9. Endodontics Flashcards

1
Q

Pulpal Diagnoses

  1. List 5 types of pulpal diagnoses
  2. Give 3 features of each pulpal diagnosis
  3. Give 3 features of a loss of vitality
A
  1. Normal pulp, reversible pulpitis, symptomatic irreversible pulpitis, asymptomatic irreversible pulpitis, pulpal necrosis

Normal pulp - asymptomatic, normal pulp test, mild/transient response to thermal cold resolving within 1-2s

Reversible pulpitis - non-spontaneous fleeting pain/discomfort/sensitivity to hot, cold or sweet, difficult to localise, not TTP, exaggerated response to pulp testing

Symptomatic irreversible pulpitis - sharp pain upon stimulus, pain may linger for several minutes, spontaneous dull throbbing pain, pain often pulsatile, easy to localise, referred pain, pain exacerbated by hot/cold stimuli and postural changes, TTP

Asymptomatic irreversible pulpitis - absence of symptoms, PAP, PA radiolucency

Pulp necrosis - non-vital tooth, negative response to pulp testing, asymptomatic, TTP, PAP

  1. Discolouration, sinus presence, gross caries, large restorations, PA radiolucency
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2
Q

Periapical Diagnoses

  1. List 5 types of PA diagnoses
  2. Give 3 features of each PA diagnosis
A
  1. Normal, symptomatic apical periodontitis, asymptomatic apical periodontitis, chronic apical abscess, acute apical abscess, condensing osteitis
  2. Normal - not TTP, uniform lamina dura, asymptomatic

Symptomatic PAP - untreated/inadequately treated irreversible pulpitis, dull, throbbing pain when biting, well localised, severely TTP, no response to sensibility test, PA changes

Asymptomatic PAP - no clinical symptoms, PA changes

Chronic apical abscess - slow onset, little/no discomfort, intermittent pus discharge, sinus tract, osseous breakdown radiographic signs

Acute apical abscess - rapid onset, severe spontaneous pain, TTP, sleep disturbance, pus accumulations welling, tooth may be mobile/extruded, ± systemic symptoms

Condensing osteitis - localised bony reaction to low-grade inflammatory stimulus

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3
Q

Dentine hypersensitivity

  1. Describe dentine hypersensitivity
  2. Describe treatment
  3. Describe cracked tooth syndrome
A
  1. Short, sharp pain arising from exposed dentine in response to thermal, tactile or osmotic stimulus. Thought to occur due to hydrodynamic theory - due to dentinal fluid movement in tubules stimulating pulpal pain receptors (A-delta and C-fibres)
  2. OHI, erosion prevention, desensitising toothpastes (strontium fluoride, potassium nitrate), varnishes
  3. Short, sharp pain on biting, often in a tooth with a large restoration
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4
Q

What is the pathogenesis of endodontic disease?

A

PDL cells express adhesion molecules
Cytokines/chemokines further attracted, influx of inflammatory cells
Increase in vascular permeability
Lymphocytes attracted
Cell-mediated immunity predominates and humoral immunity occurs (IgG and IgA)

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5
Q

Endodontic Treatment

  1. 2 aims
  2. 3 RCT indications
  3. 3 RCT contraindications
  4. RCT steps
  5. 5 functions of rubber dam
A
  1. Prevent/treat periodontitis by controlling infection and eliminate micro-organisms and remaining pulp tissue from the RC system and prevent reinfection
  2. Irreversible pulpitis, pulp necrosis, apical periodontitis, elective procedure prior to further restorative treatment
  3. Unrestorable tooth, non-functional tooth, insufficient periodontal support (bone loss)
  4. Coronal access to RC system, RC instrumentation and preparation, obturation of RC system, coronal seal, final restoration
  5. Prevent contamination, protect airway, improve access and vision, improve safety, improve isolation and moisture control, improve patient comfort, allows use of appropriate disinfectants
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6
Q

Access and preparation

  1. Key features of coronal access
  2. 2 aims of shaping
  3. 3 objectives of shaping
A
  1. Removal of existing restoration, remove entire roof of pulp chamber, complete removal of coronal pulp, locate canal orifices, finish cavity to allow unimpeded straight-line access
  2. Remove pulp debris and microbes, produce ideal shape and space for effective irritant penetration and reception of root filling material to working length
  3. Create a continuously tapering funnel shape, maintain apical foramen in original position, keep apical foramen as small as possible
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7
Q

