endo 4th year Flashcards
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
tx options for failure
monitor if asymptomatic
orthograde retx
PRS
extract +/- prosthesis
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
indications for non-surgical retx
intra-radicular infection
new complex restoration with technically poor RCT
loss of coronal seal
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
removing insoluble resins
US
removing GP
handfiles
solvent (eucalyptus oil)
reciproc
removing soluble pastes
handfiles
solvent (eucalyptus oil)
reciproc
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
how do you use a solvent?
fill orifice and pulp chamber
why should you try to avoid solvents?
they lead to more GP and sealer remnants on RC walls, chamber and inside dentinal tubules
when is WW good?
with K files
passing small files through canals
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
reciproc file features
non-cutting tip
S shaped cross section
NiTi
reciproc R25
red
narrow canals
ISO25
reciproc R40
black
medium canals
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
