all dental emergencies are as a result of pulpal or periapical disease requiring either RCT or extraction to relieve the symptoms
What are the four main types of endodontic pain?
1) pre-treatment pain
2) inter-appointment pain
3) pain immediately following obturation
4) pain occurring some time later associated with a previously treated tooth
Which analgesics are used to manage endodontic pain?
- paracetamol and/or ibuprofen
- diclofenac, co-codamol
beware of CI and cautions
Which antibiotics are used to manage endodontic pain?
for dental infection in adults either
- amoxicillin, 1x500mg cap 3x daily OR
- phenoxymethylpenicillin, 2x250mg tabs 4x daily OR
- metronidazole 1x400mg tab 3x daily
What is the recommended regimen of paracetamol for adults in dental pain (5 day regimen)?
2x500mg tablets up to 4x daily (every 4-6hrs)
What is the recommended regimen of ibuprofen for adults in dental pain (5 day regimen)?
2x200mg tablets up to 4x daily (every 4-6hrs) preferably after food
For moderate to severe dental pain for adults, what is an appropriate 5 day regimen?
either:
- increase dose of ibuprofen to 3x200mg up to 4x daily
- ibuprofen and paracetamol together, preferably after food without exceeding dose or freq of either drug
- di-clofenac (1x50mg tab 3x daily) and paracetamol together, preferably after food
For patients with severe infections (e.g. EO swelling, eye closing, trismus) what can be done to the dose of amoxicillin and phenoxymethylpenicillin?
it can be doubled
What is the maximum drug dose of paracetamol in a 24 hour period?
4g
What is the maximum drug dose of ibuprofen in a 24 hour period?
2.4g
What is the maximum drug dose of diclofenac in a 24 hour period?
150mg
What is dentine hypersensitivity?
an exaggerated response to application of a stimulus to exposed dentine regardless of its location. Short, sharp pain from exposed dentine in response to stimuli which cannot be ascribed to any other dental defect or pathology.
What kind of pain is experienced in dentine hypersensitivity?
short, sharp pain
What happens within the tooth to cause dentine hypersensitivity?
rapid fluid flow in dentinal tubules
hydrodynamic activation of A delta fibres
What are the stimuli for dentinal hypersensitivity?
- cold
- air (desiccating)
- hypertonic chemicals
What is the treatment for dentine hypersensitivity?
desensitising agents:
- disturb the transmission of nerve impulses agent - potassium nitrate
- occlude dentinal tubules agent - fluorides, adhesive systems, bioglass, oxalates, varnishes, lazer, casein-phosphopeptide-amorphous calcium phosphate
What are the symptoms of a reversible pulpitis?
- sharp pain to cold or sweet, salty, sour
- lasts a few seconds
What are the causes of a reversible pulpitis?
- caries into dentine
- broken, worn teeth
- defective restorations
- recent dental treatment
What is the treatment for a reversible pulpitis?
NOT a dental emergency
- usually just requires caries removal and a restoration/dressing to cover exposed dentine
- review periodically as pulp may quietly become necrotic (sensitivity testing)
What is irreversible pulpitis?
irritation of pulp continues from reversible pulpitis
- a severe inflammation that WILL NOT resolve even if cause removed
- pulp will slowly or quickly become necrotic
How can some irreversible pulpitis cases be asymptomatic?
no symptoms but deep caries or loss of tooth structure that if left untreated will cause symptoms of the tooth to become non-vital
How does a symptomatic irreversible pulpitis present?
- intermittent or spontaneous pain
- lasts only minutes or lasts for hours
- pain may be induced by exposure to extreme temperatures
- pain may be very difficult to localise in early stages
What is the treatment for an irreversible pulpitis?
once located correct tooth:
- RCT (if tooth restorable) - source of infection removed, complete cleaning and shaping in 1st visit where possible using CaOH as interappointment dressing
- Emergency pulpotomy (removal of coronal pulp tissue) and dressing with ledermix or odontopaste until RCT can be carried out
- Extraction
What symptoms are present in an advanced symptomatic pulpitis?
