Endodontics Flashcards
What are the problems with the apical coronal approach “step back”? (3)
- acute exacerbation of chronic inflammation
- post operative pain
- infection of periradicular tissues
What are the drawbacks of conventional hand stainless steel preparation techniques? (4)
- mishaps
- debris extrusion with filing motion
- time consuming
- less predictable shapes in curved canals
What are the advantages of rotary NiTi techniques? (4)
- less canal transportation
- less debris extrusion
- faster than hand preparation
- more predictable results
What are the ideal requirements of root canal irritants? (5)
- eliminate microbes
- inactivate endotoxins
- dissolve necrotic pulp tissue remnants
- systemically non toxic
- remove the smear layer and biofilm
What are the irritants used in RCT? (4)
- sodium hypochlorite
- citric acid
- EDTA
- 2% chlorohexidine
What are the disadvantages of sodium hypochlorite? (3)
- unpleasant taste
- high toxicity
- inability to remove smear layer when used alone
What are the symptoms of injecting sodium hypochlorite beyond the apex of the root? (4)
- extreme pain
- haematoma
- swelling
- profuse haemorrhage from the root canal
What is the treatment for when sodium hypochlorite is injected beyond the apex of the tooth? (3)
- analgesics
- external compression with cold pack
- antibiotics to prevent secondary infection
What chelating agents are used to react with calcium ions in dentine to form soluble calcium chelates to dissolve the organic components? (2)
- EDTA
- 40% citric acid
Name 3 paste lubricants
- file eze
- glide
- hibiscrub
What is the anti-inflammatory corticosteroid found in odontopaste that causes rapid pain relief?
Triamcinolone 1%
What can iodine do?
Penetrate into microorganisms and attack cell molecules such as proteins, nucleotides and fatty acids resulting in cell death
What are the properties of iodine? (4)
- bactericidal
- fungicidal
- virucidal
- sporicidal
What does povidone iodine do?
Induce cell death nonspecifically due to oxidising effects of free iodine
What are the ideal biological properties of obdurating materials? (2)
- no allergy for patient or dental staff
- antimicrobial
What are the ideal handling properties of obdurating materials? (2)
- radiopaque
- sets in adequate time
What is the composition of gutta percha? (3)
- 19-22% gutta percha
- 59-75% zinc oxide
- waxes, colouring agents, antioxidants and metallic salts
What are the types of pastes? (2)
- zinc oxide and eugenol with the addition of toxic materials such as formaldehyde
- plastics resin based
What are the alternative obturation techniques? (2)
- thermoplastic gutta percha (continuous wave of obturation)
- obturators (thermafil, gutta core)
What are stainless steel hand files made from?
Iron alloys with a minimum 10.5% chromium
What are the advantages of stainless steel hand files?
They do not easily corrode, rust or stain
What are the disadvantages of stainless steel hand files? (2)
- poor flexibility
- leads to many procedural errors during canal shaping
What are small instruments manufactured from?
Square blocks as they are more resistant to torque fractures
What are the types of stainless steel files? (3)
- barbed broaches
- reamers
- files (k file, flexofile, hedstrom file)
What are the advantages of flexofiles? (3)
- they have a non aggressive tip
- good flexibility
- efficient at cutting dentine with a low risk of transportation and ledge formation
What are hedstroem files used for?
Used in retreatment cases to help remove gutta percha or an overfilling of the root canal
What are the problems with stainless steel root canal preparation? (4)
- mishaps (ledges, blockages, transportation)
- debris extrusion with a filing motion
- time consuming
- less predictable shapes in curved canals
What are the components of NiTi? (2)
- 56% nickel
- 44% titanium
What are the disadvantages of NiTi? (4)
- instrument fracture
- expende
- access can be difficult in posterior teeth
- unsuitable for complex canal anatomy
What are the advantages of using CaOH as a medicament? (3)
- kills bacteria and inactivates endotoxins
- reduces inflammation
- helps eliminate apical exudate
What is CaOH effect on bacterial cells? (3)
- damage to bacterial cytoplasmic membrane by chemical injury
- protein denaturation
- damage to DNA
What is apexification?
