Molar endo - ALL OF NATS Flashcards
what are the biological objectives of endodontic treatment?
Confine → prevent → remove → attempt → create
According to De Deus, how many distinct patterns do accessory canals occur in mandibular first molars?
3
In a single furcation canal, what percentage of accessory canals extend from the pulp chamber into the intraradicular region?
13% - which is why we seal the floor of the pulp chamber with RMGIC
What percentage of accessory canals extend from the coronal ⅓ of the major root canal to the furcation region? and which canal is it usually?
23%, distal root canal
What percentage have both lateral and furcation canals?
About 10%
What difficulty would you face during obturation treating a tooth with multiple accessory canals?
Just use thermoplastic wtv la raite cant use cold lateral compaction - cold lateral compaction not easy → use thermoplastic technique
What is the height from the pulpal floor to the furcation?
3mm
What is the height of the pulp chamber of a mandibular molar?
1.5mm
What is the height (gross) of the pulp chamber of a maxillary molar?
2mm
What is the height from buccal cusp to pulp chamber?
6mm
How many canals are in a maxillary first molar?
3-4 canals
Where is the 2nd MB canal located?
On a line between MB and palatal orifices
How many roots are in a mandibular 1st molar? How many canals in each?
2 - 2 in mesial, 1 or 2 in distal
What is the distolingual root of the mandibular 1st molar called?
Radix entomolaris
What is the mesiobuccal root of the mandibular 1st molar called?
Radix paramolaris <5%
How many roots are usually in a mandibular 2nd molar and how many canals?
2 roots, 3 canals
What is a common cause of endodontic failure? How often are they found?
Failure to identify all canals due to less than adequate access, missing canals found in 42% of endodontically failing teeth
What shape is the access cavity design on a maxillary molar?
Blunted triangular outline, base of triangle towards buccal, apex towards palatal, enture access within mesial half of tooth
What shape of the access cavity design on a mandibular molar?
Rhomboid shape to allow for exploration of second distal canal, access cavity within mesial half of tooth but extended as far distally as necessary
What are the objectives of creating an access?
Remove all caries,
conserve tooth tissue,
remove pulp chamber and horns while creating smooth axial walls,
remove all coronal pulp tissue,
local all root canal orifices,
avoid damage/perforation,
achieve straight line access,
minimise marginal leakage of restored tooth
What type of bur do you use to access a cavity?
Non-end cutting to avoid damage to pulpal floor
What happens when there is inadequate opening by poor access preparation?
Compromised cleaning + shaping, compromised instrumentation, coronal discolouration, prevents good obturation, instrument breakage, perforation, ledging
What may happen if there is mutilation of coronal tooth due to removal of too much tooth structure?
Coronal fracture
What may happen if there is inadequate caries removal?
Carious destruction of tooth and discolouration
What happens if there is labial/furcal perforation?
Can cause periodontal destruction and weakens tooth structure
What is the best way to establish a working length?
Electronic apex locator (EAL) and size 10 file
How do you check apical patency?
The ability to pass a small flexofile passively through the apical constriction without widening it
What do you irrigate the canal with?
Sodium hypochlorite
What do you use to establish a guide path?
ProGlider
At what speed and torque do you use the ProGlider at?
300rpm, 2Ncm
At what speed and torque do you use the shaping and finishing instruments at?
300rpm, 4Ncm
What should you record in the patient’s notes after taking the working length?
Record the WL and reference points
During final irrigation what do you use?
3ml sodium hypochlorite + ultrasonic activation in order to disrupt he biofilm,
3ml citric acid + ultrasonic activation, 3ml sodium hypochlorite
What should you use when doing lateral compaction to fit accessory canals?
Size B finger spreader
How do you obturate converging canals?
One GP should be placed to full WL, 2nd GP carefully inserted as far as possible, measure shorter one and cut off from apical end and place in canal
What is eliminated in the disinfection of the canal?
Pulp tissue, microbes, irritants, smear layer (dentinal mud), biofilm
What percentage of canal walls can be contacted by instruments in oval shaped canals?
40%
How does biofilm develop?
