dx in endodontics p149 Flashcards
issue with vitality/sensibility tests
not 100% fullproof as in teeth with multiple canals there is the possibility one canal maybe diseased and another healthy
tests neurological function as opposed to vascularity which is better measure of tooth vitality
types of sensibility tests
electric pulp test
cold/ethyl chloride (thermal)
heat (thermal)
cutting as test cavity
electric pulp test
- Patient holds on to the metal as dentists gloves interfere with the conduction of the electrical stimulus
- Patient lets go once sensation has been established
- Lower electrical level = greater ‘vitality’
- up to 80
- test contra-lateral tooth
heat (thermal) test
heated HP stick
apply vaseline to enamel as heated GP will stick to enamel readily
not commonly used as can injur pulp
cold/ethyl chloride test
ethyl chloride is at -50oC
applied onto cotton pledget
cutting a test cavity
can be good in eliciting nerve response
however nerves can synapse in pulpal tissue long after the blood supply has diminshed and the pulp has become necrotic
last resort test
7 possibe pulpal dx
- normal pulp
- reversible pulpitis
- symptomatic irreversible pulpitis
- asymptomatic irreversible pulpitis
- pulp necrosis
- previously treated
- previously initiated therapy
normal pulp
symptom free
resposive to testing
reversible pulpitis
inflammation
clinical findings suggesst it should return to normal
symptomatic irreversible pulpitis
vital inflammed pulp incapable of healing
thermal pain, spontaneous pain and referred pain
asymptomatic irreversible pulpitis
vital inflamed pulp incapable of healing
no clinical symptoms but inflammation triggered by caries/caries excavation/trauma
pulp necrosis
indicatins that pulp is dead
non-responsive to pulp testing
neurvascularity is nil
previously initiated pulp therapy
previously undergone partial therapy e.g. pulpotomy/pulpectomy
6 apical dx
normal apical tissues
symptomatic apical periodontitis
asymptomatic apical periodontitis
acute apical abscess
chronic apical abscess
condensing osteitis
normal apical tissues
normal periradicular tissue
lamina dura intact
PDL space uniform
not sensitive to percussion or palpation
symptomatic apical periodontitis
inflamed apicla periodontium
associated periapical radiolucency
aymptomatic apical periodontitis
destruction and inflammation of periodontium of endodontic origin
associated periapical radiolucency
acute apical abscess
rapid onset of pain often spontaneous, tenderness of tooth to pressure
pus formation
swelling of associated tissues
chronic apical abscess
gradual onset, little to no discomfort
intermittent discharge of pus through sinus tract
condensing osteitis
diffuse radiopaque lesion
represents a localised bony reaction to low grade inflammatory stimulus
usually seen at the apex of the tooth
indication for endo tx (4)
- overdenture - decoronated teeth retained in the arch to preseve alveolar bone
- crowns - prophylactic treatment of pulp before crown added to reduce complications
- preiodontal disaese - root resection may merit elective devitalisation
- pulpal sclerosis following trauma - small proportion of teeth can suffer pulpal problems following trauma, may indicate RCT
contraindications for endodontic tx (6)
- poor OH
- insufficient PD support
- root fracture
- bizarre anatomy
- internal resorption - resorption of pulp chamber/canal = radiolucent
- external resorption - intiated in periodontium and affecting external surfaces of the tooth
principles of endodontic access
all caries and defective restorations must be removed
tooth should be capabale of isolation
periodontal status shuld be sound or capable of resolution
design objectives of endo access
- create a continuouly tapering funnel shape
- maintain apical foramen in orignial position
- keep apical opening as small as possible
objectives of endo access
entire roof of pulp chamber removed so chamber can be debrided
provide a straight line access to apical 1/3 of the canal to allow proper instrumentation
to allow temporary seal to be applied
conserver as much sound tissue as possible
stages of endo access
- initial entry made with tungsten carbide/diamond bur
- outline form completed as required
- advance bur towards roof of the pulp chamber until pulp roof just penetrated
- apply rubber dam at this stage
- removal of the pulp chamber and tapering of the walls done by safe tipped endodontic access bur
- *if pulp stones elicited from pre-op radiograph these are to be dissected out at this stage
- gently flare out the walls of the pulp chamber to improve access, this will result in a gentle funnel shape - the safe tip should be felt passively working along the floor of the pulp chamber
