Clinical stuff Flashcards
Indications for endodontics
[8]
Irreversible pulpitis
Periapical pathology
Trauma
- High risk of pulp sclerosis which would make future RCT v difficult. Consider elective RCT.
Overdenture
Periodontal disease
- Peri-endo lesions (can resect the involved root and RCT the other roots)
Post retained restorations
- But will be elective RCT on a vital tooth so consider a lot before doing this
Teeth w doubtful pulps
- Esp if planning an indirect (1 in 5 fail anyway)
ORN or MRONJ risk
Contraindications to RCT
[8]
MH - can they withstand long treatment and lie back in chair e.g. epilepsy, age, joint issue in neck?
Limited mouth opening
- after radiotherapy, TMD, microstomia
Uncompliant pt/poor OH
Tooth isn’t restorable
Non-functioning tooth
Root fractures
Periodontally involved e.g. stage 2+ mobile
Anatomical variations e.g. v curved roots.
Types of root resporption
Cervical external resorption
External replacement resorption
Internal resorption
External cervical resorption
Due to trauma, ortho, bleaching + unknown
Starts at cervical area - root replaced by granulation tissue
Clinically = a catch and pink granulation tissue showing
Rad/CBCT = moth eaten area
If it extends into the pulp it will cause pulp symptoms
Diagnose early, explore and repair surgically and do RCT if needed
External replacement resorption
Due to trauma
PDL and root replaced with bone gradually - all of root surface.
Ankylosis and root turns into bone eventually and crown falls off.
Process happens quicker in children.
Clinically = submerged, metallic noise on percussion, v stiff teeth
Rad = moth eaten area but all around the tooth
Can be self limiting but usually not - no treatment but can do implants after bc lots of bone
Internal resorption
Due to history of/chronic pulpitis
Starts in pulp and expands.
Process continues until pulp becomes non-vital so diagnose early and RCT will stop the process and preserve tooth.
Clinically = pulpitis symptoms and pink spot if happening coronally
Rad = ovoid radiolucency in root canal
GP phases
Phase 1 - Beta = 42 degrees - Alpha = 42-49 degrees Phase 2 - Amorphous = 49 degrees. Can flow
Why use endo-sealers [3]
Lubricate instruments
Fill small defects/lateral canals
Seal obturating material
Types of endo-sealers [4]
Zinc Oxide Eugenol
Calcium hydroxide - less toxic but also less antibacterial than ZnO
MTA - hard to remove for retreatment
Resin-based - bonds to dentine but hard to remove for retreatment
Types of obturation techniques [7]
Cold lateral condensation Warm lateral condensation Single file Thermomechanical technique Warm vertical condensation Carrier-based technique Apical plug
Cold lateral condensation (cons)
Slow and technique sensitive
Doesn’t fill irregularities
Warm lateral condensation (technique)
Use k-file in ultrasonic and insert into the canal with master GP and heat it up to allow it to spread.
Accessory points are inserted like normal.
Single cone endo obturation (technique, pros and cons)
Like ProTaper
Easy and quick
But master GP needs to be exactly the same flare and size of prep files.
Doesn’t fill irregularities
Thermomechanical endo obturation (technique, pros and cons)
H files in the slow handpiece placed 3-4 apical from working length
GP heated up to allow it to soften and spread apically and laterally
But H files can snap and GP can extrude beyond apex.
warm vertical condensation (technique, pros and cons)
Apical plug 3-4mm from working length
- Normal master GP chosen
- Plugger that stops 3-4mm short heated and inserted into the GP in 1 motion and wait until it reaches at least 4mm (10s to stop shrinkage of GP)
- Remove and excess GP
Backfill the rest of the canal
- In 3-4mm bursts
- Compact after each burst
Easy, quick
Fills irregularities and lateral canals really well
Needs expensive and special equipment
Carrier-based method (technique, pros and cons)
GP around a heat resistant carrier e.g. plastic or heat resistant GP.
Choose the master GP and remove any excess GP that isn’t supported by the carrier as this will be hard to control.
Heat and insert into the canal in 1 quick motion
- Technique sensitive
- Hard to re-treat or place a post if used a plastic carrier.
- But easy to learn and good 3D obturation
Apical barrier obturation for open apices (technique)
For immature apices or apices wider than 0.7mm
Apical plug (MTA or Biodentine) and then backfill
Minimal prep needed bc canal is already wide, careful not to extrude irrigants.