Deposition of a conditioning film, adhesion and colonisation of planktonic microorganisms in an extracellular amorphous matrix (EPS), co-adhesion of other organisms, detachment into surroundings
What is the chemical purpose of root canal irrigants?
To inactivate biofilm and endotoxins, dissolve tissue remnants/smear layer
What is the physical purpose of root canal irrigants?
To allow the flow of irrigant throughout RCS to detach biofilm and 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 symmetrically non-toxic, non-caustic to periodontal tissues, little potential to cause anaphylactic reaction
What are the commonly used irrigants?
Sodium hypochlorite, EDTA, citric acid
What type of flow do irrigants have within the root canal?
Laminar, turbulent
What does laminar flow do?
Remove planktonic bacteria but only effective slightly beyond tip of needle
What is the frequency of ultrasonic?
25,000 cycles/second
- What is the area of stagnation known as?
Vapour lock effect
- How does turbulent flow work?
- Which is more likely to penetrate biofilm?
By sonic/ultrasonic agitation, acoustic streaming, cavitation
Turbulent flow
- What can be used to minimise coronal leakage?
RMGIC (vitrebond), smart dentine replacement (SDR)
- What are the properties of SDR?
A flowable bulk filler that can be placed up to 4mm, self levels and minimises shrinkage stress
- How do you provide coronal seal following obturation?
Clean access cavity with alcohol on microbrush, etch + bond in access, place SDR in pulp chamber and access cavity, leave 2mm to be filled with conventional composite if indirect restoration not prescribed
- According to the European society of Endodontology’s quality guidelines when should RCT follow-up be? What happens if they are not healed?
Clinical + r/g follow-up at least 1 year after treatment; further
review for 4 years
- What is defined as an endodontic emergency?
Pain or swelling caused by various stage of inflammation or infection of pulpal or periapical tissues
- What are the different types of endodontic pain?
Pre-treatment pain, interappointment pain, pain immediately following obturation, pain occurring sometime later associated with previously treated tooth
- What is recommended for analgesics of mild to moderate dental pain in adults according to the SDCEP?
Paracetamol, 2x500mg, 4x/day or ibuprofen, 2x200mg, 4x/day after food
- What is recommended for analgesics for moderate to severe dental pain in adults according to the SDCEP?
Increase the dose of ibuprofen to 3 tablets or ibuprofen + paracetamol together, diclofenac 50mg, 3x/day + paracetamol together
- What are the recommended first line antibiotic doses for dental infection in adults?
Amoxicillin 500mg 3x/day or phenoxymethylpenicillin 2x250mg 4x/day or metronidazole 400mg 3x/day
- What is dentine hypersensitivity?
An exaggerated response to application of stimulus to exposed dentine regardless of its location
- What is the presentation of dentine hypersensitivity?
Short, sharp pain from exposed dentine in response to stimuli which cannot be ascribed to any other dental defect or pathology
- What is the treatment of dentine hypersensitivity?
Desensitising agents to disturb the transmission of nerve impulse agents and occlude dentinal tubules agents
- What is an example of a desensitising agent?
Potassium nitrate
- What are examples of occlude dentinal tubule agents?
Fluorides,
oxalates,
varnishes,
adhesive systems,
bioglass,
casein-phosphopeptide-amoourphous calcium phosphate,
laser
- What are the symptoms of irreversible pulpitis?
Intermittent or spontaneous,
lasts only minutes or lasts hours,
pain may be induced by exposure to extreme temps and very difficult to localise in early stage
- What is the treatment of irreversible pulpitis?
Once the correct tooth is located,
RCT only if its restorable, remove source of infection or emergency pulpotomy and dress with ledermix/odontopaste until RCT can be carried out
or XLA
- What should you use as an interappointment dressing?
Calcium hydroxide
- What are the symptoms of reversible pulpitis?
Sharp pain to cold or sweet/salty/sour and lasts few seconds
- What is the treatment of reversible pulpitis and is it an emergency?
NOT an emergency,
caries removal + restoration/dressing, r/v periodically as pulp may become necrotic
- For vital pulp therapy for treatment of a carious vital pulp exposure what material would you use as a dressing directly on the pulp tissue?
