endo 4th year Flashcards by Becky Wall

what is failure?

presence of clinical S/S
enlargement of existing PR lesion
development of a new PR lesion
persistence of a PR radiolucent lesion associated with a tooth that had RCT at least 4 years prev

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tx options for failure

monitor if asymptomatic
orthograde retx
PRS
extract +/- prosthesis

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what must be mentioned if it is decided to monitor failure?

inform pt of possibility of a flare up

not ideal to monitor if tooth is a critical abutment in a definitive complex Rx

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indications for non-surgical retx

intra-radicular infection
new complex restoration with technically poor RCT
loss of coronal seal

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principles of retx

remove restorative
assess restorability - check no fracture
remove all root filling
assess anatomy
refine/modify prep
complete tx as de novo case

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removing insoluble resins

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removing GP

handfiles
solvent (eucalyptus oil)
reciproc

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removing soluble pastes

handfiles
solvent (eucalyptus oil)
reciproc

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reciproc retx removing GP

remove GP from coronal 1/3 - US, GG, heat carrier

remove GP from mid 1/3 - R25 with stopper set at 2/3 of EWL - slow pecking motion

continue until GP removed from middle 1/3 of canal - use eucalyptus oil/chloroform if necessary

determine WL with small hand file

complete apical prep to CWL with R25. if necessary enlarge apical prep with R40/50 or K files

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how do you use a solvent?

fill orifice and pulp chamber

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why should you try to avoid solvents?

they lead to more GP and sealer remnants on RC walls, chamber and inside dentinal tubules

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when is WW good?

with K files

passing small files through canals

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balanced force technique

insert file and engage into dentine clockwise 1/4 turn
with continued pressure, 1/2 turn anticlockwise to strip dentine away
do 1-3 times before removing file
clean, check file, reintroduce, working your way to WL
safer for canal and file

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reciproc file features

non-cutting tip
S shaped cross section
NiTi

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reciproc R25

red
narrow canals
ISO25

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reciproc R40

black

medium canals

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reciproc R50

yellow
large canals
R50

reciproc working length

16mm

reciproc inverse/regressive taper

larger taper apically

allows for coronal shaping without unnecessary loss of tooth substance, compared to instruments with constant taper

M wire technology (NiTi)

proprietary thermal tx process
increased flexibility
increased resistance to cyclic fatigue

reciproc angles of reciprocation

150 degrees anticlockwise cutting the clockwise 30 degrees
- unequal rotation hence modified reciprocation
breaks in torque to protect instrument

what do you use to select the correct reciproc instrument?

pre op radiograph

reciproc - what do you use if the canal is partially/completely invisible and why?

R25

narrow canal

reciproc - what do you use if the canal is completely visible and why?

wide or medium canal

if hand ISO30 goes passively to WL use R50

if hand ISO20 goes passively to WL use R40

if no - use R25

what does passively to WL mean?

that the instrument goes directly to WL with a gentle WW movement (small right left rotations) but without filing action

slow pecking motion

``` in and out amplitude shouldn't exceed 3mm v light pressure the instrument will advance easily in the canal one in and out movement = 1 peck remove after 3 pecks and clean ```

clinical reciproc procedure - coronal

``` estimate WL from pre-op radiograph set stopper at 2/3 EWL ensure SL access irrigate and recapitulate pecking motion until 2/3 WL reached no additional coronal enlargement necessary e.g. GG ```

reasons for 3 peck movement

instrument does job of 4-5 rotary instruments and works from crown towards apex without instrument change if instrument not cleaned - flutes will become blocked due to high cutting efficiency - friction - instrument won't work within canal

reciproc in multirooted teeth

brush away from friction to reduce the risk of strip perforation

rotary vs reciproc

rotary - "drill" continuous clockwise direction | reciproc - back and forwards, advances automatically

reciproc - check if canal is free with hand instrument

insert to max 3mm past prepared length of canal esp at start of RC prep, length has not yet been determined so dont bring instrument to WL usually hand instrument only inserted to full/WL determination after prep of 2/3 of EWL

reciproc - when is CWL determined ?

after 2/3 canal prep | electronic length - 0.5-1mm from reading

reciproc- if ISO10 used for WL determination goes to WL without being pre-curved, what can the prep be finished with?

R25

reciproc = why is creation of a glide path not necessary?

instruments centring ability based on reciprocation instrument design (tip) reciprocs cutting efficiency

what is gradual curvature defined as?

if a hand ISO10 goes to WL even in a radiographically strong curved canal without being pre-curved, the curvature is described as gradual the radius of curvature can easily be managed with a hand instrument even in case of a strong angle of curvature

what is abrupt curvature defined as?

if hand instrument needs to be pre-curved | the radius of curvature is so small that the hand instrument can only pass if pre-curved

reciproc blue

heat treatment on traditional NiTi alloy | higher flexibility, more fatigue resistance

obturation with reciproc blue

guttafusion | variable tapered

reciproc glide path management

if ISO 15 goes to WL without pre-curved, prep can be finished with R25 if not complete with hand files

reciproc creating a glide path

ISO10 and 15 full WL once done check K25 fits and have apical control - doesn't advance with LAP past 0 if not go up to R40/50 or go up with hand files

reciproc vs wave 1

reciproc - higher cyclic fatigue resistance - may be best suited in curved canals WaveOne - higher torsional resistance - may be suited for use in constricted canals due to its ability to better resist torsional loads