- clear any remaining pulpal debris from the floor of the pulp chamber and canal orifices with an excavator
- the access cavity should then be flushed with sodium hypochlorite to remove residual debris
- the canal orifices may be located with the DG16 endo probe
- outline form modification to ensure straight line access may be carried out at this point
- Using a CT4 tip for an ultrasonic clear any sclerotic or secondary dentine away
upper central incisor
access and av length
triangle
23mm
upper lateral incisor
access and av length
triangle
21-22mm
upper canine
access and av length
ovoid
26.5mm
lower central incisor
access and av length
ovoid
21mm
lower lateral incisor
access and av length
21mm
ovoid
lower canine
access and av length
22.5mm ovoid
upper 1st premolar
access
oval
2 roots
upper 2nd premolar
access
oval
1 central root canal
watch winding technique
- back and forward oscillation of 30-60o
- light apical pressure
- Effective with K- files
- useful for passing small files through canals
balanced force technique
- clockwise 1/4 turn
- continued apical pressure
- 1/2 turn counterclockwise
- dentine should ‘click/snap’
- repeat 1/3 times to remove debris and check file
coronal flaring
modified double flare technique
WATCH WINDING
- Gates-Glidden burs - use brushing motion 4, 3, 2 sizes (STRAIGHT PORTION OF CANAL ONLY)
- create funnel shape
- take a size 10 file to EWL (from pre-op radiograph) then another radiograph for CWL
apical flaring
modified double flare technique
BALANCED FORCE TECHNIQUE
- Established corrected working length with diagnostic radiograph and no. 10 file at working length
- from that either advance further or reduce WL slightly
- Take no. 10 file to WL
- increase at WL using 15 and 20, 25, 30 (in larger canals)
- Use 10 file to recapitulate along with irrigation as normal
mid canal preparation
step back technqiue (middle stage)
Use Master apical file (i.e last file used in apical flaring) - 30/35 depending on canal size (i.e one up from the last one used in apical flare
Move back 1mm each time you move up a file size
e.g
- no. 30 - 23mm
- no. 35 - 22mm
- no. 40 - 21mm etc etc
ProTaper Process of Instrumentation
- Establish CWL with ISO 08 and 10
- Instrument to ISO 25
- S1 to CWL
- Sx for Coronal Flaring
- Use 10 for patency
- S1(again) S2, F1, F2, F3, F4, F5 as needed
- Obturate with Protaper Cone equivalent to file size
reciproc process of instrumentation
- Insert blue rotary file into orifice
- Start roation
- Use light pressure and a in and out pecking motion with oscillations not exceeding 3mm, one in and out movement = 1 peck
- Remove the instrument after 3 pecks
- clean the file itself extra-orally using the stand
- Irrigate
- Re-establish patency using an ISO 10
- Gently instrument Coronal 2/3 with this instrument
- Finish with R25 for apical 1/3
Protaper Rotary process of instrumentation
Create glide path using ISO 10, 15
S1 and S2 coronal 2/3 shaping
10, 15 to rescout
Finish apical 1/3 with S1, S2 and F1 to length
If no apical binding at F1 then go to F2 if still not then use up to ISO 25 to achieve binding
If still none then use ISO 30, and then F3 rotary
endodontic obturation
- Irrigate canal with EDTA to remove smear layer
- Dry with paper points
- final irrigation with Sodium hypochlorite
- Select Master Cone and dry fit
- MAKE SURE it goes to working length - take Radiograph if unsure
- if suitable, coat with sealer (do not leave on bench as it will deform as the sealer and GP react)
- Use in and out motion with coated point to butter the canal with sealer
- fully seat master point at working length
- use ‘A’ finger spreader at working length and displace master cone laterally for 30 seconds and have an accessory cone ready of equivalent size coated in sealer (must all happen very quickly) to insert into the space upon withdrawal of the spreader
- repeat consectutively using larger and larger spreaders and points! (A,B,C,D)
- Trim excess GP using heated instrument or dedicated GP trimmer
- Condense material into the orifice with an amalgam plugger (slighlty larger than orifice)
- Place RMGI over the orifice to complete coronal seal
- Take post operative periapical radiograph
apical limit
dentinocemental juction
- histological landmark
- impossible to determine clinically
- irregular
0 - 2.5mm from apex of root
varing constriction anatomy
increases with age
root resorption is a complicating factor
accessory anatomy
Number of apical foramina 1-16
lateral canals can be associated w/ pathology
accessory canals are common but not important in pathology
only treat main canal
Gutta Percha is
isoprene monomer can give rise to GP and natural rubber
exists in two crystalline forms α and β
- β used comercially in dentistry
Can be ISO, non standard and size matched
