Restoration of Endodontically Treated Teeth Flashcards
loss of moisture leads to
increased tooth fragility
sodium hypochlorite and chelator used in canal irrigation effect
interact with root dentin –> leading to dentin erosion and softening
less than 50% of tooth structure? anterior and posteiror?
anteiror - restore
psoterior - crown and maybe a post
where do you put post?
larger and straighter canals
pre-molar or molar - bigger
upper molar post location
palatal canal
lower molar post locaiton
distal canal
conservative endo access affects tooth stiffness by?
5%
endo access combined with an MOD prep results in?
max tooth fragility
3 reasons why we are restoring endodontically treated teeth
- protect the remianing tooth from fracture
- prevent reinfection of the root canal system
- replace the missing tooth structure
primary considerations beforeRCT?
- restorable?
- periodontally sound?
- strategic and functional?
what to restore it with? dictated by?
dictated by the amount of tooth that is left
1. direct composite restoration
- indirect restorations (composite or onlays)
- full crowns
how to evaluate? need what?
2 periapicla radiographs
1 bitewing radiograph
perio probe needed
major differences between endo treated teeth and vital teeth
- loss of tooth structure
- altered physical properties
- altered esthetics
loss of moisture and coloration
how much less fluid in RCT treated teeth
3-7% less
describe structural integrity in relation to RCT teeth
endodontic tx. requires removal of tooth structure (pulpal roof) which destroys the ‘boxed beam’ and weakend the basic structural integrity of the tooth
boxed beamcreates?
superior strength and rigidity
access cavity importance?
YES – one of the most important aspects
- unique structure and the bigger is not always better
aim in restoring these teeth?
- protect
- prevent
- replace
main functions of anterior teeth
- protect posteiror teeth from lateral forces
- esthetic considerations
- minimal restorative procedure
implication for crown
more than 50% of tooth gone
characteristics of posterior teeth
- carry occlusal load
- ‘always’ considers crowns
- posts/ cores depends on remaining tooth structure
1 cause of failure following successful RCT
CORONAL LEAKAGE
when to restore the RCT
as soon as possible
4-6 weeks
describe / explain situation with coronal leakage
timeline?
all restorations are less than perfect
- essentially remporaries (they leak)
- when saliva leaks into the gutta percha ‘seal’ contamination occurs rapidly
somewhere between 1 day and 4 weeks following exposure to saliva, contamination extends to the peri-apical tissues and retreatment becomes necessary
2 cause of RCT therapy
crown and or root fracture
materials used for temporary restorations? length of time last?
- cavit - last for 2 weeks
- IRM is less leakproof than cavit
- TERM
- Fugi XI
- Composite
how to reinforce the tooth - one big answer
FERREL EFFECT
risk 1 with use of posts
can present a formidable obstruction to re-treatment
risk 2 with post
use of the rotary drill provides
- an excellent opportunity to perforate the root (unless done correctly)
- PIEZO reamers - dangerous in the canal
risk 2 with post
use of the rotary drill provides
- an excellent opportunity to perforate the root (unless done correctly)
- PIEZO reamers - dangerous in the canal
perforation if more apical?
better prognosis because away from the saliva more
what do you do if you cannot get the ferrule effect
- crown lengthenign
- extract and FPD or RPD
- Extract and implant
discoloration comes from which mainly?
inadequate cleaning and shaping (leavingi necrotic tissue in the coronal horns)
root filling material (gutta percha) retained in teh coronal aspect
organic substances in dentin – hemoglobin breadgown
food and drink pigment
2 cause of failure following successful RCT?
crown and or root fracture
ferrule dimensions?
must be at least 2mm
- the amount of sound tooth structure located under a crown margin and the build up restorativie material
must not impinge on biological width
minimum thickness = 1mm
ferrule walls almost parallel
Indirect posts aka
Casted
direct posts aka
- prefabricated metal posts
- fiber posts
- zirconia posts
retention refers to
ability of post to resist vertical forces
resistance in a post refers to
abbility of the tooth / post combinatio to withstand lateral and rotational forces and is influenced by
- the presence of a ferrule
- the posts length and rigidity
- the presence of anti-rotational features
indicationfor post
ONLY FOR RETENTION OF THE CORONAL RESTORATION - inn a tooth that otherwise meets ALL the requirements for conventional restoration
posts increase resistance to vertical fracture?
no – may contribute to vertical and shear fracture
benefits to post
retention for crown
better than pin retained build up
perforations are what?
one of the worst iatrogenic errors we can create
tooth is compromised on all cases and repair is questionable
post requiremetns
- ferrule effect with 2 mm of crown margin on root without impinging on biological width
- 4.1mm minimum of tooth above bone
more then 50% tooth structure is gone what is indicated?
not necessarily a post – but need core / plug
3-4 mm of cervical tooth structure? type of post if using one
fiber
if do not have 2mm for ferrule?
consider crown lengthening or orthodontic extrusion
or extract for RPD FPD
minimum length of post
long as possible
minimum is 1-1.5 x length of clinical crown (so length of clinical crown)
2/3 length of the root
equal to length of crown
1/2 the bone support (need 4.1 mm of tooth above bone)
remaining root canal filling material?
4-5 mm
too big post? then what
too small post? then what
too big –> root can break
too small –> post can break
plugs use?
composite or amalgam
but only if 50% oro more tooth strucutre
purpose of the plug
holds the core and the crown – RETENTIVE FEATURE
protect the apical seal from bacterial contamination
usually it does not reinforce tooth structure