Endo instrumentation

  1. Name 4 types of hand files
  2. What are the ISO hand file colours
  3. Name 3 advantages of NiTi instruments
  4. Name 3 disadvantages of NiTi
  5. Name 5 and describe 3 types of filing motions
  6. 3 benefits of rotary
A
  1. K-files, K-reamers, H-files, barbed broach
  2. 06 - pink; 08 - grey; 10 - purple; 15/45 - white; 20/50 - yellow; 25/55 - red; 30/60 - blue; 35/70 - green; 40/80 - black
  3. Increased flexibility, increased cutting efficiency, good safety, more user friendly
  4. Instrument fracture, expense, difficult for posterior teeth, unsuitable for complex canal anatomy
  5. Filing, reaming, WW (forward and backward oscillation of 30-60d), BF (90CW, 180CCW x3), envelop of motion (brush file up sides of canal)
  6. Better predictability, easier to use, less time consuming, only one file required
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8
Q

Definitions

  1. EWL
  2. CWL
  3. MAF
A
  1. Estimated length at which instrumentation should be limited; obtained by measuring pre-operative radiograph to determine the distance between the radiographic apex and a coronal reference point minus 1mm
  2. Length at which instrumentation and obturation should be limited
  3. Largest diameter file taken to WL. Represents final prepared size of apical portion of canal
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9
Q

Initial negotiation

  1. Definition of glide path
  2. Steps involved
  3. Definition of patency filing
A
  1. Sequential introduction of smaller diameter files to WK to prevent fracture of larger diameter instruments
  2. Confirm straight-line access
    Explore anatomy
    Introduce ISO 10-25 files to coronal 2/3 to resistance only
    Coronal flare with S1 file
    Apex established by WW ISO 10 file to WL
    Irrigate and repeat with ISO 15 (WW) and ISO 25 (BF)
    Recapitulation and patency filing with copious amounts of irrigation is essential
  3. Reintroducing smaller files to WL to re-establish apex and help prevent ledges
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10
Q

Canal shaping

  1. Name of technique used
  2. Describe the technique
A
  1. Modified double flare technique
  2. Coronal third preparation (improves straight line access, avoid hydrostatic pressure in canal, allows for early removal of heavily contaminated contents)
    Negotiation of apical third
    Apical and middle third prep (step-back technique) - CWL = ISO file at apex; -1mm = apex file - 1 size; -2mm = apical file - 2 sizes, etc.
    Repeated until apical portion of canal joins coronal portion in a smooth tapering funnel
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11
Q

Problems

  1. 2 causes of instrument separation
  2. 4 common problems with hand files and descriptions
A
  1. Torsional stress, flexural stress
  2. Incomplete debridement - inability to completely clean canal
    Ledges - internal transportation of canal, when working short of WL
    Blockages - caused by dentine debris packing into apical portion of root
    Apical transportation/zipping - transportation of apical foramen occurs as a result of the tendency of instruments to straighten inside a curved canal
    Perforation - when straight-line access not complete and care not taken
    Elbow formation
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12
Q

Cleaning

  1. 1 aim
  2. 4 objectives
  3. 3 key irrigants and %
  4. 4 ideal irrigant properties
  5. 2 good features of NaOCl
  6. 4 factors that improve NaOCl function
  7. 4 problems with NaOCl
A
  1. Remove bacteria and organic debris from the RC system by chemomechanical preparation
  2. Disinfect root canal, flush out debris, eliminate microorganisms, lubricate RC instruments, dissolve organic debris, remove smear layer
  3. 3% NaOCl, 17% EDTA, 0.2% CHX
  4. Cheap, broad antimicrobial properties, dissolve organic and inorganic matter, kill biofilm microbes, non-toxic/non-irritant to PA and surrounding tissues
  5. Dissolves organic material, disrupts smear layer
  6. Concentration, contact time, volume, mechanical agitation, exchange
  7. Unable to remove smear layer, risk of hypochlorite accident, bleach/discolour fabrics, tissue necrosis risk, allergic reactions
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13
Q

Hypochlorite accident

  1. 3 reasons
  2. 5 symptoms
  3. Management
  4. 4 prevention methods
A
  1. Excessive pressure during irrigation, needle locked in canal, larger apical constrictions, higher NaOCl concentration
  2. Pain, swelling, bruising, haemorrhage, airway obstruction, neurological complications
  3. Pain relief, irrigate with saline, nsCaOH dressing, relax patient, pain relief advice, swelling reduction advice, follow-up
  4. Patency filing, manual dynamic irrigation, slow flow rate, side-vented Luer-Lock 27G needle, label syringes, silicone stops on needles, test dam with CHX, use dam with sealant, bib and glasses
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14
Q