- can be deformed by sealer
GP cones constituents
20% GP
65% Zinc Oxide
10% Radiopacifiers
5% Plasticisers
removal of obturation material
- Removal of Coronal GP using Gates-Glidden burs
- Use solvent to dissolve GP
- Chloroform - v. good at dissolving GP but potential carcinogen
- Eucalyptus Oil - not great at dissolving GP but antibacterial and non-irritant
- Use ISO or Hedström file to remove GP from there
- EDTA to remove smear layer
Protaper Retreatment kit
D1 (16mm) - Coronal 1/3
D2 (18mm) - Middle 1/3
D3 (22mm) - Apical 1/3
7 possible clinical endodontic problems
acute periapical abscess
pain following instrumentation
sclerosed canals
pulp stones
broken file
removing old root fillings
perforations
how to manage
acute periapical abscess after endo
rubber dam
open up tooth with a bur
drain and irrigate with sodium hypochlorite
how to manage sclerosed canals
canal orifice may be undefined
use ultrasonic instrument or bur to negotiate and reopen then traet conventionally
how to manage pulp stones
can be flicked out with a small file
how to manage broken file
fine mosquito tweezers
use a small file adj to dislodge it
ulstrasonic instrument on low power
how to manage removing old root filings
GG burs or NiTI rotary files can be used to remove GP points
chemicals (chloroform, eucalyptus oil) can be used but leave a smaer on the pulp canal wall
how to manage perforations and possible causes
can be iatrogenic
can be due to resorption
treated by adding non setting CaOH to lesion
4 types of root canal instruments
barbed broach
hedstrom file
k-reamers
k-files/k-flex
barbed broach files
used for extirpating pulp not enlarging
formed from a tapered round shaft like a finger spreader then lifting staggered portions of metal from the shaft to almost right angles to the shaft
use a narrower broach than the previous engaging file, but select the largest broach that will sit freely
helps to eliminate the possibility of engaging the canal walls
extremely fragile
hedstrom file
machined steel blank
used in a filing motion - cuts upon withdrawal
good cutting efficiency but can result in iatrogenic damage
no longer used in canal prep
used for removing GP or fractured instruments incases of retreatment
*Identified by black circle below file number on the side and around the top*
k reamers
manufactured by twisting a triangular shaft
cutting edges nearly parallel to long axis
roated 1/4 - 1/2 turn clockwise to cut as advanced to length must be in contact with the walls of the canal in order to be effective
*must not bind or it will break
k-files/k-flex
distinguishable by the colour or the square on the handle #
- K file = black square
- K flex = white square
manufactured by twisting a sqaure shaft
cutting edges almost perpendicular to the long axis of the instrument
can be used in a filing mtion - advanced to working length (rotated 1/4 - 1/2 turn CW)
withdrawn with concurrent lateral pressure
repeated cicrcumferentially until canal enlarged
*do not use a larger instrument too quickly*
4 problems assocaited with conventional hand instruments
canal blockage
ledging
apical zipping/transportation
perforation
canal blockage
caused by dentine debris getting packed into apical portion of the root
when packed tightly it can be as hard as surrounding dentine
attempts to remove it can result in a false canal being cut and possible perforation
ledging
internal transportation of the canal
occurs when working short of WL
can be bypassed but with difficulty
solution:
- place rubber stop marker in the vector of the curve
- place apical curve in the file to remove the ledging
note that if the curved canals are instrumented as they were straight they will create ledges and the last few mms of canal will remain diseased and infected and uninstrumentated
apical zipping / transportation
occurs with the tendency of the instrument to straighten inside a curved canal
consequences
- over enlargment of outer side of canal curvature
- under preparation of the inner aspect at apical end point
- main axis of the canal is transported
- results in teardrop of hour glass shape
avoidance
- always pre-curve the inital small sized hand instruments
- do not skip instruments in the sequence
- never rotate the instruments in curved canals
transportation of the apical foramen results in poor resistance for the packing of GP
cases tend to be overextended and poorly filled
perforation
dx
- perisitent bleeding into canal
- multiple radiographs
- electronic apex locator
- dental operating microscope
prognosis for perforation dependent on
- location
- time elapsed
- size
- perio instrumentation
- material used for repair
NiTi instruments
key adv property
superelasticity
- NiTi can be strained more than other alloys before deformation