Indications for surgical endodontics [4]
Can’t do regular RCT/re-treatment for PAP but need to save tooth
Persistant apical periodontitis
Apical surgery
Corrective surgery when you need direct visualisation e.g. perforation, GP extruding, external resorption, root resection
Types/reasons for persistent apical periodontitis [4]
Foreign material e.g. extruded GP
Cyst
Cholesterol crystals
Scar tissue formation
Contraindications to surgical endodontics [5]
MH - severe bleeding disorders, MRONJ/ORN risk, can’t withstand long surgery
Unrestorable tooth
Bone loss (apical surgery reduces crown: root ratio)
Poor surgical access
If other options are available
Surgical endodontics objectives [4]
Remove apical infection
Clean canal in a coronal direction
Seal apical portion and place filling in the canal
Allow PAP and soft tissues to heal
Surgical steps for surgical endodontics (tooth apical surgery) (brief) [11]
- NSAID and Corsodyl pre-surgery medication
- Analgesia
- Flap
- Bone removal/osteotomy
- Currettage of peri-radicular lesion
- 90-degree root apical resection
- Use special ultra-sonic equipment to debride root apex and clean/prepare canal 3-4mm at least
- Haemostasis and moisture control using epinephrine pellets
- Place a filling and seal in the canal (MTA, Biodentine)
- Suture
- POI
Incision/flap types for endodontic surgery
- Crevicular/sulcular flap with a relieving incision - but at risk for cervical recession
- Sub-gingival flap w 2 relieving incisions for crowns to avoid recession
- Papilla base incisions to leave papilla and reduce risk of recession here
Osteotomy for surgical endodontics - air rota used and why
Not contra-angle bc air is blown into the surgical field and can cause surgical emphysema and the angle is wrong.
Use a surgical air rota (correct angle and air not blown into surgical field)
POIG for surgical endodontics
Analgesia
Corsodyl to keep it clean
Usual bleeding, pain, infection post-op warnings
Stitches removed after 2-4 days
Icepacks
- Antibiotics only if worried about immunosuppressed pt
Examples of tricalcium silicates
MTA (mineral tri-oxide aggregate)
Biodentine
MTA components [4]
Medical-grade cement
With contaminants e.g. lead, arsenic removed
Radiopaque material added
Calcium Sulphate added to control the setting time
MTA benefits [6]
Non-resorptive No leakage Non-toxic Alkaline V bio-compatible (PDL and cementum can form onto it) Stimulates tertiary dentine
MTA or Biodentine uses [4]
Pulp cap Repairing perforations Repairing resorption defects Root apex surgery/apical plug Biodentine - stronger so can be used to bulk fill/as an intermediate and replaces the dentine
How to use MTA [4]
Mix with sterile water
Need to keep adding water bc the mix will dry out as you use it
If internal restoration then it will need some wet pellets to be placed next to it and left until the material has hardened.
Takes 3-4h for initial hardening, and then will continue getting stronger over 3 weeks.
Disadvantages of MTA [5]
Not that strong so shouldn’t be used for bulk fillings
Takes a long time to set and might fall out before it has set
Difficult working times/conditions
Expensive
Acidic environment affects setting so can’t be used if there’s infection
MTA vs Dycal for pulp caps
MTA studies show a continuous dentine bridge/no gap
Biodentine components [3]
Tri-Calcium Silicate/similar to MTA but add the following instead of water:
Calcium Chloride added as an accelerator
Polymer to quicken setting time
Advantages of Biodentine [5+]
Non-toxic, Biocompatible, etc.
Goes into dentine tubules and forms a plug (micromechanical retention)
When it has set it’s strong like dentine so can be used for bulk fillings (compressive strength) - 2 stage restoration w the Biodentine left behind like a core
No shrinkage = no leakage
Forms tertiary dentine
Quicker setting time (9-12mins)
Biodentine VS MTA
Can be used for bulk fillings bc greater compressive strength
Quicker setting time
Types of endodontic outcomes [5]
Strict success = no symptoms, functioning tooth, no PAP
Loose success = no symptoms, functioning tooth, PAP is smaller/not increased in size (4 years)
Survival = functioning tooth, no symptoms
- OR/better -
Favourable outcome = No PAP, symptoms and functioning tooth
Uncertain outcome = PAP hasn’t increased in size - monitor for 4 years
Unfavourable outcome = non-functioning tooth, symptoms, new/larger/non-healing PAP after 4 years
Favourable endodontic outcome
Favourable outcome = No PAP, symptoms and functioning tooth
Uncertain endodontic outcome
Uncertain outcome = PAP hasn’t increased in size - monitor for 4 years
Unfavourable endodontic outcome
Unfavourable outcome = non-functioning tooth, symptoms, new/larger/non-healing PAP after 4 years
What is the endodontic outcome affected by [5]
PAP - larger >5mm means it’s well established and more bacteria
Necrotic pulp or infected pulp
Root canal filling - voids, too short or overextended
Coronal seal - no voids, caries, etc.
Endodontic review appointment - what do you do/ask? [4]
Symptoms/pain
Clinical exam
- Coronal seal, caries, perio, TTP, fractures
Radiographic exam
- Coronal seal, caries, perio/bone levels, root canal filling, PAP size
Definitive restoration
- ASAP after symptoms have resolved or sooner if concerned about tooth
Reasons for pain post-endo [5]
Failed RCT Neurogenic pain - nerves hypersensitive after PAP Non-odontogenic pain Fractured tooth Occlusal force
Management of failure of RCT (options) [4]
Monitor
- If the tooth is asymptomatic, functioning and stable then can give this as an option
- But warn pt of risk of flare-up, may not be able to save the tooth later on, need regular monitoring
XLA
Re-RCT
- tooth needs to be restorable. More complicated and less successful.