- excruciating acute pain
- momentarily relieved by cold
- often TTP as inflammation has extended periapically
- reacts violently to heat
- radiograph shows thickening of PDL
What are the treatment options for an advanced symptomatic pulpitis?
RCT
Pulpotomy if time is limited, adjust occlusion
extraction
DO NOT PRESCRIBE ANTIBIOTICS
When is an emergency pulpotomy indicated and what does it do?
- insufficient time to complete pulp extripation, cleaning and shaping of root canals
- alleviates pain until next appointment
- do not start canal prep in cases of IP if insufficient time
What is the method for carrying out an emergency pulpotomy?
- LA
- rubber dam
- completely open pulp chamber
- wash gently with sodium hypochlorite
- amputate coronal stump using high speed
- wash and dry with CW
- seal odontopaste/ledermix into pulp chamber
What is ledermix?
combines the antibiotic action of demeclocycline hydrochloride with the anti-inflammatory action of triamcinolone acetonide. Used as a dressing or lining under temporary or definitive restorations
- demeclocycline hydrochloride, triamcinolone acetonide
What is odontopaste?
A zinc-oxide based endodontic dressing used to reduce pain, as well as to maintain a bacteria-free environment within the root canal. Contains broad spectrum antibiotic clindamycin hydrochloride, and triamcinolone acetonide a steroid-based anti-inflammatory agent, and calcium hydroxide.
What is vital pulp therapy for the treatment of IP?
the complete removal of the coronal pulp and application of a biomaterial directly onto the pulp tissue at the level of the canal orifices, prior to the placement of a direct restoration.
materials - MTA or biodentine
What materials are used to place the direct restoration in a vital pulp therapy for the treatment of IP?
MTA or biodentine
What are the contraindications for the use of odontopaste?
- not suitable for pregnant women as triamcinolone acetonide has shown teratogenic effects on test animals
- not suitable for patients with allergy to lincomycin or clindamycin
- not used on patients taking concurrent doses of erythromycin as antagonism demonstrated
- used with caution in patients with history of GI disease, particularly colitis
- used with caution on nursing mothers as clindamycin shown to be present in breast milk
What are the contraindications for the use of ledermix?
- not be used during pregnancy or lactation
- glucocorticoids pass into breast milk, triamcinolone inadvisable in first 5 months of pregnancy in particular.
- demeclocycline penetrates placenta membrane and excreted in breast milk - antianabolic effect and teratogenic effects including deposits in bones and teeth
What is pulpal necrosis?
complete breakdown of the pulpal tissue
What causes pulpal necrosis?
bacteria reach the pulp - direct exposure, dentinal tubules, cracks in enamel or dentine
What causes symptomatic periapical periodontitis?
- bacteria, toxins from infected, necrotic pulp
- procedures during RCT such as over-instrumentation that pushes debris beyond the apex
How do patients with symptomatic periapical periodontitis present clinically?
Pain - tender to biting
How do patients with symptomatic periapical periodontitis present radiographically?
radiolucent area around apex of tooth
pt should be seen ASAP for treatment
What can cause a tissue swelling?
- acute periapical abscess
- interappointment flare-up
- post-endodontic complication
What kind of swellings can occur?
- localised or diffuse
- diffuse swelling (cellulitis - more extensive spreading through adjacent soft tissues and tissue spaces along fascial planes)
- fluctuant or firm
How are tissue swellings managed?
- achieve drainage - through RC or incision of fluctuant swelling
- remove source of infection by disinfection of the root canal
What is the cause of an acute apical abscess?
- severe inflammatory response to bacteria/irritants in necrotic pulp
- bacteria from an infected root canal enters the periapical tissues and the immune system is unable to suppress the invasion
- can be acute flare-up of a chronic periapical lesion