The process of creating an environment within the root canal and periapical tissues after pulp death that allows a calcified barrier to form across the open apex of an immature root
What is internal resorption as a result of?
Chronic pulpitis
What are the types of external resorption? (6)
- surface resorption
- inflammatory resorption
- replacement resorption
- pressure resorption
- systemic resorption
- idiopathic
What is the treatment of a non vital immature permanent incisor tooth? (3)
- apexification
- apical barrier
- revascularisation
How do you do revascularisation of the reticular pulp? (5)
- irrigation with NaOCl
- dressed with a mixture of ciprofloxacin, metronidazole and minocycline for 7 days
- confirm canal is dry
- use a size 40 flexofile to irritate tissues and cause bleeding. Leave 15 mins to form a clot
- place MTA over clot, temporise with CW/coltosol
What are the disadvantages of gutta percha? (3)
- lack of adhesion to dentine
- when heated shrinkage on cooling
- cannot be heat sterilised
What are the properties of sealers? (4)
- provide a fluid tight seal
- no shrinkage with setting
- slow setting time
- fill canal irregularities
What are the types of sealers? (3)
- zinc oxide eugenol
- calcium hydroxide
- glass ionomer
What are the properties of bioceramic sealers? (4)
- biocompatible
- chemically stable
- hydrophilic
- high pH during setting
What does the bioceramic material smart paste bio do?
Releases calcium hydroxide and hydroxyapatite on setting
What are the clinical applications of MTA? (4)
- pulp capping
- perforation repair
- apical plug
- obturation
What are the complications caused by poor access preparation? (7)
- inadequate opening
- mutilation of coronal tooth due to removal of too much tooth structure
- inadequate caries removal
- labial perforation
- furcal perforation
- entering the wrong tooth
- allowing debris to clog and block the orifices of the canals
What are the types of irritant flows within root canals? (2)
Laminar- removes planktonic bacteria
Turbulent- removes biofilm
What are the treatment outcomes for primary treatment:
- without periradicular periodontitis
- with periradicular periodontitis
- overall
- 92%
- 74%
- 81%
What are the treatment outcomes for retreatment:
- without periradicular periodontitis
- with apical periodontitis
- 89-100%
- 56-84%
Don’t give odontopaste to patients taking what medication?
Erythromycin
What is the treatment of an acute apical abscess? (5)
- removal or irritants
- drainage
- dress with calcium hydroxide and seal access
- relieve the occlusion
- review in 24 hours time
What are the causes of failure of LA? (5)
- anatomy
- effect of inflammation of local tissue
- pH
- effect of inflammation on blood flow
- effect of inflammation on nociceptors
What is the effect of inflammation on local tissue pH?
Inflammation may cause ion trapping of LA in charged acid form and unable to cross cell membrane and anaesthetise the nerve
What is the effect of inflammation on blood flow?
Peripheral vasodilation induced b inflammatory mediators could reduce the concentration of LA by increasing the rate of systemic absorption
What is the effect of inflammation on nociceptors?
Inflamed tissues release neuropeptides that cause nerve sprouting
What are the causes of an endodontic flare up? (4)
- preparation beyond the apex
- over instrumentation
- pushing debris into the periapical tissues
- incomplete removal of pulp tissue
What are the causes of pain following canal preparation? (4)
- overinstrumentation
- undetected canal
- apical/lateral perforation
- temp dressing supra occlusion
What are the causes of pain following canal obturation? (4)
- restoration in supra occlusion
- over instrumentation
- sealers slightly toxic for first 24-48 hours
- root fracture
What are the causes of pain some months following RCT? (2)
- tooth in traumatic occlusion
- cracked, fractured tooth
What are the symptoms of a cracked tooth? (3)
- localised pain on chewing or biting
- unexplained sensitivity to cold
- pain on release of pressure
What are the conditions found to improve the outcome of primary root canal treatment? (4)
- preoperative absence of periapical radiolucency
- root canal filling with no voids
- root canal filling to within 2mm of radiographic apex
- satisfactory coronal restoration
What do cholesterol crystals form from?