MTA or biodentine
- What are the causes of systemic periapical periodontitis?
Bacteria,
toxins from infected,
necrotic pulp,
procedures during RCT such as over-instrumentation that pushes debris beyond the apex
- Why is odontopaste & ledermix not suitable for pregnant women?
As triamcinolone acetonide has been shown to be teratogenic on test animals
- Patients with what drug allergies shouldnt not use odontopaste?
Allergy to lincomycin or clindamycin or patients taking concurrent doses of erythromycin
- In what situation should odontopaste be used in caution with?
GI disease esp colitis
- In what situation should ledermix not be used in?
Pregnancy or lactation
What are the symptoms of advanced symptomatic pulpitis?
Excruciating acute pain,
momentarily relieved by cold,
TTP,
reacts violently to heat, r/g: thickening PDL
- When shouldn’t you prescribe antibiotics?
Irreversible pulpitis,
symptomatic apical periodontitis,
draining sinus tracts (chronic abscess),
after endo surgery,
after incision for drainage of local swelling
- What are the causes of acute apical abscess?
Severe inflammatory response to bacteria/irritants in necrotic pulp,
bacteria from an infected root canal enters periapical tissues and immune system unable to suppress the invasion,
can be acute flare-up of a chronic periapical lesion
- What is the treatment of acute periapical abscess?
URGENT, removal of irritants,
drainage,
dress with CaOH and seal access,
relieve occlusion, r/v in 24hrs/drainage through soft tissue
- What do you irrigate with when removing irritants?
Sodium hypochlorite
- How do you drain an abscess through the root canal?
Place size 10/15 file 1-3mm through the apex
- What should you use on the soft tissues to get surface analgesia on soft tissues?
Ethyl chloride
- When should antibiotics be prescribed?
When there is progressive or persistent infection with systemic signs and symptoms
- In what circumstances should antibiotics be prescribed?
Where there is a diffuse swelling/cellulitis,
where drainage cannot be achieved,
when pt has systemic involvement
- What conditions would give you concern to refer the patient to hospital for IV antibiotics?
Ludwig’s angina, cervical fasciitis
- What is the dosage of phenoxymethylpenicillin?
250mg 4x/day for 5 days
- What is the dosage of amoxicillin?
500mg 3x/day for 5 days
- What is the dosage of metronidazole?
400mg 3x/day for 5 days
- What is the incidence of pulpal anaesthesia of teeth with irreversible pulpitis of mandibular molars even when there is a presence of 100% lip numbness?
55%
- What are the causes of endodontic flare-ups?
Prep beyond apex,
overinstrumentation,
pushing debris into periapical tissues,
incomplete removal of pulpal tissues,
overextension of root canal filling material,
chemical irritants,
hyperocclusion root fractures,
microbial factors
- According to Hulsmann’s criteria what are the signs of extrusion of irrigant?
Acute pain,
swelling,
redness,
progressive swelling esp. in infra-orbital region of mouth angle,
profuse hemorrhage,
numbness,
weakness of facial nerve,
secondary infection,
sinusitis,
cellulitis
- How do you manage extrusion of irrigant?
Irrigation with saline,
analgesics,
reassurance,
cold packs 6hrs,
warm compress,
r/v in 24hrs,
may rq rf
- What are the causes of pain following canal obturation?
Restoration in supraocclusion,
overinstrumentation,
toxicity of sealers,
root fracture
- What are the causes of coronal leakage?
Delay in placement of final restoration,
coronal temp filling compromised,
tooth fractures and RCS exposed prior to placement of final restoration,
final restoration lacks marginal integrity,
recurrent decay present at restoration margins
- According to Janck et al. what is the effect of ZOE?
Zinc competes with calcium for binding sites of the surface of hydroxyapatite, eugenol increases dentine microhardness
- According to Grigoratos et al. which high concentration root canal irrigants may increase the risk of root fracture and how?
5% Sodium hypochlorite and 17% EDTA, reduced flexural strength, elastic modulus and microhardness
- What is now the name of the biological width?