- allows NiTi files to be placed in curved canals with less lateral forces exerted
- less ledging, zipping, transportation
- central perparation in harmony with canal shape
NiTi vs SS
pros
- increased flexibilty in larger sizes and tapers
- increased cutting efficiency
- if used apporpriately good safety in use
- can be more user friendly with instruments and simple sequence
cons
- instrument fracture
- expense
- access can be difficult with posterior teeth
- unsuitable for complex canal anatomy
function of endodontic sealers
seals space between dentine wall and core
fills voids and irregularitis in canal, lateral canals and between GP points used in lateral condensation
lubricates during obturation
properties of an ideal endodontic sealer
tackiness to provide good adhesion
hermetic seal (airtight)
radiopacity
easily mixed
no shrinkage on setting/no staining
bacteriostatic
slow set
insoluble in tissue fluids
tissue tolerant
soluble on retreatment
types of endo sealers (2)
resin sealers
bioceramic sealers
resin sealers
long history of use (AH26)
epoxy resin
paste-paste mixing 50/50
slow setting 8hrs
good sealing ability
good flow
inital toxicitiy declines after 24hrs
bioceramic sealers
calcium silicate, calcium phophate
dimensionally stable
non-resorbable
early high pH antibacterial
prolonged set time
properties of an ideal obturation
- easily manipulated with ample working time
- dimensinonally unaffected by tissue fluids
- seals tha canal laterally and apically
- non irritant
- impervious to moisture
- unaffected by tissue fluids
- inhibits bacterial growth
- radiopaque
- does not discolour tooth
- sterile
- easily removed if needed
issues with silver points
very rigid so couldn’t conform to irregularities in anatomy
produced cytotoxic corrosion products
law of centrality
floor of pulp chamber is always located in the centre of the tooth at the level of the ACJ
law of concentricity
walls of the pulp chamber are always concentric to the external surface of the tooth at the level of the ACJ
law of ACJ
ACJ is the most consistent repeatable landmark for locating the position of the pulp chamber
law of symmetry
except for maxillary molars
the orifices of the canal are equidistant from a line drawn mesio-distally through the pulp chamber floor
the orificies of the canals lie on a line perpendicular to the line drawn mesio-distally along the pulp chamber floor centrally
law of colour change
the colour of the pulp chamber floor is alway darker than the walls
law of orific location
orifices of RCs are located
- at the junction between the walls and floor
- angles of the junction
- terminus of the root development fusion lines
apical preparation and irrigation
ISO 30 or larger to allow irrigation
canal curvature and apical size will determine whcih is safe
gold standard irrigant
NaOCl
2.5% or above will disturb biofilm
manual dynamic irrigatioon
irrigate
in and out with GP point
v effective at removing biofilm
management of NaOCl extrusion into tissues
LA for pain relief
canals irrigated with copious amount of physiologic saline
relax the pt and assure him or her that this complication can be controlled
dress tooth with non-setting CaOH
priorty must be given to pain relief, reduction of swelling and prevention of secondary infection
- cold compresses during the first few days
- warm compresses for resolution of soft tissue swelling and elimination haemotoma
- analgesics (ibuprofen, paracetamol)
- review in 24hr
- prescription of antibiotics - case specific
- refer if severe
symptoms of NaOCl extrusion
- pain
- swelling
- ecchymosis
- hemorrhage
- neurological complications
airway onstruction
penultimate irrigation with
EDTA 17%
remove smear layer of biofilm and debris inside root anatomy
allows sealer and irrigant to penetrate tubules
NaOCl and EDTA
do not mix
dry canal thoroughly between chemicals with paper points
sequence of chemical irrigantion
- NaOCl
- Dry w/ points
- 1 minute with EDTA
- Dry w/ points
- Final rinse with NaOCl
*CHX can’t be used in Endodontics
- Poor antifungal
- Doesn’t disrupt biofilm well enough
single vs multi appointments
vital teeth - single visit usually but case by case decision
non-vital cases are more complex with greater resistance to tx
interappointment disinfection
Appropriate to use medicament between visits which will reduce and prevent multiplication of any bacteria that do remain
Odontopaste - ZnO based endo dressing contains Corticosteroid and Tetracycline antibiotic
Effective for 5-7 days
canal not obturated between visits, instead non-setting calcium hydroxide should be used must come into contact w/ bacterial cell wall to be therapeutic
Surface seal with one of the following
- Cavit
- IRM
- polycarboxylate
- GIC