Smear Layer and Irrigation

  1. Definition of smear layer
  2. 3 ways to remove
  3. Recommended irrigation protocol
A
  1. Formed during preparation, containing organic pulpal material and inorganic dentinal debris. Superficial, packing into tubules. Prevents sealer penetration and causes bacterial contamination
  2. EDTA, 10% citric acid, MTAD, sonic/ultrasonic irrigation
  3. Irrigate and recapitulate throughout
    3% NaOCl 10-15mins
    17% EDTA 1min
    3% NaOCl 5-10mins
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15
Q

Medicaments

  1. 2 functions of intra-canal medicaments
  2. 2 types and functions
A
  1. Destroy micro-organisms and prevent reinfection, reduce inflammation, control root resorption
  2. Antimicrobial (Ledermix) - hot pulps, reduces pulpal inflammation
    nsCaOH - if 2 appts required - reduces inflammation, removes tissue debris
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16
Q

Obturation

  1. 1 aim
  2. 3 objectives
  3. Material used and composition
  4. 4 properties
A
  1. Provide 3D hermetic seal to the RC that will prevent ingress of bacteria/tissue fluids
  2. Fill/seal entire RC, eliminate infection, prevent reinfection, incarcerate any remaining microbes
  3. GP - 20% GP, 65% ZnO, 10% radiopacificers, 5% plasticisers
  4. Non-irritant, inert, radiopaque, doesn’t discolour tooth, easy removal upon pretreatment, moisture resistant, bacteriostatic
17
Q

Sealants

  1. 3 funcitons
  2. 4 types
  3. 4 properties
A
  1. Seal space between dentinal wall and core, fill voids and irregularities in canal, lateral canals and between GP points, lubricate during obturation
  2. GIC, resin, ZOE, bioceramics
  3. Establish hermetic seal, radiopaque, no setting shrinkage, non-staining, bacteriostatic, soluble on retreatment
18
Q

Methods of obturation

  1. Name 4 types
  2. Describe 1 method
  3. Most important part of RCT
A
  1. Cold lateral compaction, warm lateral compaction, vertical compaction, continuous wave compaction, carrier-based obturation
  2. Check for tug-back, dry with paper points, finger spreader inserted to 2mm from apical stop, master GP point fits apical collar and forced to side of canal, insert accessory points if required to coronal section, remove excess from pulp floor, condense to 2mm below ACJ, complete obturation
  3. Coronal seal (GIC)
19
Q

Risks and failure

  1. 4 risks
  2. 3 outcomes of success and features of each
  3. 3 methods to prevent instrument failure
A
  1. Perforation, instrument separation, failure, pain
  2. Success - asymptomatic, normal PDL radiographically, no loss of function
    Success with incomplete healing - success but scar formation, rather than resolution of lesion
    Uncertain - symptoms/not. Radiographic lesion same size/reduced size for 4yrs post-Rx
    Unfavourable/failure - symptoms. Radiographic lesion same size/larger/new lesion 4yrs post-Rx, continuing root resorption
  3. Correct instrument use, create manual glide path, crown-down technique
20
Q

Retreatment

  1. 3 options for retreatment
  2. What is surgical endo
A
  1. RCT, periradicular surgery, XLA

2. Surgical shortening of root apex (2-3mm) ± retrograde sealing

21
Q

Endo laws

  1. What are all 9 laws
A

Law of centrality - the floor of the pulp chamber is always located in the centre of the tooth at the level of the ACJ

Law of concentricity - the walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the ACJ

Law of the ACJ - the ACJ is the most consistent, repeatable landmark for locating the position of the pulp chamber

Law of symmetry 1 - except for maxillary molars, the orifices of the canals are equidistant from a line drawn in the mesial-distal direction through the pulp chamber floor

Law of symmetry 2 - except for the maxillary molars, the orifices of the canals lie on a line perpendicular to a line drawn in a mesial-distal direction across the centre of the floor of the pulp chamber

Law of colour change - the colour of the pulp chamber floor is always darker than the walls

Law of orifice location 1 - the orifices of the root canals are always located at the junction of the walls and the floor

Law of orifice location 2 - the orifices of the root canals are always located at the angles in the floor-wall junction

Law of orifice location 3 - the orifices of the root canals are located at the terminus of the root developmental fusion lines