Endodontics Flashcards
pain fibres associated with reversible pulpitis
a delta
pain fibres associated with irreversible pulpitis
c fibre
features of an ideal irrigant
flushes bedris kills microorganism's dissolves organic matter lubricates non toxic inexpensive
advantages + disadvantages of sodium hypochlorite (0.5-5%)
+ = flushes, antimicrobial, tissue solvent, lubricant, inexpensive
- = irritant
advantages + disadvantages of chlorhexidine gluconate as irrigant (0.2-2%)
+ = flushes, antimicrobial, lubricant, non-irritant
- = expensive, no solvent
advantages + disadvantages of saline/water/LA as irrigant
\+ = flushes, lurbricant, non irritant - = no antimicrobial or solvent
3 options for antimicrobial dressing material between appointments
- CaHO2 non setting
- chlorhexidine gel
- odontopaste (ledermix)
features of odontopaste/ledermix
steroid/antibiotic
antimicrobial (CaOH2 + clindamycin hydrocholride)
good if LA was not successful when accessing (hyperaemic pulp) - reduces inflammation for next visit
features of CaOH2
pH11/12
broad spectrum antimicrobial - up to 3 month
dissolves organic debris
how thick must temporary filing material be
3mm
4 options for temporary filling material
- cavit
- sedanol
- IRM
- GIC
how to protect canal when temporary filling
cotton wool, sponge, PTFE tape
features of cavit
plaster of Paris + PDA
sets in contact with saliva
good seal in retentive non-load bearing sites
easy to remove
features of sedanol
good seal
good in retentive non-load bearing sites
features of IRM
ZnOE cement reinforced for PMM
stronger for load bearing sites - last 1yr
easy to remove
features of GIC
good for unretentive + load bearing site
difficult to remove
what are chelating agents used for?
soften dentine by demineralising - useful when trying to negotiate sclerosed/blocked canals
e.g. EDTA paste
5 examples of sealer cements
- CaOH2
- ZnOE
- resin
- calcium silicate
- silicone
disadvantage of MTA
can cause grey discolouration
4 basic requirements of access cavity
- pulp chamber fully unroofed
- straight line access
- no unnecessary tissue removal
- sufficient retention
at what depth should you find pulp chamber
6-7mm
tradiotoanl and contemporary approach to shaping
trad = iso stainless steel instruments - 5-10% taper by stepping back 0.5-1mm increments
contemporary = NiTi instruments - predictable taper
difference between stainless steel + NiTI
stainless steel = precurved (use for ledges)
process causing pulp to become necrotic following infection
- increase in pulpal pressure due to oedema
- venous stasis
- causes ischamia + thrombosis
- necrosis
how does pulpitis in a tooth with an open apex present?
open pulpitis - good apical blood supply
causes hyperplastic granulation tissue
pulp polyp - chronic hyperplastic pulpitis
(bleeds on probing)
types of pulp calcifications
diffuse/dystrophic
pulp stones (denticles) - coronal, true pulp, false pulp, irregular or laminated, free/adherent/interstitial
what is a true pulp stone
rare, caused by odontoblasts
what is a false pulp stone
concentric layers of mineralised tissue around blood vessel
4 vital pulp therapies
- indirect pulp cap
- direct pulp cap
- pulpotomy
- pulp revitalisation
for teeth with deep caries but no signs of irreversible pulpitis
in stepwise excavation when do you re-enter?
6 weeks
what sort of dentine is made in direct pulp capping?
odontoblast like cells migrate in - reparative tertiary dentine
if accidentally expose pulp how do you proceed
isolate
haemostats - sodium hypochlorite to remove micro-organisms
consider direct pulp capping or pulpotomy
3 main reasons for RCT
- irreversible pulpitis
- placement of crown/bridge, later access would be hard
- teeth that would be unrestorable without retention from pulp space
if you can not dry canal how should you proceed?
recline
apply non-setting caOH2
seal access
review 1-2 weeks
how much supra gingival tooth tissue needs to be left for a successful ferrule?
2-3mm
circumferential dentine, ideally extending parallel
where should restoration margins be in order to be a success?
on tooth tissue
disadvantage to using amalgam core
delayed crown/onlay prep - takes 24hours to set
only posterior teeth
how much GP is removed using gates gladden for Nayyar (amalgam) core?
3-4mm
2 core options for posterior teeth
composite or amalgam (nayyar)
avoid using posts
common materials for direct posts
fibre (most common)
pre-formed metallic - ss, titanium
ceramic - epoxy resin
what material are indirect posts normally made from?
cast metal
steps for indirect post
- prepare post channel + coronal tissue
- insert smooth, plastic impression post + record impression
- make temp post crown with smooth metal temp crown post
- send impression to lab + cast
- remove smooth impression post from model
- insert size matched plastic, serrated burnout post + wax up core
- remove pattern from model + cast in metal
- fit + cement post
- impression for permanent crown
how much apical root filling needs to retain to provide seal?
4-5mm
shape + length of posts
longer + wider + parallel posts more retentive
3 cementation options for posts in increasing retention
zinc phosphate (always for metal)
GIC/RMGIC
composite (always for fibre)
3 radiographic feature of peri apical periodontitis
- PAP
- widening of PMS
- loss of lamina dura
4 outcomes of periapical periodontist
- resolution
- periapical granuloma
- focal sclerosis osteitis
- dentoalveolar abscess
also inflammatory root resorption, hypercemtnosis, ankylosis, radicular cyst
radiograph appearance of hypercementosis
bulbous root
what causes a radicular cyst
necrotic pulp/non vital tooth
pathological cavity containing fluid (not pus), lined by epithelium
proliferation of cell rests of malaise stimulated by inflammatory mediators
epithelial proliferation, bone resorption, osmotic pressure
clinical presentation of radicular cyst
asymptomatic or symptomatic
+/- swelling
tooth mobility, displacement
radiographic appearance of radicular cyst
round, unilocular
well defined, corticated
radiolucent
causes root resorption
types of radicular cyst
pocket (more likely to heal) or true
apical, lateral or residual if left after extraction
treatment for radiuclar cyst
most heal after RCT