Supracrestal attached tissues
- What is the incidence of root perforation?
3-10%
- What is the incidence of root perforations through iatrogenic perforation of post placement?
53%
- What tooth is considered strategically important in terms of restorative evaluations for root canals?
The distal-most tooth in the quadrant, maybe for retention of the clasp of denture or bridge abutment
- Why should you avoid post in posterior teeth?
- What can be used to utilise the pulp chamber for retention?
Roots are narrow and curved so strip perforation can easily occur
Nayyar core
- Why use posts after RCT?
Following RCT - minimal coronal tooth structure left and to improve retention of core
- What can a restoration with poor coronal seal lead to?
Allow saliva, bacteria and endotoxins access to root canal leading to periradicular periodontitis
- What should be used for mechanical removal of GP?
Protaper D files and Gate-Gliddens burs in sequence
- How much GP should you leave to determine post length?
At least 4mm
- What is the incidence of failure if the length of post = crown?
2.5% failure
- What is the incidence of failure if the length of post = ¼ crown?
25% failure
- What is the ferrule effect?
- What is the recommended ferrule labially and palatally?
- It is provided by bracing of the remaining tooth structure by the indirect restoration NOT the remaining coronal tooth structure
- 1.5-2mm
- What can be done if there is insufficient coronal tooth tissue for a ferrule?
Orthodontically extrude the tooth, crown lengthening,
accept it bro, XLA and replace
- What are the two types of posts?
Active and passive
- What is an active post?
Screwed into root dentine
- What is a passive post?
Relies on luting cement for retention
- What type of post provides the best retention?
- Threaded
- serrated
- smooth
- Parallel
- tapered
- What is a type of active, self-threading post?
Dentatus screw
- What is an example of a passive post?
- What are the benefits?
* Whats the prob?
Cast post and cores - smooth sided tapered posts that conform to original taper of root canal prep
Conserves tooth tissue, reducing risk of apical perforation
Least retentive design with high failure rate
- What is the benefit of using fibre posts?
They flex slightly and under load distribute stresses to the root dentine in a more favourable manner
- What are the options for choices of luting cements for post-retained restorations?
Zinc phosphate, polycarboxylate, GI, RMGIC, Composite resins
- What can be used to remove quartz fibre posts?
RTD fibre post removal kit
- How can you achieve mechanical retention in a core build-up without posts?
Pulp chamber in posterior teeth provide a natural undercut, grooves or slots, pins
- How can you achieve chemical retention in a core build-up without posts?
Bonding of composite, amalgam bonding or core
- What are the disadvantages of using pins?
Induces internal stresses, cause dentinal crazing, self-shearing pins often do not shear at full depth of pin-hole, fracture resistance of core reduced, perforation into periodontium
Which file is used for coronal flaring?
SX file
By flaring coronal third using an SX file, you will achieve what by removing the triangles of dentine?
Straight-line access.
What is the order in work when doing the coronal 2/3s shaping?
- Flood access cavity with sodium hypochlorite
- Use SX (300rpm, 2Ncm) to create straight line access
- Irrigate sodium hypochlorite
- Glide path with size 8 or 10 flexofile with paste – precurve tip
- Expand glide path using proglider (300rpm, 2nm)
- Irrigate with sodium hypochlorite
- Shape coronal 2/3s with s1 (300rpm, 4ncm), brush, follow, irrigate, recapitulate, irrigate.
- Shape coronal 2/3s with s2, brush, follow, irrigate, recapitulate, irrigate
Which file would be used to determine the working length in a apex locator?
10 flexofile.
What must you do when taking the working length?
Record the length and the reference point in patients’ records (cuspal tip)
What is the order in work when shaping the apical 1/3?
- Take glide path to WL
- Ensure size 10 flexofile is loose at WL
- Expand glide path using proglider (300rpm 2 Ncm)
- Irrigate with sodium hypochlorite
- Use S1 (300rpm, 4Ncm) brush, follow to WL, irrigate, recapityulate, irrigate
- Use S2 (300rpm, 4Ncm) brush, follow to WL, irrigate, recapitulate, irrigate.