Dying cells during chronic inflammation
What are the techniques of post removal? (2)
- post removal with ultrasonic energy
- post removal with post pulling devices
How do you remove screw type active posts? (3)
- remove core material from around post using high speed burs and ultrasonics
- use wrench supplied by manufacture for insertion
- ultrasonics can aid process by breaking up cement
What are the causes of fractured instruments? (2)
- torsional fracture
- cyclical metal fatigue
What do you use to remove fractured instruments? (3)
- operating microscopes
- stroke air blower
- ultrasonic instruments
What materials are used for haemostasis?
Place calcium hydroxide and leave for 4-5mins then wash out with sodium hypochlorite
What matrix technique materials are used with composite repairs to exclude moisture?
Calcium sulphate and resorbing collagen
What are the causes of pathological root resorption? (2)
- injury (mechanical and chemical)
- stimulation (infection and pressure)
What are the causes of persistent periapical radiolucencies in endodontically treated teeth? (5)
- extraradicular infection
- intraradicular infection
- foreign body reaction
- true cyst
- fibrous scar tissue
What are the disadvantages of a semi lunar flap? (4)
- disruption of blood supply
- poor wound healing
- limited surgical access
- scarring
What suture material do we use in surgery?
Polypropylene
What are the types of suture materials? (3)
- nylon monofilament sutures
- polyester
- polypropylene
What do the components of zinc oxide eugenol do? (2)
- zinc competes with calcium for binding sites on the surface of hydroxyapatite
- eugenol increases dentine micro hardness
How is the structure of collagen in the organic matrix altered in endodontically treated teeth? (2)
- there are more immature cross links present
- may cause a decrease in tensile strength and an increase in brittleness
What are the supracrestal attached tissues?
This is a band of soft tissue attachment from the alveolar bone to the coronal extent of the junctional epithelium
What is the fertile effect?
Bracing effect of crown going over core and tooth
Name 3 adhesive bonding agents
- all bond 2
- amalgambond plus
- optiond 2
What are the contents of composite? (4)
- aromatic dimethyacrylate
- filler particles
- quartz
- silica
What are the types of hybrid composite? (2)
- addition of fibres, ceramic fillers, titanium and lanthanide
- multicore flow blue
What are the disadvantages of dentine pins? (4)
- induce internal stresses
- cause dentinal crazing
- fracture resistance of core is reduced
- perforation into periodontium
What are the advantages of immediate post placement? (4)
- familiarity of root canal morphology
- less risk of post perforation
- the apical seal will not be disrupted
- increased apical leakage after delayed post preparation
What is the ferrule effect provided by?
Bracing of the remaining tooth structure by the indirect restoration not the remaining coronal tooth structure
What should you do if there is a insufficient coronal tooth tissue for a ferrule? (3)
- orthodontically extrude tooth
- crown lengthen
- extract and replace with a bridge or implant
What are the designs of passive posts? (2)
- cast
- preformed/prefabricated
What are the advantages of cast post and core passive posts?
Conserves tooth tissue, reducing risk of apical perforation
What are the disadvantages of cast post and core passive posts? (3)
- time consuming with lab costs
- properties within casting can increase the risk of post fracture
- placement of burnout posts into working models may result in shorter posts
What are the features of parallel sided serated posts?
- vertical vent to allow escape of excess cement
- once seated the strain due to the build up of hydraulic pressure will dissipate
- patterned interlinking recesses
What luting cements are used for post retained restorations? (4)
- zinc phosphate
- polycarboxylate
- glass ionomer
- composite resins
What are the traditional methods of restoration of compromised anterior teeth? (4)
- apexification, immature teeth using calcium hydroxide
- apical barrier
- obturation with thermoplastic gutta percha
- metal post to retain core and crown