Apical surgery -
Fit appointment for indirects - stages
- Check the lab work and condition of the indirect
- Remove temporary
- Try in
- Cement
Fit appointment for indirects - step 1: checking the lab work and condition of the indirect
- Check cast/die for any wear or broken bits as this may affect the fit
- Check fitting surface of indirect
- Check polished surface of indirect and ICP/eccentric movement
- Check for any notes from the lab
Fit appointment for indirects - step 2: removing the temporary
- Check temporary for any signs of wear, fractures, tooth drifting of other teeth (may happen if temp is lost)
- Check function e.g. speech
- Remove temporary and clean tooth using pumice. Don’t damage tooth or soft tissues.
Fit appointment for indirects - step 3: try in of permanent
- Check proximal contacts
- Check margins
- Adjust fitting surface if not seating properly using occlude spray.
- Check occlusal contacts
Signs of correct seating of indirects
- No gaps at margins (will need to be sent back to lab)
- Seats without any rocking
- ICP contacts and eccentric contacts but no interfering contacts
- Marginal ridges of adjacent teeth are level
- Aesthetics
- Speech
Fit appointment for indirects - step 4: final cementation
- Clean, dry, isolate tooth
- Use correct cement
- Seat fully
- Remove excess
- Check occlusion
- Give POI and OHI.
Types of cements for indirect restorations
Temporary
- Zinc Oxide Eugenol (TempBond)
- Non-eugenol (TempBond NE) - bc Eugenol affects the setting of permanent resin-based cements.
- Soothes the pulp and soluble
Permanent
- Zinc phosphate/carboxylate = outdated bc soluble, exothermic acid-based reaction can irritate pulp
- GIC
- RMGIC/RelyX luting
- Resin-based = self etch or total-etch
For metal = any
For ceramics/composites = bonding resin-based for more strength
Zirconia/alumina = GIC/RMGIC
Luting adhesive cements = chemical adhesion + luting. It’s stronger so for when the material or margins are weaker (composite, resin-based, ceramics).
Luting = just filling the space. For metal or complete zirconia/alumina ceramics bc can’t bond
Ideal properties of permanent indirect restoration cements
Insoluble High tensile and compressive strength Bonds to tooth and restorative material Radiopaque No marginal breakdown Long working time but fast setting Low viscosity Cariostatic Non-toxic/biocompatible
Total etch cement for indirects
For ceramic indirect that can be etched by lab e.g. no zirconia or alumina
- Etch tooth w phosphoric acid and dentine bonding agent
- Etch fitting surface of indirect in lab
- Total etch cement + silane coupling agent on indirect
- Auto-cure, light-cure or dual-cure
Bonds to ceramic and tooth
Strong
low solubility
Self etch cement for indirects
Don’t need to etch dentine and used for when u can’t etch ceramic e.g. zirconia or alumina.
Bonds and micromechanical retention to ceramic and tooth
Strong
low solubility
GIC as a permanent indirect cement
Acid soluble so margin breaks down
Post Op sensitivity
Strong
Fluoride releasing
Adhesive
RelyX Luting/RMGIC as a permanent indirect cement
For metal-based and zirconia indirects Fluoride releasing Micromechanical retention Strong Low solubility Adhesion to tooth Low post-op sensitivity Doesn't need moisture control to use - But absorbs water over time and expands = can't be used for ceramics
Things to consider before permanently restoring RCT teeth [4]
Asymptomatic?
How good is the RCT
Can the tooth be accessed again if re-treatment is needed?
2+ surfaces lost means cuspal coverage is needed
Why provide permanent restoration after RCT [4]
To restore aesthetics, function
Provide the best coronal seal
Strengthen tooth
Coronal restorative material ideal properties [9]
Easy to place
Can be removed/accessed if re-treatment needed
Flexural, compressive and tensile strength
Similar elastic modulus and thermal expansion as tooth/dentine
Radiopaque
Retentive
Adhesive
Core-build up considerations after RCT [5]
Amalgam isn’t used anymore
Composite = good bond, compressive and tensile strengths
GIC = good bond but weak and brittle
Cut down root canal slight and use this for retention
Why provide posts after RCT
Posts provide more retention for coronal restoration/core and allow forces/stress to be spread axially. Not needed for posterior teeth bc large pulp chamber provides retention.
Types of posts (after RCT)
Materials
- Prefabricated for round preparations
- Cast for irregular shaped
- Prefabricated = Stainless steel or composite resin fibre
- Cast = metal or ni-cr
How to provide a post after RCT
Remove 2/3rd of root canal/leave 3-4mm apically
- longer means more retention and more stress dissipation but too long can affect the apical seal
Place prefabricated or cast core
- Ferrule (1.5mm of dentine between core and crown margins) for lateral stress dissipation
- Parallel sides better (taper can cause root fractures)
- Thin core to preserve dentine (but not too thin that it isn’t retentive/core breaks)
- Anti-rotation usually comes from irregularly shaped pulp chamber
Cement
- Micromechanical retention by roughening the core surface
- Adhesive luting cement that bonds to dentine
- Passive retention > active retention (like screws)