What is the order when finishing the apical third?
- Use F1 (300rpm 4Ncm) to WL, follow, brush
- 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 the correct apical size has been achieved for each canals.
What is the final irrigation procedure?
- 3mL sodium hypochlorite (+ultrasonic activation)
- 3mL citric acid (ultrasonic activation)
- 3mL sodium hypochlorite
- Dry canals with corresponding size of paper points and dress with non-setting calcium hydroxide, cotton wool/sponge, coltosol, glass ionomer.
What is the process for obturation?
- When patient returns check dressing is intact and that symptoms have improved, and sinus is present should have healed.
- Give LA, place rubber dam ad remove dressing
- Irrigate canals with citric acid to remove calcium hydroxide paste – leave canals wet
- Select correct size of gutta percha master points, measure to correct WL and place in the canals and take a radiograph (known as trial point or master apical cone radiograph)
- Have this checked by supervisor and carry out a repeat final irrigation with sodium hypochlorite, citric acid, sodium hypochlorite
- Dry the canals with correct size of paper points measured to WL before obturating
- Always use minimum amount of sealer and lateral compaction using a size B finger spreader and size b accessory cones.
How would you obturate converging canals?
- One GP should be placed to full working length, the second GP is carefully inserted as far as possible – this will be short of WL
- Remove this GP point and measure how short it is, cut this length off from the apical end of the GP and place in the canal.
- It should now reach the point of merger – take a trial cone radiograph (using MBD to separate canals)
What are you wanting to eliminate during the disinfection process?
- Pulp tissue
- Microbes
- Irritants
- Smear layer – dental mud and biofilm
In oval shaped canals, what percentage of the walls can be contacted by instruments?
40%
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 nontoxic
- Non caustic to periodontal tissues
- Little potential to cause anaphylactic reaction
Entrance to root canals and floor of pulp is sealed to prevent coronal leakage, what two materials can be used to seal the pulpal floor?
- Resin modified GI (vitrebond)
- Smart dentine replacement (SDR)
What is the process to provide a coronal seal?
- 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
For root canal, clinical and radiographic follow up at least ? year after treatment?
1 year
What is an endodontic emergency?
Defined as a 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, deep or defective restorations.
At what stages can you experience endodontic pain?
- Pre-treatment pain
- Inter-appointment pain
- Pain immediately following obturation
- Pain occurring some time latter associated with a previously treated tooth.
What is the maximum dose of ibuprofen over the counter and what is the maximum dosage dentist can prescribe?
Over the counter 1.2g dentist 2.4g
What is the maximum dosage of paracetamol?
4g
What is the dosage for amoxicillin, phenoxymethylpenicillin, and metronidazole for endodontic pain?
- Amoxicillin: 1 x 500 mg capsule 3 times daily.
- Phenoxymethylpenicillin: 2 x 250 mg tablets 4 times daily
- Metronidazole: 1 x 400 mg tablet 3 times daily
What is the pre-treatment pain plan?
- Identify the problem – patient complaining of….
- Take/update the medical history
- Locate the source (if possible) – subjective and objective examination
- Make a diagnosis
- Emergency treatment to relieve pain.
What are the pre-treatment pain – differential diagnosis?
- Dentine hypersensitivity
- Reversible pulpitis
- Irreversible pulpitis
- Systematic periapical periodontitis
- Acute apical abscess
- Pain from previously treated tooth
- Pain of non-odontogenic origin
- Pain associated with trauma
What is dentine hypersensitivity?
An exaggerated response to application of a stimulus to exposed dentine regardless of its location. It is a short, sharp pain from exposed dentine in response to stimuli which cannot be ascribed to any other dental defect or pathology. Caused by rapid flow in dentinal tubules, which results in the hydrodynamic activation of A delta fibres.
What is emergency pulpotomy method?
- LA
- Place rubber dam
- Completely open pulp chamber
- Wash gently with sodium hypochlorite
- Amputate coronal pulp using high speed
- Wash and dry with cotton wool (never with 3 in 1)
- Seal with odontopaste/ledermix into pulp chamber
