#D3/S2/W2
#Endo
Importance of diagnosis

• data gathering
  • clinical
    • history taking (general and focused)
    • examination (objective and subjective)
  • radiographic
    • definitive diagnosis
    • formulation of appropriate treatment plan

Bare minimum radiographic sequence

• preop radiography
• working length radiograph
• mastercone radiograph
• mid-obturation radiograph
• post-operative radiograph
• recall

Endodontic radiology

• use largest size film possible
• use film holder for reproducibility
• centre film on tooth of interest
• paralleling xray beam
• shift radiographs

Endo ray

• helpful to keep out of way while clamp and files are there
  Other products
• specialty holders
  • truview PSP
  • XCP-DS Fit

Paralleling technique

• more accurate length determination
• less superimposition
• reproducibility

Radiographs are not optional

• delphin v martin 2012
  • failure to take a preoperative radiograph is negligent

Multiple films

• bare minimum = 1PA + 1 shift PA (10-15 degrees) and BW

Example cases

• 

  • no tender to percussion
  • pain disturbing sleep
  • normal response to ice, pulp response normal
  • chronic infection
  • 
  • chief response was not even tooth in question, was maxillary tooth, hard to localise

• 

• 

• 

shift views

Trauma

• 
  • shift in beam shows the previously thought horizontal root fracture has magically moved, therefore it is not a horizontal root fracture but rather an alveolar fracture

Diagnosis

• tracing GP using sinus tract

Pre-op assessment

• take your own bitewing and PA to assess

**Cracks **

• reactions to cracks (J shaped radiolucency)
• large cracks

Mid treatment radiograph

• essential to
  • confirm depth of cavity
  • confirm working length
  • confirm anatomy
  • confirm disinfection
  • confirm obturation length and density

Working length film

• minimum size 15K
• if longer or short by 2mm retake radiograph

Mastercone radiograph

• may require more than one depending on number of roots and access
• confirms instrumentation level, obturation length and size
• can identify problems before its too late to pull out

MId obturation

• check length prior to melting
• check density prior to melting
• remedy defects early

post obturation

• identify extra roots etc.
• asymmetric radiograph
  • off-centre ~85% have 2nd canal - Hoen et al 2002

Periapical index

Tracking disease progression

• histological changes taken 2-4 months in infected cases
• radiographic change in relation to pulpal infection can take up to 6 months

Importance of recall radiographs

• ensure there is a change in radiographic healing (or absence of)
• reversal of healing

Digital radiography

• introduced in 1987
• good and bad

Limitations

• 2d film, cant see 3d
• double exposure
• moisture on fingers
• superimposition of structures
  • supernumerary
  • plates
  • other teeth
  • zygomatic buttress
• need a lot of bone mineral loss to see it on the radiograph (cortical plate involvement)
• anatomical stuctures
  • mental foramen
  • incisive foramen

gag reflex

• salt
• LA
• discussion
• referral
  • cbct
  • behavioural Mx
  • sedation

Cone beam CT 3d

• endo indications
  • morphological assessment
  • difficult diagnoses
  • pre-surgical assessment
  • resorption
  • cracks
  • misadventures
  • non odontogenic anomalies
  • trauma
• unusual anatomy
  • dens invaginatus
  • 
• Anatomy
  • close proximity to inferior alveolar, mental nerve
• resorptive defect
• perforation

Dosages

• ALARA
  • as low as reasonably achievable
  • young patient
  • thyroid cancer
  • pregnant patient (especially 1st trimester)

Working length

working length

• distance from a coronal reference point to point which canal prepartion and obturation should end

rational for length determination

• optimise treatment effectiveness
• avoid problems of underextension
• avoid problems of overextension

Does it matter?

• critically important for infected cases, undisturbed biofilm in untreated RC system
  • 69-75% healing if underinstrumentation
  • 90-95% healing if instrumented to optimal length
  • overinstrumentation related to lower success rates (not always true)

Pulpal vs periodontal

• tissue that includes and supports odontoblasts is pulpal
• tissue icluding and supporting cementoblasts is periodontal

radiographs arent entirely reliable

• magnification/distortion
• lack of third dimension
• inability to see soft tissue
• anatomic superimposition
• inter observer disagreement
• intra observer disagreement
• Benefits
  • documentation
  • relative length
  • determines degree of curvature/canal anatomy
  • 3d approx.
  • cant reach constriction or PDL

other means

• paper point
  • not accurate
  • relies on blood etc.
• tactile sensation
  • unreliable
  • operator dependant
• visually
  • not reliable
• patient sensation
  • if no vital pulp
  • if PDL at apical foramen

Electronic canal length measurement

• how do they work
  • landmark: conductive tissue
  • dentine: good insulator
  • different generators
  • file is a conductor with lip clip (mucous membrane), as dentine stops insulating then a circuit is formed
  • electrical resistance between instrument and oral mucous membrane is a constant (6.5kV)
  • 
• difference in generations
  • 1 resistance only
  • 2 impedence only
  • 3 two frequency, impedance ratio
  • 4 two frequency, impedance difference
• Contraindication
  • pacemakers or other electrical implanted devices (not really)
  • allergic to metal
  • in children
• • Inappropriate signal paths to periodontium
    • metal restoration
    • caries
    • gingival tissue
    • perforations/fractures (horizontal but not vertical)
    • large accessory canals
    • conductive fluid i.e. NaOCl, blood, pus, saline, LA
• Trouble shooting
  • check connections
  • check for haemostasis
  • no fluid in pulp chamber
  • water flush
  • lubricants (RC prep)
  • apical test
• Method
  • do a few passes back and forth during test to make sure you get the same reading at same point each time
  • 
• Safety nets
  • anatomical statistics
  • radiographic reasonableness
  • paper point/bleeding
  • apical stop/tug back
  • tactile reporting
• other uses
  • detection of perforations, root fractures

Apex

• 
• 
• 
• not anatomic apex
• not radiographic apex
• physiologic apex or apical constriction
• constriction varies 0.2-3.8mm from radiographic anatomic apex
  • can be different for same tooth different roots as well

Changes to apical anatomy

• deviation dependant on age and tooth
• non-uniform position of AC
• pathological changes (resorption)
• 
• not always a constriction